allows patch levels (ie 9.5.14)

[ojongerius]

This broke after #25 went in

  ×  postgres-02: Use stable postgresql version (1 failed)
     ×  Command psql -V stdout should match /\b9\.[3-6]$|\b10\.5$/
     expected "psql (PostgreSQL) 9.5.14\n" to match /\b9\.[3-6]$|\b10\.5$/
     Diff:
     @@ -1,2 +1,2 @@
     -/\b9\.[3-6]$|\b10\.5$/
     +psql (PostgreSQL) 9.5.14

Using this PR:

  ✔  postgres-02: Use stable postgresql version
     ✔  Command psql -V stdout should match /(\b9\.[3-6]|\b10\.5)\.[0-9]+$/
     ✔  Command psql -V stdout should not match /RC/
     ✔  Command psql -V stdout should not match /DEVEL/
     ✔  Command psql -V stdout should not match /BETA/

See http://rubular.com/r/2aiU6kIEG6

[chris-rock]

@ojongerius Thank you for highlighting the issue and your first time contribution. 💯 You are right that we should support all patch versions.

I propose the following regex instead \b((9\.[3-6]|\b10\.5)(\.\d*)*)$. Yours only matched releases that had a patch version.

[ojongerius]

Good catch! Should be addressed in 5947fa4. Let me know if you prefer me to rebase to one commit.

[pmav99]

Please check this too: inspec/inspec#3349

I believe that neither regex will match postgresql 10 output on ubuntu:

$ psql -V
psql (PostgreSQL) 10.5 (Ubuntu 10.5-1.pgdg16.04+1)

I think that using a look behind is necessary here. E.g.

(?<=\)\s)\b((9\.[3-6]|\b10\.5)(\.\d+)*)\b

http://rubular.com/r/yEW71p2lph

[chris-rock]

Thank you for pointing this out @pmav99 I think it is right to fix the detection upstream in InSpec. Could we also use a simpler regex for the detection? ^psql\s\(PostgreSQL\)\s((9\.[3-6]|10\.5)(\.\d*)*) http://rubular.com/r/ErwU6FlP4J

[pmav99]

@chris-rock I think that the regex you propose is not correct because it does match the text too. I don't have much experience with ruby but according to this ruby regexes do not support non-capturing groups. This is why I proposed a look behind.

Although it seems that there is indeed a simpler solution:

"psql (PostgreSQL) 9.6.10".split[2]
"psql (PostgreSQL) 10.5 (Ubuntu 10.5-1.pgdg16.04+1)".split[2]

[ojongerius]

I'm not too familiar with Inspec, what does the match matcher do exactly?

Does it test if something matched at all? ie are we trying to make something like 'psql (PostgreSQL) 10.5 (Ubuntu 10.5-1.pgdg16.04+1)' =~ /^psql\s\(PostgreSQL\)\s((9\.[3-6]|10\.5)(\.\d*)*)/ return anything other than nil or does Inspec compare the left side (stdout of a command in this case) of 'should match' with a particular match from the right side (the regexp).

Generally simpler is better, both easier to read and maintain, how about /^psql\s\(PostgreSQL\)\s(9\.[3-6]|10\.5).*/ ? Anyone packaging Postgres could add their own version strings, and we only care about the major and minor versions.

[chris-rock]

The inspec matcher is just running the regular expression and checks if it matches. Maybe we should write a simple pg_version resource that parses the output and returns a version struct. This allows us to focus on version numbers only for the comparison. It also is easier to read and understand.

[ojongerius]

@chris-rock ta. Would that resource do more than test if /^psql\s\(PostgreSQL\)\s(9\.[3-6]|10\.5).*/ matches?

If not, I'd say let's go with /^psql\s\(PostgreSQL\)\s(9\.[3-6]|10\.5).*/ and be done with it.

[ojongerius]

@chris-rock ping!

[chris-rock]

Thank you @ojongerius for addressing that issue and for your contribution. This looks good to me. Lets see if we need to improve this further later.