Use the hub CLI instead of PR outs. (GoogleCloudPlatform#3)

PR resource maintainer doesn't want to add 'create' to the PRs, so
we'll need to manage them ourselves.  It's okay - doesn't really
reduce usability, and the hub CLI only requires the token (which
is already present in the config).

ci.yml

@@ -50,20 +50,6 @@ resources:
           only_mergeable: true
           require_review_approval: true
 
-    - name: mm-prs-out
-      type: github-pull-request
-      source:
-          repo: ((username))/magic-modules
-          private_key: ((repo_key))
-          access_token: ((repo_access))
-
-    - name: terraform-prs-out
-      type: github-pull-request
-      source:
-          repo: ((username))/terraform-provider-google
-          private_key: ((repo_key))
-          access_token: ((repo_access))
-
 jobs:
     - name: mm-generate
       plan:
@@ -116,31 +102,30 @@ jobs:
             params:
                 submodules: [build/terraform]
             passed: [terraform-test, mm-generate]
-            # TODO(@ndmckinley): This get/task/put/task/put flow is confusing and should be cleaned up.
           - get: mm-initial-pr
             resource: magic-modules-new-prs
             passed: [mm-generate]
             version: every
-          - task: make-pr
-            file: ci/magic-modules/make-pr.yml
+          - task: create-pr
+            file: ci/magic-modules/create-pr.yml
+            params:
+                GITHUB_TOKEN: ((repo_access))
+                TERRAFORM_REPO: ((username))/terraform-provider-google
+            on_failure:
+              put: magic-modules-new-prs
+              params:
+                  status: failure
+                  path: mm-initial-pr
           - put: magic-modules
             params:
                 branch_file: mm-initial-pr/.git/branch
-                repository: magic-modules-out
+                repository: magic-modules
                 only_if_diff: true
-          - put: terraform-prs-out
-            params:
-                path: magic-modules-out/build/terraform
-                status: success
-          - task: make-comment
-            file: ci/magic-modules/make-comment.yml
-            params:
-                GH_USERNAME: ((username))
-          - put: mm-prs-out
+          - put: magic-modules-new-prs
             params:
                 status: success
-                path: magic-modules-comment
-                comment: magic-modules-comment/pr_comment
+                path: mm-initial-pr
+                comment: magic-modules-with-comment/pr_comment
 
     - name: merge-prs
       plan:

containers/hub/Dockerfile

@@ -0,0 +1,5 @@
+from nmckinley/go-ruby:1.9-2.5
+
+RUN apt-get update
+RUN apt-get install -y ca-certificates
+RUN go get github.com/github/hub

magic-modules/create-pr.sh

@@ -10,15 +10,32 @@ set -e
 set -x
 
 shopt -s dotglob
-cp -r magic-modules/* magic-modules-out
+cp -r magic-modules/* magic-modules-with-comment
 
-cd magic-modules-out
+pushd magic-modules-with-comment
 
 # This says "check out the branch which contains HEAD, and set it up to track its upstream."
-git checkout -t "$(git branch -a --contains "$(git rev-parse HEAD)" | grep -v "detached")"
+# The 'checkout' command tells us to checkout the branch, the '-t' says "which tracks".
+# This 'git branch -a --contains' command lists all branches which contain the SHA provided
+# by 'git rev-parse HEAD' (which returns the rev at HEAD).  Then we remove the 'detached'
+# branch which we're currently on, collapse whitespace, and check it out.
+# This will resolve to something like 'git checkout -t remotes/origin/abcdef12'
+git checkout -t "$(git branch -a --contains "$(git rev-parse HEAD)" | grep -v "detached" | xargs echo -n)"
 
-cd build/terraform
+pushd build/terraform
 
-git checkout -t "$(git branch -a --contains "$(git rev-parse HEAD)" | grep -v "detached")"
-# This special string 'new' tells the PR resource to create a new PR.
-git config pullrequest.id new
+cat << EOF > ./downstream_body
+$(git log -1 --pretty=%B)
+
+<!-- This change is generated by MagicModules. -->
+EOF
+git checkout -t "$(git branch -a --contains "$(git rev-parse HEAD)" | grep -v "detached" | xargs echo -n)"
+TF_PR=$(hub pull-request -b "$TERRAFORM_REPO:master" -F ./downstream_body)
+popd
+
+cat << EOF > ./pr_comment 
+I am a robot that works on MagicModules PRs!
+
+I built this PR into one or more PRs on other repositories, and when those are closed, this PR will also be merged and closed.
+depends: $TF_PR
+EOF

magic-modules/create-pr.yml

@@ -0,0 +1,25 @@
+---
+# This takes in the magic-modules repo in detached-HEAD state,
+# creates a PR on downstream modules, and writes a comment into
+# a file so that the PR can be updated with that comment.
+platform: linux
+
+image_resource:
+    type: docker-image
+    source:
+        repository: nmckinley/hub
+        tag: 'latest'
+
+inputs:
+    - name: magic-modules
+    - name: ci
+
+outputs:
+    - name: magic-modules-with-comment
+
+run:
+    path: ci/magic-modules/create-pr.sh
+
+params:
+  GITHUB_TOKEN: ""
+  TERRAFORM_REPO: ""