Merge tag 'gdb/initial/v1' from seastar-dev.git

From Avi:

Add pretty-print support for sstring, uuid; add commands to query
where database objects, keyspace objects, and column_family objects are
located.

debug.hh

@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2015 Cloudius Systems, Ltd.
+ */
+
+#pragma once
+
+#include <seastar/core/sharded.hh>
+
+class database;
+
+namespace debug {
+
+extern seastar::sharded<database>* db;
+
+
+}
+

main.cc

@@ -18,6 +18,7 @@
 #include "utils/runtime.hh"
 #include "dns.hh"
 #include "log.hh"
+#include "debug.hh"
 #include <cstdio>
 
 namespace bpo = boost::program_options;
@@ -67,6 +68,7 @@ int main(int ac, char** av) {
         ;
 
     distributed<database> db;
+    debug::db = &db;
     distributed<cql3::query_processor> qp;
     auto& proxy = service::get_storage_proxy();
     api::http_context ctx(db, proxy);
@@ -168,3 +170,9 @@ int main(int ac, char** av) {
         });
     });
 }
+
+namespace debug {
+
+seastar::sharded<database>* db;
+
+}

scylla-gdb.py

@@ -0,0 +1,103 @@
+import gdb, gdb.printing, uuid
+
+def uint64_t(val):
+    val = int(val)
+    if val < 0:
+        val += 1 << 64
+    return val
+
+class sstring_printer(gdb.printing.PrettyPrinter):
+    'print an sstring'
+    def __init__(self, val):
+        self.val = val
+    def to_string(self):
+        if self.val['u']['internal']['size'] >= 0:
+            array = self.val['u']['internal']['str']
+            len = self.val['u']['internal']['size']
+            return ''.join([chr(array[x]) for x in range(len)])
+        else:
+            return self.val['u']['external']['str']
+    def display_hint(self):
+        return 'string'
+
+class uuid_printer(gdb.printing.PrettyPrinter):
+    'print a uuid'
+    def __init__(self, val):
+        self.val = val
+    def to_string(self):
+        msb = uint64_t(self.val['most_sig_bits'])
+        lsb = uint64_t(self.val['least_sig_bits'])
+        return str(uuid.UUID(int=(msb << 64) | lsb))
+    def display_hint(self):
+        return 'string'
+    
+
+def build_pretty_printer():
+    pp = gdb.printing.RegexpCollectionPrettyPrinter('scylla')
+    pp.add_printer('sstring', r'^basic_sstring<char,.*>$', sstring_printer)
+    pp.add_printer('uuid', r'^utils::UUID$', uuid_printer)
+    return pp
+
+gdb.printing.register_pretty_printer(gdb.current_objfile(), build_pretty_printer())
+
+def cpus():
+    return gdb.parse_and_eval('smp::count')
+
+def find_db(shard):
+    return gdb.parse_and_eval('debug::db')['_instances']['_M_impl']['_M_start'][shard]
+
+def find_dbs():
+    return [find_db(shard) for shard in range(cpus())]
+
+def list_unordered_map(map):
+    kt = map.type.template_argument(0)
+    vt = map.type.template_argument(1)
+    value_type = gdb.lookup_type('std::pair<{} const, {}>'.format(kt.name, vt.name))
+    hashnode_ptr_type = gdb.lookup_type('std::__detail::_Hash_node<' + value_type.name + ', true>').pointer()
+    h = map['_M_h']
+    p = h['_M_before_begin']['_M_nxt']
+    while p:
+        pc = p.cast(hashnode_ptr_type)['_M_storage']['_M_storage']['__data'].cast(value_type.pointer())
+        yield (pc['first'], pc['second'].address)
+        p = p['_M_nxt'] 
+    raise StopIteration()
+
+class scylla(gdb.Command):
+    def __init__(self):
+        gdb.Command.__init__(self, 'scylla', gdb.COMMAND_USER, gdb.COMPLETE_COMMAND, True)
+
+class scylla_databases(gdb.Command):
+    def __init__(self):
+        gdb.Command.__init__(self, 'scylla databases', gdb.COMMAND_USER, gdb.COMPLETE_COMMAND)
+    def invoke(self, arg, from_tty):
+        for shard in range(cpus()): 
+            db = find_db(shard)
+            gdb.write('{:5} (database*){}\n'.format(shard, db))
+
+class scylla_keyspaces(gdb.Command):
+    def __init__(self):
+        gdb.Command.__init__(self, 'scylla keyspaces', gdb.COMMAND_USER, gdb.COMPLETE_COMMAND)
+    def invoke(self, arg, from_tty):
+        for shard in range(cpus()):
+            db = find_db(shard)
+            keyspaces = db['_keyspaces']
+            for (key, value) in list_unordered_map(keyspaces):
+                gdb.write('{:5} {:20} (keyspace*){}\n'.format(shard, key, value))
+
+class scylla_column_families(gdb.Command):
+    def __init__(self):
+        gdb.Command.__init__(self, 'scylla column_families', gdb.COMMAND_USER, gdb.COMPLETE_COMMAND)
+    def invoke(self, arg, from_tty):
+        for shard in range(cpus()):
+            db = find_db(shard)
+            cfs = db['_column_families']
+            for (key, value) in list_unordered_map(cfs):
+                value = value['_p']['_value']  # it's a lw_shared_ptr
+                schema = value['_schema']['_p']['_value']
+                name = str(schema['_raw']['_ks_name']) + '/' + str(schema['_raw']['_cf_name'])
+                gdb.write('{:5} {} {:45} (column_family*){}\n'.format(shard, key, name, value.address))
+
+scylla()
+scylla_databases()
+scylla_keyspaces()
+scylla_column_families()