Add script to post Travid build errors on PRs (tldr-pages#1138)

.gitignore

@@ -9,6 +9,10 @@
 node_modules
 npm-debug.log
 
+# A temp file used to store the output from npm test
+# used to update a PR with a comment
+test_result
+
 # We used to have an index file in the repository,
 # but it's been superseded by a static asset
 # hosted at https://tldr-pages.github.io/assets/index.json

.travis.yml

@@ -10,6 +10,9 @@ cache: false
 after_success:
 - bash scripts/build.sh
 
+after_failure:
+- cat test_result | python scripts/post_pr_comment.py
+
 env:
   global:
   - secure: ewQMcFd3wH8IHOeGhIkBr2kAgadONmesv2KB+9bPRCZ5gvtFFwlkCMdPnQBR9Kd3GKC8r+EO0JNNFWOvrDjPYhEHi9Ab26Q/qodwfwne9YloKXT+C48Zrbrj8q7kb/FeMYPev+RMuM96j5E5QyqBVohGP7hC2bpU3mvAhQ2wBCE=

package.json

@@ -12,7 +12,7 @@
     "precommit": "npm test",
     "lint-markdown": "markdownlint pages/**/*.md",
     "lint-tldr": "tldr-lint ./pages",
-    "test": "markdownlint pages/ && tldr-lint ./pages",
+    "test": "markdownlint pages/ && tldr-lint ./pages 2>&1 | tee test_result",
     "build-index": "node ./scripts/build-index.js > pages/index.json"
   },
   "repository": "tldr-pages/tldr",

scripts/post_pr_comment.py

@@ -0,0 +1,42 @@
+import json
+import os
+import sys
+import urllib2
+
+GITHUB_URL = 'https://api.github.com'
+
+def post_comment(pr_id, repo_slug, comment_body, user_token):
+	# Constructing the url
+	url = '{api_url}/repos/{slug}/issues/{number}/comments'.format(
+        api_url=GITHUB_URL, slug=repo_slug, number=pr_id)
+	req = urllib2.Request(url=url,
+                       data=json.dumps({'body': comment_body}))
+	req.add_header('Authorization', 'token ' + user_token)
+	# Making the request
+	f = urllib2.urlopen(req)
+	if f.getcode() != 201:
+		print f.read()
+
+
+# Get the environment variables
+PR_NUMBER = os.environ.get('TRAVIS_PULL_REQUEST')
+REPO_SLUG = os.environ.get('TRAVIS_REPO_SLUG') # owner_name/repo_name
+BOT_TOKEN = os.environ.get('TRAVIS_BOT_GITHUB_TOKEN')
+BUILD_ID = os.environ.get('TRAVIS_BUILD_ID')
+
+# Read the test result output from stdin
+test_result = sys.stdin.read().strip()
+# Populate the template text
+comment = (
+"The [build]"
+"(https://travis-ci.org/tldr-pages/tldr/builds/{build_id})"
+" for this PR has failed with the following message:"
+"\n```\n"
+"{comment_body}"
+"\n```\n"
+"Please fix the error(s) and push again."
+).format(build_id=BUILD_ID, comment_body=test_result)
+
+# If its a PR, post a comment on it
+if PR_NUMBER != "false":
+	post_comment(PR_NUMBER, REPO_SLUG, comment, BOT_TOKEN)