zuul/zuul
Code Issues Proposed changes
b0f080e7b7
zuul/zuul/merger/server.py
James E. Blair 1f026bd49c Finish circular dependency refactor 
This change completes the circular dependency refactor.

The principal change is that queue items may now include
more than one change simultaneously in the case of circular
dependencies.

In dependent pipelines, the two-phase reporting process is
simplified because it happens during processing of a single
item.

In independent pipelines, non-live items are still used for
linear depnedencies, but multi-change items are used for
circular dependencies.

Previously changes were enqueued recursively and then
bundles were made out of the resulting items.  Since we now
need to enqueue entire cycles in one queue item, the
dependency graph generation is performed at the start of
enqueing the first change in a cycle.

Some tests exercise situations where Zuul is processing
events for old patchsets of changes.  The new change query
sequence mentioned in the previous paragraph necessitates
more accurate information about out-of-date patchsets than
the previous sequence, therefore the Gerrit driver has been
updated to query and return more data about non-current
patchsets.

This change is not backwards compatible with the existing
ZK schema, and will require Zuul systems delete all pipeline
states during the upgrade.  A later change will implement
a helper command for this.

All backwards compatability handling for the last several
model_api versions which were added to prepare for this
upgrade have been removed.  In general, all model data
structures involving frozen jobs are now indexed by the
frozen job's uuid and no longer include the job name since
a job name no longer uniquely identifies a job in a buildset
(either the uuid or the (job name, change) tuple must be
used to identify it).

Job deduplication is simplified and now only needs to
consider jobs within the same buildset.

The fake github driver had a bug (fakegithub.py line 694) where
it did not correctly increment the check run counter, so our
tests that verified that we closed out obsolete check runs
when re-enqueing were not valid.  This has been corrected, and
in doing so, has necessitated some changes around quiet dequeing
when we re-enqueue a change.

The reporting in several drivers has been updated to support
reporting information about multiple changes in a queue item.

Change-Id: I0b9e4d3f9936b1e66a08142fc36866269dc287f1
Depends-On: https://review.opendev.org/907627
2024-02-09 07:39:40 -08:00

573 lines
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Python
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# Copyright 2014 OpenStack Foundation
# Copyright 2021-2022, 2024 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
# MODEL_API < 26:
changes = args.get('changes')
old_format = False
if changes is None:
changes = [args]
old_format = True
results = []
for change in changes:
connection_name = change['connection']
project_name = change['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,
change['branch'], change['tosha'],
zuul_event_id=zuul_event_id)
results.append(files)
except Exception:
return dict(updated=False)
if old_format:
# MODEL_API < 26:
return dict(updated=True, files=results[0])
else:
return dict(updated=True, files=results)
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,
merge_request.event_id,
)
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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