sshpeer: initial definition and implementation of new SSH protocol
The existing SSH protocol has several design flaws. Future commits
will elaborate on these flaws as new features are introduced
to combat these flaws. For now, hopefully you can take me for my
word that a ground up rewrite of the SSH protocol is needed.
This commit lays the foundation for a new SSH protocol by defining
a mechanism to upgrade the SSH transport channel away from the
default (version 1) protocol to something modern (which we'll call
"version 2" for now).
This upgrade process is detailed in the internals documentation
for the wire protocol. The gist of it is the client sends a
request line preceding the "hello" command/line which basically
says "I'm requesting an upgrade: here's what I support." If the
server recognizes that line, it processes the upgrade request and
the transport channel is switched to use the new version of the
protocol. If not, it sends an empty response, which is how all
Mercurial SSH servers from the beginning of time reacted to unknown
commands. The upgrade request is effectively ignored and the client
continues to use the existing version of the protocol as if nothing
happened.
The new version of the SSH protocol is completely identical to
version 1 aside from the upgrade dance and the bytes that follow.
The immediate bytes that follow the protocol switch are defined to
be a length framed "capabilities: " line containing the remote's
advertised capabilities. In reality, this looks very similar to
what the "hello" response would look like. But it will evolve
quickly.
The methodology by which the protocol will evolve is important.
I'm not going to introduce the new protocol all at once. That would
likely lead to endless bike shedding and forward progress would
stall. Instead, I intend to tricle out new features and diversions
from the existing protocol in small, incremental changes.
To support the gradual evolution of the protocol, the on-the-wire
advertised protocol name contains an "exp" to denote "experimental"
and a 4 digit field to capture the sub-version of the protocol.
Whenever we make a BC change to the wire protocol, we can increment
this version and lock out all older clients because it will appear
as a completely different protocol version. This means we can incur
as many breaking changes as we want. We don't have to commit to
supporting any one feature or idea for a long period of time. We
can even evolve the handshake mechanism, because that is defined
as being an implementation detail of the negotiated protocol version!
Hopefully this lowers the barrier to accepting changes to the
protocol and for experimenting with "radical" ideas during its
development.
In core, sshpeer received most of the attention. We haven't even
implemented the server bits for the new protocol in core yet.
Instead, we add very primitive support to our test server, mainly
just to exercise the added code paths in sshpeer.
Differential Revision: https://phab.mercurial-scm.org/D2061
# no-check-commit because of required foo_bar naming
# notify.py - email notifications for mercurial
#
# Copyright 2006 Vadim Gelfer <vadim.gelfer@gmail.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''hooks for sending email push notifications
This extension implements hooks to send email notifications when
changesets are sent from or received by the local repository.
First, enable the extension as explained in :hg:`help extensions`, and
register the hook you want to run. ``incoming`` and ``changegroup`` hooks
are run when changesets are received, while ``outgoing`` hooks are for
changesets sent to another repository::
[hooks]
# one email for each incoming changeset
incoming.notify = python:hgext.notify.hook
# one email for all incoming changesets
changegroup.notify = python:hgext.notify.hook
# one email for all outgoing changesets
outgoing.notify = python:hgext.notify.hook
This registers the hooks. To enable notification, subscribers must
be assigned to repositories. The ``[usersubs]`` section maps multiple
repositories to a given recipient. The ``[reposubs]`` section maps
multiple recipients to a single repository::
[usersubs]
# key is subscriber email, value is a comma-separated list of repo patterns
user@host = pattern
[reposubs]
# key is repo pattern, value is a comma-separated list of subscriber emails
pattern = user@host
A ``pattern`` is a ``glob`` matching the absolute path to a repository,
optionally combined with a revset expression. A revset expression, if
present, is separated from the glob by a hash. Example::
[reposubs]
*/widgets#branch(release) = qa-team@example.com
This sends to ``qa-team@example.com`` whenever a changeset on the ``release``
branch triggers a notification in any repository ending in ``widgets``.
In order to place them under direct user management, ``[usersubs]`` and
``[reposubs]`` sections may be placed in a separate ``hgrc`` file and
incorporated by reference::
[notify]
config = /path/to/subscriptionsfile
Notifications will not be sent until the ``notify.test`` value is set
to ``False``; see below.
Notifications content can be tweaked with the following configuration entries:
notify.test
If ``True``, print messages to stdout instead of sending them. Default: True.
notify.sources
Space-separated list of change sources. Notifications are activated only
when a changeset's source is in this list. Sources may be:
:``serve``: changesets received via http or ssh
:``pull``: changesets received via ``hg pull``
:``unbundle``: changesets received via ``hg unbundle``
:``push``: changesets sent or received via ``hg push``
:``bundle``: changesets sent via ``hg unbundle``
Default: serve.
notify.strip
Number of leading slashes to strip from url paths. By default, notifications
reference repositories with their absolute path. ``notify.strip`` lets you
turn them into relative paths. For example, ``notify.strip=3`` will change
``/long/path/repository`` into ``repository``. Default: 0.
notify.domain
Default email domain for sender or recipients with no explicit domain.
notify.style
Style file to use when formatting emails.
notify.template
Template to use when formatting emails.
notify.incoming
Template to use when run as an incoming hook, overriding ``notify.template``.
notify.outgoing
Template to use when run as an outgoing hook, overriding ``notify.template``.
notify.changegroup
Template to use when running as a changegroup hook, overriding
``notify.template``.
notify.maxdiff
Maximum number of diff lines to include in notification email. Set to 0
to disable the diff, or -1 to include all of it. Default: 300.
notify.maxsubject
Maximum number of characters in email's subject line. Default: 67.
notify.diffstat
Set to True to include a diffstat before diff content. Default: True.
notify.merge
If True, send notifications for merge changesets. Default: True.
notify.mbox
If set, append mails to this mbox file instead of sending. Default: None.
notify.fromauthor
If set, use the committer of the first changeset in a changegroup for
the "From" field of the notification mail. If not set, take the user
from the pushing repo. Default: False.
If set, the following entries will also be used to customize the
notifications:
email.from
Email ``From`` address to use if none can be found in the generated
email content.
web.baseurl
Root repository URL to combine with repository paths when making
references. See also ``notify.strip``.
'''
from __future__ import absolute_import
import email
import email.parser as emailparser
import fnmatch
import socket
import time
from mercurial.i18n import _
from mercurial import (
error,
logcmdutil,
mail,
patch,
registrar,
util,
)
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'
configtable = {}
configitem = registrar.configitem(configtable)
configitem('notify', 'changegroup',
default=None,
)
configitem('notify', 'config',
default=None,
)
configitem('notify', 'diffstat',
default=True,
)
configitem('notify', 'domain',
default=None,
)
configitem('notify', 'fromauthor',
default=None,
)
configitem('notify', 'incoming',
default=None,
)
configitem('notify', 'maxdiff',
default=300,
)
configitem('notify', 'maxsubject',
default=67,
)
configitem('notify', 'mbox',
default=None,
)
configitem('notify', 'merge',
default=True,
)
configitem('notify', 'outgoing',
default=None,
)
configitem('notify', 'sources',
default='serve',
)
configitem('notify', 'strip',
default=0,
)
configitem('notify', 'style',
default=None,
)
configitem('notify', 'template',
default=None,
)
configitem('notify', 'test',
default=True,
)
# template for single changeset can include email headers.
single_template = '''
Subject: changeset in {webroot}: {desc|firstline|strip}
From: {author}
changeset {node|short} in {root}
details: {baseurl}{webroot}?cmd=changeset;node={node|short}
description:
\t{desc|tabindent|strip}
'''.lstrip()
# template for multiple changesets should not contain email headers,
# because only first set of headers will be used and result will look
# strange.
multiple_template = '''
changeset {node|short} in {root}
details: {baseurl}{webroot}?cmd=changeset;node={node|short}
summary: {desc|firstline}
'''
deftemplates = {
'changegroup': multiple_template,
}
class notifier(object):
'''email notification class.'''
def __init__(self, ui, repo, hooktype):
self.ui = ui
cfg = self.ui.config('notify', 'config')
if cfg:
self.ui.readconfig(cfg, sections=['usersubs', 'reposubs'])
self.repo = repo
self.stripcount = int(self.ui.config('notify', 'strip'))
self.root = self.strip(self.repo.root)
self.domain = self.ui.config('notify', 'domain')
self.mbox = self.ui.config('notify', 'mbox')
self.test = self.ui.configbool('notify', 'test')
self.charsets = mail._charsets(self.ui)
self.subs = self.subscribers()
self.merge = self.ui.configbool('notify', 'merge')
mapfile = None
template = (self.ui.config('notify', hooktype) or
self.ui.config('notify', 'template'))
if not template:
mapfile = self.ui.config('notify', 'style')
if not mapfile and not template:
template = deftemplates.get(hooktype) or single_template
spec = logcmdutil.templatespec(template, mapfile)
self.t = logcmdutil.changesettemplater(self.ui, self.repo, spec)
def strip(self, path):
'''strip leading slashes from local path, turn into web-safe path.'''
path = util.pconvert(path)
count = self.stripcount
while count > 0:
c = path.find('/')
if c == -1:
break
path = path[c + 1:]
count -= 1
return path
def fixmail(self, addr):
'''try to clean up email addresses.'''
addr = util.email(addr.strip())
if self.domain:
a = addr.find('@localhost')
if a != -1:
addr = addr[:a]
if '@' not in addr:
return addr + '@' + self.domain
return addr
def subscribers(self):
'''return list of email addresses of subscribers to this repo.'''
subs = set()
for user, pats in self.ui.configitems('usersubs'):
for pat in pats.split(','):
if '#' in pat:
pat, revs = pat.split('#', 1)
else:
revs = None
if fnmatch.fnmatch(self.repo.root, pat.strip()):
subs.add((self.fixmail(user), revs))
for pat, users in self.ui.configitems('reposubs'):
if '#' in pat:
pat, revs = pat.split('#', 1)
else:
revs = None
if fnmatch.fnmatch(self.repo.root, pat):
for user in users.split(','):
subs.add((self.fixmail(user), revs))
return [(mail.addressencode(self.ui, s, self.charsets, self.test), r)
for s, r in sorted(subs)]
def node(self, ctx, **props):
'''format one changeset, unless it is a suppressed merge.'''
if not self.merge and len(ctx.parents()) > 1:
return False
self.t.show(ctx, changes=ctx.changeset(),
baseurl=self.ui.config('web', 'baseurl'),
root=self.repo.root, webroot=self.root, **props)
return True
def skipsource(self, source):
'''true if incoming changes from this source should be skipped.'''
ok_sources = self.ui.config('notify', 'sources').split()
return source not in ok_sources
def send(self, ctx, count, data):
'''send message.'''
# Select subscribers by revset
subs = set()
for sub, spec in self.subs:
if spec is None:
subs.add(sub)
continue
revs = self.repo.revs('%r and %d:', spec, ctx.rev())
if len(revs):
subs.add(sub)
continue
if len(subs) == 0:
self.ui.debug('notify: no subscribers to selected repo '
'and revset\n')
return
p = emailparser.Parser()
try:
msg = p.parsestr(data)
except email.Errors.MessageParseError as inst:
raise error.Abort(inst)
# store sender and subject
sender, subject = msg['From'], msg['Subject']
del msg['From'], msg['Subject']
if not msg.is_multipart():
# create fresh mime message from scratch
# (multipart templates must take care of this themselves)
headers = msg.items()
payload = msg.get_payload()
# for notification prefer readability over data precision
msg = mail.mimeencode(self.ui, payload, self.charsets, self.test)
# reinstate custom headers
for k, v in headers:
msg[k] = v
msg['Date'] = util.datestr(format="%a, %d %b %Y %H:%M:%S %1%2")
# try to make subject line exist and be useful
if not subject:
if count > 1:
subject = _('%s: %d new changesets') % (self.root, count)
else:
s = ctx.description().lstrip().split('\n', 1)[0].rstrip()
subject = '%s: %s' % (self.root, s)
maxsubject = int(self.ui.config('notify', 'maxsubject'))
if maxsubject:
subject = util.ellipsis(subject, maxsubject)
msg['Subject'] = mail.headencode(self.ui, subject,
self.charsets, self.test)
# try to make message have proper sender
if not sender:
sender = self.ui.config('email', 'from') or self.ui.username()
if '@' not in sender or '@localhost' in sender:
sender = self.fixmail(sender)
msg['From'] = mail.addressencode(self.ui, sender,
self.charsets, self.test)
msg['X-Hg-Notification'] = 'changeset %s' % ctx
if not msg['Message-Id']:
msg['Message-Id'] = ('<hg.%s.%s.%s@%s>' %
(ctx, int(time.time()),
hash(self.repo.root), socket.getfqdn()))
msg['To'] = ', '.join(sorted(subs))
msgtext = msg.as_string()
if self.test:
self.ui.write(msgtext)
if not msgtext.endswith('\n'):
self.ui.write('\n')
else:
self.ui.status(_('notify: sending %d subscribers %d changes\n') %
(len(subs), count))
mail.sendmail(self.ui, util.email(msg['From']),
subs, msgtext, mbox=self.mbox)
def diff(self, ctx, ref=None):
maxdiff = int(self.ui.config('notify', 'maxdiff'))
prev = ctx.p1().node()
if ref:
ref = ref.node()
else:
ref = ctx.node()
chunks = patch.diff(self.repo, prev, ref,
opts=patch.diffallopts(self.ui))
difflines = ''.join(chunks).splitlines()
if self.ui.configbool('notify', 'diffstat'):
s = patch.diffstat(difflines)
# s may be nil, don't include the header if it is
if s:
self.ui.write(_('\ndiffstat:\n\n%s') % s)
if maxdiff == 0:
return
elif maxdiff > 0 and len(difflines) > maxdiff:
msg = _('\ndiffs (truncated from %d to %d lines):\n\n')
self.ui.write(msg % (len(difflines), maxdiff))
difflines = difflines[:maxdiff]
elif difflines:
self.ui.write(_('\ndiffs (%d lines):\n\n') % len(difflines))
self.ui.write("\n".join(difflines))
def hook(ui, repo, hooktype, node=None, source=None, **kwargs):
'''send email notifications to interested subscribers.
if used as changegroup hook, send one email for all changesets in
changegroup. else send one email per changeset.'''
n = notifier(ui, repo, hooktype)
ctx = repo[node]
if not n.subs:
ui.debug('notify: no subscribers to repository %s\n' % n.root)
return
if n.skipsource(source):
ui.debug('notify: changes have source "%s" - skipping\n' % source)
return
ui.pushbuffer()
data = ''
count = 0
author = ''
if hooktype == 'changegroup' or hooktype == 'outgoing':
start, end = ctx.rev(), len(repo)
for rev in xrange(start, end):
if n.node(repo[rev]):
count += 1
if not author:
author = repo[rev].user()
else:
data += ui.popbuffer()
ui.note(_('notify: suppressing notification for merge %d:%s\n')
% (rev, repo[rev].hex()[:12]))
ui.pushbuffer()
if count:
n.diff(ctx, repo['tip'])
else:
if not n.node(ctx):
ui.popbuffer()
ui.note(_('notify: suppressing notification for merge %d:%s\n') %
(ctx.rev(), ctx.hex()[:12]))
return
count += 1
n.diff(ctx)
if not author:
author = ctx.user()
data += ui.popbuffer()
fromauthor = ui.config('notify', 'fromauthor')
if author and fromauthor:
data = '\n'.join(['From: %s' % author, data])
if count:
n.send(ctx, count, data)