scripts: rfr: Direct email support

Add support for `rfr' to send emails directly to the nvgpu-core mailing
list. Copying the email contents and then manually updating it is
annoying. This streamlines that process greatly!

Since most people always write something extra past what the `rfr'
script generates you can edit the message before it sends. If you don't
specify a message explicitly with '--msg' then an editor based on your
setting of $EDITOR is opened up with the contents of the email. What
you edit into there will be sent verbatim. If for some reason you want
nothing to be added there's the '--no-msg' option.

Change-Id: Icb0ccba936357cf5e3a93001a5c22aeacf906e11
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1595544
GVS: Gerrit_Virtual_Submit
Reviewed-by: Konsta Holtta <kholtta@nvidia.com>
Tested-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

scripts/rfr

@@ -5,9 +5,14 @@
 
 import os
 import re
+import sys
 import json
 import argparse
+import tempfile
 import subprocess
+import smtplib
+
+from email.mime.text import MIMEText
 
 VERSION = '1.0.0'
 
@@ -50,6 +55,14 @@ Otherwise it's treated as a git commit ID.
                         help='print the program version')
     parser.add_argument('-m', '--msg', action='store', default=None,
                         help='Custom message to add to the RFR email')
+    parser.add_argument('-N', '--no-msg', action='store_true', default=False,
+                        help='Force no message in output.')
+    parser.add_argument('-e', '--email', action='store_true', default=False,
+                        help='Use direct email to post the RFR.')
+    parser.add_argument('-s', '--subject', action='store', default=None,
+                        help='Specify the email\'s subject.')
+    parser.add_argument('-R', '--sender', action='store', default=None,
+                        help='Specify a special from: email address.')
 
     # Positionals: the gerrit URLs.
     parser.add_argument('commits', metavar='Commit-IDs',
@@ -148,15 +161,39 @@ def git_sha1_from_commit(commit_ish):
 
     return stdout_data.decode('utf-8')
 
+def get_user_message(start_msg):
+    """
+    Get a user message from the user. This is done with the default text
+    editor.
+    """
+
+    editor = os.environ.get('EDITOR', 'vim')
+
+    with tempfile.NamedTemporaryFile(suffix=".tmp") as filp:
+        filp.write(start_msg)
+        filp.flush()
+
+        edit_cmd = editor + ' ' + filp.name
+
+        try:
+            subprocess.call(edit_cmd.split())
+        except:
+            print('Failed to run editor: `%s\'' % edit_cmd)
+            return None
+
+        filp.seek(0)
+        return filp.read()
+
 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_info, extra_message):
+def format_commits(commits_info, extra_message):
     """
-    Takes a list of the commit info objects to print.
+    Takes a list of the commit info objects and returns a string with the
+    text to print. This can either be directly printed or emailed.
     """
 
     whole_template = """
@@ -193,9 +230,62 @@ Thanks!
                                            cmtmsg=indent_lines(
                                                c['commitMessage'], '  '))
 
-    print(whole_template.format(cmt_descriptions=cmt_descriptions,
+    return whole_template.format(cmt_descriptions=cmt_descriptions,
                                  extra_message=extra_message,
-                                cmt_verbose=cmt_verbose))
+                                 cmt_verbose=cmt_verbose)
+
+def display_commits(commits_info, extra_message):
+    """
+    Print the list of commits to the directly to the terminal.
+    """
+
+    print(format_commits(commits_info, extra_message))
+
+def email_commits(commits_info, sender, subject, args):
+    """
+    Directly email commits to the nvgpu-core mailing list for review!
+    """
+
+    to_addr = 'SW-Mobile-nvgpu-core <SW-Mobile-nvgpu-core@exchange.nvidia.com>'
+
+    if args.no_msg:
+        args.msg = None
+
+    body = format_commits(commits_info, args.msg)
+
+    # Most people like to write a little description of their patch series
+    # in the email body. This aims to take care of that.
+    #
+    # If arg_parser.msg is set then we can just use that. If there's no
+    # args.msg field then we will try to fire up a text editor and let the
+    # user write something we will copy into the email the same way as
+    # args.msg. This makes it easier to a write paragraph - passing that much
+    # text on the CLI is annoying!
+    #
+    # However, if the user decides no message is a must then they can use
+    # the '--no-msg' argument to supress this message. This arg will also
+    # supress a message supplied with '--msg'.
+
+    if not args.msg and not args.no_msg:
+        text = get_user_message(body)
+
+        if not text or text.strip() == '':
+            print 'Empty user message: aborting!'
+            return
+
+        msg = MIMEText(text)
+    else:
+        msg = MIMEText(body)
+
+    msg['To'] = to_addr
+    msg['From'] = sender
+    msg['Subject'] = subject
+
+    s = smtplib.SMTP('mail.nvidia.com')
+    s.sendmail(sender,
+               [to_addr],
+               msg.as_string())
+    s.quit()
 
 def main():
     """
@@ -228,6 +318,23 @@ def main():
         else:
             print('Warning: \'%s\' doesn\'t appear to be a commit!' % cmt)
 
+    if arg_parser.email:
+        # If no subject was specified then use the first commit subject as
+        # the subject.
+        subject = arg_parser.subject
+        if not subject:
+            subject = '[RFR] %s' % commits_info[0]['subject']
+
+        # If no specified sender then use the name from the environment as
+        # the sender (plus @nvidia.com). This arg is primarily useful for
+        # people who do not have a username for the Linux machine that matches
+        # their SSO ID.
+        sender = arg_parser.sender
+        if not sender:
+            sender = '%s@nvidia.com' % user
+
+        email_commits(commits_info, sender, subject, arg_parser)
+    else:
         display_commits(commits_info, arg_parser.msg)
 
 if __name__ == '__main__':