Weekly cleanups

contrib/pyln-testing/pyln/testing/fixtures.py

@@ -1,6 +1,6 @@
 from concurrent import futures
 from pyln.testing.db import SqliteDbProvider, PostgresDbProvider
-from pyln.testing.utils import NodeFactory, BitcoinD, ElementsD, env, DEVELOPER, LightningNode, TEST_DEBUG
+from pyln.testing.utils import NodeFactory, BitcoinD, ElementsD, env, DEVELOPER, LightningNode, TEST_DEBUG, Throttler
 from typing import Dict
 
 import logging
@@ -198,15 +198,21 @@ def teardown_checks(request):
 
 
 @pytest.fixture
-def node_factory(request, directory, test_name, bitcoind, executor, db_provider, teardown_checks, node_cls):
+def throttler():
+    yield Throttler()
+
+
+@pytest.fixture
+def node_factory(request, directory, test_name, bitcoind, executor, db_provider, teardown_checks, node_cls, throttler):
     nf = NodeFactory(
         request,
         test_name,
         bitcoind,
         executor,
         directory=directory,
         db_provider=db_provider,
-        node_cls=node_cls
+        node_cls=node_cls,
+        throttler=throttler,
     )
 
     yield nf

contrib/pyln-testing/pyln/testing/utils.py

@@ -6,6 +6,7 @@
 from collections import OrderedDict
 from decimal import Decimal
 from ephemeral_port_reserve import reserve  # type: ignore
+from filelock import FileLock
 from pyln.client import LightningRpc
 from pyln.client import Millisatoshi
 
@@ -14,6 +15,7 @@
 import lzma
 import math
 import os
+import psutil  # type: ignore
 import random
 import re
 import shutil
@@ -321,7 +323,16 @@ def __getattr__(self, name):
         proxy = BitcoinProxy(btc_conf_file=self.__btc_conf_file__)
 
         def f(*args):
-            return proxy._call(name, *args)
+            logging.debug("Calling {name} with arguments {args}".format(
+                name=name,
+                args=args
+            ))
+            res = proxy._call(name, *args)
+            logging.debug("Result for {name} call: {res}".format(
+                name=name,
+                res=res,
+            ))
+            return res
 
         # Make debuggers show <function bitcoin.rpc.name> rather than <function
         # bitcoin.rpc.<lambda>>
@@ -401,6 +412,14 @@ def generate_block(self, numblocks=1, wait_for_mempool=0):
                 wait_for(lambda: all(txid in self.rpc.getrawmempool() for txid in wait_for_mempool))
             else:
                 wait_for(lambda: len(self.rpc.getrawmempool()) >= wait_for_mempool)
+
+        mempool = self.rpc.getrawmempool()
+        logging.debug("Generating {numblocks}, confirming {lenmempool} transactions: {mempool}".format(
+            numblocks=numblocks,
+            mempool=mempool,
+            lenmempool=len(mempool),
+        ))
+
         # As of 0.16, generate() is removed; use generatetoaddress.
         return self.rpc.generatetoaddress(numblocks, self.rpc.getnewaddress())
 
@@ -1021,10 +1040,59 @@ def passes_filters(hmsg, filters):
         return msgs
 
 
+class Throttler(object):
+    """Throttles the creation of system-processes to avoid overload.
+
+    There is no reason to overload the system with too many processes
+    being spawned or run at the same time. It causes timeouts by
+    aggressively preempting processes and swapping if the memory limit is
+    reached. In order to reduce this loss of performance we provide a
+    `wait()` method which will serialize the creation of processes, but
+    also delay if the system load is too high.
+
+    Notice that technically we are throttling too late, i.e., we react
+    to an overload, but chances are pretty good that some other
+    already running process is about to terminate, and so the overload
+    is short-lived. We throttle when the process object is first
+    created, not when restarted, in order to avoid delaying running
+    tests, which could cause more timeouts.
+
+    """
+    def __init__(self, target: float = 75):
+        """If specified we try to stick to a load of target (in percent).
+        """
+        self.target = target
+        self.lock = FileLock("/tmp/ltest.lock")
+        self.current_load = self.target  # Start slow
+        psutil.cpu_percent()  # Prime the internal load metric
+
+    def wait(self):
+        start_time = time.time()
+        with self.lock.acquire(poll_intervall=0.250):
+            # We just got the lock, assume someone else just released it
+            self.current_load = 100
+            while self.load() >= self.target:
+                time.sleep(1)
+
+            delay = time.time() - start_time
+            with open("/tmp/ltest-throttler.csv", "a") as f:
+                f.write("{}, {}, {}, {}\n".format(time.time(), self.load(), self.target, delay))
+            self.current_load = 100  # Back off slightly to avoid triggering right away
+
+    def load(self):
+        """An exponential moving average of the load
+        """
+        decay = 0.5
+        load = psutil.cpu_percent()
+        self.current_load = decay * load + (1 - decay) * self.current_load
+        return self.current_load
+
+
 class NodeFactory(object):
     """A factory to setup and start `lightningd` daemons.
     """
-    def __init__(self, request, testname, bitcoind, executor, directory, db_provider, node_cls):
+    def __init__(self, request, testname, bitcoind, executor, directory,
+                 db_provider, node_cls, throttler):
         if request.node.get_closest_marker("slow_test") and SLOW_MACHINE:
             self.valgrind = False
         else:
@@ -1038,6 +1106,7 @@ def __init__(self, request, testname, bitcoind, executor, directory, db_provider
         self.lock = threading.Lock()
         self.db_provider = db_provider
         self.node_cls = node_cls
+        self.throttler = throttler
 
     def split_options(self, opts):
         """Split node options from cli options
@@ -1098,7 +1167,7 @@ def get_node(self, node_id=None, options=None, dbfile=None,
                  feerates=(15000, 11000, 7500, 3750), start=True,
                  wait_for_bitcoind_sync=True, may_fail=False,
                  expect_fail=False, cleandir=True, **kwargs):
-
+        self.throttler.wait()
         node_id = self.get_node_id() if not node_id else node_id
         port = self.get_next_port()
 

contrib/pyln-testing/requirements.txt

@@ -5,3 +5,5 @@ cheroot==8.2.1
 ephemeral-port-reserve==1.1.1
 python-bitcoinlib==0.10.2
 psycopg2-binary==2.8.4
+filelock==3.0.*
+psutil==5.7.*

tests/fixtures.py

@@ -1,5 +1,5 @@
 from utils import DEVELOPER, TEST_NETWORK  # noqa: F401,F403
-from pyln.testing.fixtures import directory, test_base_dir, test_name, chainparams, node_factory, bitcoind, teardown_checks, db_provider, executor, setup_logging  # noqa: F401,F403
+from pyln.testing.fixtures import directory, test_base_dir, test_name, chainparams, node_factory, bitcoind, teardown_checks, throttler, db_provider, executor, setup_logging  # noqa: F401,F403
 from pyln.testing import utils
 from utils import COMPAT