I have a daemon that should run behind my rails app doing db modifications.I implemented that daemon using ruby daemons gem. I want to start that daemon at the start of my app. Whenever my app starts, I need to start that daemon.
How can I do this..?
If you must start it during Rails initialization:
Create a ruby file that will start the daemon. Say invoke_daemon.rb
Put this file in config/initializers/invoke_daemon.rb
However if it isn't mandatory, I would suggest creating a binary executable or a rake task and manually starting it through command line. This way it runs as a separate process. You can simply add it to your deployment scripts for production boxes and on development box run it manually. A few examples would be searchd, the search daemon for sphinx and thinking_sphinx:delayed_delta rake task from thinking_sphinx.
For your knowledge you have to take look of
Rails Life cycle
I have just implemented this thing. I have implemented on Windows7.
I have created one batch file let's say my_batch.bat, which contains ruby command i.e. ruby my_daemon.rb file.
In addition, to execute this file when my app starts , I have just added one statement in environment.rb file which executes that batch file. i.e. system ("my_batch.bat").
But I am not sure that this is a good way to implement this task.
Related
I need to run a command after or before starting Rails. It will start a server on port 9292 so my chat app will work.
This command should preferably be executed automatically with Rails (on production and development).
How do we do that in Rails 4?
Is Capistrano the only option? Can we schedule it to be executed when Rails starts?
Use capistrano and forman or systemd to manage your chat server instance, like, for example you would do for sidekiq.
A good start would be : http://anlek.com/2015/01/using-foreman-with-upstart-capistrano/
You have 2 options that I know of if you don't want to use Capistrano. In your config/application.rb
config.after_initialize do
# ....
end
http://guides.rubyonrails.org/configuring.html
or you can write a custom initializer that is run with on_server_start event.
There's a whole section of config/ intended for startup behavior: config/initializers/. If you need to do anything as part of the startup of your app, you can create an initializer file here, and it will automatically get run as Rails starts.
To do this, simply create a new file: config/initializers/chat_app.rb:
# This file will start and establish an initial connection to the chat app
`chat-app --some-arg` # <== The chat app
We use this for various startup and system sanity checks for the application. It's independent of your deployment, so if you need it for other deployment purposes, creating a Capistrano (or even Rake) task is the better option.
I have a rake task which parses a streaming API and enters data into database. The streaming API is live feed and the rake task should run continuously for the live data to enter the database. The rake task once called will run continuously and parse the data. Now i have started the rake task and it is running. The problem is that if i close the terminal or reboot the server, the rake task wil be stopped. So, i want a script in linux (something like the one used to start, or stop apache server), which does the following:
1. start the rake task by calling rake command (rake parse:stream) from the RAILS-ROOT (application directory of Rails app)
2. stop the rake task by killing the process.
3. start the rake task automatically when the server reboots.
i am not familiar to linux scripts and i dont know where to start. i am using ubuntu server. can anyone help me?
Here's an article that might help you also. It discussed various options for managing Ruby applications and their related processes:
http://michaelvanrooijen.com/articles/2011/06/08-managing-and-monitoring-your-ruby-application-with-foreman-and-upstart/
You need to run your script as a daemon. When I create this kind of startup scripts I usually make 2 files, one that stays in /etc/init.d and handles the start/stop/status/restart commands and another one that actually does the job and gets called by the first script.
Here is one solution, and although the daemon script is written in perl, you want to run some command lines only, so daemonizing a perl script could do your job easily.
If you want, there are also ruby gems for daemonizing scripts, so you can write a script in ruby that does the rake tasks.
And if you want to go hardcore, there are solutions for writing bash scripts that can daemonize, but I'm not sure I would recommend a solution like that; at least I find them pretty difficult to use.
Take a look at how Github's Resque project does it.
Essentially they create tasks for starting/restarting/stopping a particular task, in this case resque:work. Note that the restart_workers task simply invokes the other tasks, stop and start. It should be really easy to change this for what you want.
I would like my development environment for Rails to automatically start redis and resque (and potentially in other projects, mongod, mysql-server etc.) for me, in the following cases:
When starting up the development server rails server.
Additionally, it would be nice if the following cases detect already running services, and, if not running start them up too:
Rake rspec, rspec /spec, when running tests.
When starting up a rails console.
When shutting down the rails server, the started child-services should be shut down too.
What is the correct place for such additional startup scripts?
And how to avoid them being started in production too (where I run everything trough /etc/init.d services)?
A lot of these built-in tasks are available as rake tasks already.
You can create a master rake task that does it all.
For example, with resque, you get "rake resque:start" "rake resque:scheduler:start", etc.
You can create a generic "start" task that depends on the rest. Similarly, a "stop" task would shut everything down.
So you would do:
rake start # starts all associated processes
rake stop # stops them all
This is also very use to use from Capistrano, when you end up deploying your code somewhere else. Rake tasks are very easy to call from Capistrano.
I think it's really better to do that in some external script. Do it in your rails server command can be really annoying to anyone to try your code.
By example, in one year, a nez developper come to your project. He can be desoriented if your rails server commande launch a such of other application in background.
In same idea, if you do that you need maintain your code in your rails env. Can be a little tricky. Maintain an independant script can be more usefull.
You can add your script in script directory. That be a good pratice. But not when you launch a command with a manual who do not that.
I finally got the DelayedJobs plugin working for Rails 2, and it does indeed work fine...as long as I run:
rake jobs:work
Just like the readme says, to be fair.
BUT, this doesn't fit my requirements...what kind of background task requires you to have a shell open, and a command running? That'd be like having to say script/server to run my rails app, and never getting that -d option so it'll keep running even after I close my shell.
Is there ANY way to keep the workers getting processed in the backgroun, or in daemon mode, or whatever?
I had a ray of hope when I saw the
You can also run by writing a simple
#script/job_runner#, and invoking it
externally:
Line in the readme...but...that just does the exact same thing the rake task does, you just call it a different way.
What I want:
I want to start my rails app, then start whatever will process the workers, and have BOTH of them run invisibly in the background, without the need for me to babysit it and keep the shell that started it running.
(My server is something I SSH into, so I don't want to have that shell that SSHed into it running 24/7 (especially since I like to turn off my local computer now and again)).
Is there any way to acomplish this?
You can make any *nix command run on the background by appending an & to its end:
rake jobs:work &
Just make sure you exit the shell (or use the disown command) to detach the process from your login session... Otherwise, if your session disconnects, the processes you own will be killed with it.
Perhaps Beanstalkd and Stalker?
Beanstalk is a fast and easy way to queue background tasks. Stalker provides a nice wrapper interface for creating these jobs.
See the railscast on it for more information
Edit:
You could also run that rake task as a cronjob which would mean the server would run it periodically without you needing to be logged in
Use the collectiveidea fork of delayed_job... It's more actively developed and has support for running the jobs in a daemon without any extra messing about.
My capistrano script calls
RAILS_ENV=production script/delayed_job start
I don't want to keep sphinx running all the time on my dev machine. I'd like a way to automatically execute rake thinking_sphinx:start when I run my app via netbeans. Is there a way to do this
[also - I am using Windows]
Thinking sphinx needs to run as a separate process.
You will need a third-party program called PsExec to do this. Otherwise you won't be able to start a background process using Ruby on Windows.
First of all download PsExec here. Unpack (at least) psexec.exe and run it once manually - you have to agree to the license :-/.
After that add the following line to script/server of your Rails app:
system 'PATH_TO_PSEXEC/psexec -d rake.bat'
Now you create the rake.bat with the commands to run in parallel to your server. Put the file with the following contents into your Rails app's root directory.
rake thinking_sphinx:start
This line should do the trick, but it may fail e.g. when NetBeans' JRuby version differs from Ruby installed on your host. Or if Ruby isn't installed at all. In that case you should call rake with the complete path of JRuby:
"PATH_TO_NETBEANS/ruby2/jruby-1.2.0/bin/jruby" "PATH_TO_NETBEANS/ruby2/jruby-1.2.0/bin/rake" thinking_sphinx:start
When you start the server now, an additional Windows command-line pops up with the running rake task.
Needless to say that you shouldn't add the code to script/server on your production server.