post-receive

#!/usr/bin/env python
#
# Git Deploy
# Copyright (c) Ryan Kadwell <ryan@riaka.ca>
#
# For the full copyright and license information, please view the LICENSE
# file that was distributed with this source code.
#
# Simple post-receive hook to perform deploys based on tags in the commit
# messages for git repositories.
#

import subprocess
import fileinput
import re
import sys
import os

# Targets dict lists allowed deploy targets in a key=target value=path dictionary
#
# targets = {
#   "live": "/var/www/path-to-live-repo",
#   "beta": "/var/www/path-to-beta-repo"
# }
#
targets = {}

def git(args):
    """
    Function for running git command through subprocess
    """
    cmd = subprocess.Popen(['git'] + args, stdout = subprocess.PIPE)
    output = cmd.stdout.read()
    output = output.strip()
    return output

def get_timestamp(commit_hash):
    """
    Get the commit timestamp for a given commit
    """
    result = git(["show", "--stat", "--format=%ct", commit_hash])
    result_lines = result.split("\n")
    # make sure that we got a valid response
    if re.match(r'^[0-9]+$', result_lines[0]):
        return result_lines[0]
    else:
        return 0

if not targets:
    print('deploy: No targets are defined. Go to http://github.com/ryakad/git-deploy'
        ' for information on how to set up this script')
    sys.exit(0)

print('deploy: reading pushed commit messages')

deploy_targets = {} # commit objects that need to be checked for deploy.
pattern = re.compile(r'#HASH#')

for line in fileinput.input():
    parts = line.split(" ") # <old_value> SP <ne_value> SP <ref_name>

    # if this commit is the first on a branch we take the log for it
    if parts[0] == "0000000000000000000000000000000000000000":
        # TODO: Can't deploy with the first push of a branch.
        # Need to be able to get a log for this branch only or give more
        # detailed information to the user.
        continue
    else:
        commitlog = git(["log", "--pretty=#HASH#%H%n%B", parts[0] + '..' + parts[1]])

    for line in commitlog.split("\n"):
        # check if the line starts with #HASH# and if so add an entry to the
        # commits array. If not we will want to append the string to the
        # previous commit message
        if pattern.match(line):
            current_hash = re.sub(pattern, '', line)
            deploy_targets[current_hash] = []
            continue

        deploy_targets[current_hash].append(line)

# We now have our targets and can look for which ones need to be deployed.
deploys = {}
invalid_targets = []

deploy_pattern = re.compile(r'\[deploy-([a-z]+)\]')
for commit in deploy_targets:
    commit_message = "\n".join(deploy_targets[commit])
    for target in re.findall(deploy_pattern, commit_message):
        # Check that they have provided a valid target
        if target in targets.keys():
            if not target in deploys.keys():
                deploys[target] = []

            deploys[target].append(commit)
        else:
            invalid_targets.append(target)

# Notify users of what deploy targets we will be skipping before we start
if invalid_targets:
    for target in invalid_targets:
        print('deploy: skipping unknown target: "' + target + '"')

if not deploys:
    print('deploy: nothing to deploy')
    sys.exit(1)

root_repo = os.getcwd()
# Need to find the commit with the newest commit-date and then update to that
for target in deploys:
    os.chdir(root_repo)
    os.unsetenv('GIT_DIR')

    newest = None
    for commit_hash in deploys[target]:
        if newest == None:
            newest = commit_hash
            continue

        print("deploy: comparing commits " + newest + " with " + commit_hash)

        previous_timestamp = get_timestamp(newest)
        current_timestamp = get_timestamp(commit_hash)
        if previous_timestamp > current_timestamp:
            newest = newest
        else:
            newest = commit_hash

    # deploy if it is newer than the last deploy
    wants_deploy = get_timestamp(newest)
    os.chdir(targets[target])
    os.unsetenv('GIT_DIR')

    currently_on = get_timestamp(git(["rev-parse", "HEAD"]))
    if wants_deploy > currently_on:
        print('deploy: Deploying ' + newest + ' to ' + target)
        print(git(["reset", "--hard", "HEAD"]))
        print(git(["pull", "--all"]))
        print(git(["checkout", newest]))
    else:
        print("deploy: latest in repo is a newer version than " + newest + ". skipping.")