Fix postgresql_set module if single-value param contains comma in value

[RealGreenDragon]

SUMMARY

The PR #357 fix the multi-value parameters management (issue #78), but the new check assumes as multi-value each parameter with a comma in the value, that is incorrect as there are single-value parameters with comma in value.

If a single-value parameter is treated as a multi-value, the 'param_set' function builds an ALTER SYSTEM SET command with multiple comma-separated values, that fails with the message:

ERROR:  SET log_line_prefix takes only one argument

Single-value parameters with possible comma in value are "_command" and "_prefix" that for exmple in v12 are:

• ssl_passphrase_command
• archive_command
• restore_command
• archive_cleanup_command
• recovery_end_command
• log_line_prefix

The most critical (that I add in tests) is 'log_line_prefix' because often it contains comma and a space at the end.

I simply fix the check to evaluate as single-value all parameters that ends with '_command' and '_prefix'.

If the fix is accepted, It can be back-ported also in stable branch.

ISSUE TYPE

• Bugfix Pull Request

COMPONENT NAME

postgresql_set

[hunleyd]

set pgaudit.log = 'write, ddl';
set pgaudit.log_relation = on;

would still be handled incorrectly, yes?

[RealGreenDragon]

Hi hunleyd,

the parameters pgaudit.log and pgaudit.log_relation are not affected by my PR.
pgaudit.log_relation does not contains commas, so always go to the standard management.
pgaudit.log contains commas but is multi-value, so it is correctly not not affected by my PR (i.e. still go to specific management).

Small example with python3 and pg 12.13 (from postgres user):

$ python3
>>> value='role, ddl'
>>> ','.join(["'" + elem.strip() + "'" for elem in value.split(',')])
"'role','ddl'"
>>>

$ psql
postgres=# alter system set pgaudit.log = 'role','ddl';
ALTER SYSTEM

$ grep "pgaudit.log =" 12/data/postgresql.auto.conf
pgaudit.log = 'role, ddl'

[Andersson007]

@RealGreenDragon hi, welcome and thanks for the PR!

A couple of minor things from me.

[RealGreenDragon]

@Andersson007 Suggestions applied, thank you very much!

[hunleyd]

thx @RealGreenDragon !

[patchback]

Backport to stable-1: 💚 backport PR created

✅ Backport PR branch: patchback/backports/stable-1/939c2cd611e06017e234931afeadaab4a271b973/pr-400

Backported as #403

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[Andersson007]

@RealGreenDragon thanks for the contribution!

@hunleyd @jchancojr thanks for reviewing!

@RealGreenDragon if you're not in the #postgresql:ansible.com room on Matrix yet, welcome!