Files
scylladb/alternator/executor.cc
Nadav Har'El d6a8626e90 alternator: correct catch table-already-exists exception
Our CreateTable handler assumed that the function
migration_manager::announce_new_column_family()
returns a failed future if the table already exists. But in some of
our code branches, this is not the case - the function itself throws
instead of returning a failed future. The solution is to use
seastar::futurize_apply() to handle both possibilities (direct exception
or future holding an exception).

This fixes a failure of the test_table.py::test_create_table_already_exists
test case.

Signed-off-by: Nadav Har'El <nyh@scylladb.com>
2019-08-19 15:49:52 +03:00

1630 lines
81 KiB
C++

/*
* Copyright 2019 ScyllaDB
*/
/*
* This file is part of Scylla.
*
* See the LICENSE.PROPRIETARY file in the top-level directory for licensing information.
*/
#include <regex>
#include "base64.hh"
#include "alternator/executor.hh"
#include "log.hh"
#include "json.hh"
#include "schema_builder.hh"
#include "exceptions/exceptions.hh"
#include "timestamp.hh"
#include "database.hh"
#include "types/map.hh"
#include "schema.hh"
#include "query-request.hh"
#include "query-result-reader.hh"
#include "cql3/selection/selection.hh"
#include "cql3/result_set.hh"
#include "bytes.hh"
#include "cql3/update_parameters.hh"
#include "server.hh"
#include "service/pager/query_pagers.hh"
#include <functional>
#include "error.hh"
#include "serialization.hh"
#include "expressions.hh"
#include "conditions.hh"
#include "cql3/constants.hh"
#include <optional>
#include "utils/big_decimal.hh"
#include <boost/algorithm/cxx11/any_of.hpp>
#include <boost/range/adaptors.hpp>
static logging::logger elogger("alternator-executor");
namespace alternator {
static map_type attrs_type() {
static thread_local auto t = map_type_impl::get_instance(utf8_type, bytes_type, true);
return t;
}
static const column_definition& attrs_column(const schema& schema) {
const column_definition* cdef = schema.get_column_definition(bytes(executor::ATTRS_COLUMN_NAME));
assert(cdef);
return *cdef;
}
struct make_jsonable : public json::jsonable {
Json::Value _value;
public:
explicit make_jsonable(Json::Value&& value) : _value(std::move(value)) {}
virtual std::string to_json() const override {
return _value.toStyledString();
}
};
struct json_string : public json::jsonable {
std::string _value;
public:
explicit json_string(std::string&& value) : _value(std::move(value)) {}
virtual std::string to_json() const override {
return _value;
}
};
static void supplement_table_info(Json::Value& descr, const schema& schema) {
descr["CreationDateTime"] = std::chrono::duration_cast<std::chrono::seconds>(gc_clock::now().time_since_epoch()).count();
descr["TableStatus"] = "ACTIVE";
descr["TableId"] = schema.id().to_sstring().c_str();
}
// The DynamoDB developer guide, https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/HowItWorks.NamingRulesDataTypes.html#HowItWorks.NamingRules
// specifies that table names "names must be between 3 and 255 characters long
// and can contain only the following characters: a-z, A-Z, 0-9, _ (underscore), - (dash), . (dot)
// validate_table_name throws the appropriate api_error if this validation fails.
static void validate_table_name(const std::string& name) {
// FIXME: Although we would like to support table names up to 255
// bytes, like DynamoDB, Scylla creates a directory whose name is the
// table's name plus 33 bytes (dash and UUID), and since directory names
// are limited to 255 bytes, we need to limit table names to 222 bytes,
// instead of 255. See https://github.com/scylladb/scylla/issues/4480
if (name.length() < 3 || name.length() > 222) {
throw api_error("ValidationException",
"TableName must be at least 3 characters long and at most 222 characters long");
}
static const std::regex valid_table_name_chars ("[a-zA-Z0-9_.-]*");
if (!std::regex_match(name.c_str(), valid_table_name_chars)) {
throw api_error("ValidationException",
"TableName must satisfy regular expression pattern: [a-zA-Z0-9_.-]+");
}
}
/** Extract table name from a request.
* Most requests expect the table's name to be listed in a "TableName" field.
* This convenience function returns the name, with appropriate validation
* and api_error in case the table name is missing or not a string, or
* doesn't pass validate_table_name().
*/
static std::string get_table_name(const Json::Value& request) {
Json::Value table_name_value = request.get("TableName", Json::nullValue);
if (!table_name_value.isString()) {
throw api_error("ValidationException",
"Missing or non-string TableName field in request");
}
std::string table_name = table_name_value.asString();
validate_table_name(table_name);
return table_name;
}
/** Extract table schema from a request.
* Many requests expect the table's name to be listed in a "TableName" field
* and need to look it up as an existing table. This convenience function
* does this, with the appropriate validation and api_error in case the table
* name is missing, invalid or the table doesn't exist. If everything is
* successful, it returns the table's schema.
*/
static schema_ptr get_table(service::storage_proxy& proxy, const Json::Value& request) {
std::string table_name = get_table_name(request);
try {
return proxy.get_db().local().find_schema(executor::KEYSPACE_NAME, table_name);
} catch(no_such_column_family&) {
throw api_error("ResourceNotFoundException",
format("Requested resource not found: Table: {} not found", table_name));
}
}
future<json::json_return_type> executor::describe_table(std::string content) {
_stats.api_operations.describe_table++;
Json::Value request = json::to_json_value(content);
elogger.trace("Describing table {}", request.toStyledString());
schema_ptr schema = get_table(_proxy, request);
Json::Value table_description(Json::objectValue);
table_description["TableName"] = schema->cf_name().c_str();
// FIXME: take the tables creation time, not the current time!
table_description["CreationDateTime"] = std::chrono::duration_cast<std::chrono::seconds>(gc_clock::now().time_since_epoch()).count();
// FIXME: In DynamoDB the CreateTable implementation is asynchronous, and
// the table may be in "Creating" state until creating is finished.
// We don't currently do this in Alternator - instead CreateTable waits
// until the table is really available. So/ DescribeTable returns either
// ACTIVE or doesn't exist at all (and DescribeTable returns an error).
// The other states (CREATING, UPDATING, DELETING) are not currently
// returned.
table_description["TableStatus"] = "ACTIVE";
// FIXME: more attributes! Check https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_TableDescription.html#DDB-Type-TableDescription-TableStatus but also run a test to see what DyanmoDB really fills
// maybe for TableId or TableArn use schema.id().to_sstring().c_str();
// Of course, the whole schema is missing!
Json::Value response(Json::objectValue);
response["Table"] = std::move(table_description);
elogger.trace("returning {}", response.toStyledString());
return make_ready_future<json::json_return_type>(make_jsonable(std::move(response)));
}
future<json::json_return_type> executor::delete_table(std::string content) {
_stats.api_operations.delete_table++;
Json::Value request = json::to_json_value(content);
elogger.trace("Deleting table {}", request.toStyledString());
std::string table_name = get_table_name(request);
if (!_proxy.get_db().local().has_schema(KEYSPACE_NAME, table_name)) {
throw api_error("ResourceNotFoundException",
format("Requested resource not found: Table: {} not found", table_name));
}
return _mm.announce_column_family_drop(KEYSPACE_NAME, table_name).then([table_name = std::move(table_name)] {
// FIXME: need more attributes?
Json::Value table_description(Json::objectValue);
table_description["TableName"] = table_name.c_str();
table_description["TableStatus"] = "DELETING";
Json::Value response(Json::objectValue);
response["TableDescription"] = std::move(table_description);
elogger.trace("returning {}", response.toStyledString());
return make_ready_future<json::json_return_type>(make_jsonable(std::move(response)));
});
}
static data_type parse_key_type(const std::string& type) {
// Note that keys are only allowed to be string, blob or number (S/B/N).
// The other types: boolean and various lists or sets - are not allowed.
if (type.length() == 1) {
switch (type[0]) {
case 'S': return utf8_type;
case 'B': return bytes_type;
case 'N': return decimal_type; // FIXME: use a specialized Alternator type, not the general "decimal_type".
}
}
throw api_error("ValidationException",
format("Invalid key type '{}', can only be S, B or N.", type));
}
static void add_column(schema_builder& builder, const std::string& name, const Json::Value& attribute_definitions, column_kind kind) {
for (const Json::Value& attribute_info : attribute_definitions) {
if (attribute_info["AttributeName"].asString() == name) {
auto type = attribute_info["AttributeType"].asString();
builder.with_column(to_bytes(name), parse_key_type(type), kind);
return;
}
}
throw api_error("ValidationException",
format("KeySchema key '{}' missing in AttributeDefinitions", name));
}
future<json::json_return_type> executor::create_table(std::string content) {
_stats.api_operations.create_table++;
Json::Value table_info = json::to_json_value(content);
elogger.trace("Creating table {}", table_info.toStyledString());
std::string table_name = get_table_name(table_info);
const Json::Value& key_schema = table_info["KeySchema"];
const Json::Value& attribute_definitions = table_info["AttributeDefinitions"];
schema_builder builder(KEYSPACE_NAME, table_name);
// DynamoDB requires that KeySchema includes up to two elements, the
// first must be a HASH, the optional second one can be a RANGE.
// These key names must also be present in the attributes_definitions.
if (!key_schema.isArray() || key_schema.size() < 1 || key_schema.size() > 2) {
throw api_error("ValidationException",
"KeySchema must list exactly one or two key columns");
}
if (key_schema[0]["KeyType"] != "HASH") {
throw api_error("ValidationException",
"First key in KeySchema must be a HASH key");
}
add_column(builder, key_schema[0]["AttributeName"].asString(), attribute_definitions, column_kind::partition_key);
if (key_schema.size() == 2) {
if (key_schema[1]["KeyType"] != "RANGE") {
throw api_error("ValidationException",
"Second key in KeySchema must be a RANGE key");
}
add_column(builder, key_schema[1]["AttributeName"].asString(), attribute_definitions, column_kind::clustering_key);
}
builder.with_column(bytes(ATTRS_COLUMN_NAME), attrs_type(), column_kind::regular_column);
const Json::Value& gsi = table_info["GlobalSecondaryIndexes"];
if (!gsi.isNull()) {
throw api_error("ValidationException", "FIXME: GSI not yet supported.");
}
schema_ptr schema = builder.build();
return futurize_apply([&] { return _mm.announce_new_column_family(schema, false); }).then([table_info = std::move(table_info), schema] () mutable {
Json::Value status(Json::objectValue);
supplement_table_info(table_info, *schema);
status["TableDescription"] = std::move(table_info);
return make_ready_future<json::json_return_type>(make_jsonable(std::move(status)));
}).handle_exception_type([table_name = std::move(table_name)] (exceptions::already_exists_exception&) {
return make_exception_future<json::json_return_type>(
api_error("ResourceInUseException",
format("Table {} already exists", table_name)));
});
}
// attribute_collector is a helper class used to accept several attribute
// puts or deletes, and collect them as single collection mutation.
// The implementation is somewhat complicated by the need of cells in a
// collection to be sorted by key order.
class attribute_collector {
std::map<bytes, atomic_cell, serialized_compare> collected;
void add(bytes&& name, atomic_cell&& cell) {
collected.emplace(std::move(name), std::move(cell));
}
public:
attribute_collector() : collected(attrs_type()->get_keys_type()->as_less_comparator()) { }
void put(bytes&& name, bytes&& val, api::timestamp_type ts) {
add(std::move(name), atomic_cell::make_live(*bytes_type, ts, std::move(val), atomic_cell::collection_member::yes));
}
void del(bytes&& name, api::timestamp_type ts) {
add(std::move(name), atomic_cell::make_dead(ts, gc_clock::now()));
}
collection_type_impl::mutation to_mut() {
collection_type_impl::mutation ret;
for (auto&& e : collected) {
ret.cells.emplace_back(e.first, std::move(e.second));
}
return ret;
}
};
static mutation make_item_mutation(const Json::Value& item, schema_ptr schema) {
partition_key pk = pk_from_json(item, schema);
clustering_key ck = ck_from_json(item, schema);
mutation m(schema, pk);
attribute_collector attrs_collector;
auto ts = api::new_timestamp();
for (auto it = item.begin(); it != item.end(); ++it) {
bytes column_name = to_bytes(it.key().asString());
const column_definition* cdef = schema->get_column_definition(column_name);
if (!cdef || !cdef->is_primary_key()) {
bytes value = serialize_item(*it);
attrs_collector.put(std::move(column_name), std::move(value), ts);
}
}
auto serialized_map = attrs_type()->serialize_mutation_form(attrs_collector.to_mut());
auto& row = m.partition().clustered_row(*schema, ck);
row.cells().apply(attrs_column(*schema), std::move(serialized_map));
// To allow creation of an item with no attributes, we need a row marker.
row.apply(row_marker(ts));
// PutItem is supposed to completely replace the old item, so we need to
// also have a tombstone removing old cells. We can't use the timestamp
// ts, because when data and tombstone tie on timestamp, the tombstone
// wins. So we need to use ts-1. Note that we use this trick also in
// Scylla proper, to implement the operation to replace an entire
// collection ("UPDATE .. SET x = ..") - see
// cql3::update_parameters::make_tombstone_just_before().
row.apply(tombstone(ts-1, gc_clock::now()));
return m;
}
future<json::json_return_type> executor::put_item(std::string content) {
_stats.api_operations.put_item++;
Json::Value update_info = json::to_json_value(content);
elogger.trace("Updating value {}", update_info.toStyledString());
schema_ptr schema = get_table(_proxy, update_info);
const Json::Value& item = update_info["Item"];
mutation m = make_item_mutation(item, schema);
return _proxy.mutate(std::vector<mutation>{std::move(m)}, db::consistency_level::LOCAL_QUORUM, db::no_timeout, tracing::trace_state_ptr()).then([] () {
// Without special options on what to return, PutItem returns nothing.
return make_ready_future<json::json_return_type>(json_string(""));
});
}
// After calling pk_from_json() and ck_from_json() to extract the pk and ck
// components of a key, and if that succeeded, call check_key() to further
// check that the key doesn't have any spurious components.
static void check_key(const Json::Value& key, const schema_ptr& schema) {
if (key.size() != (schema->clustering_key_size() == 0 ? 1 : 2)) {
throw api_error("ValidationException", "Given key attribute not in schema");
}
}
static mutation make_delete_item_mutation(const Json::Value& key, schema_ptr schema) {
partition_key pk = pk_from_json(key, schema);
clustering_key ck = ck_from_json(key, schema);
check_key(key, schema);
mutation m(schema, pk);
auto& row = m.partition().clustered_row(*schema, ck);
row.apply(tombstone(api::new_timestamp(), gc_clock::now()));
return m;
}
future<json::json_return_type> executor::delete_item(std::string content) {
_stats.api_operations.delete_item++;
Json::Value update_info = json::to_json_value(content);
schema_ptr schema = get_table(_proxy, update_info);
const Json::Value& key = update_info["Key"];
mutation m = make_delete_item_mutation(key, schema);
check_key(key, schema);
return _proxy.mutate(std::vector<mutation>{std::move(m)}, db::consistency_level::LOCAL_QUORUM, db::no_timeout, tracing::trace_state_ptr()).then([] () {
// Without special options on what to return, DeleteItem returns nothing.
return make_ready_future<json::json_return_type>(json_string(""));
});
}
static schema_ptr get_table_from_batch_request(const service::storage_proxy& proxy, const Json::Value::const_iterator& batch_request) {
std::string table_name = batch_request.key().asString(); // JSON keys are always strings
validate_table_name(table_name);
try {
return proxy.get_db().local().find_schema(executor::KEYSPACE_NAME, table_name);
} catch(no_such_column_family&) {
throw api_error("ResourceNotFoundException", format("Requested resource not found: Table: {} not found", table_name));
}
}
using primary_key = std::pair<partition_key, clustering_key>;
struct primary_key_hash {
schema_ptr _s;
size_t operator()(const primary_key& key) const {
return utils::hash_combine(partition_key::hashing(*_s)(key.first), clustering_key::hashing(*_s)(key.second));
}
};
struct primary_key_equal {
schema_ptr _s;
bool operator()(const primary_key& k1, const primary_key& k2) const {
return partition_key::equality(*_s)(k1.first, k2.first) && clustering_key::equality(*_s)(k1.second, k2.second);
}
};
future<json::json_return_type> executor::batch_write_item(std::string content) {
_stats.api_operations.batch_write_item++;
Json::Value batch_info = json::to_json_value(content);
Json::Value& request_items = batch_info["RequestItems"];
std::vector<mutation> mutations;
mutations.reserve(request_items.size());
for (auto it = request_items.begin(); it != request_items.end(); ++it) {
schema_ptr schema = get_table_from_batch_request(_proxy, it);
std::unordered_set<primary_key, primary_key_hash, primary_key_equal> used_keys(1, primary_key_hash{schema}, primary_key_equal{schema});
for (auto&& request : *it) {
if (!request.isObject() || request.size() != 1) {
throw api_error("ValidationException", format("Invalid BatchWriteItem request: {}", request.toStyledString()));
}
auto r = request.begin();
if (r.key() == "PutRequest") {
const Json::Value& put_request = *r;
const Json::Value& item = put_request["Item"];
mutations.push_back(make_item_mutation(item, schema));
// make_item_mutation returns a mutation with a single clustering row
auto mut_key = std::make_pair(mutations.back().key(), mutations.back().partition().clustered_rows().begin()->key());
if (used_keys.count(mut_key) > 0) {
throw api_error("ValidationException", "Provided list of item keys contains duplicates");
}
used_keys.insert(std::move(mut_key));
} else if (r.key() == "DeleteRequest") {
const Json::Value& key = (*r)["Key"];
mutations.push_back(make_delete_item_mutation(key, schema));
// make_delete_item_mutation returns a mutation with a single clustering row
auto mut_key = std::make_pair(mutations.back().key(), mutations.back().partition().clustered_rows().begin()->key());
if (used_keys.count(mut_key) > 0) {
throw api_error("ValidationException", "Provided list of item keys contains duplicates");
}
used_keys.insert(std::move(mut_key));
} else {
throw api_error("ValidationException", format("Unknown BatchWriteItem request type: {}", r.key()));
}
}
}
return _proxy.mutate(std::move(mutations), db::consistency_level::LOCAL_QUORUM, db::no_timeout, tracing::trace_state_ptr()).then([] () {
// Without special options on what to return, BatchWriteItem returns nothing,
// unless there are UnprocessedItems - it's possible to just stop processing a batch
// due to throttling. TODO(sarna): Consider UnprocessedItems when returning.
Json::Value ret;
ret["UnprocessedItems"] = Json::Value(Json::objectValue);
return make_ready_future<json::json_return_type>(make_jsonable(std::move(ret)));
});
}
// resolve_update_path() takes a path given in an update expression, replaces
// references like #name with the real name from ExpressionAttributeNames,
// and returns the fixed path. We also verify that the top-level attribute
// being modified is NOT one of the key attributes - those cannot be updated.
// If one of the above checks fails, a validation exception is thrown.
// FIXME: currently, we only support top-level attribute updates, and this
// function returns the column name;
struct allow_key_columns_tag;
using allow_key_columns = bool_class<allow_key_columns_tag>;
static std::string resolve_update_path(const parsed::path& p,
const Json::Value& update_info,
const schema_ptr& schema,
std::unordered_set<std::string>& used_attribute_names,
allow_key_columns allow_key_columns) {
if (p.has_operators()) {
throw api_error("ValidationException", "UpdateItem does not yet support nested updates (FIXME)");
}
auto column_name = p.root();
if (column_name.size() > 0 && column_name[0] == '#') {
const Json::Value& value = update_info["ExpressionAttributeNames"].get(column_name, Json::nullValue);
if (!value.isString()) {
throw api_error("ValidationException",
format("ExpressionAttributeNames missing entry '{}' required by UpdateExpression",
column_name));
}
used_attribute_names.emplace(std::move(column_name));
column_name = value.asString();
}
const column_definition* cdef = schema->get_column_definition(to_bytes(column_name));
if (!allow_key_columns && cdef && cdef->is_primary_key()) {
throw api_error("ValidationException",
format("UpdateItem cannot update key column {}", column_name));
}
return column_name;
}
// Fail the expression if it has unused attribute names or values. This is
// how DynamoDB behaves, so we do too.
static void verify_all_are_used(const Json::Value& req, const char* field,
const std::unordered_set<std::string>& used, const char* operation) {
auto& attribute_names = req[field];
for (auto it = attribute_names.begin(); it != attribute_names.end(); ++it) {
if (!used.count(it.key().asString())) {
throw api_error("ValidationException",
format("{} has spurious '{}', not used in {}",
field, it.key().asString(), operation));
}
}
}
// Check if a given JSON object encodes a list (i.e., it is a {"L": [...]}
// and returns a pointer to that list.
static const Json::Value* unwrap_list(const Json::Value& v) {
if (!v.isObject() || v.size() != 1) {
return nullptr;
}
auto it = v.begin();
if (it.key() != "L") {
return nullptr;
}
return &(*it);
}
static std::string get_item_type_string(const Json::Value& v) {
if (!v.isObject() || v.size() != 1) {
throw api_error("ValidationException", format("Item has invalid format: {}", v.toStyledString()));
}
auto it = v.begin();
return it.key().asString();
}
// Check if a given JSON object encodes a set (i.e., it is a {"SS": [...]}, or "NS", "BS"
// and returns set's type and a pointer to that set. If the object does not encode a set,
// returned value is {"", nullptr}
static const std::pair<std::string, const Json::Value*> unwrap_set(const Json::Value& v) {
if (!v.isObject() || v.size() != 1) {
return {"", nullptr};
}
auto it = v.begin();
const auto& it_key = it.key().asString();
if (it_key != "SS" && it_key != "BS" && it_key != "NS") {
return {"", nullptr};
}
return std::make_pair(it_key, &(*it));
}
// Take two JSON-encoded list values (remember that a list value is
// {"L": [...the actual list]}) and return the concatenation, again as
// a list value.
static Json::Value list_concatenate(const Json::Value& v1, const Json::Value& v2) {
const Json::Value* list1 = unwrap_list(v1);
const Json::Value* list2 = unwrap_list(v2);
if (!list1 || !list2) {
throw api_error("ValidationException", "UpdateExpression: list_append() given a non-list");
}
Json::Value cat = *list1;
for (const auto& a : *list2) {
cat.append(a);
}
Json::Value ret(Json::objectValue);
ret["L"] = std::move(cat);
return ret;
}
// Take two JSON-encoded set values (e.g. {"SS": [...the actual set]}) and return the sum of both sets,
// again as a set value.
static Json::Value set_sum(const Json::Value& v1, const Json::Value& v2) {
auto [set1_type, set1] = unwrap_set(v1);
auto [set2_type, set2] = unwrap_set(v2);
if (set1_type != set2_type) {
throw api_error("ValidationException", format("Mismatched set types: {} and {}", set1_type, set2_type));
}
if (!set1 || !set2) {
throw api_error("ValidationException", "UpdateExpression: ADD operation for sets must be given sets as arguments");
}
Json::Value sum = *set1;
std::set<Json::Value> set1_raw(sum.begin(), sum.end());
for (const auto& a : *set2) {
if (set1_raw.count(a) == 0) {
sum.append(a);
}
}
Json::Value ret(Json::objectValue);
ret[set1_type] = std::move(sum);
return ret;
}
// Take two JSON-encoded set values (e.g. {"SS": [...the actual list]}) and return the difference of s1 - s2,
// again as a set value.
static Json::Value set_diff(const Json::Value& v1, const Json::Value& v2) {
auto [set1_type, set1] = unwrap_set(v1);
auto [set2_type, set2] = unwrap_set(v2);
if (set1_type != set2_type) {
throw api_error("ValidationException", format("Mismatched set types: {} and {}", set1_type, set2_type));
}
if (!set1 || !set2) {
throw api_error("ValidationException", "UpdateExpression: DELETE operation can only be performed on a set");
}
std::set<Json::Value> set1_raw(set1->begin(), set1->end());
for (const auto& a : *set2) {
set1_raw.erase(a);
}
Json::Value ret(Json::objectValue);
Json::Value& result_set = ret[set1_type];
for (const auto& a : set1_raw) {
result_set.append(a);
}
return ret;
}
// Check if a given JSON object encodes a number (i.e., it is a {"N": [...]}
// and returns an object representing it.
static big_decimal unwrap_number(const Json::Value& v) {
if (!v.isObject() || v.size() != 1) {
throw api_error("ValidationException", "UpdateExpression: invalid number object");
}
auto it = v.begin();
if (it.key() != "N") {
throw api_error("ValidationException",
format("UpdateExpression: expected number, found type '{}'", it.key()));
}
if (!it->isString()) {
throw api_error("ValidationException", "UpdateExpression: improperly formatted number constant");
}
// FIXME: to not lose precision, we really need to do something like:
// return decimal_type->from_string(it->asString());
return big_decimal(it->asString());
}
// Take two JSON-encoded numeric values ({"N": "thenumber"}) and return the
// sum, again as a JSON-encoded number.
static Json::Value number_add(const Json::Value& v1, const Json::Value& v2) {
auto n1 = unwrap_number(v1);
auto n2 = unwrap_number(v2);
Json::Value ret(Json::objectValue);
ret["N"] = std::string((n1 + n2).to_string());
return ret;
}
static Json::Value number_subtract(const Json::Value& v1, const Json::Value& v2) {
auto n1 = unwrap_number(v1);
auto n2 = unwrap_number(v2);
Json::Value ret(Json::objectValue);
ret["N"] = std::string((n1 - n2).to_string());
return ret;
}
template<class... Ts> struct overloaded : Ts... { using Ts::operator()...; };
template<class... Ts> overloaded(Ts...) -> overloaded<Ts...>;
// Given a parsed::value, which can refer either to a constant value from
// ExpressionAttributeValues, to the value of some attribute, or to a function
// of other values, this function calculates the resulting value.
static Json::Value calculate_value(const parsed::value& v,
const Json::Value& expression_attribute_values,
std::unordered_set<std::string>& used_attribute_names,
std::unordered_set<std::string>& used_attribute_values,
const Json::Value& update_info,
schema_ptr schema,
const std::unique_ptr<Json::Value>& previous_item) {
return std::visit(overloaded {
[&] (const std::string& valref) -> Json::Value {
const Json::Value& value = expression_attribute_values.get(valref, Json::nullValue);
if (value.isNull()) {
throw api_error("ValidationException",
format("ExpressionAttributeValues missing entry '{}' required by UpdateExpression", valref));
}
used_attribute_values.emplace(std::move(valref));
return value;
},
[&] (const parsed::value::function_call& f) -> Json::Value {
if (f._function_name == "list_append") {
if (f._parameters.size() != 2) {
throw api_error("ValidationException",
format("UpdateExpression: list_append() accepts 2 parameters, got {}", f._parameters.size()));
}
Json::Value v1 = calculate_value(f._parameters[0], expression_attribute_values, used_attribute_names, used_attribute_values, update_info, schema, previous_item);
Json::Value v2 = calculate_value(f._parameters[1], expression_attribute_values, used_attribute_names, used_attribute_values, update_info, schema, previous_item);
return list_concatenate(v1, v2);
} else if (f._function_name == "if_not_exists") {
if (f._parameters.size() != 2) {
throw api_error("ValidationException",
format("UpdateExpression: if_not_exists() accepts 2 parameters, got {}", f._parameters.size()));
}
if (!std::holds_alternative<parsed::path>(f._parameters[0]._value)) {
throw api_error("ValidationException", "UpdateExpression: if_not_exists() must include path as its first argument");
}
Json::Value v1 = calculate_value(f._parameters[0], expression_attribute_values, used_attribute_names, used_attribute_values, update_info, schema, previous_item);
Json::Value v2 = calculate_value(f._parameters[1], expression_attribute_values, used_attribute_names, used_attribute_values, update_info, schema, previous_item);
return v1.isNull() ? v2 : v1;
} else {
throw api_error("ValidationException",
format("UpdateExpression: unknown function '{}' called.", f._function_name));
}
},
[&] (const parsed::path& p) -> Json::Value {
if (!previous_item) {
return Json::nullValue;
}
std::string update_path = resolve_update_path(p, update_info, schema, used_attribute_names, allow_key_columns::yes);
return (*previous_item)["Item"].get(update_path, Json::nullValue);
}
}, v._value);
}
// Same as calculate_value() above, except takes a set_rhs, which may be
// either a single value, or v1+v2 or v1-v2.
static Json::Value calculate_value(const parsed::set_rhs& rhs,
const Json::Value& expression_attribute_values,
std::unordered_set<std::string>& used_attribute_names,
std::unordered_set<std::string>& used_attribute_values,
const Json::Value& update_info,
schema_ptr schema,
const std::unique_ptr<Json::Value>& previous_item) {
switch(rhs._op) {
case 'v':
return calculate_value(rhs._v1, expression_attribute_values, used_attribute_names, used_attribute_values, update_info, schema, previous_item);
case '+': {
Json::Value v1 = calculate_value(rhs._v1, expression_attribute_values, used_attribute_names, used_attribute_values, update_info, schema, previous_item);
Json::Value v2 = calculate_value(rhs._v2, expression_attribute_values, used_attribute_names, used_attribute_values, update_info, schema, previous_item);
return number_add(v1, v2);
}
case '-': {
Json::Value v1 = calculate_value(rhs._v1, expression_attribute_values, used_attribute_names, used_attribute_values, update_info, schema, previous_item);
Json::Value v2 = calculate_value(rhs._v2, expression_attribute_values, used_attribute_names, used_attribute_values, update_info, schema, previous_item);
return number_subtract(v1, v2);
}
}
// Can't happen
return Json::Value::null;
}
static std::string resolve_projection_path(const parsed::path& p,
const Json::Value& expression_attribute_names,
std::unordered_set<std::string>& used_attribute_names,
std::unordered_set<std::string>& seen_column_names) {
if (p.has_operators()) {
// FIXME:
throw api_error("ValidationException", "Non-toplevel attributes in ProjectionExpression not yet implemented (FIXME)");
}
auto column_name = p.root();
if (column_name.size() > 0 && column_name[0] == '#') {
const Json::Value& value = expression_attribute_names.get(column_name, Json::nullValue);
if (!value.isString()) {
throw api_error("ValidationException",
format("ExpressionAttributeNames missing entry '{}' required by ProjectionExpression", column_name));
}
used_attribute_names.emplace(std::move(column_name));
column_name = value.asString();
}
// FIXME: this check will need to change when we support non-toplevel attributes
if (!seen_column_names.insert(column_name).second) {
throw api_error("ValidationException",
format("Invalid ProjectionExpression: two document paths overlap with each other: {} and {}.",
column_name, column_name));
}
return column_name;
}
// calculate_attrs_to_get() takes either AttributesToGet or
// ProjectionExpression parameters (having both is *not* allowed),
// and returns the list of cells we need to read.
// In our current implementation, only top-level attributes are stored
// as cells, and nested documents are stored serialized as JSON.
// So this function currently returns only the the top-level attributes
// but we also need to add, after the query, filtering to keep only
// the parts of the JSON attributes that were chosen in the paths'
// operators. Because we don't have such filtering yet (FIXME), we fail here
// if the requested paths are anything but top-level attributes.
std::unordered_set<std::string> calculate_attrs_to_get(const Json::Value& req) {
const Json::Value& attributes_to_get = req["AttributesToGet"];
const Json::Value& projection_expression = req["ProjectionExpression"];
if (attributes_to_get && projection_expression) {
throw api_error("ValidationException",
format("GetItem does not allow both ProjectionExpression and AttributesToGet to be given together"));
}
if (attributes_to_get) {
return boost::copy_range<std::unordered_set<std::string>>(attributes_to_get |
boost::adaptors::transformed(std::bind(&Json::Value::asString, std::placeholders::_1)));
} else if (projection_expression){
const Json::Value& expression_attribute_names = req["ExpressionAttributeNames"];
std::vector<parsed::path> paths_to_get;
try {
paths_to_get = parse_projection_expression(projection_expression.asString());
} catch(expressions_syntax_error& e) {
throw api_error("ValidationException", e.what());
}
std::unordered_set<std::string> used_attribute_names;
std::unordered_set<std::string> seen_column_names;
auto ret = boost::copy_range<std::unordered_set<std::string>>(paths_to_get |
boost::adaptors::transformed([&] (const parsed::path& p) {
return resolve_projection_path(p, expression_attribute_names, used_attribute_names, seen_column_names);
}));
verify_all_are_used(req, "ExpressionAttributeNames", used_attribute_names, "ProjectionExpression");
return ret;
}
// An empty set asks to read everything
return {};
}
static std::optional<Json::Value> describe_single_item(schema_ptr schema, const query::partition_slice& slice, const cql3::selection::selection& selection, foreign_ptr<lw_shared_ptr<query::result>> query_result, std::unordered_set<std::string>&& attrs_to_get) {
Json::Value item(Json::objectValue);
cql3::selection::result_set_builder builder(selection, gc_clock::now(), cql_serialization_format::latest());
query::result_view::consume(*query_result, slice, cql3::selection::result_set_builder::visitor(builder, *schema, selection));
auto result_set = builder.build();
if (result_set->empty()) {
// If there is no matching item, we're supposed to return an empty
// object without an Item member - not one with an empty Item member
return {};
}
// FIXME: I think this can't really be a loop, there should be exactly
// one result after above we handled the 0 result case
for (auto& result_row : result_set->rows()) {
const auto& columns = selection.get_columns();
auto column_it = columns.begin();
for (const bytes_opt& cell : result_row) {
std::string column_name = (*column_it)->name_as_text();
if (cell && column_name != executor::ATTRS_COLUMN_NAME) {
if (attrs_to_get.empty() || attrs_to_get.count(column_name) > 0) {
Json::Value& field = item[column_name.c_str()];
field[type_to_string((*column_it)->type)] = json_key_column_value(*cell, **column_it);
}
} else if (cell) {
auto deserialized = attrs_type()->deserialize(*cell, cql_serialization_format::latest());
auto keys_and_values = value_cast<map_type_impl::native_type>(deserialized);
for (auto entry : keys_and_values) {
std::string attr_name = value_cast<sstring>(entry.first);
if (attrs_to_get.empty() || attrs_to_get.count(attr_name) > 0) {
bytes value = value_cast<bytes>(entry.second);
item[attr_name] = deserialize_item(value);
}
}
}
++column_it;
}
}
return item;
}
static Json::Value describe_item(schema_ptr schema, const query::partition_slice& slice, const cql3::selection::selection& selection, foreign_ptr<lw_shared_ptr<query::result>> query_result, std::unordered_set<std::string>&& attrs_to_get) {
std::optional<Json::Value> opt_item = describe_single_item(std::move(schema), slice, selection, std::move(query_result), std::move(attrs_to_get));
if (!opt_item) {
// If there is no matching item, we're supposed to return an empty
// object without an Item member - not one with an empty Item member
return Json::objectValue;
}
Json::Value item_descr(Json::objectValue);
item_descr["Item"] = *opt_item;
return item_descr;
}
static bool check_needs_read_before_write(const parsed::value& v) {
return std::visit(overloaded {
[&] (const std::string& valref) -> bool {
return false;
},
[&] (const parsed::value::function_call& f) -> bool {
return boost::algorithm::any_of(f._parameters, [&] (const parsed::value& param) {
return check_needs_read_before_write(param);
});
},
[&] (const parsed::path& p) -> bool {
return true;
}
}, v._value);
}
static bool check_needs_read_before_write(const std::vector<parsed::update_expression::action>& actions) {
return boost::algorithm::any_of(actions, [](const parsed::update_expression::action& action) {
return std::visit(overloaded {
[&] (const parsed::update_expression::action::set& a) -> bool {
return check_needs_read_before_write(a._rhs._v1) || (a._rhs._op != 'v' && check_needs_read_before_write(a._rhs._v2));
},
[&] (const parsed::update_expression::action::remove& a) -> bool {
return false;
},
[&] (const parsed::update_expression::action::add& a) -> bool {
return true;
},
[&] (const parsed::update_expression::action::del& a) -> bool {
return true;
}
}, action._action);
});
}
// FIXME: Getting the previous item does not offer any synchronization guarantees nor linearizability.
// It should be overridden once we can leverage a consensus protocol.
static future<std::unique_ptr<Json::Value>> maybe_get_previous_item(service::storage_proxy& proxy, schema_ptr schema, const partition_key& pk, const clustering_key& ck,
const Json::Value& update_expression, const parsed::update_expression& expression) {
const bool needs_read_before_write = update_expression && check_needs_read_before_write(expression.actions());
if (!needs_read_before_write) {
return make_ready_future<std::unique_ptr<Json::Value>>();
}
dht::partition_range_vector partition_ranges{dht::partition_range(dht::global_partitioner().decorate_key(*schema, pk))};
std::vector<query::clustering_range> bounds;
if (schema->clustering_key_size() == 0) {
bounds.push_back(query::clustering_range::make_open_ended_both_sides());
} else {
bounds.push_back(query::clustering_range::make_singular(ck));
}
query::column_id_vector regular_columns{attrs_column(*schema).id};
auto selection = cql3::selection::selection::wildcard(schema);
auto partition_slice = query::partition_slice(std::move(bounds), {}, std::move(regular_columns), selection->get_query_options());
auto command = ::make_lw_shared<query::read_command>(schema->id(), schema->version(), partition_slice, query::max_partitions);
auto cl = db::consistency_level::LOCAL_QUORUM;
//TODO(sarna): RBW stats
return proxy.query(schema, std::move(command), std::move(partition_ranges), cl, service::storage_proxy::coordinator_query_options(db::no_timeout)).then(
[schema, partition_slice = std::move(partition_slice), selection = std::move(selection)] (service::storage_proxy::coordinator_query_result qr) {
auto previous_item = describe_item(schema, partition_slice, *selection, std::move(qr.query_result), {});
return make_ready_future<std::unique_ptr<Json::Value>>(std::make_unique<Json::Value>(std::move(previous_item)));
});
}
future<json::json_return_type> executor::update_item(std::string content) {
_stats.api_operations.update_item++;
Json::Value update_info = json::to_json_value(content);
elogger.trace("update_item {}", update_info.toStyledString());
schema_ptr schema = get_table(_proxy, update_info);
// FIXME: handle missing Key.
const Json::Value& key = update_info["Key"];
partition_key pk = pk_from_json(key, schema);
clustering_key ck = ck_from_json(key, schema);
check_key(key, schema);
mutation m(schema, pk);
attribute_collector attrs_collector;
auto ts = api::new_timestamp();
const Json::Value& attribute_updates = update_info["AttributeUpdates"];
const Json::Value& update_expression = update_info["UpdateExpression"];
// DynamoDB forbids having both old-style AttributeUpdates and new-style
// UpdateExpression in the same request
if (attribute_updates && update_expression) {
throw api_error("ValidationException",
format("UpdateItem does not allow both AttributeUpdates and UpdateExpression to be given together"));
}
parsed::update_expression expression;
if (update_expression) {
try {
expression = parse_update_expression(update_expression.asString());
} catch(expressions_syntax_error& e) {
throw api_error("ValidationException", e.what());
}
if (expression.empty()) {
throw api_error("ValidationException", "Empty expression in UpdateExpression is not allowed");
}
}
return maybe_get_previous_item(_proxy, schema, pk, ck, update_expression, expression).then(
[this, schema, expression = std::move(expression), update_expression = std::move(update_expression), ck = std::move(ck),
update_info = std::move(update_info), m = std::move(m), attrs_collector = std::move(attrs_collector), attribute_updates = std::move(attribute_updates), ts] (std::unique_ptr<Json::Value> previous_item) mutable {
if (update_expression) {
std::unordered_set<std::string> seen_column_names;
std::unordered_set<std::string> used_attribute_values;
std::unordered_set<std::string> used_attribute_names;
for (auto& action : expression.actions()) {
std::string column_name = resolve_update_path(action._path, update_info, schema, used_attribute_names, allow_key_columns::no);
// DynamoDB forbids multiple updates in the same expression to
// modify overlapping document paths. Updates of one expression
// have the same timestamp, so it's unclear which would "win".
// FIXME: currently, without full support for document paths,
// we only check if the paths' roots are the same.
if (!seen_column_names.insert(column_name).second) {
throw api_error("ValidationException",
format("Invalid UpdateExpression: two document paths overlap with each other: {} and {}.",
column_name, column_name));
}
std::visit(overloaded {
[&] (const parsed::update_expression::action::set& a) {
auto value = calculate_value(a._rhs, update_info["ExpressionAttributeValues"], used_attribute_names, used_attribute_values, update_info, schema, previous_item);
attrs_collector.put(to_bytes(column_name), serialize_item(value), ts);
},
[&] (const parsed::update_expression::action::remove& a) {
attrs_collector.del(to_bytes(column_name), ts);
},
[&] (const parsed::update_expression::action::add& a) {
parsed::value base;
parsed::value addition;
base.set_path(action._path);
addition.set_valref(a._valref);
Json::Value v1 = calculate_value(base, update_info["ExpressionAttributeValues"], used_attribute_names, used_attribute_values, update_info, schema, previous_item);
Json::Value v2 = calculate_value(addition, update_info["ExpressionAttributeValues"], used_attribute_names, used_attribute_values, update_info, schema, previous_item);
Json::Value result;
std::string v1_type = get_item_type_string(v1);
if (v1_type == "N") {
if (get_item_type_string(v2) != "N") {
throw api_error("ValidationException", format("Incorrect operand type for operator or function. Expected {}: {}", v1_type, v2));
}
result = number_add(v1, v2);
} else if (v1_type == "SS" || v1_type == "NS" || v1_type == "BS") {
if (get_item_type_string(v2) != v1_type) {
throw api_error("ValidationException", format("Incorrect operand type for operator or function. Expected {}: {}", v1_type, v2));
}
result = set_sum(v1, v2);
} else {
throw api_error("ValidationException", format("An operand in the update expression has an incorrect data type: {}", v1));
}
attrs_collector.put(to_bytes(column_name), serialize_item(result), ts);
},
[&] (const parsed::update_expression::action::del& a) {
parsed::value base;
parsed::value subset;
base.set_path(action._path);
subset.set_valref(a._valref);
Json::Value v1 = calculate_value(base, update_info["ExpressionAttributeValues"], used_attribute_names, used_attribute_values, update_info, schema, previous_item);
Json::Value v2 = calculate_value(subset, update_info["ExpressionAttributeValues"], used_attribute_names, used_attribute_values, update_info, schema, previous_item);
Json::Value result = set_diff(v1, v2);
attrs_collector.put(to_bytes(column_name), serialize_item(result), ts);
}
}, action._action);
}
verify_all_are_used(update_info, "ExpressionAttributeNames", used_attribute_names, "UpdateExpression");
verify_all_are_used(update_info, "ExpressionAttributeValues", used_attribute_values, "UpdateExpression");
}
for (auto it = attribute_updates.begin(); it != attribute_updates.end(); ++it) {
// Note that it.key() is the name of the column, *it is the operation
bytes column_name = to_bytes(it.key().asString());
const column_definition* cdef = schema->get_column_definition(column_name);
if (cdef && cdef->is_primary_key()) {
throw api_error("ValidationException",
format("UpdateItem cannot update key column {}", it.key().asString()));
}
std::string action = (*it)["Action"].asString();
if (action == "DELETE") {
// FIXME: Currently we support only the simple case where the
// "Value" field is missing. If it were not missing, we would
// we need to verify the old type and/or value is same as
// specified before deleting... We don't do this yet.
if (!it->get("Value", "").asString().empty()) {
throw api_error("ValidationException",
format("UpdateItem DELETE with checking old value not yet supported"));
}
attrs_collector.del(std::move(column_name), ts);
} else if (action == "PUT") {
const Json::Value& value = (*it)["Value"];
if (value.size() != 1) {
throw api_error("ValidationException",
format("Value field in AttributeUpdates must have just one item", it.key().asString()));
}
attrs_collector.put(std::move(column_name), serialize_item(value), ts);
} else {
// FIXME: need to support "ADD" as well.
throw api_error("ValidationException",
format("Unknown Action value '{}' in AttributeUpdates", action));
}
}
auto serialized_map = attrs_type()->serialize_mutation_form(attrs_collector.to_mut());
auto& row = m.partition().clustered_row(*schema, ck);
row.cells().apply(attrs_column(*schema), std::move(serialized_map));
// To allow creation of an item with no attributes, we need a row marker.
// Note that unlike Scylla, even an "update" operation needs to add a row
// marker. TODO: a row marker isn't really needed for a DELETE operation.
row.apply(row_marker(ts));
elogger.trace("Applying mutation {}", m);
return _proxy.mutate(std::vector<mutation>{std::move(m)}, db::consistency_level::LOCAL_QUORUM, db::no_timeout, tracing::trace_state_ptr()).then([] () {
// Without special options on what to return, UpdateItem returns nothing.
return make_ready_future<json::json_return_type>(json_string(""));
});
});
}
// Check according to the request's "ConsistentRead" field, which consistency
// level we need to use for the read. The field can be True for strongly
// consistent reads, or False for eventually consistent reads, or if this
// field is absense, we default to eventually consistent reads.
// In Scylla, eventually-consistent reads are implemented as consistency
// level LOCAL_ONE, and strongly-consistent reads as LOCAL_QUORUM.
static db::consistency_level get_read_consistency(const Json::Value& request) {
Json::Value consistent_read_value = request.get("ConsistentRead", Json::nullValue);
bool consistent_read = false;
if (!consistent_read_value.isNull()) {
if (consistent_read_value.isBool()) {
consistent_read = consistent_read_value.asBool();
} else {
throw api_error("ValidationException", "ConsistentRead flag must be a boolean");
}
}
return consistent_read ? db::consistency_level::LOCAL_QUORUM : db::consistency_level::LOCAL_ONE;
}
future<json::json_return_type> executor::get_item(std::string content) {
_stats.api_operations.get_item++;
Json::Value table_info = json::to_json_value(content);
elogger.trace("Getting item {}", table_info.toStyledString());
schema_ptr schema = get_table(_proxy, table_info);
Json::Value query_key = table_info["Key"];
db::consistency_level cl = get_read_consistency(table_info);
partition_key pk = pk_from_json(query_key, schema);
dht::partition_range_vector partition_ranges{dht::partition_range(dht::global_partitioner().decorate_key(*schema, pk))};
std::vector<query::clustering_range> bounds;
if (schema->clustering_key_size() == 0) {
bounds.push_back(query::clustering_range::make_open_ended_both_sides());
} else {
clustering_key ck = ck_from_json(query_key, schema);
bounds.push_back(query::clustering_range::make_singular(std::move(ck)));
}
check_key(query_key, schema);
//TODO(sarna): It would be better to fetch only some attributes of the map, not all
query::column_id_vector regular_columns{attrs_column(*schema).id};
auto selection = cql3::selection::selection::wildcard(schema);
auto partition_slice = query::partition_slice(std::move(bounds), {}, std::move(regular_columns), selection->get_query_options());
auto command = ::make_lw_shared<query::read_command>(schema->id(), schema->version(), partition_slice, query::max_partitions);
auto attrs_to_get = calculate_attrs_to_get(table_info);
return _proxy.query(schema, std::move(command), std::move(partition_ranges), cl, service::storage_proxy::coordinator_query_options(db::no_timeout)).then(
[schema, partition_slice = std::move(partition_slice), selection = std::move(selection), attrs_to_get = std::move(attrs_to_get)] (service::storage_proxy::coordinator_query_result qr) mutable {
return make_ready_future<json::json_return_type>(make_jsonable(describe_item(schema, partition_slice, *selection, std::move(qr.query_result), std::move(attrs_to_get))));
});
}
future<json::json_return_type> executor::batch_get_item(std::string content) {
// FIXME: In this implementation, an unbounded batch size can cause
// unbounded response JSON object to be buffered in memory, unbounded
// parallelism of the requests, and unbounded amount of non-preemptable
// work in the following loops. So we should limit the batch size, and/or
// the response size, as DynamoDB does.
_stats.api_operations.batch_get_item++;
Json::Value req = json::to_json_value(content);
Json::Value& request_items = req["RequestItems"];
// We need to validate all the parameters before starting any asynchronous
// query, and fail the entire request on any parse error. So we parse all
// the input into our own vector "requests".
struct table_requests {
schema_ptr schema;
db::consistency_level cl;
std::unordered_set<std::string> attrs_to_get;
struct single_request {
partition_key pk;
clustering_key ck;
};
std::vector<single_request> requests;
};
std::vector<table_requests> requests;
for (auto it = request_items.begin(); it != request_items.end(); ++it) {
table_requests rs;
rs.schema = get_table_from_batch_request(_proxy, it);
rs.cl = get_read_consistency(*it);
rs.attrs_to_get = calculate_attrs_to_get(*it);
for (const Json::Value& key : (*it)["Keys"]) {
rs.requests.push_back({pk_from_json(key, rs.schema), ck_from_json(key, rs.schema)});
check_key(key, rs.schema);
}
requests.emplace_back(std::move(rs));
}
// If got here, all "requests" are valid, so let's start them all
// in parallel. The requests object are then immediately destroyed.
std::vector<future<std::tuple<std::string, std::unique_ptr<Json::Value>>>> response_futures;
for (const auto& rs : requests) {
for (const auto &r : rs.requests) {
dht::partition_range_vector partition_ranges{dht::partition_range(dht::global_partitioner().decorate_key(*rs.schema, std::move(r.pk)))};
std::vector<query::clustering_range> bounds;
if (rs.schema->clustering_key_size() == 0) {
bounds.push_back(query::clustering_range::make_open_ended_both_sides());
} else {
bounds.push_back(query::clustering_range::make_singular(std::move(r.ck)));
}
query::column_id_vector regular_columns{attrs_column(*rs.schema).id};
auto selection = cql3::selection::selection::wildcard(rs.schema);
auto partition_slice = query::partition_slice(std::move(bounds), {}, std::move(regular_columns), selection->get_query_options());
auto command = ::make_lw_shared<query::read_command>(rs.schema->id(), rs.schema->version(), partition_slice, query::max_partitions);
future<std::tuple<std::string, std::unique_ptr<Json::Value>>> f = _proxy.query(rs.schema, std::move(command), std::move(partition_ranges), rs.cl, service::storage_proxy::coordinator_query_options(db::no_timeout)).then(
[schema = rs.schema, partition_slice = std::move(partition_slice), selection = std::move(selection), attrs_to_get = rs.attrs_to_get] (service::storage_proxy::coordinator_query_result qr) mutable {
std::optional<Json::Value> json = describe_single_item(schema, partition_slice, *selection, std::move(qr.query_result), std::move(attrs_to_get));
// Unfortunately, future<std::optional<Json::Value>> doesn't
// work because Json::Value doesn't have a non-throwing move
// constructor. So we need to convert it to a std::unique_ptr.
std::unique_ptr<Json::Value> v;
if (json) {
v = std::make_unique<Json::Value>(std::move(*json));
}
return make_ready_future<std::tuple<std::string, std::unique_ptr<Json::Value>>>(
std::make_tuple(schema->cf_name(), std::move(v)));
});
response_futures.push_back(std::move(f));
}
}
// Wait for all requests to complete, and then return the response.
// FIXME: If one of the requests failed this will fail the entire request.
// What we should do instead is to return the failed key in the array
// UnprocessedKeys (which the BatchGetItem API supports) and let the user
// try again. Note that simply a missing key is *not* an error (we already
// handled it above), but this case does include things like timeouts,
// unavailable CL, etc.
return when_all_succeed(response_futures.begin(), response_futures.end()).then(
[] (std::vector<std::tuple<std::string, std::unique_ptr<Json::Value>>> responses) {
Json::Value response = Json::objectValue;
response["Responses"] = Json::objectValue;
for (const auto& t : responses) {
if (std::get<1>(t)) {
response["Responses"][std::get<0>(t)].append(*std::get<1>(t));
} else {
// Even if all items requested for a particular table are
// missing, we still need to return an empty array.
Json::Value& x = response["Responses"][std::get<0>(t)];
if (x.isNull()) {
x = Json::arrayValue;
}
}
}
return make_ready_future<json::json_return_type>(make_jsonable(std::move(response)));
});
}
class describe_items_visitor {
typedef std::vector<const column_definition*> columns_t;
const columns_t& _columns;
const std::unordered_set<std::string>& _attrs_to_get;
typename columns_t::const_iterator _column_it;
Json::Value _item;
Json::Value _items;
public:
describe_items_visitor(const columns_t& columns, const std::unordered_set<std::string>& attrs_to_get)
: _columns(columns)
, _attrs_to_get(attrs_to_get)
, _column_it(columns.begin())
, _item(Json::objectValue)
, _items(Json::arrayValue)
{ }
void start_row() {
_column_it = _columns.begin();
}
void accept_value(const std::optional<query::result_bytes_view>& result_bytes_view) {
if (!result_bytes_view) {
++_column_it;
return;
}
result_bytes_view->with_linearized([this] (bytes_view bv) {
std::string column_name = (*_column_it)->name_as_text();
if (column_name != executor::ATTRS_COLUMN_NAME) {
if (_attrs_to_get.empty() || _attrs_to_get.count(column_name) > 0) {
Json::Value& field = _item[column_name.c_str()];
field[type_to_string((*_column_it)->type)] = json_key_column_value(bv, **_column_it);
}
} else {
auto deserialized = attrs_type()->deserialize(bv, cql_serialization_format::latest());
auto keys_and_values = value_cast<map_type_impl::native_type>(deserialized);
for (auto entry : keys_and_values) {
std::string attr_name = value_cast<sstring>(entry.first);
if (_attrs_to_get.empty() || _attrs_to_get.count(attr_name) > 0) {
bytes value = value_cast<bytes>(entry.second);
_item[attr_name] = deserialize_item(value);
}
}
}
});
++_column_it;
}
void end_row() {
_items.append(std::move(_item));
_item = Json::objectValue;
}
Json::Value get_items() && {
return std::move(_items);
}
};
static Json::Value describe_items(schema_ptr schema, const query::partition_slice& slice, const cql3::selection::selection& selection, std::unique_ptr<cql3::result_set> result_set, std::unordered_set<std::string>&& attrs_to_get) {
describe_items_visitor visitor(selection.get_columns(), attrs_to_get);
result_set->visit(visitor);
Json::Value items = std::move(visitor).get_items();
Json::Value items_descr(Json::objectValue);
items_descr["Count"] = items.size();
items_descr["ScannedCount"] = items.size(); // TODO(sarna): Update once filtering is implemented
items_descr["Items"] = std::move(items);
return items_descr;
}
static Json::Value encode_paging_state(const schema& schema, const service::pager::paging_state& paging_state) {
Json::Value last_evaluated_key(Json::objectValue);
std::vector<bytes> exploded_pk = paging_state.get_partition_key().explode();
auto exploded_pk_it = exploded_pk.begin();
for (const column_definition& cdef : schema.partition_key_columns()) {
Json::Value& key_entry = last_evaluated_key[cdef.name_as_text()];
key_entry[type_to_string(cdef.type)] = json::to_json_value(cdef.type->to_json_string(*exploded_pk_it));
++exploded_pk_it;
}
auto ck = paging_state.get_clustering_key();
if (ck) {
auto exploded_ck = ck->explode();
auto exploded_ck_it = exploded_ck.begin();
for (const column_definition& cdef : schema.clustering_key_columns()) {
Json::Value& key_entry = last_evaluated_key[cdef.name_as_text()];
key_entry[type_to_string(cdef.type)] = json::to_json_value(cdef.type->to_json_string(*exploded_ck_it));
++exploded_ck_it;
}
}
return last_evaluated_key;
}
static future<json::json_return_type> do_query(schema_ptr schema,
const Json::Value& exclusive_start_key,
dht::partition_range_vector&& partition_ranges,
std::vector<query::clustering_range>&& ck_bounds,
std::unordered_set<std::string>&& attrs_to_get,
uint32_t limit,
db::consistency_level cl,
::shared_ptr<cql3::restrictions::statement_restrictions> filtering_restrictions) {
::shared_ptr<service::pager::paging_state> paging_state = nullptr;
if (!exclusive_start_key.empty()) {
partition_key pk = pk_from_json(exclusive_start_key, schema);
std::optional<clustering_key> ck;
if (schema->clustering_key_size() > 0) {
ck = ck_from_json(exclusive_start_key, schema);
}
paging_state = ::make_shared<service::pager::paging_state>(pk, ck, query::max_partitions, utils::UUID(), service::pager::paging_state::replicas_per_token_range{}, std::nullopt, 0);
}
query::column_id_vector regular_columns{attrs_column(*schema).id};
auto selection = cql3::selection::selection::wildcard(schema);
auto partition_slice = query::partition_slice(std::move(ck_bounds), {}, std::move(regular_columns), selection->get_query_options());
auto command = ::make_lw_shared<query::read_command>(schema->id(), schema->version(), partition_slice, query::max_partitions);
//FIXME(sarna): This context will need to be provided once we start gathering statistics, authenticating, etc. Right now these are just stubs.
static thread_local cql3::cql_stats dummy_stats;
static thread_local service::client_state dummy_client_state{service::client_state::internal_tag()};
static thread_local service::query_state dummy_query_state(dummy_client_state);
command->slice.options.set<query::partition_slice::option::allow_short_read>();
auto query_options = std::make_unique<cql3::query_options>(cl, infinite_timeout_config, std::vector<cql3::raw_value>{});
query_options = std::make_unique<cql3::query_options>(std::move(query_options), std::move(paging_state));
auto p = service::pager::query_pagers::pager(schema, selection, dummy_query_state, *query_options, command, std::move(partition_ranges), dummy_stats, filtering_restrictions);
return p->fetch_page(limit, gc_clock::now(), db::no_timeout).then(
[p, schema, partition_slice = std::move(partition_slice), selection = std::move(selection), attrs_to_get = std::move(attrs_to_get), query_options = std::move(query_options)](std::unique_ptr<cql3::result_set> rs) mutable {
if (!p->is_exhausted()) {
rs->get_metadata().set_paging_state(p->state());
}
auto paging_state = rs->get_metadata().paging_state();
auto items = describe_items(schema, partition_slice, *selection, std::move(rs), std::move(attrs_to_get));
if (paging_state) {
items["LastEvaluatedKey"] = encode_paging_state(*schema, *paging_state);
}
return make_ready_future<json::json_return_type>(make_jsonable(std::move(items)));
});
}
// TODO(sarna):
// 1. Paging must have 1MB boundary according to the docs. IIRC we do have a replica-side reply size limit though - verify.
// 2. Filtering - by passing appropriately created restrictions to pager as a last parameter
// 3. Proper timeouts instead of gc_clock::now() and db::no_timeout
// 4. Implement parallel scanning via Segments
future<json::json_return_type> executor::scan(std::string content) {
_stats.api_operations.scan++;
Json::Value request_info = json::to_json_value(content);
elogger.trace("Scanning {}", request_info.toStyledString());
schema_ptr schema = get_table(_proxy, request_info);
Json::Value exclusive_start_key = request_info["ExclusiveStartKey"];
//FIXME(sarna): ScanFilter is deprecated in favor of FilterExpression
const Json::Value& scan_filter = request_info["ScanFilter"];
db::consistency_level cl = get_read_consistency(request_info);
uint32_t limit = request_info.get("Limit", query::max_partitions).asUInt();
if (limit <= 0) {
throw api_error("ValidationException", "Limit must be greater than 0");
}
auto attrs_to_get = calculate_attrs_to_get(request_info);
dht::partition_range_vector partition_ranges{dht::partition_range::make_open_ended_both_sides()};
std::vector<query::clustering_range> ck_bounds{query::clustering_range::make_open_ended_both_sides()};
auto filtering_restrictions = get_filtering_restrictions(schema, attrs_column(*schema), scan_filter);
return do_query(schema, exclusive_start_key, std::move(partition_ranges), std::move(ck_bounds), std::move(attrs_to_get), limit, cl, std::move(filtering_restrictions));
}
static dht::partition_range calculate_pk_bound(schema_ptr schema, const column_definition& pk_cdef, comparison_operator_type op, const Json::Value& attrs) {
if (attrs.size() != 1) {
throw api_error("ValidationException", format("Only a single attribute is allowed for a hash key restriction: {}", attrs.toStyledString()));
}
bytes raw_value = pk_cdef.type->from_string(attrs[0][type_to_string(pk_cdef.type)].asString());
partition_key pk = partition_key::from_singular(*schema, pk_cdef.type->deserialize(raw_value));
auto decorated_key = dht::global_partitioner().decorate_key(*schema, pk);
if (op != comparison_operator_type::EQ) {
throw api_error("ValidationException", format("Hash key {} can only be restricted with equality operator (EQ)"));
}
return dht::partition_range(decorated_key);
}
static query::clustering_range get_clustering_range_for_begins_with(bytes&& target, const clustering_key& ck, schema_ptr schema, data_type t) {
auto it = boost::range::find_end(target, bytes("\xFF"), std::not_equal_to<bytes::value_type>());
if (it != target.end()) {
++*it;
target.resize(std::distance(target.begin(), it) + 1);
clustering_key upper_limit = clustering_key::from_singular(*schema, t->deserialize(target));
return query::clustering_range::make(query::clustering_range::bound(ck), query::clustering_range::bound(upper_limit, false));
}
return query::clustering_range::make_starting_with(query::clustering_range::bound(ck));
}
static query::clustering_range calculate_ck_bound(schema_ptr schema, const column_definition& ck_cdef, comparison_operator_type op, const Json::Value& attrs) {
const size_t expected_attrs_size = (op == comparison_operator_type::BETWEEN) ? 2 : 1;
if (attrs.size() != expected_attrs_size) {
throw api_error("ValidationException", format("{} arguments expected for a sort key restriction: {}", expected_attrs_size, attrs.toStyledString()));
}
bytes raw_value = ck_cdef.type->from_string(attrs[0][type_to_string(ck_cdef.type)].asString());
clustering_key ck = clustering_key::from_singular(*schema, ck_cdef.type->deserialize(raw_value));
switch (op) {
case comparison_operator_type::EQ:
return query::clustering_range(ck);
case comparison_operator_type::LE:
return query::clustering_range::make_ending_with(query::clustering_range::bound(ck));
case comparison_operator_type::LT:
return query::clustering_range::make_ending_with(query::clustering_range::bound(ck, false));
case comparison_operator_type::GE:
return query::clustering_range::make_starting_with(query::clustering_range::bound(ck));
case comparison_operator_type::GT:
return query::clustering_range::make_starting_with(query::clustering_range::bound(ck, false));
case comparison_operator_type::BETWEEN: {
bytes raw_upper_limit = ck_cdef.type->from_string(attrs[1][type_to_string(ck_cdef.type)].asString());
clustering_key upper_limit = clustering_key::from_singular(*schema, ck_cdef.type->deserialize(raw_upper_limit));
return query::clustering_range::make(query::clustering_range::bound(ck), query::clustering_range::bound(upper_limit));
}
case comparison_operator_type::BEGINS_WITH: {
if (raw_value.empty()) {
return query::clustering_range::make_open_ended_both_sides();
}
// NOTICE(sarna): A range starting with given prefix and ending (non-inclusively) with a string "incremented" by a single
// character at the end. Throws for NUMBER instances.
if (!ck_cdef.type->is_byte_order_comparable()) {
throw api_error("ValidationException", format("BEGINS_WITH operator cannot be applied to type {}", type_to_string(ck_cdef.type)));
}
std::string raw_upper_limit_str = attrs[0][type_to_string(ck_cdef.type)].asString();
bytes raw_upper_limit = ck_cdef.type->from_string(raw_upper_limit_str);
return get_clustering_range_for_begins_with(std::move(raw_upper_limit), ck, schema, ck_cdef.type);
}
default:
throw api_error("ValidationException", format("Unknown primary key bound passed: {}", int(op)));
}
}
// Calculates primary key bounds from the list of conditions
static std::pair<dht::partition_range_vector, std::vector<query::clustering_range>>
calculate_bounds(schema_ptr schema, const Json::Value& conditions) {
dht::partition_range_vector partition_ranges;
std::vector<query::clustering_range> ck_bounds;
for (auto it = conditions.begin(); it != conditions.end(); ++it) {
std::string key = it.key().asString();
const Json::Value& condition = *it;
Json::Value comp_definition = condition.get("ComparisonOperator", Json::Value());
Json::Value attr_list = condition.get("AttributeValueList", Json::Value(Json::arrayValue));
auto op = get_comparison_operator(comp_definition);
const column_definition& pk_cdef = schema->partition_key_columns().front();
const column_definition* ck_cdef = schema->clustering_key_size() > 0 ? &schema->clustering_key_columns().front() : nullptr;
if (sstring(key) == pk_cdef.name_as_text()) {
if (!partition_ranges.empty()) {
throw api_error("ValidationException", "Currently only a single restriction per key is allowed");
}
partition_ranges.push_back(calculate_pk_bound(schema, pk_cdef, op, attr_list));
}
if (ck_cdef && sstring(key) == ck_cdef->name_as_text()) {
if (!ck_bounds.empty()) {
throw api_error("ValidationException", "Currently only a single restriction per key is allowed");
}
ck_bounds.push_back(calculate_ck_bound(schema, *ck_cdef, op, attr_list));
}
}
// Validate that a query's conditions must be on the hash key, and
// optionally also on the sort key if it exists.
if (partition_ranges.empty()) {
throw api_error("ValidationException", format("Query missing condition on hash key '{}'", schema->partition_key_columns().front().name_as_text()));
}
if (schema->clustering_key_size() == 0) {
if (conditions.size() != 1) {
throw api_error("ValidationException", "Only one condition allowed in table with only hash key");
}
} else {
if (conditions.size() == 2 && ck_bounds.empty()) {
throw api_error("ValidationException", format("Query missing condition on sort key '{}'", schema->clustering_key_columns().front().name_as_text()));
} else if (conditions.size() > 2) {
throw api_error("ValidationException", "Only one or two conditions allowed in table with hash key and sort key");
}
}
if (ck_bounds.empty()) {
ck_bounds.push_back(query::clustering_range::make_open_ended_both_sides());
}
return {std::move(partition_ranges), std::move(ck_bounds)};
}
future<json::json_return_type> executor::query(std::string content) {
_stats.api_operations.query++;
Json::Value request_info = json::to_json_value(content);
elogger.trace("Querying {}", request_info.toStyledString());
schema_ptr schema = get_table(_proxy, request_info);
Json::Value exclusive_start_key = request_info["ExclusiveStartKey"];
db::consistency_level cl = get_read_consistency(request_info);
uint32_t limit = request_info.get("Limit", query::max_partitions).asUInt();
if (limit <= 0) {
throw api_error("ValidationException", "Limit must be greater than 0");
}
//FIXME(sarna): KeyConditions are deprecated in favor of KeyConditionExpression
const Json::Value& conditions = request_info["KeyConditions"];
//FIXME(sarna): QueryFilter is deprecated in favor of FilterExpression
const Json::Value& query_filter = request_info["QueryFilter"];
auto [partition_ranges, ck_bounds] = calculate_bounds(schema, conditions);
auto attrs_to_get = calculate_attrs_to_get(request_info);
auto filtering_restrictions = get_filtering_restrictions(schema, attrs_column(*schema), query_filter);
return do_query(schema, exclusive_start_key, std::move(partition_ranges), std::move(ck_bounds), std::move(attrs_to_get), limit, cl, std::move(filtering_restrictions));
}
static void validate_limit(int limit) {
if (limit < 1 || limit > 100) {
throw api_error("ValidationException", "Limit must be greater than 0 and no greater than 100");
}
}
future<json::json_return_type> executor::list_tables(std::string content) {
_stats.api_operations.list_tables++;
Json::Value table_info = json::to_json_value(content);
elogger.trace("Listing tables {}", table_info.toStyledString());
std::string exclusive_start = table_info.get("ExclusiveStartTableName", "").asString();
int limit = table_info.get("Limit", 100).asInt();
validate_limit(limit);
auto table_names = _proxy.get_db().local().get_column_families()
| boost::adaptors::map_values
| boost::adaptors::filtered([] (const lw_shared_ptr<table>& t) {
return t->schema()->ks_name() == KEYSPACE_NAME && !t->schema()->is_view();
})
| boost::adaptors::transformed([] (const lw_shared_ptr<table>& t) {
return t->schema()->cf_name();
});
Json::Value response;
Json::Value& all_tables = response["TableNames"];
all_tables = Json::Value(Json::arrayValue);
//TODO(sarna): Dynamo doesn't declare any ordering when listing tables,
// but our implementation is vulnerable to changes, because the tables
// are stored in an unordered map. We may consider (partially) sorting
// the results before returning them to the client, especially if there
// is an implicit order of elements that Dynamo imposes.
auto table_names_it = [&table_names, &exclusive_start] {
if (!exclusive_start.empty()) {
auto it = boost::find_if(table_names, [&exclusive_start] (const sstring& table_name) { return table_name == exclusive_start; });
return std::next(it, it != table_names.end());
} else {
return table_names.begin();
}
}();
while (limit > 0 && table_names_it != table_names.end()) {
all_tables.append(Json::Value(table_names_it->c_str()));
--limit;
++table_names_it;
}
if (table_names_it != table_names.end()) {
response["LastEvaluatedTableName"] = *std::prev(all_tables.end());
}
return make_ready_future<json::json_return_type>(make_jsonable(std::move(response)));
}
future<json::json_return_type> executor::describe_endpoints(std::string content, std::string host_header) {
_stats.api_operations.describe_endpoints++;
Json::Value response;
// Without having any configuration parameter to say otherwise, we tell
// the user to return to the same endpoint they used to reach us. The only
// way we can know this is through the "Host:" header in the request,
// which typically exists (and in fact is mandatory in HTTP 1.1).
// A "Host:" header includes both host name and port, exactly what we need
// to return.
if (host_header.empty()) {
throw api_error("ValidationException", "DescribeEndpoints needs a 'Host:' header in request");
}
response["Endpoints"][0]["Address"] = host_header;
response["Endpoints"][0]["CachePeriodInMinutes"] = 1440;
return make_ready_future<json::json_return_type>(make_jsonable(std::move(response)));
}
future<> executor::start() {
if (engine().cpu_id() != 0) {
return make_ready_future<>();
}
// FIXME: the RF of this keyspace should be configurable: RF=1 makes
// sense on test setups, but not on real clusters.
auto ksm = keyspace_metadata::new_keyspace(KEYSPACE_NAME, "org.apache.cassandra.locator.SimpleStrategy", {{"replication_factor", "1"}}, true);
try {
return _mm.announce_new_keyspace(ksm, api::min_timestamp, false);
} catch(exceptions::already_exists_exception& ignored) {
return make_ready_future<>();
} catch(...) {
return make_exception_future(std::current_exception());
}
}
}