mitmproxy/mitmproxy/addonmanager.py
Aldo Cortesi 9dcd15d350 asyncio: ditch the handler context
There are a few reasons for this. First, logs are now async, and can be called
at any time. Second, the event loop is thread local, so there can only ever be
one master per thread. These two things together completely obviate the need
for a handler context.
2018-04-07 09:04:14 +12:00

272 lines
8.1 KiB
Python

import types
import typing
import traceback
import contextlib
import sys
from mitmproxy import exceptions
from mitmproxy import eventsequence
from mitmproxy import controller
from mitmproxy import flow
from . import ctx
import pprint
def _get_name(itm):
return getattr(itm, "name", itm.__class__.__name__.lower())
def cut_traceback(tb, func_name):
"""
Cut off a traceback at the function with the given name.
The func_name's frame is excluded.
Args:
tb: traceback object, as returned by sys.exc_info()[2]
func_name: function name
Returns:
Reduced traceback.
"""
tb_orig = tb
for _, _, fname, _ in traceback.extract_tb(tb):
tb = tb.tb_next
if fname == func_name:
break
return tb or tb_orig
class StreamLog:
def __init__(self, lg):
self.log = lg
def write(self, buf):
if buf.strip():
self.log(buf)
def flush(self): # pragma: no cover
# Click uses flush sometimes, so we dummy it up
pass
@contextlib.contextmanager
def safecall():
stdout_replacement = StreamLog(lambda message: ctx.log.warn(message))
try:
with contextlib.redirect_stdout(stdout_replacement):
yield
except (exceptions.AddonHalt, exceptions.OptionsError):
raise
except Exception as e:
etype, value, tb = sys.exc_info()
tb = cut_traceback(tb, "invoke_addon")
ctx.log.error(
"Addon error: %s" % "".join(
traceback.format_exception(etype, value, tb)
)
)
class Loader:
"""
A loader object is passed to the load() event when addons start up.
"""
def __init__(self, master):
self.master = master
def add_option(
self,
name: str,
typespec: type,
default: typing.Any,
help: str,
choices: typing.Optional[typing.Sequence[str]] = None
) -> None:
"""
Add an option to mitmproxy.
Help should be a single paragraph with no linebreaks - it will be
reflowed by tools. Information on the data type should be omitted -
it will be generated and added by tools as needed.
"""
if name in self.master.options:
existing = self.master.options._options[name]
same_signature = (
existing.name == name and
existing.typespec == typespec and
existing.default == default and
existing.help == help and
existing.choices == choices
)
if same_signature:
return
else:
ctx.log.warn("Over-riding existing option %s" % name)
self.master.options.add_option(
name,
typespec,
default,
help,
choices
)
def add_command(self, path: str, func: typing.Callable) -> None:
self.master.commands.add(path, func)
def traverse(chain):
"""
Recursively traverse an addon chain.
"""
for a in chain:
yield a
if hasattr(a, "addons"):
yield from traverse(a.addons)
class AddonManager:
def __init__(self, master):
self.lookup = {}
self.chain = []
self.master = master
master.options.changed.connect(self._configure_all)
def _configure_all(self, options, updated):
self.trigger("configure", updated)
def clear(self):
"""
Remove all addons.
"""
for i in self.chain:
self.remove(i)
def get(self, name):
"""
Retrieve an addon by name. Addon names are equal to the .name
attribute on the instance, or the lower case class name if that
does not exist.
"""
return self.lookup.get(name, None)
def register(self, addon):
"""
Register an addon, call its load event, and then register all its
sub-addons. This should be used by addons that dynamically manage
addons.
If the calling addon is already running, it should follow with
running and configure events. Must be called within a current
context.
"""
for a in traverse([addon]):
name = _get_name(a)
if name in self.lookup:
raise exceptions.AddonManagerError(
"An addon called '%s' already exists." % name
)
l = Loader(self.master)
self.invoke_addon(addon, "load", l)
for a in traverse([addon]):
name = _get_name(a)
self.lookup[name] = a
for a in traverse([addon]):
self.master.commands.collect_commands(a)
return addon
def add(self, *addons):
"""
Add addons to the end of the chain, and run their load event.
If any addon has sub-addons, they are registered.
"""
for i in addons:
self.chain.append(self.register(i))
def remove(self, addon):
"""
Remove an addon and all its sub-addons.
If the addon is not in the chain - that is, if it's managed by a
parent addon - it's the parent's responsibility to remove it from
its own addons attribute.
"""
for a in traverse([addon]):
n = _get_name(a)
if n not in self.lookup:
raise exceptions.AddonManagerError("No such addon: %s" % n)
self.chain = [i for i in self.chain if i is not a]
del self.lookup[_get_name(a)]
self.invoke_addon(a, "done")
def __len__(self):
return len(self.chain)
def __str__(self):
return pprint.pformat([str(i) for i in self.chain])
def __contains__(self, item):
name = _get_name(item)
return name in self.lookup
async def handle_lifecycle(self, name, message):
"""
Handle a lifecycle event.
"""
if not hasattr(message, "reply"): # pragma: no cover
raise exceptions.ControlException(
"Message %s has no reply attribute" % message
)
# We can use DummyReply objects multiple times. We only clear them up on
# the next handler so that we can access value and state in the
# meantime.
if isinstance(message.reply, controller.DummyReply):
message.reply.reset()
self.trigger(name, message)
if message.reply.state == "start":
message.reply.take()
if not message.reply.has_message:
message.reply.ack()
message.reply.commit()
if isinstance(message.reply, controller.DummyReply):
message.reply.mark_reset()
if isinstance(message, flow.Flow):
self.trigger("update", [message])
def invoke_addon(self, addon, name, *args, **kwargs):
"""
Invoke an event on an addon and all its children.
"""
if name not in eventsequence.Events:
name = "event_" + name
for a in traverse([addon]):
func = getattr(a, name, None)
if func:
if callable(func):
func(*args, **kwargs)
elif isinstance(func, types.ModuleType):
# we gracefully exclude module imports with the same name as hooks.
# For example, a user may have "from mitmproxy import log" in an addon,
# which has the same name as the "log" hook. In this particular case,
# we end up in an error loop because we "log" this error.
pass
else:
raise exceptions.AddonManagerError(
"Addon handler {} ({}) not callable".format(name, a)
)
def trigger(self, name, *args, **kwargs):
"""
Trigger an event across all addons.
"""
for i in self.chain:
try:
with safecall():
self.invoke_addon(i, name, *args, **kwargs)
except exceptions.AddonHalt:
return