github-backup

#!/usr/bin/env python

from __future__ import print_function

import argparse
import base64
import calendar
import errno
import json
import logging
import os
import re
import select
import subprocess
import sys
import time
import urllib
import urllib2

from github_backup import __version__


def log_error(message):
    if type(message) == str:
        message = [message]

    for msg in message:
        sys.stderr.write("{0}\n".format(msg))

    sys.exit(1)


def log_info(message):
    if type(message) == str:
        message = [message]

    for msg in message:
        sys.stdout.write("{0}\n".format(msg))


def logging_subprocess(popenargs, logger, stdout_log_level=logging.DEBUG, stderr_log_level=logging.ERROR, **kwargs):
    """
    Variant of subprocess.call that accepts a logger instead of stdout/stderr,
    and logs stdout messages via logger.debug and stderr messages via
    logger.error.
    """
    child = subprocess.Popen(popenargs, stdout=subprocess.PIPE,
                             stderr=subprocess.PIPE, **kwargs)

    log_level = {child.stdout: stdout_log_level,
                 child.stderr: stderr_log_level}

    def check_io():
        ready_to_read = select.select([child.stdout, child.stderr], [], [], 1000)[0]
        for io in ready_to_read:
            line = io.readline()
            if not logger:
                continue
            if not (io == child.stderr and not line):
                logger.log(log_level[io], line[:-1])

    # keep checking stdout/stderr until the child exits
    while child.poll() is None:
        check_io()

    check_io()  # check again to catch anything after the process exits

    rc = child.wait()

    if rc != 0:
        print(u'{} returned {}:'.format(popenargs[0], rc), file=sys.stderr)
        print('\t', u' '.join(popenargs), file=sys.stderr)

    return rc


def mkdir_p(*args):
    for path in args:
        try:
            os.makedirs(path)
        except OSError as exc:  # Python >2.5
            if exc.errno == errno.EEXIST and os.path.isdir(path):
                pass
            else:
                raise


def parse_args():
    parser = argparse.ArgumentParser(description='Backup a github users account', prog='Github Backup')
    parser.add_argument('user', metavar='USER', type=str, help='github username')
    parser.add_argument('-u', '--username', dest='username', help='username for basic auth')
    parser.add_argument('-p', '--password', dest='password', help='password for basic auth')
    parser.add_argument('-t', '--token', dest='token', help='personal access or OAuth token')
    parser.add_argument('-o', '--output-directory', default='.', dest='output_directory', help='directory at which to backup the repositories')
    parser.add_argument('--starred', action='store_true', dest='include_starred', help='include starred repositories in backup')
    parser.add_argument('--watched', action='store_true', dest='include_watched', help='include watched repositories in backup')
    parser.add_argument('--all', action='store_true', dest='include_everything', help='include everything in backup')
    parser.add_argument('--issues', action='store_true', dest='include_issues', help='include issues in backup')
    parser.add_argument('--issue-comments', action='store_true', dest='include_issue_comments', help='include issue comments in backup')
    parser.add_argument('--issue-events', action='store_true', dest='include_issue_events', help='include issue events in backup')
    parser.add_argument('--pulls', action='store_true', dest='include_pulls', help='include pull requests in backup')
    parser.add_argument('--pull-comments', action='store_true', dest='include_pull_comments', help='include pull request review comments in backup')
    parser.add_argument('--pull-commits', action='store_true', dest='include_pull_commits', help='include pull request commits in backup')
    parser.add_argument('--repositories', action='store_true', dest='include_repository', help='include repository clone in backup')
    parser.add_argument('--wikis', action='store_true', dest='include_wiki', help='include wiki clone in backup')
    parser.add_argument('--skip-existing', action='store_true', dest='skip_existing', help='skip project if a backup directory exists')
    parser.add_argument('-L', '--languages', dest='languages', help='only allow these languages', nargs='*')
    parser.add_argument('-N', '--name-regex', dest='name_regex', help='python regex to match names against')
    parser.add_argument('-H', '--github-host', dest='github_host', help='GitHub Enterprise hostname')
    parser.add_argument('-O', '--organization', action='store_true', dest='organization', help='whether or not this is a query for an organization')
    parser.add_argument('-R', '--repository', dest='repository', help='name of repository to limit backup to')
    parser.add_argument('-P', '--private', action='store_true', dest='private', help='include private repositories')
    parser.add_argument('-F', '--fork', action='store_true', dest='fork', help='include forked repositories')
    parser.add_argument('--prefer-ssh', action='store_true', help='Clone repositories using SSH instead of HTTPS')
    parser.add_argument('-v', '--version', action='version', version='%(prog)s ' + __version__)
    return parser.parse_args()


def get_auth(args):
    auth = None
    if args.token:
        auth = base64.b64encode(args.token + ':' + 'x-oauth-basic')
    elif args.username and args.password:
        auth = base64.b64encode(args.username + ':' + args.password)
    elif args.username and not args.password:
        log_error('You must specify a password for basic auth when specifying a username')
    elif args.password and not args.username:
        log_error('You must specify a username for basic auth when specifying a password')

    return auth

def get_github_api_host(args):
    if args.github_host:
        host = args.github_host + '/api/v3'
    else:
        host = 'api.github.com'

    return host

def get_github_ssh_host(args):
    if args.github_host:
        host = args.github_host
    else:
        host = 'github.com'

    return host

def retrieve_data(args, template, query_args=None, single_request=False):
    auth = get_auth(args)
    per_page = 100
    page = 0
    data = []
    if not query_args:
        query_args = {}

    while True:
        page = page + 1
        querystring = urllib.urlencode(dict({
            'per_page': per_page,
            'page': page
        }.items() + query_args.items()))

        request = urllib2.Request(template + '?' + querystring)
        if auth is not None:
            request.add_header('Authorization', 'Basic ' + auth)

        errors = []

        # We'll make requests in a loop so we can delay and retry in the case of rate-limiting
        while True:
            try:
                r = urllib2.urlopen(request)
            except urllib2.HTTPError as exc:
                # HTTPError behaves like a Response so we can check the status code and headers to see exactly
                # what failed.

                limit_remaining = int(exc.headers.get('x-ratelimit-remaining', 0))

                if exc.code == 403 and limit_remaining < 1:
                    # The X-RateLimit-Reset header includes a timestamp telling us when the limit will reset
                    # so we can calculate how long to wait rather than inefficiently polling:
                    gm_now = calendar.timegm(time.gmtime())
                    reset = int(exc.headers.get('x-ratelimit-reset', 0)) or gm_now
                    # We'll never sleep for less than 10 seconds:
                    delta = max(10, reset - gm_now)

                    limit = exc.headers.get('x-ratelimit-limit')
                    print('Exceeded rate limit of {} requests; waiting {} seconds to reset'.format(limit, delta),
                          file=sys.stderr)

                    ratelimit_error = 'No more requests remaining'
                    if auth is None:
                        ratelimit_error = ratelimit_error + '; authenticate to raise your GitHub rate limit'
                    errors.append(ratelimit_error)

                    time.sleep(delta)
                    continue

            break

        status_code = int(r.getcode())

        if status_code != 200:
            errors.append('API request returned HTTP {}: {}'.format(status_code, r.reason))
            log_error(errors)

        response = json.loads(r.read())
        if len(errors) == 0:
            if type(response) == list:
                data.extend(response)
                if len(response) < per_page:
                    break
            elif type(response) == dict and single_request:
                data.append(response)

        if len(errors) > 0:
            log_error(errors)

        if single_request:
            break

    return data


def retrieve_repositories(args):
    log_info('Retrieving repositories')
    single_request = False
    template = 'https://{0}/users/{1}/repos'.format(get_github_api_host(args), args.user)
    if args.organization:
        template = 'https://{0}/orgs/{1}/repos'.format(get_github_api_host(args), args.user)

    if args.repository:
        single_request = True
        template = 'https://{0}/repos/{1}/{2}'.format(get_github_api_host(args), args.user, args.repository)

    return retrieve_data(args, template, single_request=single_request)


def filter_repositories(args, repositories):
    log_info('Filtering repositories')
    name_regex = None
    if args.name_regex:
        name_regex = re.compile(args.name_regex)

    languages = None
    if args.languages:
        languages = [x.lower() for x in args.languages]

    if not args.fork:
        repositories = [r for r in repositories if not r['fork']]
    if not args.private:
        repositories = [r for r in repositories if not r['private']]
    if languages:
        repositories = [r for r in repositories if r['language'] and r['language'].lower() in languages]
    if name_regex:
        repositories = [r for r in repositories if name_regex.match(r['name'])]

    return repositories


def backup_repositories(args, output_directory, repositories):
    log_info('Backing up repositories')
    repos_template = 'https://{0}/repos'.format(get_github_api_host(args))

    issue_states = ['open', 'closed']
    pull_states = ['open', 'closed']

    for repository in repositories:
        backup_cwd = os.path.join(output_directory, 'repositories')
        repo_cwd = os.path.join(backup_cwd, repository['name'])
        repo_dir = os.path.join(repo_cwd, 'repository')

        if args.prefer_ssh:
            repo_url = repository['ssh_url']
        else:
            repo_url = repository['git_url']

        if args.include_repository or args.include_everything:
            fetch_repository(repository['name'], repo_url, repo_dir, skip_existing=args.skip_existing)

        if repository['has_wiki'] and (args.include_wiki or args.include_everything):
            fetch_repository(repository['name'],
                             repo_url.replace('.git', '.wiki.git'),
                             os.path.join(repo_cwd, 'wiki'),
                             skip_existing=args.skip_existing)

        if args.include_issues or args.include_everything:
            if args.skip_existing and os.path.isdir('{0}/issues/.git'.format(repo_cwd)):
                continue

            log_info('Retrieving {0} issues'.format(repository['full_name']))
            issue_cwd = os.path.join(repo_cwd, 'issues')
            mkdir_p(backup_cwd, repo_cwd, issue_cwd)

            issues = {}
            _issue_template = '{0}/{1}/issues'.format(repos_template, repository['full_name'])

            for issue_state in issue_states:
                query_args = {
                    'filter': 'all',
                    'state': issue_state
                }

                _issues = retrieve_data(args, _issue_template, query_args=query_args)
                for issue in _issues:
                    issues[issue['number']] = issue

            log_info('Saving {0} issues to disk'.format(len(issues.keys())))
            for number, issue in issues.iteritems():
                comments_template = _issue_template + '/{0}/comments'
                events_template = _issue_template + '/{0}/events'
                if args.include_issue_comments or args.include_everything:
                    issues[number]['comment_data'] = retrieve_data(args, comments_template.format(number))
                if args.include_issue_events or args.include_everything:
                    issues[number]['event_data'] = retrieve_data(args, events_template.format(number))

                with open('{0}/{1}.json'.format(issue_cwd, number), 'w') as issue_file:
                    json.dump(issue, issue_file, sort_keys=True, indent=4, separators=(',', ': '))

        if args.include_pulls or args.include_everything:
            if args.skip_existing and os.path.isdir('{0}/pulls/.git'.format(repo_cwd)):
                continue

            log_info('Retrieving {0} pull requests'.format(repository['full_name']))
            pulls_cwd = os.path.join(repo_cwd, 'pulls')
            mkdir_p(backup_cwd, repo_cwd, pulls_cwd)

            pulls = {}
            _pulls_template = '{0}/{1}/pulls'.format(repos_template, repository['full_name'])

            for pull_state in pull_states:
                query_args = {
                    'filter': 'all',
                    'state': pull_state
                }

                _pulls = retrieve_data(args, _pulls_template, query_args=query_args)
                for pull in _pulls:
                    pulls[pull['number']] = pull

            log_info('Saving {0} pull requests to disk'.format(len(pulls.keys())))
            for number, pull in pulls.iteritems():
                comments_template = _pulls_template + '/{0}/comments'
                commits_template = _pulls_template + '/{0}/commits'
                if args.include_pull_comments or args.include_everything:
                    pulls[number]['comment_data'] = retrieve_data(args, comments_template.format(number))
                if args.include_pull_commits or args.include_everything:
                    pulls[number]['commit_data'] = retrieve_data(args, commits_template.format(number))

                with open('{0}/{1}.json'.format(pulls_cwd, number), 'w') as pull_file:
                    json.dump(pull, pull_file, sort_keys=True, indent=4, separators=(',', ': '))


def fetch_repository(name, remote_url, local_dir, skip_existing=False):
    clone_exists = os.path.exists(os.path.join(local_dir, '.git'))

    if clone_exists and skip_existing:
        return

    if clone_exists:
        log_info('Updating {} in {}'.format(name, local_dir))
        git_command = ['git', 'fetch', '--all', '--tags', '--prune']
        logging_subprocess(git_command, None, cwd=local_dir)
    else:
        log_info('Cloning {} repository from {} to {}'.format(name, remote_url, local_dir))
        git_command = ['git', 'clone', remote_url, local_dir]
        logging_subprocess(git_command, None)


def backup_account(args, output_directory):
    account_cwd = os.path.join(output_directory, 'account')
    if args.include_starred or args.include_everything:
        if not args.skip_existing or not os.path.exists('{0}/starred.json'.format(account_cwd)):
            log_info('Retrieving {0} starred repositories'.format(args.user))
            mkdir_p(account_cwd)

            starred_template = "https://{0}/users/{1}/starred"
            starred = retrieve_data(args, starred_template.format(get_github_api_host(args), args.user))
            log_info('Writing {0} starred repositories'.format(len(starred)))
            with open('{0}/starred.json'.format(account_cwd), 'w') as starred_file:
                json.dump(starred, starred_file, sort_keys=True, indent=4, separators=(',', ': '))

    if args.include_watched or args.include_everything:
        if not args.skip_existing or not os.path.exists('{0}/watched.json'.format(account_cwd)):
            log_info('Retrieving {0} watched repositories'.format(args.user))
            mkdir_p(account_cwd)

            watched_template = "https://{0}/users/{1}/subscriptions"
            watched = retrieve_data(args, watched_template.format(get_github_api_host(args), args.user))
            log_info('Writing {0} watched repositories'.format(len(watched)))
            with open('{0}/watched.json'.format(account_cwd), 'w') as watched_file:
                json.dump(watched, watched_file, sort_keys=True, indent=4, separators=(',', ': '))


def main():
    args = parse_args()

    output_directory = os.path.realpath(args.output_directory)
    if not os.path.isdir(output_directory):
        log_error('Specified output directory is not a directory: {0}'.format(output_directory))

    log_info('Backing up user {0} to {1}'.format(args.user, output_directory))

    repositories = retrieve_repositories(args)
    repositories = filter_repositories(args, repositories)
    backup_repositories(args, output_directory, repositories)
    backup_account(args, output_directory)


if __name__ == '__main__':
    main()