linux-nvgpu/scripts/rfr

#!/usr/bin/python
#
# Simple script for formatting RFR messages for nvgpu changes.
#

import os
import re
import json
import argparse
import subprocess

VERSION = '1.0.0'

# Gerrit commit URL formats. These are regular expressions to match the
# incoming URLs against.
gr_fmts = [ r'http://git-master/r/(\d+)',
            r'http://git-master/r/#/c/(\d+)/',
            r'http://git-master.nvidia.com/r/(\d+)',
            r'http://git-master.nvidia.com/r/#/c/(\d+)/',
            r'https://git-master/r/(\d+)',
            r'https://git-master/r/#/c/(\d+)/',
            r'https://git-master.nvidia.com/r/(\d+)',
            r'https://git-master.nvidia.com/r/#/c/(\d+)/' ]

# The user to use. May be overridden but the default comes from the environment.
user = os.environ['USER']

# Gerrit query command to obtain the patch URL. The substitution will be the
# gerrit Change-ID parsed from the git commit message.
gr_query_cmd = 'ssh %s@git-master -p 29418 gerrit query --format json %s'

def parse_args():
    """
    Parse arguments to rfr.
    """

    ep="""This program will format commit messages into something that can be
sent to the nvgpu mailing list for review
"""
    help_msg="""Git or gerrit commits to describe. Can be either a git or gerrit
commit ID. If the ID starts with a 'I' then it will be treated as a gerrit ID.
If the commit ID looks like a gerrit URL then it is treated as a gerrit URL.
Otherwise it's treated as a git commit ID.
"""
    parser = argparse.ArgumentParser(description='RFR formatting tool',
                                     epilog=ep)

    parser.add_argument('-V', '--version', action='store_true', default=False,
                        help='print the program version')
    parser.add_argument('-m', '--msg', action='store', default=None,
                        help='Custom message to add to the RFR email')

    # Positionals: the gerrit URLs.
    parser.add_argument('commits', metavar='Commit-IDs',
                        nargs='+',
                        help=help_msg)

    arg_parser = parser.parse_args()

    return arg_parser

def get_gerrit_url_id(cmt):
    """
    Determines if the passed cmt is a gerrit commit URL. If it is then this
    returns the URL ID; otherwise it returns None.
    """

    for fmt in gr_fmts:
        p = re.compile(fmt)
        m = p.search(cmt)
        if m:
            return m.group(1)

    return None

def gerrit_query(change):
    """
    Query gerrit for the JSON change information. Return a python object
    describing the JSON data.

    change can either be a Change-Id or the numeric change number from a URL.

    Note there is an interesting limitation with this: gerrit can have multiple
    changes with the same Change-Id (./sigh). So if you query a change ID that
    points to multiple changes you get back all of them.

    This script just uses the first. Ideally one could filter by branch or by
    some other distinguishing factor.
    """

    query_cmd = gr_query_cmd % (user, change)

    prog = subprocess.Popen(query_cmd, shell=True,
                            stdout=subprocess.PIPE, stderr=subprocess.PIPE)

    stdout_data, stderr_data = prog.communicate()
    if prog.returncode != 0:
        print('`%s\' failed!' % query_cmd)
        return False

    commit = json.loads(stdout_data.decode('utf-8').splitlines()[0])
    if 'id' not in commit:
        print('%s is not a gerrit commit!?' % change)
        print('Most likely you need to push the change.')
        return None

    return commit

def commit_info_from_gerrit_change_id(change_id):
    """
    Return a dict with all the gerrit info from a gerrit change ID.
    """

    return gerrit_query(change_id)

def gerrit_change_id_from_gerrit_cl(cmt):
    """
    Return the gerrit Change-Id from the passed Gerrit URL.
    """

    cl = get_gerrit_url_id(cmt)
    if not cl:
        return None

    commit = gerrit_query(cl)
    if not commit:
        return None

    return commit['id']

def gerrit_change_id_from_git_commit(cmt_id):
    """
    Return the gerrit Change-Id from the passed git cmt_id. Returns None if
    this doesn't appear to be a cmt_id or doesn't have a Change-Id line.
    """

    cid_re = re.compile(r'Change-Id: (I[a-z0-9]{40})')

    # First obtain the commit message itself.
    prog = subprocess.Popen('git show --stat %s' % cmt_id, shell=True,
                            stdout=subprocess.PIPE, stderr=subprocess.PIPE)

    stdout_data, stderr_data = prog.communicate()
    if prog.returncode != 0:
        print('`git show %s\' failed?!' % cmt_id)
        return None

    m = cid_re.search(stdout_data.decode('utf-8'))
    if m:
        return m.group(1)

    return None

def indent_lines(text, ind):
    """
    Prepend each new line in the passed text with ind.
    """
    return ''.join(ind + l + '\n' for l in text.splitlines())

def display_commits(commits, extra_message):
    """
    Takes a list of the commits to print.
    """

    whole_template = """
Hi All,

I would like you to review the following changes.
{extra_message}
{cmt_descriptions}
Thanks!
{cmt_verbose}"""

    cmt_template = """
+----------------------------------------
| {url}
| Author: {author}

{cmtmsg}"""

    commits_info = [ ]
    for cmt in commits:
        commits_info.append(commit_info_from_gerrit_change_id(cmt))

    cmt_descriptions = ''
    for c in commits_info:
        cmt_descriptions += "  %s - %s\n" % (c['url'], c['subject'])

    # Add new lines around the extra_message, if applicable. Otherwise we don't
    # want anything to show up for extra_message.
    if extra_message:
        extra_message = '\n%s\n' % extra_message
    else:
        extra_message = ''

    cmt_verbose = ''
    for c in commits_info:
        cmt_verbose += cmt_template.format(url=c['url'],
                                           author=c['owner']['name'],
                                           cmtmsg=indent_lines(
                                               c['commitMessage'], '  '))

    print(whole_template.format(cmt_descriptions=cmt_descriptions,
                                extra_message=extra_message,
                                cmt_verbose=cmt_verbose))

def main():
    """
    The magic happens here.
    """

    arg_parser = parse_args()
    commits = [ ]

    if arg_parser.version:
        print('Version: %s' % VERSION)
        exit(0)

    # Builds a dictionary of Gerrit Change-Ids. From the Change-Ids we can then
    # get the commit message and URL.
    #
    # This also builds an array of those same commit IDs to track the ordering
    # of the commits so that the user can choose the order of the patches based
    # on the order in which they pass the commits.
    for cmt in arg_parser.commits:
        if cmt[0] == 'I':
            cid = cmt
        elif get_gerrit_url_id(cmt):
            cid = gerrit_change_id_from_gerrit_cl(cmt)
        else:
            cid = gerrit_change_id_from_git_commit(cmt)

        if cid:
            commits.append(cid)
        else:
            print('Warning: \'%s\' doesn\'t appear to be a commit!' % cmt)

    display_commits(commits, arg_parser.msg)

if __name__ == '__main__':
    main()