feat: Make the max_connections of the shared PostgreSQL configurable

[ZPascal]

All Cloud Foundry components share one PostgreSQL instance. With its default of 100 connections, it can run out during a long load, and UAA (and then everything that needs a token) fails with FATAL: sorry, too many clients already.

I ran into this when running the integration tests of cf-java-client against kind-deployment (cloudfoundry/cf-java-client#1381, related to #339): after roughly 30-50 minutes, every Spring test context failed with scim: Failed to obtain JDBC Connection, and 529 to 901 of 903 tests errored.

The default stays as it is. This PR only makes max_connections configurable, so a workflow that needs more connections can ask for them when PostgreSQL is installed. The alternative is to raise the limit after the deployment with ALTER SYSTEM, restart PostgreSQL, and then restart every component that holds pooled connections (the cloud controller does not validate pooled connections and answers a 500 for each dead one).

Verification

cloudfoundry/cf-java-client#1381

[c0d1ngm0nk3y]

Hi,

I see the use case and this will work of course. But for this rather specific case, it is a bit too much imho. The environment variable and the changes to the github action are only convinience, so I am not sure if this is worth it.

Alternative: additional-values-files is already supported. What is missing is that we pass a postgresql property down to the chart in case it is present. So, I guess 4 lines and the if is probably not even necessary :)

WDYT?

[ZPascal]

Hi,

I see the use case and this will work of course. But for this rather specific case, it is a bit too much imho. The environment variable and the changes to the github action are only convinience, so I am not sure if this is worth it.

Alternative: additional-values-files is already supported. What is missing is that we pass a postgresql property down to the chart in case it is present. So, I guess 4 lines and the if is probably not even necessary :)

WDYT?

I've updated the implementation.