[Command] Add support for single-process commands #3586
Comments
|
It is a not so trivial issue to fix (I mean, if we want to do it right and avoid any race condition -- what if for instance a script writes the pidfile and it then dies without removing the pidfile? You need to check that the process is still running and the way to do this depends on the filesystem). -1 to add this support to Symfony. |
|
It's fairly easy to check if a process is still running, or has died, using the |
|
I think it's doable in a decent way for unix, but it's probably be hard to make it work on windows. Then again I would still welcome such a feature. It's just hard to make generic enough. Another feature that would be nice is a timeout, so that if a process just hangs for some reason (IO deadlock or whatever) it gets killed anyway after X seconds. Say |
|
On a side note, maybe it's better to have this in the command definition, rather than implementing a method. |
|
@CodeMeme wrote a wrapper for the System_Daemon Pear package which basically does what you want https://github.com/CodeMeme/CodeMemeDaemonBundle |
|
If @fabpot doesn't really like this in the core and there's a bundle that can handle the requested feature should this issue be closed or should it be implemented by someone? If it's the later then I could pick it up and start working on something. |
|
If we can implement something that works reliably on both Linux and Windows, I'm +1. But without seeing a working implementation, it's difficult to say if I would accept it in core or not. |
|
if i am not mistaken this can be closed @fabpot as we now hace Process component 👶 |
|
@cordoval This issue is not related to the Process component. |
|
@fabpot, I think, that POSIX support is more important. And a think, that we can implement it for POSIX at the first time with abstract interfaces for all components and implement Windows support later. Because Windows Server used rarely than Unix in production and on php-developers' computers. |
|
Hey @jakzal, could you label this issue console instead of process ? |
|
@romainneutron done |
This PR was merged into the 2.6-dev branch. Discussion ---------- [Filesystem] Added a LockHandler | Q | A | ------------- | --- | Bug fix? | no | New feature? | yes | BC breaks? | no | Deprecations? | no | Tests pass? | yes | Fixed tickets | #9357 , #3586 | License | MIT | Doc PR | https://github.com/symfony/symfony-docs/pull/3956/files Code sample: ```php /** * {@inheritdoc} */ protected function execute(InputInterface $input, OutputInterface $output) { $lockHelper = new LockHandler('/tmp/acme/hello.lock'); if (!$lockHelper->lock()) { $output->writeln('The command is already running in another process.'); return 0; } $output->writeln(sprintf('Hello <comment>%s</comment>!', $input->getArgument('who'))); for (;;) { } $output->writeln(sprintf('bye <comment>%s</comment>!', $input->getArgument('who'))); $lockHelper->unlock(); } ```  Commits ------- 9ad8957 [Filesystem] Added a lock handler
I frequently need a command to only run by one process at a time. Most of the time this command would be invoked by a cronjob, but it would not have finished by the time the crontab executes this command again (think long imports and such).
It's fairly easy to fix this by setting a pidfile, and checking for existence (and running process), but it's tedious to do this, and I think it would be a nice feature to implement a "isSingleProcess" method in your command, or something, to accomplish this.
I have implemented this myself, and so if this is a desired feature, I can attach some code to this issue. Also, I'm not really sure what the technical term for this is (it's not a daemon, but I don't know how this is commonly called).
The text was updated successfully, but these errors were encountered: