rework sync public pr pipeline in use ruby and open PRs

.buildkite/pipeline.sync_public_pr.yml

@@ -7,5 +7,16 @@ steps:
         text: "Pull Request Number"
         format: "^[0-9]+$"
 
-  - command: "bin/sync-public-pr"
+  - label: ":git: Sync Public PR to Private Repo"
+    command: "bin/sync-public-pr"
     depends_on: collect_pr_number
+    plugins:
+      - docker#v5.11.0:
+          image: "ruby:3.3-bookworm"
+          propagate-environment: true
+          mount-buildkite-agent: true
+          mount-ssh-agent: true
+          environment:
+            - GH_TOKEN
+            - GH_PRIVATE_REPO
+            - GH_PUBLIC_REPO

bin/sync-public-pr

@@ -1,24 +1,129 @@
-#!/usr/bin/env bash
+#!/usr/bin/env ruby
 
-set -euo pipefail
+require "net/http"
+require "open3"
+require "json"
 
-PR_NUMBER=$(buildkite-agent meta-data get "pull_request_number")
-TARGET_BRANCH="docs-public-pr-${PR_NUMBER}"
-SOURCE_REF="pull/${PR_NUMBER}/head"
+# Job params
+GH_TOKEN        = ENV.fetch("GH_TOKEN")
+PUBLIC_GH_REPO  = ENV.fetch("PUBLIC_GH_REPO")
+PRIVATE_GH_REPO = ENV.fetch("PRIVATE_GH_REPO")
 
-echo "+++ Syncing PR #${PR_NUMBER} to local branch ${TARGET_BRANCH}"
+PR_NUMBER       = `buildkite-agent meta-data get "pull_request_number"`.strip.to_i
+TARGET_BRANCH   = "docs-public-pr-#{PR_NUMBER}"
 
-set -x
+class GithubClient
+  def initialize
+    @client = Net::HTTP.new("api.github.com", 443)
+    @client.use_ssl = true
+  end
 
-git fetch "git@github.com:${PUBLIC_GH_REPO}.git" "${SOURCE_REF}:${TARGET_BRANCH}"
+  def public_pr(pr_number)
+    # https://docs.github.com/en/rest/pulls/pulls?apiVersion=2022-11-28#get-a-pull-request
+    response = @client.get("/repos/#{PUBLIC_GH_REPO}/pulls/#{pr_number}", headers)
+    puts response
+    JSON.parse(response.body)
+  end
 
-git push --force origin "${TARGET_BRANCH}"
+  def private_pr_for_branch(branch_name)
+    # https://docs.github.com/en/rest/pulls/pulls?apiVersion=2022-11-28#list-pull-requests
+    # note this ignores closed/merged PRs
+    response = @client.get("/repos/#{PRIVATE_GH_REPO}/pulls?head=buildkite:#{branch_name}", headers)
+    puts response
+    JSON.parse(response.body).first
+  end
 
-CREATE_PR_LINK="https://github.com/${PRIVATE_GH_REPO}/compare/${TARGET_BRANCH}?expand=1"
+  def open_pr(title:, body:, branch:)
+    # https://docs.github.com/en/rest/pulls/pulls?apiVersion=2022-11-28#create-a-pull-request
+    response = @client.post("/repos/#{PRIVATE_GH_REPO}/pulls", {
+      title: title,
+      body: body,
+      head: branch,
+      base: "main"
+    }.to_json, headers)
+    puts response
+    JSON.parse(response.body)
+  end
 
-ANNOTATION_CONTENT="Synced PR ${PUBLIC_GH_REPO}#${PR_NUMBER} to private repo branch \`${TARGET_BRANCH}\`.
+  private
 
-Open PR: ${CREATE_PR_LINK}
-"
+  def headers
+    {
+      "Accept"               => "application/vnd.github+json",
+      "Authorization"        => "Bearer #{GH_TOKEN}",
+      "X-GitHub-Api-Version" =>"2022-11-28"
+    }
+  end
+end
 
-buildkite-agent annotate --context pr-link --style "info" "${ANNOTATION_CONTENT}"
+def write_annotation(content, style: "info")
+  Open3.capture2("buildkite-agent", "annotate", "--style", style, stdin_data: content)
+end
+
+client = GithubClient.new
+
+puts "+++ :git: Syncing #{PUBLIC_GH_REPO} PR ##{PR_NUMBER} to local branch #{TARGET_BRANCH}"
+
+# pull the magic PR ref from the public repo into local docs-public-pr-<PR_NUMBER> branch
+source_ref = "pull/#{PR_NUMBER}/head"
+
+# https://git-scm.com/docs/git-fetch see docs on refspec format
+refspec = "#{source_ref}:#{TARGET_BRANCH}"
+
+`git fetch --force "git@github.com:#{PUBLIC_GH_REPO}.git" "#{refspec}"`
+
+
+puts "+++ :git: Pushing branch #{TARGET_BRANCH} to #{PRIVATE_GH_REPO}"
+
+`git push --force origin "#{TARGET_BRANCH}"`
+
+puts "+++ :github: Fetching original PR #{PUBLIC_GH_REPO} ##{PR_NUMBER}"
+
+public_pr = client.public_pr(PR_NUMBER)
+
+puts "--- :octocat: Checking for PR for #{TARGET_BRANCH} in #{PRIVATE_GH_REPO}"
+
+private_pr = client.private_pr_for_branch(TARGET_BRANCH)
+puts private_pr
+
+if private_pr
+  annotation_content = <<~ANNOTATION
+    :open-pr: Re-synced PR #{PUBLIC_GH_REPO} ##{PR_NUMBER} to private repo branch `#{TARGET_BRANCH}`.
+
+    Original PR: https://github.com/#{PUBLIC_GH_REPO}/pull/#{PR_NUMBER}
+
+    Private PR: #{private_pr["html_url"]} :robot_face:
+  ANNOTATION
+
+  write_annotation(annotation_content)
+  exit 0
+end
+
+puts "+++ :open-pr: Creating PR for #{TARGET_BRANCH} in #{PRIVATE_GH_REPO}"
+
+pr_description = <<-PR_DESCRIPTION
+
+:robot: Synced by #{ENV["BUILDKITE_BUILD_URL"]} :robot:
+
+_Note_: The original public PR will automatically close when this PR is merged. If there are additional changes to sync from the public PR, re-run the [Docs (Sync public PR)](https://buildkite.com/buildkite/docs-sync-public-pr) Pipeline.
+
+---
+
+## [docs##{PR_NUMBER}](#{public_pr["html_url"]}): #{public_pr["title"]}
+
+Opened by @#{public_pr.dig("user", "login")}
+
+#{public_pr["body"]}
+PR_DESCRIPTION
+
+private_pr = client.open_pr(title: public_pr["title"], body: pr_description, branch: TARGET_BRANCH)
+
+annotation_content = <<~ANNOTATION
+  :open-pr: Synced PR #{PUBLIC_GH_REPO} ##{PR_NUMBER} to private repo branch `#{TARGET_BRANCH}`.
+
+  Original PR: #{public_pr["html_url"]} - #{public_pr["title"]} by @#{public_pr.dig("user", "login")}
+
+  Private PR: #{private_pr["html_url"]} :robot_face:
+ANNOTATION
+
+write_annotation(annotation_content)