forked_pr_trigger_hot_fix.md

Tweak your CircleCI server to build forked PRs even if the fork has an active CircleCI project

Overview

This instruction consists of 2 parts:

1. Apply a patch to examine the special project flag.

2. Set a special flag for projects which should run pipelines for every forked PRs.

   Note: Run this step for all the original projects which has forks.

   For example, assuming there are following projects:

   * `org-a/project-x`
   * `org-a/project-y`
   * `user-k/project-x` (fork of `org-a/project-x`)
   * `user-l/project-x` (fork of `org-a/project-x`)
   * `user-m/project-y` (fork of `org-a/project-y`)
   * `user-n/project-y` (fork of `org-a/project-y`)
   

   please run this instruction 2 times: for org-a/project-x and org-a/project-y.

Step 1: Apply a patch to examine the special project flag

Run the following shell script on a machine with kubectl being capable of communicating with you K8s cluster hosting CircleCI:

#!/bin/bash

# YOUR_PRIVATE_IP_ADDRESS - IP address of your computer running this script
# If you are running this script on non-Linux environment you will need to modify it accordingly
YOUR_PRIVATE_IP_ADDRESS="$(ip -4 route get 192.0.2.1 | grep -oP 'src \S+' | awk '{ print $2 }')"

# Port forward nREPL for frontend
kubectl port-forward "$(kubectl get po -l app=frontend -n circleci-server -o jsonpath='{.items[0].metadata.name}')" --address "${YOUR_PRIVATE_IP_ADDRESS}" 6005 -n circleci-server &

# Start nREPL and apply the patch there
sudo docker run --rm -i clojure lein repl :connect "${YOUR_PRIVATE_IP_ADDRESS}":6005 <<EOD
(ns circle.http.pull-requests.github)
(defn- should-build-from-pr-with-explanation [action head-proj base-proj]
  (let [fork-pr? (not= (:_id head-proj)
                       (:_id base-proj))]
    (cond
      (and (not fork-pr?)
           (feature/build-prs-only base-proj)
           (contains? #{"opened" "synchronize" "reopened"} action))
      [true "yes: project only builds from PRs"]

      (and fork-pr?
           (->> base-proj :features :always-build-fork-prs))
      [true "yes: always-build-fork-prs feature is set for the project"]

      (and fork-pr?
           (project/configured-to-build? head-proj))
      [false "no: fork is followed"]

      (and (not (project/oss? base-proj))
           (not (feature/build-fork-prs base-proj)))
      [false "no: private project without flag set"]

      (and fork-pr?
           (feature/build-fork-prs base-proj))
      [true "yes: flag set"]

      :else
      [false "no: feature not set"])))
EOD

# Close the forwarding port
kill $!

Step 2: Set a special flag for projects which should run pipelines for every forked PRs

For each project of interest run the following command on a machine with kubectl being capable of communicating with you K8s cluster hosting CircleCI (replace the part org-a/project-x with an actual project name accordingly):

kubectl exec -i "$(kubectl get po -l app=frontend -n circleci-server -o jsonpath='{.items[0].metadata.name}')" -n circleci-server -- lein repl :connect 6005 <<EOD
(circle.http.api.admin-commands/set-project-feature-by-url-unsafe "gh/org-a/project-x" :always-build-fork-prs)
EOD