Patching and Running GitLab with a Custom CI Config Path as a URL

ci_yaml_http.patch

diff --git a/app/models/ci/pipeline.rb b/app/models/ci/pipeline.rb
index a2126cffdc..adfb4ca9b0 100644
--- a/app/models/ci/pipeline.rb
+++ b/app/models/ci/pipeline.rb
@@ -346,17 +346,21 @@ module Ci
         project.ci_config_path
       end
     end
-
+    require 'open-uri' #replace with another approach as desired
     def ci_yaml_file
       return @ci_yaml_file if defined?(@ci_yaml_file)
-
       @ci_yaml_file = begin
-        project.repository.gitlab_ci_yml_for(sha, ci_yaml_file_path)
-      rescue Rugged::ReferenceError, GRPC::NotFound, GRPC::Internal
-        self.yaml_errors =
-          "Failed to load CI/CD config file at #{ci_yaml_file_path}"
-        nil
-      end
+                        if ci_yaml_file_path =~ URI::regexp # if this is a URL
+                          url_with_GITREF = ci_yaml_file_path.gsub('GITREF',@attributes['ref'].value)
+                          open(url_with_GITREF).read() # open and read the contents
+                        else # otherwise treat it as relative path within repo (at this commit)
+                          project.repository.gitlab_ci_yml_for(sha, ci_yaml_file_path)
+                        end
+                      rescue Rugged::ReferenceError, GRPC::NotFound, GRPC::Internal
+                        self.yaml_errors =
+                          "Failed to load CI/CD config file at #{ci_yaml_file_path}"
+                        nil
+                      end
     end
 
     def has_yaml_errors?

docker-compose-yaml

version: '2'
services:
  gitlab.my.coop:
    # replace image with patched build from above
    #image: gitlab/gitlab-ce:10.7.3-ce.0
    build:
      context: ./
      # dockerfile: Dockerfile-patch-gitlab
    # configure as normal
    ports: # you'll need to run your hosts ssh on another port
       - "22:22"
       - "80:80"
       - "443:443"
    environment:
      GITLAB_PROMETHEUS_METRICS_ENABLED: 'true'
      GITLAB_OMNIBUS_CONFIG: |
        # Configure gitlab here

Dockerfile

FROM gitlab/gitlab-ce:10.7.3-ce.0
COPY *.patch /opt/gitlab/embedded/service/gitlab-rails/
RUN apt-get update ; apt-get install -y patch
# Allows http urls for .gitlab-ci.yml
# This patch may need some work cleanly apply with recent versions
RUN cd /opt/gitlab/embedded/service/gitlab-rails ; \
    patch -p1 < ci_yaml_http.patch