TUN-9800: Add pipeline to sync between gitlab and github repos

Author: jcsf

.ci/github.gitlab-ci.yml

@@ -0,0 +1,17 @@
+include:
+  - local: .ci/commons.gitlab-ci.yml
+
+######################################
+### Sync master branch with Github ###
+######################################
+push-github:
+  stage: sync
+  rules:
+    - !reference [.default-rules, run-on-master]
+  script:
+    - ./.ci/scripts/github-push.sh
+  secrets:
+    CLOUDFLARED_DEPLOY_SSH_KEY:
+      vault: gitlab/cloudflare/tun/cloudflared/_branch/master/cloudflared_github_ssh/data@kv
+      file: false
+  cache: {}

.ci/scripts/github-push.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+set -e -o pipefail
+
+BRANCH="master"
+TMP_PATH="$PWD/tmp"
+PRIVATE_KEY_PATH="$TMP_PATH/github-deploy-key"
+PUBLIC_KEY_GITHUB_PATH="$TMP_PATH/github.pub"
+
+mkdir -p $TMP_PATH
+
+# Setup Private Key
+echo "$CLOUDFLARED_DEPLOY_SSH_KEY" > $PRIVATE_KEY_PATH
+chmod 400 $PRIVATE_KEY_PATH
+
+# Download GitHub Public Key for KnownHostsFile
+ssh-keyscan -t ed25519 github.com > $PUBLIC_KEY_GITHUB_PATH
+
+# Setup git ssh command with the right configurations
+export GIT_SSH_COMMAND="ssh -o UserKnownHostsFile=$PUBLIC_KEY_GITHUB_PATH -o IdentitiesOnly=yes -i $PRIVATE_KEY_PATH"
+
+# Add GitHub as a new remote
+git remote add github [email protected]:cloudflare/cloudflared.git || true
+
+# GitLab doesn't pull branch references, instead it creates a new one on each pipeline.
+# Therefore, we need to manually fetch the reference to then push it to GitHub.
+git fetch origin $BRANCH:$BRANCH
+git push -u github $BRANCH
+
+if TAG="$(git describe --tags --exact-match 2>/dev/null)"; then
+  git push -u github "$TAG"
+fi

.gitlab-ci.yml

@@ -7,14 +7,19 @@ default:
     VAULT_ID_TOKEN:
       aud: https://vault.cfdata.org
 
-stages: [pre-build, build, validate, test, package, release]
+stages: [sync, pre-build, build, validate, test, package, release]
 
 include:
   #####################################################
   ########## Import Commons Configurations ############
   #####################################################
   - local: .ci/commons.gitlab-ci.yml
 
+  #####################################################
+  ########### Sync Repository with Github #############
+  #####################################################
+  - local: .ci/github.gitlab-ci.yml
+
   #####################################################
   ############# Build or Fetch CI Image ###############
   #####################################################