Files
scylladb/alternator-test
Piotr Sarna cbe6f260ef alternator: add guarding stack height for JSON parsing
In order to avoid stack overflow issues represented by the attached
test case, rapidjson's parser now has a limit of nested level.
Previous iterations of this patch used iterative parsing
provided by rapidjson, but that solution has two main flaws:
1. While parsing can be done iteratively, printing the document
   is based on a recursive algorithm, which makes the iteratively
   parsed JSON still prone to stack overflow on reads.
   Documents with depth 35k were already prone to that.
2. Even if reading the document would have been performed iteratively,
   its destruction is stack-based as well - the chain of C++ destructors
   is called. This error is sneaky, because it only shows with depths
   around 100k with my local configuration, but it's just as dangerous.

Long story short, capping the depth of the object to an arguably large
value (39) was introduced to prevent stack overflows. Real life
objects are expected to rarely have depth of 10, so 39 sounds like
a safe value both for the clients and for the stack.
DynamoDB has a nesting limit of 32.

Fixes #5842
Tests: alternator-test(local,remote)
Message-Id: <b083bacf9df091cc97e4a9569aad415cf6560daa.1582194420.git.sarna@scylladb.com>
2020-02-20 13:05:58 +02:00
..
2019-09-11 18:01:05 +03:00

Tests for Alternator that should also pass, identically, against DynamoDB.

Tests use the boto3 library for AWS API, and the pytest frameworks (both are available from Linux distributions, or with "pip install").

To run all tests against the local installation of Alternator on http://localhost:8000, just run pytest.

Some additional pytest options:

  • To run all tests in a single file, do pytest test_table.py.
  • To run a single specific test, do pytest test_table.py::test_create_table_unsupported_names.
  • Additional useful pytest options, especially useful for debugging tests:
    • -v: show the names of each individual test running instead of just dots.
    • -s: show the full output of running tests (by default, pytest captures the test's output and only displays it if a test fails)

Add the --aws option to test against AWS instead of the local installation. For example - pytest --aws test_item.py or pytest --aws.

If you plan to run tests against AWS and not just a local Scylla installation, the files ~/.aws/credentials should be configured with your AWS key:

[default]
aws_access_key_id = XXXXXXXXXXXXXXXXXXXX
aws_secret_access_key = xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

and ~/.aws/config with the default region to use in the test:

[default]
region = us-east-1

HTTPS support

In order to run tests with HTTPS, run pytest with --https parameter. Note that the Scylla cluster needs to be provided with alternator_https_port configuration option in order to initialize a HTTPS server. Moreover, running an instance of a HTTPS server requires a certificate. Here's how to easily generate a key and a self-signed certificate, which is sufficient to run --https tests:

openssl genrsa 2048 > scylla.key
openssl req -new -x509 -nodes -sha256 -days 365 -key scylla.key -out scylla.crt

If this pair is put into conf/ directory, it will be enough to allow the alternator HTTPS server to think it's been authorized and properly certified. Still, boto3 library issues warnings that the certificate used for communication is self-signed, and thus should not be trusted. For the sake of running local tests this warning is explicitly ignored.

Authorization

By default, boto3 prepares a properly signed Authorization header with every request. In order to confirm the authorization, the server recomputes the signature by using user credentials (user-provided username + a secret key known by the server), and then checks if it matches the signature from the header. Early alternator code did not verify signatures at all, which is also allowed by the protocol. A partial implementation of the authorization verification can be allowed by providing a Scylla configuration parameter:

  alternator_enforce_authorization: true

The implementation is currently coupled with Scylla's system_auth.roles table, which means that an additional step needs to be performed when setting up Scylla as the test environment. Tests will use the following credentials: Username: alternator Secret key: secret_pass

With CQLSH, it can be achieved by executing this snipped:

cqlsh -x "INSERT INTO system_auth.roles (role, salted_hash) VALUES ('alternator', 'secret_pass')"

Most tests expect the authorization to succeed, so they will pass even with alternator_enforce_authorization turned off. However, test cases from test_authorization.py may require this option to be turned on, so it's advised.