From 00eec8f85c4e566a653c87c3e6a5c4b33548c766 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sybren=20A=2E=20St=C3=BCvel?= <sybren@stuvel.eu>
Date: Thu, 13 Apr 2017 11:06:43 +0200
Subject: [PATCH] Writing PID file whenever Flamenco-Worker is running.
Added optional creation and removal of a PID file. This only happens when
the `pid` configuration option is given, pointing to the location of the
PID file.
This is an attempt to prevent the sysv script from starting Flamenco-Worker
when it is already running (i.e. after two "service flamenco-worker start"
commands).
---
CHANGELOG.md | 6 +++++
README.md | 5 ++++
flamenco-worker.cfg | 2 ++
flamenco_worker/cli.py | 33 +++++++++++++++++++++++++
flamenco_worker/config.py | 1 +
system-integration/sysv/flamenco-worker | 4 +--
6 files changed, 49 insertions(+), 2 deletions(-)
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f28115ac..aeaef822 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,12 @@ This file logs the changes that are actually interesting to users (new features,
changed functionality, fixed bugs).
+## Version 2.0.3 (under development)
+
+- Added optional creation and removal of a PID file. This only happens when the `pid`
+ configuration option is given, pointing to the location of the PID file.
+
+
## Version 2.0.2 (released 2017-04-07)
- Added support for task types. Workers only get tasks of the types they support.
diff --git a/README.md b/README.md
index e3639f00..205e4cf4 100644
--- a/README.md
+++ b/README.md
@@ -36,6 +36,11 @@ config files.
- `job_types`: Space-separated list of job types this worker may execute.
- `task_update_queue_db`: filename of the SQLite3 database holding the queue of task
updates to be sent to the Master.
+- `pid`: Location of the PID file that'll be created when Flamenco-Worker is running,
+ and removed on startup. It'll contain the process ID. This is required when using the
+ SysV service script. When not present (or with empty value), the PID file will neither
+ be created nor removed.
+
These configuration keys are also required, but are created automatically upon startup
when they don't exist yet:
diff --git a/flamenco-worker.cfg b/flamenco-worker.cfg
index 7b774fae..dee7ca1b 100644
--- a/flamenco-worker.cfg
+++ b/flamenco-worker.cfg
@@ -1,4 +1,6 @@
[flamenco-worker]
+# Uncomment to create a PID file at the configured location.
+# pid = /var/run/flamenco-worker/flamenco-worker.pid
manager_url = http://localhost:8083/
task_types = sleep blender-render file-management
task_update_queue_db = flamenco-worker.db
diff --git a/flamenco_worker/cli.py b/flamenco_worker/cli.py
index fd39d1e0..adfa2090 100644
--- a/flamenco_worker/cli.py
+++ b/flamenco_worker/cli.py
@@ -4,10 +4,36 @@ import argparse
import asyncio
import logging
import logging.config
+import pathlib
import requests
+def create_pidfile(path: pathlib.Path):
+ """Creates a PID file in the given location.
+
+ Als uses the atexit module to remove the PID file once the process is terminated.
+ """
+
+ import atexit
+ import os
+
+ def remove_pidfile():
+ if path.exists():
+ path.unlink()
+
+ atexit.register(remove_pidfile)
+
+ log = logging.getLogger(__name__)
+ pid = os.getpid()
+
+ if path.exists():
+ log.info('Overwriting PID file %s with our PID %i', path, pid)
+ else:
+ log.info('Creating PID file %s with our PID %i', path, pid)
+ path.write_text(str(pid), encoding='ascii')
+
+
def main():
parser = argparse.ArgumentParser()
parser.add_argument('-c', '--config',
@@ -25,6 +51,13 @@ def main():
log = logging.getLogger(__name__)
log.debug('Starting')
+ # Create the PID file, if the location is configured.
+ pidfile = confparser.value('pid')
+ if pidfile:
+ create_pidfile(pathlib.Path(pidfile))
+ else:
+ log.info("Not creating PID file because the configuration has no value for the 'pid' key.")
+
# Patch AsyncIO
from . import patch_asyncio
patch_asyncio.patch_asyncio()
diff --git a/flamenco_worker/config.py b/flamenco_worker/config.py
index d3481cd7..7b364b65 100644
--- a/flamenco_worker/config.py
+++ b/flamenco_worker/config.py
@@ -14,6 +14,7 @@ CONFIG_SECTION = 'flamenco-worker'
DEFAULT_CONFIG = {
'flamenco-worker': collections.OrderedDict([
+ ('pid', ''), # Optional location of the PID-file
('manager_url', 'http://flamenco-manager/'),
('task_types', 'unknown sleep blender-render'),
('task_update_queue_db', 'flamenco-worker.db'),
diff --git a/system-integration/sysv/flamenco-worker b/system-integration/sysv/flamenco-worker
index 4bd6032b..148dd298 100644
--- a/system-integration/sysv/flamenco-worker
+++ b/system-integration/sysv/flamenco-worker
@@ -21,7 +21,7 @@ DESC="Flamenco Worker"
NAME=flamenco-worker
DAEMON=$FLAMENCO_WORKER
SCRIPTNAME=/etc/init.d/$NAME
-PIDFILE=/var/run/$NAME.pid
+PIDFILE=/home/guest/local-flamenco-worker/$NAME.pid
USER=guest
GROUP=guest
@@ -38,7 +38,7 @@ do_start()
{
sudo -u $USER mkdir -p /home/guest/local-flamenco-worker
start-stop-daemon --start --quiet --pidfile $PIDFILE --name $NAME \
- --exec $DAEMON --chuid $USER:$GROUP --chdir $WORK_DIR --make-pidfile --background
+ --exec $DAEMON --chuid $USER:$GROUP --chdir $WORK_DIR --background
return "$?"
}
--
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