Use GitHub token file to avoid rate limiting

Closes #18.

CHANGELOG.md

@@ -2,6 +2,11 @@
 
 All notable changes to this project will be documented in this file. This project adheres to [Semantic Versioning](http://semver.org/).
 
+## [1.1.1] - Unreleased
+
+### Added
+- Recipe Robot now uses the AutoPkg GitHub token file at ~/.autopkg_gh_token, if it exists. This can help you avoid rate limiting if you're creating many GitHub recipes in a short time. (#18)
+
 
 ## [1.1.0] - 2019-02-12
 
@@ -185,6 +190,7 @@ All notable changes to this project will be documented in this file. This projec
 
 - Initial public release of Recipe Robot (beta).
 
+[1.1.1]: https://github.com/homebysix/recipe-robot/compare/v1.1.0...HEAD
 [1.1.0]: https://github.com/homebysix/recipe-robot/compare/v1.0.5...v1.1.0
 [1.0.5]: https://github.com/homebysix/recipe-robot/compare/v1.0.4...v1.0.5
 [1.0.4]: https://github.com/homebysix/recipe-robot/compare/v1.0.3...v1.0.4

scripts/recipe_robot_lib/inspect.py

@@ -1102,6 +1102,16 @@ def inspect_download_url(input_path, args, facts):
     return facts
 
 
+def github_urlopen(url, github_token):
+    '''For a given URL, return the urlopen response after adding the GitHub token.'''
+
+    req = Request(url)
+    if github_token:
+        req.add_header('Authorization', 'token ' + github_token)
+
+    return urlopen(req)
+
+
 def inspect_github_url(input_path, args, facts):
     """Process a GitHub URL
 
@@ -1124,16 +1134,27 @@ def inspect_github_url(input_path, args, facts):
     else:
         facts["inspections"].append("github_url")
 
+    # Use AutoPkg GitHub token, if file exists.
+    # TODO: Also check for GITHUB_TOKEN preference.
+    github_token_file = os.path.expanduser('~/.autopkg_gh_token')
+    github_token = None
+    if os.path.isfile(github_token_file):
+        try:
+            with open(github_token_file, 'r') as tokenfile:
+                github_token = tokenfile.read().strip()
+        except IOError as err:
+            facts['warnings'].append('Couldn\'t read GitHub token file at '
+                                     '{}.'.format(github_token_file))
+
     # Grab the GitHub repo path.
     github_repo = ""
     robo_print("Getting GitHub repo...", LogLevel.VERBOSE)
     # Matches all these examples:
-    # [x] https://github.com/jbtule/cdto/releases/download/2_6_0/cdto_2_6.zip
-    # [x] https://github.com/lindegroup/autopkgr
-    # [x] https://raw.githubusercontent.com/macmule/AutoCasperNBI/master/README.md
-    # [X] https://api.github.com/repos/macmule/AutoCasperNBI
-    # [X] https://hjuutilainen.github.io/munkiadmin/
-    github_repo = ""
+    # - https://github.com/jbtule/cdto/releases/download/2_6_0/cdto_2_6.zip
+    # - https://github.com/lindegroup/autopkgr
+    # - https://raw.githubusercontent.com/macmule/AutoCasperNBI/master/README.md
+    # - https://api.github.com/repos/macmule/AutoCasperNBI
+    # - https://hjuutilainen.github.io/munkiadmin/
     parsed_url = urlparse(input_path)
     path = parsed_url.path.split("/")
     path.remove("")
@@ -1161,9 +1182,6 @@ def inspect_github_url(input_path, args, facts):
                     "Try using the --ignore-existing flag if you want me to "
                     "create recipes for myself.")
 
-        # TODO(Elliot): How can we use GitHub tokens to prevent rate
-        # limiting? (#18)
-
         # Use GitHub API to obtain information about the repo and
         # releases.
         repo_api_url = "https://api.github.com/repos/%s" % github_repo
@@ -1172,9 +1190,9 @@ def inspect_github_url(input_path, args, facts):
 
         # Download the information from the GitHub API.
         try:
-            raw_json_repo = urlopen(repo_api_url).read()
-            raw_json_release = urlopen(releases_api_url).read()
-            raw_json_user = urlopen(user_api_url).read()
+            raw_json_repo = github_urlopen(repo_api_url, github_token).read()
+            raw_json_release = github_urlopen(releases_api_url, github_token).read()
+            raw_json_user = github_urlopen(user_api_url, github_token).read()
         except HTTPError as err:
             if err.code == 403:
                 facts["warnings"].append(