debugcommands: add debugwireproto command
We currently don't have a low-level mechanism for sending
arbitrary wire protocol commands. Having a generic and robust
mechanism for sending wire protocol commands, examining wire
data, etc would make it vastly easier to test the wire protocol
and debug server operation. This is a problem I've wanted a
solution for numerous times, especially recently as I've been
hacking on a new version of the wire protocol.
This commit establishes a `hg debugwireproto` command for sending
data to a peer.
The command invents a mini language for specifying actions to take.
This will enable a lot of flexibility for issuing commands and testing
variations for how commands are sent.
Right now, we only support low-level raw sends and receives. These
are probably the least valuable commands to intended users of this
command. But they are the most useful commands to implement to
bootstrap the feature (I've chosen to reimplement test-ssh-proto.t
using this command to prove its usefulness).
My eventual goal of `hg debugwireproto` is to allow calling wire
protocol commands with a human-friendly interface. Essentially,
people can type in a command name and arguments and
`hg debugwireproto` will figure out how to send that on the wire.
I'd love to eventually be able to save the server's raw response
to a file. This would allow us to e.g. call "getbundle" wire
protocol commands easily.
test-ssh-proto.t has been updated to use the new command in lieu
of piping directly to a server process. As part of the transition,
test behavior improved. Before, we piped all request data to the
server at once. Now, we have explicit control over the ordering of
operations. e.g. we can send one command, receive its response,
then send another command. This will allow us to more robustly
test race conditions, buffering behavior, etc.
There were some subtle changes in test behavior. For example,
previous behavior would often send trailing newlines to the server.
The new mechanism doesn't treat literal newlines specially and
requires newlines be escaped in the payload.
Because the new logging code is very low level, it is easy to
introduce race conditions in tests. For example, the number of bytes
returned by a read() may vary depending on load. This is why tests
make heavy use of "readline" for consuming data: the result of
that operation should be deterministic and not subject to race
conditions. There are still some uses of "readavailable." However,
those are only for reading from stderr. I was able to reproduce
timing issues with my system under load when using "readavailable"
globally. But if I "readline" to grab stdout, "readavailable"
appears to work deterministically for stderr. I think this is
because the server writes to stderr first. As long as the OS
delivers writes to pipes in the same order they were made, this
should work. If there are timing issues, we can introduce a
mechanism to readline from stderr.
Differential Revision: https://phab.mercurial-scm.org/D2392
# httppeer.py - HTTP repository proxy classes for mercurial
#
# Copyright 2005, 2006 Matt Mackall <mpm@selenic.com>
# 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.
from __future__ import absolute_import
import errno
import io
import os
import socket
import struct
import tempfile
from .i18n import _
from . import (
bundle2,
error,
httpconnection,
pycompat,
statichttprepo,
url,
util,
wireproto,
)
httplib = util.httplib
urlerr = util.urlerr
urlreq = util.urlreq
def encodevalueinheaders(value, header, limit):
"""Encode a string value into multiple HTTP headers.
``value`` will be encoded into 1 or more HTTP headers with the names
``header-<N>`` where ``<N>`` is an integer starting at 1. Each header
name + value will be at most ``limit`` bytes long.
Returns an iterable of 2-tuples consisting of header names and
values as native strings.
"""
# HTTP Headers are ASCII. Python 3 requires them to be unicodes,
# not bytes. This function always takes bytes in as arguments.
fmt = pycompat.strurl(header) + r'-%s'
# Note: it is *NOT* a bug that the last bit here is a bytestring
# and not a unicode: we're just getting the encoded length anyway,
# and using an r-string to make it portable between Python 2 and 3
# doesn't work because then the \r is a literal backslash-r
# instead of a carriage return.
valuelen = limit - len(fmt % r'000') - len(': \r\n')
result = []
n = 0
for i in xrange(0, len(value), valuelen):
n += 1
result.append((fmt % str(n), pycompat.strurl(value[i:i + valuelen])))
return result
def _wraphttpresponse(resp):
"""Wrap an HTTPResponse with common error handlers.
This ensures that any I/O from any consumer raises the appropriate
error and messaging.
"""
origread = resp.read
class readerproxy(resp.__class__):
def read(self, size=None):
try:
return origread(size)
except httplib.IncompleteRead as e:
# e.expected is an integer if length known or None otherwise.
if e.expected:
msg = _('HTTP request error (incomplete response; '
'expected %d bytes got %d)') % (e.expected,
len(e.partial))
else:
msg = _('HTTP request error (incomplete response)')
raise error.PeerTransportError(
msg,
hint=_('this may be an intermittent network failure; '
'if the error persists, consider contacting the '
'network or server operator'))
except httplib.HTTPException as e:
raise error.PeerTransportError(
_('HTTP request error (%s)') % e,
hint=_('this may be an intermittent network failure; '
'if the error persists, consider contacting the '
'network or server operator'))
resp.__class__ = readerproxy
class _multifile(object):
def __init__(self, *fileobjs):
for f in fileobjs:
if not util.safehasattr(f, 'length'):
raise ValueError(
'_multifile only supports file objects that '
'have a length but this one does not:', type(f), f)
self._fileobjs = fileobjs
self._index = 0
@property
def length(self):
return sum(f.length for f in self._fileobjs)
def read(self, amt=None):
if amt <= 0:
return ''.join(f.read() for f in self._fileobjs)
parts = []
while amt and self._index < len(self._fileobjs):
parts.append(self._fileobjs[self._index].read(amt))
got = len(parts[-1])
if got < amt:
self._index += 1
amt -= got
return ''.join(parts)
def seek(self, offset, whence=os.SEEK_SET):
if whence != os.SEEK_SET:
raise NotImplementedError(
'_multifile does not support anything other'
' than os.SEEK_SET for whence on seek()')
if offset != 0:
raise NotImplementedError(
'_multifile only supports seeking to start, but that '
'could be fixed if you need it')
for f in self._fileobjs:
f.seek(0)
self._index = 0
class httppeer(wireproto.wirepeer):
def __init__(self, ui, path):
self._path = path
self._caps = None
self._urlopener = None
self._requestbuilder = None
u = util.url(path)
if u.query or u.fragment:
raise error.Abort(_('unsupported URL component: "%s"') %
(u.query or u.fragment))
# urllib cannot handle URLs with embedded user or passwd
self._url, authinfo = u.authinfo()
self._ui = ui
ui.debug('using %s\n' % self._url)
self._urlopener = url.opener(ui, authinfo)
self._requestbuilder = urlreq.request
def __del__(self):
urlopener = getattr(self, '_urlopener', None)
if urlopener:
for h in urlopener.handlers:
h.close()
getattr(h, "close_all", lambda: None)()
def _openurl(self, req):
if (self._ui.debugflag
and self._ui.configbool('devel', 'debug.peer-request')):
dbg = self._ui.debug
line = 'devel-peer-request: %s\n'
dbg(line % '%s %s' % (req.get_method(), req.get_full_url()))
hgargssize = None
for header, value in sorted(req.header_items()):
if header.startswith('X-hgarg-'):
if hgargssize is None:
hgargssize = 0
hgargssize += len(value)
else:
dbg(line % ' %s %s' % (header, value))
if hgargssize is not None:
dbg(line % ' %d bytes of commands arguments in headers'
% hgargssize)
if req.has_data():
data = req.get_data()
length = getattr(data, 'length', None)
if length is None:
length = len(data)
dbg(line % ' %d bytes of data' % length)
start = util.timer()
ret = self._urlopener.open(req)
if self._ui.configbool('devel', 'debug.peer-request'):
dbg(line % ' finished in %.4f seconds (%s)'
% (util.timer() - start, ret.code))
return ret
# Begin of _basepeer interface.
@util.propertycache
def ui(self):
return self._ui
def url(self):
return self._path
def local(self):
return None
def peer(self):
return self
def canpush(self):
return True
def close(self):
pass
# End of _basepeer interface.
# Begin of _basewirepeer interface.
def capabilities(self):
# self._fetchcaps() should have been called as part of peer
# handshake. So self._caps should always be set.
assert self._caps is not None
return self._caps
# End of _basewirepeer interface.
# look up capabilities only when needed
def _fetchcaps(self):
self._caps = set(self._call('capabilities').split())
def _callstream(self, cmd, _compressible=False, **args):
args = pycompat.byteskwargs(args)
if cmd == 'pushkey':
args['data'] = ''
data = args.pop('data', None)
headers = args.pop('headers', {})
self.ui.debug("sending %s command\n" % cmd)
q = [('cmd', cmd)]
headersize = 0
varyheaders = []
# Important: don't use self.capable() here or else you end up
# with infinite recursion when trying to look up capabilities
# for the first time.
postargsok = self._caps is not None and 'httppostargs' in self._caps
# Send arguments via POST.
if postargsok and args:
strargs = urlreq.urlencode(sorted(args.items()))
if not data:
data = strargs
else:
if isinstance(data, bytes):
i = io.BytesIO(data)
i.length = len(data)
data = i
argsio = io.BytesIO(strargs)
argsio.length = len(strargs)
data = _multifile(argsio, data)
headers[r'X-HgArgs-Post'] = len(strargs)
elif args:
# Calling self.capable() can infinite loop if we are calling
# "capabilities". But that command should never accept wire
# protocol arguments. So this should never happen.
assert cmd != 'capabilities'
httpheader = self.capable('httpheader')
if httpheader:
headersize = int(httpheader.split(',', 1)[0])
# Send arguments via HTTP headers.
if headersize > 0:
# The headers can typically carry more data than the URL.
encargs = urlreq.urlencode(sorted(args.items()))
for header, value in encodevalueinheaders(encargs, 'X-HgArg',
headersize):
headers[header] = value
varyheaders.append(header)
# Send arguments via query string (Mercurial <1.9).
else:
q += sorted(args.items())
qs = '?%s' % urlreq.urlencode(q)
cu = "%s%s" % (self._url, qs)
size = 0
if util.safehasattr(data, 'length'):
size = data.length
elif data is not None:
size = len(data)
if data is not None and r'Content-Type' not in headers:
headers[r'Content-Type'] = r'application/mercurial-0.1'
# Tell the server we accept application/mercurial-0.2 and multiple
# compression formats if the server is capable of emitting those
# payloads.
protoparams = []
mediatypes = set()
if self._caps is not None:
mt = self.capable('httpmediatype')
if mt:
protoparams.append('0.1')
mediatypes = set(mt.split(','))
if '0.2tx' in mediatypes:
protoparams.append('0.2')
if '0.2tx' in mediatypes and self.capable('compression'):
# We /could/ compare supported compression formats and prune
# non-mutually supported or error if nothing is mutually supported.
# For now, send the full list to the server and have it error.
comps = [e.wireprotosupport().name for e in
util.compengines.supportedwireengines(util.CLIENTROLE)]
protoparams.append('comp=%s' % ','.join(comps))
if protoparams:
protoheaders = encodevalueinheaders(' '.join(protoparams),
'X-HgProto',
headersize or 1024)
for header, value in protoheaders:
headers[header] = value
varyheaders.append(header)
if varyheaders:
headers[r'Vary'] = r','.join(varyheaders)
req = self._requestbuilder(pycompat.strurl(cu), data, headers)
if data is not None:
self.ui.debug("sending %d bytes\n" % size)
req.add_unredirected_header(r'Content-Length', r'%d' % size)
try:
resp = self._openurl(req)
except urlerr.httperror as inst:
if inst.code == 401:
raise error.Abort(_('authorization failed'))
raise
except httplib.HTTPException as inst:
self.ui.debug('http error while sending %s command\n' % cmd)
self.ui.traceback()
raise IOError(None, inst)
# Insert error handlers for common I/O failures.
_wraphttpresponse(resp)
# record the url we got redirected to
resp_url = pycompat.bytesurl(resp.geturl())
if resp_url.endswith(qs):
resp_url = resp_url[:-len(qs)]
if self._url.rstrip('/') != resp_url.rstrip('/'):
if not self.ui.quiet:
self.ui.warn(_('real URL is %s\n') % resp_url)
self._url = resp_url
try:
proto = pycompat.bytesurl(resp.getheader(r'content-type', r''))
except AttributeError:
proto = pycompat.bytesurl(resp.headers.get(r'content-type', r''))
safeurl = util.hidepassword(self._url)
if proto.startswith('application/hg-error'):
raise error.OutOfBandError(resp.read())
# accept old "text/plain" and "application/hg-changegroup" for now
if not (proto.startswith('application/mercurial-') or
(proto.startswith('text/plain')
and not resp.headers.get('content-length')) or
proto.startswith('application/hg-changegroup')):
self.ui.debug("requested URL: '%s'\n" % util.hidepassword(cu))
raise error.RepoError(
_("'%s' does not appear to be an hg repository:\n"
"---%%<--- (%s)\n%s\n---%%<---\n")
% (safeurl, proto or 'no content-type', resp.read(1024)))
if proto.startswith('application/mercurial-'):
try:
version = proto.split('-', 1)[1]
version_info = tuple([int(n) for n in version.split('.')])
except ValueError:
raise error.RepoError(_("'%s' sent a broken Content-Type "
"header (%s)") % (safeurl, proto))
# TODO consider switching to a decompression reader that uses
# generators.
if version_info == (0, 1):
if _compressible:
return util.compengines['zlib'].decompressorreader(resp)
return resp
elif version_info == (0, 2):
# application/mercurial-0.2 always identifies the compression
# engine in the payload header.
elen = struct.unpack('B', resp.read(1))[0]
ename = resp.read(elen)
engine = util.compengines.forwiretype(ename)
return engine.decompressorreader(resp)
else:
raise error.RepoError(_("'%s' uses newer protocol %s") %
(safeurl, version))
if _compressible:
return util.compengines['zlib'].decompressorreader(resp)
return resp
def _call(self, cmd, **args):
fp = self._callstream(cmd, **args)
try:
return fp.read()
finally:
# if using keepalive, allow connection to be reused
fp.close()
def _callpush(self, cmd, cg, **args):
# have to stream bundle to a temp file because we do not have
# http 1.1 chunked transfer.
types = self.capable('unbundle')
try:
types = types.split(',')
except AttributeError:
# servers older than d1b16a746db6 will send 'unbundle' as a
# boolean capability. They only support headerless/uncompressed
# bundles.
types = [""]
for x in types:
if x in bundle2.bundletypes:
type = x
break
tempname = bundle2.writebundle(self.ui, cg, None, type)
fp = httpconnection.httpsendfile(self.ui, tempname, "rb")
headers = {r'Content-Type': r'application/mercurial-0.1'}
try:
r = self._call(cmd, data=fp, headers=headers, **args)
vals = r.split('\n', 1)
if len(vals) < 2:
raise error.ResponseError(_("unexpected response:"), r)
return vals
except urlerr.httperror:
# Catch and re-raise these so we don't try and treat them
# like generic socket errors. They lack any values in
# .args on Python 3 which breaks our socket.error block.
raise
except socket.error as err:
if err.args[0] in (errno.ECONNRESET, errno.EPIPE):
raise error.Abort(_('push failed: %s') % err.args[1])
raise error.Abort(err.args[1])
finally:
fp.close()
os.unlink(tempname)
def _calltwowaystream(self, cmd, fp, **args):
fh = None
fp_ = None
filename = None
try:
# dump bundle to disk
fd, filename = tempfile.mkstemp(prefix="hg-bundle-", suffix=".hg")
fh = os.fdopen(fd, pycompat.sysstr("wb"))
d = fp.read(4096)
while d:
fh.write(d)
d = fp.read(4096)
fh.close()
# start http push
fp_ = httpconnection.httpsendfile(self.ui, filename, "rb")
headers = {r'Content-Type': r'application/mercurial-0.1'}
return self._callstream(cmd, data=fp_, headers=headers, **args)
finally:
if fp_ is not None:
fp_.close()
if fh is not None:
fh.close()
os.unlink(filename)
def _callcompressable(self, cmd, **args):
return self._callstream(cmd, _compressible=True, **args)
def _abort(self, exception):
raise exception
def instance(ui, path, create):
if create:
raise error.Abort(_('cannot create new http repository'))
try:
if path.startswith('https:') and not url.has_https:
raise error.Abort(_('Python support for SSL and HTTPS '
'is not installed'))
inst = httppeer(ui, path)
inst._fetchcaps()
return inst
except error.RepoError as httpexception:
try:
r = statichttprepo.instance(ui, "static-" + path, create)
ui.note(_('(falling back to static-http)\n'))
return r
except error.RepoError:
raise httpexception # use the original http RepoError instead