git-commit: prepend all messages with own filename

[racktables] / gateways / git-commit

#!/bin/sh

# This file is a part of RackTables, a datacenter and server room management
# framework. See accompanying file "COPYING" for the full copyright and
# licensing information.

# This script implements a simple (one file at a time) one-way feed into a git
# repository. To make a commit it takes the following PHP code:
#
# $params = array
# (
#   'racktables_pseudo_user',
#   '/path/to/repository',
#   'path/to/file/within/the/repository',
#   'commit message text',
# );
# $rc = callScript ('git-commit', $params, $file_contents, $stdout, $stderr);
#
# The meaning of $stdout and $stderr is the same as in queryTerminal().
# The specified repository must exist and the specified pseudo-user must be
# able to write to the repository and run "git pull", "git commit" and "git push"
# without any user interaction (i.e. the git remote must be on a local
# filesystem or be configured to use SSH keys).
#
# The commit message text is optional; when omitted or empty, a default value
# will be used. The message may be a multi-line string, in which case it should
# follow the format recommended in the "discussion" section of the
# git-commit(1) man page.
#
# This script uses sudo to switch between the pseudo-users and requires an
# entry in sudoers along the following lines:
# httpduser ALL=(racktablesuser) NOPASSWD:/path/to/racktables/gateways/git-commit

THISFILE=`basename "$0"`
[ $# -eq 3 -o $# -eq 4 ] || {
	echo "Usage: $THISFILE <pseudo-user> <repo dir> <path to file> [commit message]" >&2
	exit 1
}

SUDOUSER=$1
REPODIR="$2"
FILEPATH="$3"
COMMITMSG="${4:-update $FILEPATH}"

[ `whoami` = "$SUDOUSER" ] || {
	sudo --non-interactive --set-home --user=$SUDOUSER -- "$0" "$@"
	exit $?
}

cd "$REPODIR"
git pull --quiet || {
	echo "$THISFILE: failed to run 'git pull' (rc=$?)" >&2
	exit 2
}

# git processes the path to the file automatically, but the shell
# redirection obviously does not.
DIRNAME=`dirname "$FILEPATH"`
[ -d "$DIRNAME" ] || mkdir -p "$DIRNAME"

# New file contents is on stdin.
cat > "$FILEPATH" || {
	echo "$THISFILE: failed to write new file contents, trying to roll back." >&2
	git checkout --quiet -- "$FILEPATH" || {
		echo "$THISFILE: failed to run 'git checkout' after a write error." >&2
		exit 4
	}
	exit 3
}

# git-diff exits with 0 if the file is not in the repository.
if ! git cat-file -e HEAD:"$FILEPATH" 2>/dev/null || ! git diff --quiet -- "$FILEPATH"; then
	git add -- "$FILEPATH"
	git commit --quiet --message="$COMMITMSG" -- "$FILEPATH"
	git push --quiet || {
		echo "$THISFILE: failed to run 'git push' (rc=$?)" >&2
		exit 5
	}
fi

exit 0