scripts: Add an 'rfr' program

Add an RFR program to generate RFR emails. Since there are many emails
sent with either no information or lacking information this script
will help make RFR emails more useful to developers interested in
conducting reviews.

The help is as follows:

  $ ./rfr --help
  usage: rfr [-h] [-V] [-m MSG] Commit-IDs [Commit-IDs ...]

  RFR formatting tool

  positional arguments:
    Commit-IDs         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.

  optional arguments:
    -h, --help         show this help message and exit
    -V, --version      print the program version
    -m MSG, --msg MSG  Custom message to add to the RFR email

  This program will format commit messages into something that can be sent to
  the nvgpu mailing list for review

The Commit IDs can be a git commit ID, gerrit change ID, or a gerrit URL. For
example:

  # Git commit IDs (abbreviated are ok)
  $ ./rfr 89e2470807
  $ ./rfr 89e2470807571ef6dc545ece8f5f7e43e27b0c12

  # Gerrit Change-Id (also can be abbreviated)
  $ ./rfr I0524ae1982fbce9eb4da976e72102e08e2dcd017
  $ ./rfr I0524ae198

  # And lastly, several different URL formats:
  https://git-master.nvidia.com/r/#/c/1553782/2
  https://git-master.nvidia.com/r/#/c/1553782/
  https://git-master.nvidia.com/r/1553782
  https://git-master/r/1553782

The only currently known bug is that if yo have multiple versions of a
commit that share the same gerrit Change-ID then this script will only
take the first one. For example if there's a bunch of cherry-picks then
which commit is taken is undefined.

It seems like generally the order that gerrit returns changes puts open
changes first, but this is not tested nor should this be relied upon. At
some point supporting some mechanism to filter will be necessary.

Change-Id: I0524ae1982fbce9eb4da976e72102e08e2dcd017
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1552173
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 243 insertions, 0 deletions

diff --git a/scripts/rfr b/scripts/rfr
new file mode 100755
index 00000000..1b12a9ce
--- /dev/null
+++ b/scripts/rfr
@@ -0,0 +1,243 @@
+#!/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}
+| {subject}
+| 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'])
+        print(cmt_descriptions)
+
+    # 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'], subject=c['subject'],
+                                           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()