Mirror a git repository under an archival github user's account

mirror-repo.sh

#!/bin/bash
set -eu

ARCHIVE_USER="${ARCHIVE_USER-my-archive-user}"
ssh_key="$HOME/.ssh/key.mirror-repo"

usage() {
    cat >&2 <<EOM
usage: $(basename "$0") [options] SOURCE_REPO DEST_NAME

SOURCE_REPO: the source repository to copy just <ORG/REPO>, no host
DEST_NAME: the destination repository under $ARCHIVE_USER

Set \$ARCHIVE_USER to the user account where all the repos will be mirrored.

Repos will be cloned under repos/<DATE>/ and not removed afterwards
    set DATE=YYYY-MM-DD to override the date used

Github repo creation expects a github.netrc file at repo root:
    machine api.github.com login <ARCHIVE_USER> password <PASSWORD-OR-AUTH-TOKEN>

options:
    --up: mirror up an existing repo
    --no-up: skip upload step
    --no-github-ssh: don't automatically use ssh for github.com
    --no-create-repo: don't automatically create the repo
    --ssh-key KEY: use KEY instead of default $ssh_key

example:
    $(basename "$0") someorg/demo f025-someorg-demo


EOM
}

echo_red() {
    echo -en '\033[1;31m'
    echo -n "$*"
    echo -e '\033[m'
}
echo_blue() {
    echo -en '\033[1;34m'
    echo -n "$*"
    echo -e '\033[m'
}

run() {
    echo >&2 "+ $*"
    "$@"
}

netrc_file="$(dirname "$0")/../github.netrc"

upload=
skip_upload=
github_auto=1
create_repo=1

while [ $# -gt 0 ]; do
    case "$1" in
        --up)
            upload=1
            ;;
        --no-up)
            skip_upload=1
            ;;
        --no-github-ssh)
            github_auto=
            ;;
        --no-create-repo)
            create_repo=
            ;;
        --ssh-key)
            ssh_key="$2"
            shift
            ;;
        -*)
            usage
            echo >&2 "Unknown option: $1"
            exit 2
            ;;
        *)
            break
            ;;
    esac

    shift
done

if [ $# -lt 2 ]; then
    usage
    exit 1
fi

src="$1"
dst="$2"

if [[ $src != *:* ]]; then
    echo "Assuming $src is from github.com"
    src="git@github.com:$src"
fi

orig_src="$1"

if [[ $github_auto ]]; then
    if [[ $src == https://github.com/* ]]; then
        echo "Rewriting $src to be SSH / git@github.com"
        src="git@github.com:${src:19}"
        echo "New URL: $src"
    fi

    if [[ $dst == https://github.com/$ARCHIVE_USER/* ]]; then
        echo "Rewriting $dst to be just basename"
        dst="$(basename "$dst")"
    fi
fi

if [ ! -e "$ssh_key" ]; then
    run ssh-keygen -t rsa -f "$ssh_key"
    echo "Generated a new key in $ssh_key"
    echo "Please add this key to the $ARCHIVE_USER account"
    echo "https://github.com/settings/keys"
    cat "$ssh_key"
    exit 1
fi

export GIT_SSH_COMMAND="ssh -o identitiesonly=yes -i $ssh_key"

echo_blue "Mirroring..."
echo_blue "from:"
echo_blue " - $src"
echo_blue "to:"
echo_blue " - https://github.com/$ARCHIVE_USER/$dst"

date="${DATE-$(date +%F)}"

cd "$(dirname "$0")/.."
mkdir -vp "repos/$date"
cd "repos/$date"

echo_blue "cloning into $PWD/$dst"

if [ -e "$dst" ]; then
    if [ -n "$upload" ]; then
        echo "$dst already exists, uploading"
    else
        echo "$dst already exists, aborting. Pass --up to use existing"
        exit 3
    fi
else
    run git clone --mirror "$src" "$dst"
fi

if [[ $skip_upload ]]; then
    echo_blue "--no-up passed, not creating dst repo or uploading"
    exit
fi

cd "$dst"

if [[ $create_repo ]]; then
    echo_blue "Checking for dst repo existence"

    if [ ! -e "$netrc_file" ]; then
        echo >&2 "netrc file does not exist: $netrc_file"
        echo >&2 "Pass --no-create-repo to skip github API operations"
        exit 4
    fi

    if run curl -sSf --netrc-file "$netrc_file" \
        "https://api.github.com/repos/$ARCHIVE_USER/$dst" >/dev/null
    then
        echo_blue "Repo already exists"
    else
        echo_blue "Creating target repo"

        # create target repo
        run curl -sSf --netrc-file "$netrc_file" -d '@-' \
            https://api.github.com/user/repos >/dev/null <<EOM
{"name":"$dst", "private":true, "description": "Mirror of $orig_src"}
EOM
        sleep 1
    fi
else
    echo_blue "Skipping repo creation"
fi

if ! run git remote get-url archive >/dev/null; then
    run git remote add archive "git@github.com:$ARCHIVE_USER/$dst"
fi

run git push --mirror archive && ret=$? || ret=$?

echo_blue "Done."
echo_blue "https://github.com/$ARCHIVE_USER/$dst"

exit $ret