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591 lines
20 KiB
591 lines
20 KiB
from collections import OrderedDict
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from enum import Enum
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from .lightning import LightningRpc, Millisatoshi
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from threading import RLock
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import inspect
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import json
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import os
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import re
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import sys
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import traceback
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class MethodType(Enum):
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RPCMETHOD = 0
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HOOK = 1
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class RequestState(Enum):
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PENDING = 'pending'
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FINISHED = 'finished'
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FAILED = 'failed'
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class Method(object):
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"""Description of methods that are registered with the plugin.
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These can be one of the following:
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- RPC exposed by RPC passthrough
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- HOOK registered to be called synchronously by lightningd
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"""
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def __init__(self, name, func, mtype=MethodType.RPCMETHOD, category=None,
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desc=None, long_desc=None):
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self.name = name
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self.func = func
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self.mtype = mtype
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self.category = category
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self.background = False
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self.desc = desc
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self.long_desc = long_desc
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class Request(dict):
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"""A request object that wraps params and allows async return
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"""
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def __init__(self, plugin, req_id, method, params, background=False):
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self.method = method
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self.params = params
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self.background = background
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self.plugin = plugin
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self.state = RequestState.PENDING
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self.id = req_id
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def getattr(self, key):
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if key == "params":
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return self.params
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elif key == "id":
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return self.id
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elif key == "method":
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return self.method
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def set_result(self, result):
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if self.state != RequestState.PENDING:
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raise ValueError(
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"Cannot set the result of a request that is not pending, "
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"current state is {state}".format(self.state))
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self.result = result
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self._write_result({
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'jsonrpc': '2.0',
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'id': self.id,
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'result': self.result
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})
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def set_exception(self, exc):
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if self.state != RequestState.PENDING:
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raise ValueError(
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"Cannot set the exception of a request that is not pending, "
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"current state is {state}".format(self.state))
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self.exc = exc
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self._write_result({
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'jsonrpc': '2.0',
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'id': self.id,
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"error": "Error while processing {method}: {exc}".format(
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method=self.method, exc=repr(exc)
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),
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})
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def _write_result(self, result):
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self.plugin._write_locked(result)
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class Plugin(object):
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"""Controls interactions with lightningd, and bundles functionality.
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The Plugin class serves two purposes: it collects RPC methods and
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options, and offers a control loop that dispatches incoming RPC
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calls and hooks.
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"""
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def __init__(self, stdout=None, stdin=None, autopatch=True, dynamic=True):
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self.methods = {'init': Method('init', self._init, MethodType.RPCMETHOD)}
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self.options = {}
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# A dict from topics to handler functions
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self.subscriptions = {}
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if not stdout:
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self.stdout = sys.stdout
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if not stdin:
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self.stdin = sys.stdin
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self.lightning_version = None
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if os.getenv('LIGHTNINGD_VERSION'):
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self.lightning_version = os.getenv('LIGHTNINGD_VERSION')
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if os.getenv('LIGHTNINGD_PLUGIN') and autopatch:
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monkey_patch(self, stdout=True, stderr=True)
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self.add_method("getmanifest", self._getmanifest, background=False)
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self.rpc_filename = None
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self.lightning_dir = None
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self.rpc = None
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self.startup = True
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self.dynamic = dynamic
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self.child_init = None
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self.write_lock = RLock()
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def add_method(self, name, func, background=False, category=None, desc=None,
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long_desc=None):
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"""Add a plugin method to the dispatch table.
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The function will be expected at call time (see `_dispatch`)
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and the parameters from the JSON-RPC call will be mapped to
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the function arguments. In addition to the parameters passed
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from the JSON-RPC call we add a few that may be useful:
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- `plugin`: gets a reference to this plugin.
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- `request`: gets a reference to the raw request as a
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dict. This corresponds to the JSON-RPC message that is
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being dispatched.
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Notice that due to the python binding logic we may be mapping
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the arguments wrongly if we inject the plugin and/or request
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in combination with positional binding. To prevent issues the
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plugin and request argument should always be the last two
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arguments and have a default on None.
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The `background` argument can be used to specify whether the method is
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going to return a result that should be sent back to the lightning
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daemon (`background=False`) or whether the method will return without
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sending back a result. In the latter case the method MUST use
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`request.set_result` or `result.set_exception` to return a result or
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raise an exception for the call.
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The `category` argument can be used to specify the category of the
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newly created rpc command.
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"""
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if name in self.methods:
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raise ValueError(
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"Name {} is already bound to a method.".format(name)
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)
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# Register the function with the name
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method = Method(name, func, MethodType.RPCMETHOD, category, desc, long_desc)
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method.background = background
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self.methods[name] = method
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def add_subscription(self, topic, func):
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"""Add a subscription to our list of subscriptions.
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A subscription is an association between a topic and a handler
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function. Adding a subscription means that we will
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automatically subscribe to events from that topic with
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`lightningd` and, upon receiving a matching notification, we
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will call the associated handler. Notice that in order for the
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automatic subscriptions to work, the handlers need to be
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registered before we send our manifest, hence before
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`Plugin.run` is called.
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"""
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if topic in self.subscriptions:
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raise ValueError(
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"Topic {} already has a handler".format(topic)
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)
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# Make sure the notification callback has a **kwargs argument so that it
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# doesn't break if we add more arguments to the call later on. Issue a
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# warning if it does not.
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s = inspect.signature(func)
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kinds = [p.kind for p in s.parameters.values()]
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if inspect.Parameter.VAR_KEYWORD not in kinds:
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self.log(
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"Notification handler {} for notification {} does not have a "
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"variable keyword argument. It is strongly suggested to add "
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"`**kwargs` as last parameter to hook and notification "
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"handlers.".format(func.__name__, topic), level="warn")
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self.subscriptions[topic] = func
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def subscribe(self, topic):
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"""Function decorator to register a notification handler.
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"""
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def decorator(f):
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self.add_subscription(topic, f)
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return f
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return decorator
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def add_option(self, name, default, description, opt_type="string"):
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"""Add an option that we'd like to register with lightningd.
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Needs to be called before `Plugin.run`, otherwise we might not
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end up getting it set.
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"""
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if name in self.options:
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raise ValueError(
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"Name {} is already used by another option".format(name)
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)
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self.options[name] = {
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'name': name,
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'default': default,
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'description': description,
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'type': opt_type,
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'value': None,
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}
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def get_option(self, name):
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if name not in self.options:
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raise ValueError("No option with name {} registered".format(name))
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if self.options[name]['value'] is not None:
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return self.options[name]['value']
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else:
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return self.options[name]['default']
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def async_method(self, method_name, category=None, desc=None, long_desc=None):
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"""Decorator to add an async plugin method to the dispatch table.
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Internally uses add_method.
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"""
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def decorator(f):
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self.add_method(method_name, f, background=True, category=category,
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desc=desc, long_desc=long_desc)
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return f
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return decorator
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def method(self, method_name, category=None, desc=None, long_desc=None):
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"""Decorator to add a plugin method to the dispatch table.
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Internally uses add_method.
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"""
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def decorator(f):
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self.add_method(method_name, f, background=False, category=category,
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desc=desc, long_desc=long_desc)
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return f
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return decorator
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def add_hook(self, name, func, background=False):
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"""Register a hook that is called synchronously by lightningd on events
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"""
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if name in self.methods:
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raise ValueError(
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"Method {} was already registered".format(name, self.methods[name])
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)
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# Make sure the hook callback has a **kwargs argument so that it
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# doesn't break if we add more arguments to the call later on. Issue a
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# warning if it does not.
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s = inspect.signature(func)
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kinds = [p.kind for p in s.parameters.values()]
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if inspect.Parameter.VAR_KEYWORD not in kinds:
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self.log(
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"Hook handler {} for hook {} does not have a variable keyword "
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"argument. It is strongly suggested to add `**kwargs` as last "
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"parameter to hook and notification handlers.".format(
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func.__name__, name), level="warn")
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method = Method(name, func, MethodType.HOOK)
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method.background = background
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self.methods[name] = method
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def hook(self, method_name):
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"""Decorator to add a plugin hook to the dispatch table.
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Internally uses add_hook.
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"""
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def decorator(f):
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self.add_hook(method_name, f, background=False)
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return f
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return decorator
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def async_hook(self, method_name):
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"""Decorator to add an async plugin hook to the dispatch table.
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Internally uses add_hook.
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"""
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def decorator(f):
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self.add_hook(method_name, f, background=True)
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return f
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return decorator
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def init(self, *args, **kwargs):
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"""Decorator to add a function called after plugin initialization
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"""
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def decorator(f):
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if self.child_init is not None:
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raise ValueError('The @plugin.init decorator should only be used once')
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self.child_init = f
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return f
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return decorator
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@staticmethod
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def _coerce_arguments(func, ba):
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args = OrderedDict()
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annotations = func.__annotations__ if hasattr(func, "__annotations__") else {}
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for key, val in ba.arguments.items():
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annotation = annotations.get(key, None)
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if annotation is not None and annotation == Millisatoshi:
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args[key] = Millisatoshi(val)
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else:
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args[key] = val
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ba.arguments = args
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return ba
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def _bind_pos(self, func, params, request):
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"""Positional binding of parameters
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"""
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assert(isinstance(params, list))
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sig = inspect.signature(func)
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# Collect injections so we can sort them and insert them in the right
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# order later. If we don't apply inject them in increasing order we
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# might shift away an earlier injection.
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injections = []
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if 'plugin' in sig.parameters:
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pos = list(sig.parameters.keys()).index('plugin')
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injections.append((pos, self))
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if 'request' in sig.parameters:
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pos = list(sig.parameters.keys()).index('request')
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injections.append((pos, request))
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injections = sorted(injections)
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for pos, val in injections:
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params = params[:pos] + [val] + params[pos:]
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ba = sig.bind(*params)
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self._coerce_arguments(func, ba)
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ba.apply_defaults()
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return ba
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def _bind_kwargs(self, func, params, request):
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"""Keyword based binding of parameters
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"""
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assert(isinstance(params, dict))
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sig = inspect.signature(func)
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# Inject additional parameters if they are in the signature.
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if 'plugin' in sig.parameters:
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params['plugin'] = self
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elif 'plugin' in params:
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del params['plugin']
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if 'request' in sig.parameters:
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params['request'] = request
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elif 'request' in params:
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del params['request']
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ba = sig.bind(**params)
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self._coerce_arguments(func, ba)
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return ba
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def _exec_func(self, func, request):
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params = request.params
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if isinstance(params, list):
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ba = self._bind_pos(func, params, request)
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return func(*ba.args, **ba.kwargs)
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elif isinstance(params, dict):
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ba = self._bind_kwargs(func, params, request)
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return func(*ba.args, **ba.kwargs)
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else:
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raise TypeError("Parameters to function call must be either a dict or a list.")
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def _dispatch_request(self, request):
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name = request.method
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if name not in self.methods:
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raise ValueError("No method {} found.".format(name))
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method = self.methods[name]
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request.background = method.background
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try:
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result = self._exec_func(method.func, request)
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if not method.background:
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# Only if this is not an async (background) call do we need to
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# return the result, otherwise the callee will eventually need
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# to call request.set_result or request.set_exception to
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# return a result or raise an exception.
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request.set_result(result)
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except Exception as e:
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request.set_exception(e)
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self.log(traceback.format_exc())
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def _dispatch_notification(self, request):
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if request.method not in self.subscriptions:
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raise ValueError("No subscription for {name} found.".format(
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name=request.method))
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func = self.subscriptions[request.method]
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try:
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self._exec_func(func, request)
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except Exception:
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self.log(traceback.format_exc())
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def _write_locked(self, obj):
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# ensure_ascii turns UTF-8 into \uXXXX so we need to suppress that,
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# then utf8 ourselves.
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s = bytes(json.dumps(obj, cls=LightningRpc.LightningJSONEncoder, ensure_ascii=False) + "\n\n", encoding='utf-8')
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with self.write_lock:
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self.stdout.buffer.write(s)
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self.stdout.flush()
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def notify(self, method, params):
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payload = {
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'jsonrpc': '2.0',
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'method': method,
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'params': params,
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}
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self._write_locked(payload)
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def log(self, message, level='info'):
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# Split the log into multiple lines and print them
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# individually. Makes tracebacks much easier to read.
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for line in message.split('\n'):
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self.notify('log', {'level': level, 'message': line})
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def _parse_request(self, jsrequest):
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request = Request(
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plugin=self,
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req_id=jsrequest.get('id', None),
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method=jsrequest['method'],
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params=jsrequest['params'],
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background=False,
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)
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return request
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def _multi_dispatch(self, msgs):
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"""We received a couple of messages, now try to dispatch them all.
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Returns the last partial message that was not complete yet.
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"""
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for payload in msgs[:-1]:
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# Note that we use function annotations to do Millisatoshi conversions
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# in _exec_func, so we don't use LightningJSONDecoder here.
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request = self._parse_request(json.loads(payload.decode('utf8')))
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# If this has an 'id'-field, it's a request and returns a
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# result. Otherwise it's a notification and it doesn't
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# return anything.
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if request.id is not None:
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self._dispatch_request(request)
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else:
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self._dispatch_notification(request)
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return msgs[-1]
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def run(self):
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partial = b""
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for l in self.stdin.buffer:
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partial += l
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msgs = partial.split(b'\n\n')
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if len(msgs) < 2:
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continue
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partial = self._multi_dispatch(msgs)
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def _getmanifest(self, **kwargs):
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methods = []
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hooks = []
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for method in self.methods.values():
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# Skip the builtin ones, they don't get reported
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if method.name in ['getmanifest', 'init']:
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continue
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if method.mtype == MethodType.HOOK:
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hooks.append(method.name)
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continue
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doc = inspect.getdoc(method.func)
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if not doc:
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self.log(
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'RPC method \'{}\' does not have a docstring.'.format(method.name)
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)
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doc = "Undocumented RPC method from a plugin."
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doc = re.sub('\n+', ' ', doc)
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# Handles out-of-order use of parameters like:
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# def hello_obfus(arg1, arg2, plugin, thing3, request=None, thing5='at', thing6=21)
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argspec = inspect.getfullargspec(method.func)
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defaults = argspec.defaults
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num_defaults = len(defaults) if defaults else 0
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start_kwargs_idx = len(argspec.args) - num_defaults
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args = []
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for idx, arg in enumerate(argspec.args):
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if arg in ('plugin', 'request'):
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continue
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# Positional arg
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if idx < start_kwargs_idx:
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args.append("%s" % arg)
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# Keyword arg
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else:
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args.append("[%s]" % arg)
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methods.append({
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'name': method.name,
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'category': method.category if method.category else "plugin",
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'usage': " ".join(args),
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'description': doc if not method.desc else method.desc
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})
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if method.long_desc:
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methods[len(methods) - 1]["long_description"] = method.long_desc
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return {
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'options': list(self.options.values()),
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'rpcmethods': methods,
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'subscriptions': list(self.subscriptions.keys()),
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'hooks': hooks,
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'dynamic': self.dynamic
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}
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def _init(self, options, configuration, request):
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self.rpc_filename = configuration['rpc-file']
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self.lightning_dir = configuration['lightning-dir']
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path = os.path.join(self.lightning_dir, self.rpc_filename)
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self.rpc = LightningRpc(path)
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self.startup = configuration['startup']
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|
for name, value in options.items():
|
|
self.options[name]['value'] = value
|
|
|
|
# Dispatch the plugin's init handler if any
|
|
if self.child_init:
|
|
return self._exec_func(self.child_init, request)
|
|
return None
|
|
|
|
|
|
class PluginStream(object):
|
|
"""Sink that turns everything that is written to it into a notification.
|
|
"""
|
|
|
|
def __init__(self, plugin, level="info"):
|
|
self.plugin = plugin
|
|
self.level = level
|
|
self.buff = ''
|
|
|
|
def write(self, payload):
|
|
self.buff += payload
|
|
|
|
if len(payload) > 0 and payload[-1] == '\n':
|
|
self.flush()
|
|
|
|
def flush(self):
|
|
lines = self.buff.split('\n')
|
|
if len(lines) < 2:
|
|
return
|
|
|
|
for l in lines[:-1]:
|
|
self.plugin.log(l, self.level)
|
|
|
|
# lines[-1] is either an empty string or a partial line
|
|
self.buff = lines[-1]
|
|
|
|
|
|
def monkey_patch(plugin, stdout=True, stderr=False):
|
|
"""Monkey patch stderr and stdout so we use notifications instead.
|
|
|
|
A plugin commonly communicates with lightningd over its stdout and
|
|
stdin filedescriptor, so if we use them in some other way
|
|
(printing, logging, ...) we're breaking our communication
|
|
channel. This function monkey patches these streams in the `sys`
|
|
module to be redirected to a `PluginStream` which wraps anything
|
|
that would get written to these streams into valid log
|
|
notifications that can be interpreted and printed by `lightningd`.
|
|
|
|
"""
|
|
if stdout:
|
|
setattr(sys, "stdout", PluginStream(plugin, level="info"))
|
|
if stderr:
|
|
setattr(sys, "stderr", PluginStream(plugin, level="warn"))
|
|
|