feat: add support for Ruby ActiveRecord

[olavloite]

Adds experimental support for Ruby ActiveRecord 7.x. This PR adds:

• Tests using an in-mem mock Spanner server to verify that the requests that we receive from Ruby ActiveRecord.
• Integration tests running against a real Cloud Spanner instance.
• A sample application using all supported data types.
• Documentation and instructions for how to set up an application to use Ruby ActiveRecord with PGAdapter, including known limitations.

[codecov]

Codecov Report

Merging #749 (b5c185b) into postgresql-dialect (6ef7240) will increase coverage by 3.48%.
The diff coverage is 95.74%.

@@                   Coverage Diff                    @@
##             postgresql-dialect     #749      +/-   ##
========================================================
+ Coverage                 86.32%   89.81%   +3.48%     
- Complexity                 1914     2383     +469     
========================================================
  Files                       122      131       +9     
  Lines                      6216     7942    +1726     
  Branches                    849     1141     +292     
========================================================
+ Hits                       5366     7133    +1767     
+ Misses                      605      564      -41     
  Partials                    245      245              

Flag	Coverage Δ
all_tests	89.81% <95.74%> (+3.48%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
.../cloud/spanner/pgadapter/session/SessionState.java	94.92% <ø> (-0.11%)	⬇️
...panner/pgadapter/statements/BackendConnection.java	93.92% <ø> (+3.39%)	⬆️
...nner/pgadapter/statements/ClientSideResultSet.java	85.71% <ø> (ø)
...ud/spanner/pgadapter/statements/CopyStatement.java	95.36% <ø> (+10.51%)	⬆️
.../spanner/pgadapter/statements/CopyToStatement.java	100.00% <ø> (+4.83%)	⬆️
...nner/pgadapter/statements/DeallocateStatement.java	97.36% <ø> (+0.14%)	⬆️
...spanner/pgadapter/statements/ExecuteStatement.java	91.52% <ø> (+0.29%)	⬆️
...apter/statements/ExtendedQueryProtocolHandler.java	98.03% <ø> (+0.36%)	⬆️
...dapter/statements/IntermediatePortalStatement.java	93.75% <ø> (-2.41%)	⬇️
...pter/statements/IntermediatePreparedStatement.java	95.08% <ø> (+7.86%)	⬆️
... and 64 more

... and 8 files with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[olavloite]

@palladius FYI

[hengfengli]

nits: 2022 -> 2023

[olavloite]

Done

[hengfengli]

Generally, LGTM. Why do we need a mock server just for ruby/active record? Can't we have one for all cases?

[olavloite]

Generally, LGTM. Why do we need a mock server just for ruby/active record? Can't we have one for all cases?

Thanks for the view. We have a specific mock server for Ruby/ActiveRecord, but it is based on the generic mock server that we have for other tests:

pgadapter/src/test/java/com/google/cloud/spanner/pgadapter/ruby/AbstractRubyMockServerTest.java

Line 47 in ef17dba

public class AbstractRubyMockServerTest extends AbstractMockServerTest {

The reason that we have a specific one for Ruby is that the Ruby driver will execute some specific queries either when a new connection is created, or when specific methods are executed on the driver (e.g. it will check for the existence of specific types the first time those types are used). We keep these specific queries in separate mock servers per driver/ecosystem. We for example also have a similar setup for .NET, as the .NET driver also executes specific queries when some data types are used.