(maint) Add commit checks

We want to make sure we aren't using private projects in our commit
messages. This will allow maint, doc, docs, packaging, pa, and cpr

.travis.yml

@@ -12,3 +12,5 @@ matrix:
   include:
     - rvm: 2.1.7
       env: "CHECK='rubocop -D'"
+    - rvm: 2.1.7
+      env: "CHECK='rake commits'"

Rakefile

@@ -36,3 +36,41 @@ if File.exist?(build_defs_file)
     end
   end
 end
+
+desc "verify that commit messages match CONTRIBUTING.md requirements"
+task(:commits) do
+  commits = ENV['TRAVIS_COMMIT_RANGE']
+  if commits.nil?
+    puts "TRAVIS_COMMIT_RANGE is undefined, I don't know what to check."
+    exit
+  end
+
+  %x{git log --no-merges --pretty=%s #{commits}}.each_line do |commit_summary|
+    error_message=<<-HEREDOC
+\n\n\n\tThis commit summary didn't match CONTRIBUTING.md guidelines:\n \
+\n\t\t#{commit_summary}\n \
+\tThe commit summary (i.e. the first line of the commit message) should start with one of:\n  \
+\t\t(docs)\n \
+\t\t(maint)\n \
+\t\t(packaging)\n \
+\t\t(<ANY PUBLIC JIRA TICKET>)\n \
+\n\tThis test for the commit summary is case-insensitive.\n\n\n
+    HEREDOC
+
+    if /^\((maint|doc|docs|packaging)\)|revert|bumping/i.match(commit_summary).nil?
+      ticket = commit_summary.match(/^\(([[:alpha:]]+-[[:digit:]]+)\).*/)
+      if ticket.nil?
+        raise error_message
+      else
+        require 'net/http'
+        require 'uri'
+        uri = URI.parse("https://tickets.puppetlabs.com/browse/#{ticket[1]}")
+        response = Net::HTTP.get_response(uri)
+        if response.code != "200"
+          raise error_message
+        end
+      end
+    end
+  end
+end
+