Crontab regex matching

[ecbrodie]

Description

The crontab resource is unable to apply Regex matching via the to match matcher. It would be nice if this were a feature, since I prefer to match a part of the command instead of the whole command in my test. This is especially useful if there are parts of a command that don't care too much about to verify working behaviour, such as paths to a command that are dynamically created by factors including programming language versions.

For example, suppose that I am adding a cron in my cookbook for running a custom rake task nightly. The rake task could be something like custom_task, so I just want my test to ensure that there is a cron command that matches to the regex /rake custom_task/.

describe corntab do
  its ('commands') { should match /rake custom_task/ }
end

Unfortunately, it looks like I can only do an equality check via include instead of a regex check with match. So I have to add some hardcoded paths to my test code, which makes me cringe slightly.

describe corntab do
  its ('commands') { should include '/home/deploy/ruby-2.3.1/bin/rake custom_task' }
end

InSpec and Platform Version

Inspec version 1.15.0
MacOS 10.12.3 (host machine where I am running tests from)

Replication Case

See Description

Possible Solutions

My workaround is to bite my tongue and just use the include matcher. I do not think I know the best way to write a PR for this. But I imagine that new code should allow for match matcher support in lib/resources/crontab.rb.

[adamleff]

Hi, @ecbrodie! Thanks for submitting this issue!

With resources such as crontab that use our FilterTable module under the covers, the way we normally accomplish this is with a #where filter:

describe crontab.where { command =~ /rake custom_task/ } do
  its('entries.length') { should cmp 1 }
end

Would this approach meet your needs?

[ecbrodie]

@adamleff This code did the trick and allowed me to apply the regex matching on my crontabs like I intended.

I would say that it would be nice to support a regex matcher through an its statement instead of through where. If that's not feasible, then I say at least add this an an example to the documentation.

[adamleff]

@ecbrodie I'm glad to hear that you're unblocked.

Native RSpec doesn't support using match with an array return:

     Failure/Error: expect(['echo foo', 'echo bar']).to match(/foo/)

       expected ["echo foo", "echo bar"] to match /foo/
       Diff:
       @@ -1,2 +1,2 @@
       -/foo/
       +["echo foo", "echo bar"]

... requiring you to do something like this:

expect(['echo foo', 'echo bar'].select { |x| x.match(/foo/) }).not_to eq([])

In addition to the where syntax, you could convert the commands array to a string and match that:

describe crontab do
  its('commands.to_s') { should match /foo/ }
end

I think the where syntax is cleaner and allows you to pass a more complicated block if needed, but you do have a few options here.

I will update the documentation with a where example though. Thanks for the suggestion!