. Init

.gitignore

+/mirror-g2g.conf

README.md

+# DESCRIPTION
+This script helps you to create GitHub mirrors of your GitLab repositories. You should have filesystem access to your GitLab server as **root** or **\<gitlab system user>** to use it. Original respository: https://git.woland.me/adm/mirror-g2g
+
+# CONFIGURATION
+* Copy `mirror-g2g.conf.samle` to `mirror.g2g.conf`.
+* Configure your github username, name of the gitlab system user and gitlab repositories dir (as described at **"Gitlab custom hooks"**).
+* `su - <gitlab system user> -c ssh-keygen`.
+* add **~\<gitlab system user>/.ssh/id_rsa.pub** to github deploy keys.
+
+# USAGE
+To create mirror of **\<group>/\<repository>.git**:
+* Create **\<repository>** GitHub repository (or import it from GitLab with GitHub importing tool).
+* Run `mirror-g2g.sh <group>/<repository>` as **root** or **\<gitlab system user>** user.
+
+# HELP TOPICS
+## StackExchange
+1. GitLab to GitHub mirror configuring: https://stackoverflow.com/questions/21962872/how-to-create-a-gitlab-webhook-to-update-a-mirror-repo-on-github  
+	See also:  
+		https://stackoverflow.com/questions/14288288/gitlab-repository-mirroring
+2. Checking for remote git repository: https://superuser.com/questions/227509/git-ping-check-if-remote-repository-exists
+3. Scripting with 'su': https://stackoverflow.com/questions/3420280/can-i-run-su-in-the-middle-of-a-bash-script
+
+## GitLab custom hooks
+https://docs.gitlab.com/ee/administration/custom_hooks.html
+
+## Native GitLab Enterprise mirroring feature
+https://about.gitlab.com/2016/05/10/feature-highlight-push-to-remote-repository/

mirror-g2g.conf.sample

+GITHUB_USER="wolandtel"
+GITLAB_SYS_USER="git"
+REPODIR="/var/opt/gitlab/git-data/repositories"

mirror-g2g.sh

+#!/bin/bash
+
+scriptName="$(basename $0)"
+cfgName=${scriptName/.sh/.conf}
+cfg=("$(dirname $0)/$cfgName" $HOME/.config/$cfgName)
+for c in ${cfg[@]}; do
+	[ -r "$c" ] && {
+		. "$c"
+		break
+	}
+done
+[[ -z "$GITHUB_USER" || -z "$GITLAB_SYS_USER" || -z "$REPODIR" ]] && \
+{
+	if [ -r "$c" ]; then
+		echo "Configuration file '$c' is incomplete" >&2
+	else
+		echo "Configuration file doesn't exist" >&2
+	fi
+	exit 1
+}
+
+CH_DIR="custom_hooks"
+HOOK_FILE="post-receive"
+HOOK="/usr/bin/git push --quiet github &"
+
+function usage ()
+{
+	echo "USAGE: $scriptName <namespace>/<repository>"
+}
+
+if [[ $(id -u) -eq 0 ]]; then
+	su - $GITLAB_SYS_USER -c "'$0' $@"
+	let res=1000+$?
+	exit $res
+fi
+
+if [[ "$(id -un)" != "$GITLAB_SYS_USER" ]]; then
+	echo "ERROR: You should be root or $GITLAB_SYS_USER to perform operation" >&2
+	exit 2
+fi
+
+r=($(echo "$1" | sed -r 's#.*/([^/]+/[^/]+)#\1#; s#\.git$##; s#/# #'))
+namespace=${r[0]}
+repository=${r[1]}
+
+if [[ -z "$namespace" || -z "$repository" ]]; then
+	usage
+	exit 3
+fi
+
+github="git@github.com:$GITHUB_USER/$repository.git"
+gitlab="$REPODIR/$namespace/$repository.git"
+
+[ -d "$gitlab" ] || {
+	echo "ERROR: GitLab repository $namespace/$repository doesn't exists" >&2
+	exit 4
+}
+
+git ls-remote -qh "$github" > /dev/null 2>&1 || {
+	echo "ERROR: GitHub repository '$repository' doesn't exists or deploy key hasn't been configured on GitHub" >&2
+	exit 5
+}
+
+cd "$gitlab"
+git remote add --mirror=push github "$github" || exit 6
+
+[ -d "$CH_DIR" ] || mkdir "$CH_DIR"
+cd "$CH_DIR"
+
+[ -e "$HOOK_FILE" ] && {
+	echo "ERROR: $(pwd)/$HOOK_FILE already exists. Please add string '$HOOK' manually if hook is bash script"
+	exit 7
+}
+
+cat > "$HOOK_FILE" <<EOF
+#!/bin/bash
+$HOOK
+EOF
+chmod 755 "$HOOK_FILE"