Validates PostgreSQL table name

[ramondeklein]

The PostgreSQL store can be for submitting events to a table. This table can be configured, but it is inserted using Sprintf(...) to generate INSERT, UPDATE, DELETE statements. Despite it being a configuration value (and not originating from user input) it is still a good idea to validate or sanitize the value.

This PR checks the table name and only allows the use of valid PSQL identifiers. Note that PostgreSQL identifier rules also allow diacritics as valid identifier names, but they are only accepted here when used with quotes. Creating a regular expression that accepts diacritics is hard and probably not used often.

[klauspost]

A bit overly dramatic title. Unless something else is wrong this should not be available for anyone but admins to set.

I suggest "Sanitize postgres event table name" or something less "dramatic".

[ramondeklein]

A bit overly dramatic title. Unless something else is wrong this should not be available for anyone but admins to set.
I suggest "Sanitize postgres event table name" or something less "dramatic".

You're right. Updated commit message and PR title.

[klauspost]

Good find. Could we imagine any existing table names becoming invalid now (other than the ones containing a quote)?

[ramondeklein]

Good find. Could we imagine any existing table names becoming invalid now (other than the ones containing a quote)?

If you're using a table name with diacritics, then they may be marked as invalid (where previously they were working fine). I do think that's a rare scenario and it can be easily fixed by using quotes (although that's always tricky on command-line and/or YAML).

I did check if I could find an existing function in one of the Go packages that would validate the name, but I couldn't find one. What I could do is first normalize the name using golang.org/x/text/uniccode/norm and then check it. Let me try that...

[klauspost]

@ramondeklein Yeah. It will probably be pretty annoying to upgrade to this, if valid (even if strange) names would be rejected, since they would have to build a new table.

[ramondeklein]

@ramondeklein Yeah. It will probably be pretty annoying to upgrade to this, if valid (even if strange) names would be rejected, since they would have to build a new table.

They could also update the configuration to use the name with diacritics within double quotes, but I pushed a fix that also allows diacritics.

[harshavardhana]

@ramondeklein please make branches on your fork, instead of the origin.

[ramondeklein]

@ramondeklein please make branches on your fork, instead of the origin.

Will do that next time.