zuul/zuul
Code Issues Proposed changes
zuul/zuul/merger/server.py
Simon Westphahl b17dfc13ed
Cleanup leaked git index.lock files on checkout 
When the git command crashes or is aborted due to a timeout we might end
up with a leaked index.lock file in the affected repository.

This has the effect that all subsequent git operations that try to
create the lock will fail. Since Zuul maintains a separate lock for
serializing operations on a repositotry, we can be sure that the lock
file was leaked in a previous operation and can be removed safely.

Unable to checkout 8a87ff7cc0d0c73ac14217b653f9773a7cfce3a7
Traceback (most recent call last):
  File "/opt/zuul/lib/python3.10/site-packages/zuul/merger/merger.py", line 1045, in _mergeChange
    repo.checkout(ref, zuul_event_id=zuul_event_id)
  File "/opt/zuul/lib/python3.10/site-packages/zuul/merger/merger.py", line 561, in checkout
    repo.head.reset(working_tree=True)
  File "/opt/zuul/lib/python3.10/site-packages/git/refs/head.py", line 82, in reset
    self.repo.git.reset(mode, commit, '--', paths, **kwargs)
  File "/opt/zuul/lib/python3.10/site-packages/git/cmd.py", line 542, in <lambda>
    return lambda *args, **kwargs: self._call_process(name, *args, **kwargs)
  File "/opt/zuul/lib/python3.10/site-packages/git/cmd.py", line 1005, in _call_process
    return self.execute(call, **exec_kwargs)
  File "/opt/zuul/lib/python3.10/site-packages/git/cmd.py", line 822, in execute
    raise GitCommandError(command, status, stderr_value, stdout_value)
git.exc.GitCommandError: Cmd('git') failed due to: exit code(128)
  cmdline: git reset --hard HEAD --
  stderr: 'fatal: Unable to create '/var/lib/zuul/merger-git/github/foo/foo%2Fbar/.git/index.lock': File exists.
  Another git process seems to be running in this repository, e.g.
  an editor opened by 'git commit'. Please make sure all processes
  are terminated then try again. If it still fails, a git process
  may have crashed in this repository earlier:
  remove the file manually to continue.'

Change-Id: I97334383df476809c39e0d03b1af50cb59ee0cc7
2022-11-15 07:03:21 +01:00

561 lines
20 KiB
Python
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# Copyright 2014 OpenStack Foundation
# Copyright 2021-2022 Acme Gating, LLC
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import json
import logging
import socket
import sys
import threading
import time
from abc import ABCMeta
from configparser import ConfigParser
from kazoo.exceptions import NoNodeError
from zuul.lib import commandsocket
from zuul.lib.config import get_default
from zuul.lib.logutil import get_annotated_logger
from zuul.lib import tracing
from zuul.merger import merger
from zuul.merger.merger import nullcontext
from zuul.model import (
FilesChangesCompletedEvent, MergeCompletedEvent, MergeRequest
)
from zuul.lib.monitoring import MonitoringServer
from zuul.version import get_version_string
from zuul.zk import ZooKeeperClient
from zuul.zk.components import MergerComponent
from zuul.zk.event_queues import PipelineResultEventQueue
from zuul.zk.merger import MergerApi
COMMANDS = [
commandsocket.StopCommand,
commandsocket.PauseCommand,
commandsocket.UnPauseCommand,
commandsocket.GracefulCommand
]
class BaseRepoLocks(metaclass=ABCMeta):
def getRepoLock(self, connection_name, project_name):
return nullcontext()
class RepoLocks(BaseRepoLocks):
def __init__(self):
self.locks = {}
def getRepoLock(self, connection_name, project_name):
key = '%s:%s' % (connection_name, project_name)
self.locks.setdefault(key, threading.Lock())
return self.locks[key]
class BaseMergeServer(metaclass=ABCMeta):
log = logging.getLogger("zuul.BaseMergeServer")
_repo_locks_class = BaseRepoLocks
def __init__(
self,
config: ConfigParser,
component: str,
connections,
):
self.connections = connections
self._merger_running = False
self._merger_paused = False
self.merge_email = get_default(config, 'merger', 'git_user_email',
'zuul.merger.default@example.com')
self.merge_name = get_default(config, 'merger', 'git_user_name',
'Zuul Merger Default')
self.merge_speed_limit = get_default(
config, 'merger', 'git_http_low_speed_limit', '1000')
self.merge_speed_time = get_default(
config, 'merger', 'git_http_low_speed_time', '30')
self.git_timeout = get_default(config, 'merger', 'git_timeout', 300)
self.merge_root = get_default(config, component, 'git_dir',
'/var/lib/zuul/{}-git'.format(component))
self.config = config
self.tracing = tracing.Tracing(self.config)
self.zk_client = ZooKeeperClient.fromConfig(self.config)
self.zk_client.connect()
self.result_events = PipelineResultEventQueue.createRegistry(
self.zk_client
)
self.merger_thread = threading.Thread(
target=self.runMerger,
name="Merger",
)
self.merger_loop_wake_event = threading.Event()
self.merger_api = MergerApi(
self.zk_client,
merge_request_callback=self.merger_loop_wake_event.set,
)
# This merger and its git repos are used to maintain
# up-to-date copies of all the repos that are used by jobs, as
# well as to support the merger:cat functon to supply
# configuration information to Zuul when it starts.
self.merger = self._getMerger(self.merge_root, None,
execution_context=False)
# Repo locking is needed on the executor
self.repo_locks = self._repo_locks_class()
def _getMerger(self, root, cache_root, logger=None,
execution_context=True, scheme=None,
cache_scheme=None):
return merger.Merger(
root,
self.connections,
self.zk_client,
self.merge_email,
self.merge_name,
self.merge_speed_limit,
self.merge_speed_time,
cache_root,
logger,
execution_context=execution_context,
git_timeout=self.git_timeout,
scheme=scheme,
cache_scheme=cache_scheme,
)
def _repoLock(self, connection_name, project_name):
# The merger does not need locking so return a null lock.
return nullcontext()
def _update(self, connection_name, project_name, zuul_event_id=None):
# The executor overrides _update so it can do the update
# asynchronously.
self.merger.updateRepo(connection_name, project_name,
zuul_event_id=zuul_event_id)
def start(self):
self.log.debug('Starting merger')
self._merger_running = True
self.merger_thread.start()
def stop(self):
self.log.debug('Stopping base merge server')
self._merger_running = False
self.merger_loop_wake_event.set()
self.tracing.stop()
self.log.debug('Stopped base merge server')
def join(self):
self.log.debug('Joining base merge server')
self.merger_loop_wake_event.set()
self.merger_thread.join()
self.zk_client.disconnect()
self.log.debug('Joined base merge server')
def pause(self):
self.log.debug('Pausing merger')
self._merger_paused = True
def unpause(self):
self.log.debug('Resuming merger')
self._merger_paused = False
self.merger_loop_wake_event.set()
def runMerger(self):
while self._merger_running:
self.merger_loop_wake_event.wait()
self.merger_loop_wake_event.clear()
if self._merger_paused:
continue
try:
for merge_request in self.merger_api.next():
if not self._merger_running:
break
self._lockAndRunMergeJob(merge_request)
except Exception:
self.log.exception("Error in merge thread:")
time.sleep(5)
self.merger_loop_wake_event.set()
def _lockAndRunMergeJob(self, merge_request):
# Lock and update the merge request
if not self.merger_api.lock(merge_request, blocking=False):
return
with tracing.startSpanInContext(
merge_request.span_context, "MergerJob",
attributes={"merger": self.hostname}):
self._runMergeJob(merge_request)
def _runMergeJob(self, merge_request):
log = get_annotated_logger(
self.log, merge_request.event_id
)
# Ensure that the request is still in state requested. This method is
# called based on cached data and there might be a mismatch between the
# cached state and the real state of the request. The lock might
# have been successful because the request is already completed and
# thus unlocked.
if merge_request.state != MergeRequest.REQUESTED:
self._retry(merge_request.lock, log, self.merger_api.unlock,
merge_request)
try:
merge_request.state = MergeRequest.RUNNING
params = self.merger_api.getParams(merge_request)
except Exception:
log.exception("Exception while preparing to start merge job")
# If we failed at this point, we have not written anything
# to ZK yet; the only thing we need to do is to ensure
# that we release the lock, and another merger will be
# able to grab the request.
self._retry(merge_request.lock, log, self.merger_api.unlock,
merge_request)
return
result = None
try:
self.merger_api.clearParams(merge_request)
# Directly update the merge request in ZooKeeper, so we
# don't loop over and try to lock it again and again.
self.merger_api.update(merge_request)
self.log.debug("Next executed merge job: %s", merge_request)
try:
result = self.executeMergeJob(merge_request, params)
except Exception:
log.exception("Error running merge job:")
finally:
self.completeMergeJob(merge_request, result)
def executeMergeJob(self, merge_request, params):
result = None
start = time.monotonic()
if merge_request.job_type == MergeRequest.MERGE:
result = self.merge(merge_request, params)
elif merge_request.job_type == MergeRequest.CAT:
result = self.cat(merge_request, params)
elif merge_request.job_type == MergeRequest.REF_STATE:
result = self.refstate(merge_request, params)
elif merge_request.job_type == MergeRequest.FILES_CHANGES:
result = self.fileschanges(merge_request, params)
end = time.monotonic()
result['elapsed_time'] = end - start
return result
def cat(self, merge_request, args):
self.log.debug("Got cat job: %s", merge_request.uuid)
connection_name = args['connection']
project_name = args['project']
lock = self.repo_locks.getRepoLock(connection_name, project_name)
try:
self._update(connection_name, project_name)
with lock:
files = self.merger.getFiles(connection_name, project_name,
args['branch'], args['files'],
args.get('dirs'))
except Exception:
result = dict(update=False)
else:
result = dict(updated=True, files=files)
return result
def merge(self, merge_request, args):
self.log.debug("Got merge job: %s", merge_request.uuid)
zuul_event_id = merge_request.event_id
errors = []
result = dict(merged=False,
commit=None,
files=None,
repo_state=None,
zuul_event_id=zuul_event_id,
errors=errors)
for item in args['items']:
try:
self._update(item['connection'], item['project'])
except Exception:
msg = (f"Unable to update {item['connection']}/"
f"{item['project']}")
errors.append(msg)
return result
ret = self.merger.mergeChanges(
args['items'], args.get('files'),
args.get('dirs', []),
args.get('repo_state'),
branches=args.get('branches'),
repo_locks=self.repo_locks,
zuul_event_id=zuul_event_id,
errors=errors)
if ret is not None:
result['merged'] = True
(result['commit'], result['files'], result['repo_state'],
recent, orig_commit) = ret
return result
def refstate(self, merge_request, args):
self.log.debug("Got refstate job: %s", merge_request.uuid)
zuul_event_id = merge_request.event_id
success, repo_state, item_in_branches = \
self.merger.getRepoState(
args['items'], self.repo_locks, branches=args.get('branches'))
result = dict(updated=success,
repo_state=repo_state,
item_in_branches=item_in_branches)
result['zuul_event_id'] = zuul_event_id
return result
def fileschanges(self, merge_request, args):
self.log.debug("Got fileschanges job: %s", merge_request.uuid)
zuul_event_id = merge_request.event_id
connection_name = args['connection']
project_name = args['project']
lock = self.repo_locks.getRepoLock(connection_name, project_name)
try:
self._update(connection_name, project_name,
zuul_event_id=zuul_event_id)
with lock:
files = self.merger.getFilesChanges(
connection_name, project_name,
args['branch'], args['tosha'],
zuul_event_id=zuul_event_id)
except Exception:
result = dict(update=False)
else:
result = dict(updated=True, files=files)
result['zuul_event_id'] = zuul_event_id
return result
def completeMergeJob(self, merge_request, result):
log = get_annotated_logger(self.log, merge_request.event_id)
# Always provide a result event, even if we have no
# information; otherwise items can get stuck in the queue.
if result is None:
result = {}
payload = json.dumps(result, sort_keys=True)
self.log.debug("Completed %s job %s: payload size: %s",
merge_request.job_type, merge_request.uuid,
sys.getsizeof(payload))
merged = result.get("merged", False)
updated = result.get("updated", False)
commit = result.get("commit")
repo_state = result.get("repo_state", {})
item_in_branches = result.get("item_in_branches", [])
files = result.get("files", {})
errors = result.get("errors", [])
elapsed_time = result.get("elapsed_time")
log.info(
"Merge %s complete, merged: %s, updated: %s, commit: %s, "
"branches: %s",
merge_request,
merged,
updated,
commit,
item_in_branches,
)
lock_valid = merge_request.lock.is_still_valid()
if not lock_valid:
return
# Provide a result either via a result future or a result event
if merge_request.result_path:
log.debug(
"Providing synchronous result via future for %s",
merge_request,
)
self._retry(merge_request.lock, log,
self.merger_api.reportResult, merge_request, result)
elif merge_request.build_set_uuid:
log.debug(
"Providing asynchronous result via result event for %s",
merge_request,
)
if merge_request.job_type == MergeRequest.FILES_CHANGES:
event = FilesChangesCompletedEvent(
merge_request.uuid,
merge_request.build_set_uuid,
files,
elapsed_time,
merge_request.span_info,
)
else:
event = MergeCompletedEvent(
merge_request.uuid,
merge_request.build_set_uuid,
merged,
updated,
commit,
files,
repo_state,
item_in_branches,
errors,
elapsed_time,
merge_request.span_info,
)
def put_complete_event(log, merge_request, event):
try:
self.result_events[merge_request.tenant_name][
merge_request.pipeline_name].put(event)
except NoNodeError:
log.warning("Pipeline was removed: %s",
merge_request.pipeline_name)
self._retry(merge_request.lock, log,
put_complete_event, log, merge_request, event)
# Set the merge request to completed, unlock and delete it. Although
# the state update is mainly for consistency reasons, it might come in
# handy in case the deletion or unlocking failes. Thus, we know that
# the merge request was already processed and we have a result in the
# result queue.
merge_request.state = MergeRequest.COMPLETED
self._retry(merge_request.lock, log,
self.merger_api.update, merge_request)
self._retry(merge_request.lock, log,
self.merger_api.unlock, merge_request)
# TODO (felix): If we want to optimize ZK requests, we could only call
# the remove() here.
self.merger_api.remove(merge_request)
def _retry(self, lock, log, fn, *args, **kw):
"""Retry a method to deal with ZK connection issues
This is a helper method to retry ZK operations as long as it
makes sense to do so. If we have encountered a suspended
connection, we can probably just retry the ZK operation until
it succeeds. If we have fully lost the connection, then we
have lost the lock, so we may not care in that case.
This method exits when one of the following occurs:
* The callable function completes.
* This server stops.
* The lock (if supplied) is invalidated due to connection loss.
Pass None as the lock parameter if the lock issue is not
relevant.
"""
while True:
if lock and not lock.is_still_valid():
return
try:
return fn(*args, **kw)
except Exception:
log.exception("Exception retrying %s", fn)
if not self._running:
return
time.sleep(5)
class MergeServer(BaseMergeServer):
log = logging.getLogger("zuul.MergeServer")
def __init__(
self,
config: ConfigParser,
connections,
):
super().__init__(config, 'merger', connections)
self.hostname = socket.getfqdn()
self.component_info = MergerComponent(
self.zk_client, self.hostname, version=get_version_string())
self.component_info.register()
self.monitoring_server = MonitoringServer(self.config, 'merger',
self.component_info)
self.monitoring_server.start()
self.command_map = {
commandsocket.StopCommand.name: self.stop,
# Stop for the mergers is always graceful. We add this alias
# to make it clearer to users that they can gracefully stop.
commandsocket.GracefulCommand.name: self.stop,
commandsocket.PauseCommand.name: self.pause,
commandsocket.UnPauseCommand.name: self.unpause,
}
command_socket = get_default(
self.config, 'merger', 'command_socket',
'/var/lib/zuul/merger.socket')
self.command_socket = commandsocket.CommandSocket(command_socket)
self._command_running = False
def start(self):
super().start()
self._command_running = True
self.log.debug("Starting command processor")
self.command_socket.start()
self.command_thread = threading.Thread(
target=self.runCommand, name='command')
self.command_thread.daemon = True
self.command_thread.start()
self.component_info.state = self.component_info.RUNNING
def stop(self):
self.log.debug("Stopping merger")
self.component_info.state = self.component_info.STOPPED
super().stop()
self._command_running = False
self.command_socket.stop()
self.monitoring_server.stop()
self.log.debug("Stopped merger")
def join(self):
self.log.debug("Joining merger")
super().join()
self.monitoring_server.join()
self.log.debug("Joined merger")
def pause(self):
self.log.debug('Pausing')
self.component_info.state = self.component_info.PAUSED
super().pause()
def unpause(self):
self.log.debug('Resuming')
super().unpause()
self.component_info.state = self.component_info.RUNNING
def runCommand(self):
while self._command_running:
try:
command, args = self.command_socket.get()
if command != '_stop':
self.command_map[command](*args)
except Exception:
self.log.exception("Exception while processing command")
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