Provide build revision with GITHUB_SHA environment variable

Gemfile

@@ -14,7 +14,7 @@ group :jekyll_plugins do
   gem "jekyll-feed", "~> 0.12"
   gem "jekyll-last-modified-at"
   gem "jekyll-redirect-from"
-  gem "jekyll-github-metadata"
+  gem 'jekyll-environment-variables'
   gem "jekyll-sitemap"
 end
 

Gemfile.lock

@@ -10,29 +10,6 @@ GEM
       http_parser.rb (~> 0)
     eventmachine (1.2.7)
     eventmachine (1.2.7-x64-mingw32)
-    faraday (1.10.0)
-      faraday-em_http (~> 1.0)
-      faraday-em_synchrony (~> 1.0)
-      faraday-excon (~> 1.1)
-      faraday-httpclient (~> 1.0)
-      faraday-multipart (~> 1.0)
-      faraday-net_http (~> 1.0)
-      faraday-net_http_persistent (~> 1.0)
-      faraday-patron (~> 1.0)
-      faraday-rack (~> 1.0)
-      faraday-retry (~> 1.0)
-      ruby2_keywords (>= 0.0.4)
-    faraday-em_http (1.0.0)
-    faraday-em_synchrony (1.0.0)
-    faraday-excon (1.1.0)
-    faraday-httpclient (1.0.1)
-    faraday-multipart (1.0.3)
-      multipart-post (>= 1.2, < 3)
-    faraday-net_http (1.0.1)
-    faraday-net_http_persistent (1.2.0)
-    faraday-patron (1.0.0)
-    faraday-rack (1.0.0)
-    faraday-retry (1.0.3)
     ffi (1.15.5)
     ffi (1.15.5-x64-mingw32)
     forwardable-extended (2.6.0)
@@ -54,11 +31,10 @@ GEM
       rouge (~> 3.0)
       safe_yaml (~> 1.0)
       terminal-table (~> 1.8)
+    jekyll-environment-variables (1.0.1)
+      jekyll (>= 3.0, < 5.x)
     jekyll-feed (0.15.1)
       jekyll (>= 3.7, < 5.0)
-    jekyll-github-metadata (2.13.0)
-      jekyll (>= 3.4, < 5.0)
-      octokit (~> 4.0, != 4.4.0)
     jekyll-last-modified-at (1.3.0)
       jekyll (>= 3.7, < 5.0)
       posix-spawn (~> 0.3.9)
@@ -66,8 +42,6 @@ GEM
       jekyll (>= 3.3, < 5.0)
     jekyll-sass-converter (2.2.0)
       sassc (> 2.0.1, < 3.0)
-    jekyll-seo-tag (2.7.1)
-      jekyll (>= 3.8, < 5.0)
     jekyll-sitemap (1.4.0)
       jekyll (>= 3.7, < 5.0)
     jekyll-watch (2.2.1)
@@ -81,14 +55,6 @@ GEM
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.4.0)
-    minima (2.5.1)
-      jekyll (>= 3.5, < 5.0)
-      jekyll-feed (~> 0.9)
-      jekyll-seo-tag (~> 2.1)
-    multipart-post (2.1.1)
-    octokit (4.22.0)
-      faraday (>= 0.9)
-      sawyer (~> 0.8.0, >= 0.5.3)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     posix-spawn (0.3.15)
@@ -98,15 +64,11 @@ GEM
       ffi (~> 1.0)
     rexml (3.2.5)
     rouge (3.28.0)
-    ruby2_keywords (0.0.5)
     safe_yaml (1.0.5)
     sassc (2.4.0)
       ffi (~> 1.9)
     sassc (2.4.0-x64-mingw32)
       ffi (~> 1.9)
-    sawyer (0.8.2)
-      addressable (>= 2.3.5)
-      faraday (> 0.8, < 2.0)
     terminal-table (1.8.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
     thread_safe (0.3.6)
@@ -124,12 +86,11 @@ PLATFORMS
 
 DEPENDENCIES
   jekyll (~> 4.1.1)
+  jekyll-environment-variables
   jekyll-feed (~> 0.12)
-  jekyll-github-metadata
   jekyll-last-modified-at
   jekyll-redirect-from
   jekyll-sitemap
-  minima (~> 2.5)
   tzinfo (~> 1.2)
   tzinfo-data
   wdm (~> 0.1.1)

_config.yml

@@ -11,6 +11,7 @@ plugins:
   - jekyll-redirect-from
   - jekyll-sitemap
   - jekyll-last-modified-at
+  - jekyll-environment-variables
 include:
   - _pages
   - CNAME

_layouts/default.html

@@ -60,7 +60,7 @@ layout: base
 <p style="text-align: center;">
     <a href="/feed.xml">Atom</a> |
     <span id="commit-id" class="build-revision"><a
-            href="{{ site.github.repository_url }}/commit/{{ site.github.build_revision }}">
+            href="{{ site.github.repository_url }}/commit/{{ site.github.build_revision | default: site.env.GITHUB_SHA }}">
         #{{ site.github.build_revision | truncate: 7, "" }}
     </a></span>
 </p>