Interop binaries: wait for database to be up

[divergentdave]

This waits for the Postgres database to come up before starting janus_interop_aggregator etc. This is for #1977. I tried this out locally, and saw the following on stdout from the setup job. (the first two lines are from pg_isready)

/var/run/postgresql:5432 - no response
/var/run/postgresql:5432 - accepting connections
janus_interop_aggregator: started
aggregation_job_creator: started
aggregation_job_driver: started
collection_job_driver: started

[tgeoghegan]

Nice find, David. @c02-student, since none of us have been able to reproduce this, do you think you could check whether this patch fixes your issue?

[tgeoghegan]

This will wait for postgres forever, right? I think we should give up after some delay so that e.g. postgres crashing on startup due to misconfiguration doesn't cause a test to hang forever.

[inahga]

Consider running this script with set -e or perhaps better adding || "timeout waiting for postgres to be ready" && exit 1. Otherwise the script will fall through on failure.

This is a nit since we'll be able to see the results in the logs anyways, can take it or leave it.

[c02-student]

I was able to resolve the issue with this change !
I have tested it in my local environment for both release/0.5 and 0.6.0-prerelease-1, and both passed successfully.

Thank you .