Postgres Support

[acx1729]

This PR adds support for postgres as as a built-in alternative to sqlite for storing orchestration state. There is an other PR, which appears to have gone stale (#33).

[acx1729]

@microsoft-github-policy-service agree company="Open Governance Inc."

[cgillum]

This is great to see! Is it possible to add some tests to confirm that the Postgres backend is working as designed?

[acx1729]

Sure! Working on it.

[Mahanmmi]

I've added the tests with using the current test suit for sqlite, the line is commented out to avoid any errors in automation pipelines since it does need a running postgres and I was not sure if or how you are planning to add it to the pipeline, but I tested it locally and it passes all tests.

[acx1729]

Hi @cgillum

Greetings. Let me know if there is anything else you wish to see in this PR.

Thank you!

[cgillum]

@acx1729 @Mahanmmi looks great, thanks! I've kicked off a test run to see if everything works as expected, and everything looks green.

One more thing: I worry a little about the dev experience of running tests locally and requiring postgres to be running. Would it be possible to have the postgres variant run only when a particular environment variable is specified, and then set that variable as part of the CI process? That way testing with postgres can be opt-in. Ideally, we'd document this environment variable flag in a README.md file in the backend/postgres directory.

[acx1729]

Thank you @Mahanmmi
Hopefully we are all OK @cgillum

[cgillum]

Looks good - thanks!