ci: add check for commit messages

.travis.yml

@@ -13,6 +13,9 @@ rvm: "2.2"
 
 sudo: false
 
+before_install:
+  - script/commit_message.py
+
 install:
   - pip install -r requirements_dev.txt
 

script/commit_message.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python
+import re
+import sys
+import subprocess
+
+examples = """+ 61c8ca9 fix: navbar not responsive on mobile
++ 479c48b test: prepared test cases for user authentication
++ a992020 chore: moved to semantic versioning
++ b818120 fix: button click even handler firing twice
++ c6e9a97 fix: login page css
++ dfdc715 feat(auth): added social login using twitter
+"""
+
+
+def main():
+
+    cmd = "git log --pretty=format:'%s' master..HEAD"
+    commits = subprocess.check_output(cmd, shell=True)
+    commits = commits.decode("utf-8").split('\n')
+    for commit in commits:
+        pattern = r'(build|ci|docs|feat|fix|perf|refactor|style|test|chore|revert)(\([\w\-]+\))?:\s.*'  # noqa
+        m = re.match(pattern, commit)
+        if m is None:
+            print("\nError with git message '{}' style".format(commit))
+            print("\nPlease change commit message to the conventional format and try to commit again. Examples:")  # noqa
+
+            print("\n" + examples)
+            sys.exit(1)
+
+    print("Commit messages valid")
+
+
+if __name__ == "__main__":
+    main()