fix: Add support for postgres 9.2 and lower

[KijongHan]

What does this PR do?

This PR adds support for running Postgres containers below version 9.3. Adds to the PostgreSqlBuilder.Build method to check for Postgres versions below 9.3 (which doesn't have support for pg_isready to check for database readiness) using Image.MatchVersion - for these versions check for message logged in container using UntilMessageIsLogged helper method for the message "PostgreSQL init process complete; ready for start up."

Other strategies tried

• using psql to connect to container db and running select 1 or select version() - these were not reliable and the database was not in a state ready to accept connections
• using "database system is ready to accept connections" - but couldn't reliably connect on the first instance of the message

related github discussion that helped determine above strategy: docker-library/postgres#146

Why is it important?

some older codebases are built on older versions of postgres, and being able to build tests using those older versions before migrating the version gives peace of mind for validating successful migration

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[HofmeisterAn]

Thanks for the PR! The changes look good. However, TBH I'm not sure if I like adding support for a version that is EOL. Developers can simply override the default wait strategy or fall back to the generic container builder. But I agree that it is very difficult for developers to understand which versions are supported and which are not. This is something I've been thinking about a lot, but I haven't come up with a proper solution yet.

I don't know how to proceed from here. It's probably best to merge it so that other developers don't run into the same issue 🤔.

Note: I believe it was necessary to wait until the log messages were logged twice (for a reliable indication). I need to double-check the other language implementations.

[0xced]

I have a UntilDatabaseIsAvailable branch on my fork which would solve this issue. The UntilDatabaseIsAvailable wait strategy works with any ADO.NET provider. It could even have been used to workaround #1383! I actually copy/pasted this wait strategy in two projects as a workaround while waiting for Testcontainers 4.4.0 to be released.

I think it would be a perfect fit for this use case too (supporting PostgreSQL containers below version 9.3) and for any other potentially flaky wait strategy for database containers.

Edit: I just opened #1401. Then it could be used like this:

new PostgreSqlBuilder()
    .WithImage("postgres:9.2")
    .WithWaitStrategy(Wait.ForUnixContainer().UntilDatabaseIsAvailable(NpgsqlFactory.Instance));

[HofmeisterAn]

Thanks for the PR. I had a quick discussion in our Slack workspace and created this discussion this morning: #1407, LMKWYT. I am heading out for a few days off now, I will review your (@0xced) PR when I get back. After that, we can decide how to proceed with this PR. Thanks again 🙏.

[KijongHan]

Thanks for the PR. I had a quick discussion in our Slack workspace and created this discussion this morning: #1407, LMKWYT. I am heading out for a few days off now, I will review your (@0xced) PR when I get back. After that, we can decide how to proceed with this PR. Thanks again 🙏.

Yeah I think your proposal there is quite reasonable, given this image is outside the LTS Im happy to close off this PR until the need arises. Appreciate your efforts!