Handle inexistant config file

[blogh]

This PR is for #61.

@dlax is there a better way to do this ?

[dlax]

Did you try using a click.File() argument type? According to its documentation, click will try to open the file early enough to report I/O errors to the user:

$ check_patroni --config no-such-file
Usage: check_patroni [OPTIONS] COMMAND [ARGS]...
Try 'check_patroni --help' for help.

Error: Invalid value for '--config': 'no-such-file': No such file or directory

[blogh]

yes but a nagos plugin shoud return a string like "UNKNOWN: click.exceptions.UsageError: Config File not found" and RC 3 in that case.

[dlax]

Why 3? This is ESRCH 3 No such process. ENOENT 2 No such file or directory seems more appropriate.

[blogh]

It's the norm they propose in the Nagios Plugins Development Guidelines.

https://nagios-plugins.org/doc/guidelines.html#AEN78

[dlax]

I have pushed a better implementation, in branch "fix_configfile_error" on the main repo: https://github.com/dalibo/check_patroni/compare/fix_configfile_error (based on your commit).

The idea is to only handle IO errors in the configure() callback, and then possibly exit (with rc 3) from there.

[dlax]

WIth the version posted above:

$ check_patroni --config no-such-file
failed to read configuration: [Errno 2] No such file or directory: 'no-such-file'
$ echo $?
3
$ check_patroni --config /etc/postgresql/16/main/pg_hba.conf 
failed to read configuration: [Errno 13] Permission denied: '/etc/postgresql/16/main/pg_hba.conf'
$ echo $?
3

[blogh]

ha yes, mutch better. Th. I'll use that one instead.