I have a Rails runner task that I want to run from cron, but of course cron runs as root and so the environment is set up improperly to get RVM to work properly. I've tried a number of things and none have worked thus far. The crontab entry is:
* 0 * * * root cd /home/deploy/rails_apps/supercharger/current/ && /usr/local/rvm/wrappers/ruby-1.9.3-p484/ruby bundle exec rails runner -e production "Charger.start"
Apologies for the super long command line. Anyhow, the error I'm getting from this is:
ruby: No such file or directory -- bundle (LoadError)
So ruby is being found in the RVM directory, but again, the environment is wrong.
I tried rvm alias delete [alias_name] and it seemed to do something, but darn if I know where the wrapper it generated went. I looked in /usr/local/rvm/wrappers and didn't see one with the name I had specified.
This seems like a common problem -- common enough that the whenever gem exists. The runner command I'm using is so simple, it seemed like a slam dunk to just put this entry in the crontab and go, but not so much...
Any help with this is appreciated.
It sounds like you could use a third-party tool to tether your Rails app to cron: Whenever. You already know about it, but it seems you never tried it. This gem includes a simple DSL that could be applied in your case like:
every :day # Or specify another period, or something else, see README
runner "Charger.start"
end
Once you've defined your schedule, you'll need to write it into crontab with whenever command line utility. See README file and whenever --help for details.
It should not cause any performance impact at runtime since all it does is conversion into crontab format upon deployment or explicit command. It's not needed, once the server is running, everything is done by cron after that.
If you don't want an extra gem anyway, you might as well check what command does it issue for executing your task. Still, an automated way of adding a cron task is easier to maintain and to deploy. Sure, just tossing a line into the crontab is easier — just for you and just this once. Then it starts to get repetitive and tiring, not to mention confusion for other potential developers who will have to set up something similar on their own machines.
You can run cron as different user than root. Even in your example the task begins with
* 0 * * * root cd
root is the user that runs the command. You can edit it with crontab -e -u username.
If you insist on running cron task as root or running as other user does not work for some reason, you can switch user with su. For example:
su - username -c "bundle exec rails runner -e production "Charger.start"
Related
I was wondering if it was possible to run migrations automatically during deployment with Google App Engine. I have been using AWS Elasticbeanstalk for a while and they were ran automatically but now I am considering moving to the Google App Engine for my future projects.
Right now, I must run this command manually:
bundle exec rake appengine:exec -- bundle exec rake db:migrate GAE_CONFIG=app.yml
Thank you
WARNING: As discussed in comments, there is a race condition in migrations if deployment is done on multiple containers in parallel, because it will try to run migration on all containers. Solution is being discussed in comments, i will update this answer when we land on something.
Disclaimer: This answer is not exactly what was asked for, but it solves same problem and it works. And from what i can tell from question, doing it with some appengine config is not a requirement, rather he just want the migrations to run automatically.
I will expand on my comment on question, here is something i tried and it works. I am strong believer of KISS(keep it simple and stupid). So instead of trying to figure out appengine(which i have never used anyway) if i were you, i would take a generic approach. Which is, to plug into rails server booting process and trigger migrations. For this we have multiple approaches.
With my understanding of appengine and suggested by this official doc link appengine has a app.yaml file, this file has an entry something like:
entrypoint: rails server
So we will use this entry point to plug in our code to run migrations before starting server. For this i did this:
Make a new file in bin directory, i named it
rails_with_migrations.sh you can name it whatever you like.
Give it execute permissions with chmod +x bin/rails_with_migrations.sh
Put this code inside it:
#!/bin/bash
bundle exec rake db:migrate
bundle exec rails $#
Of course you can give whatever RAILS_ENV you want to give these.
Now in app.yaml on the entrypoint section, instead of rails server give it bin/rails_with_migrations.sh server and it should be it. It worked on local, should work everywhere.
NOTE: In entrypoint: i have bin/rails_with_migrations.sh server here, server is rails command parameter, you can pass as much parameters as you like these all will be passed to rails server command with $#'s magic. It is there to allow you to pass port and any other parameters you may need to provide for your environment. Also it allows you to run rails console locally with bin/rails_with_migrations.sh console which will also cause migrations to get triggered.
UPDATE1: As per comment, i checked what happens if migration fails, and it starts server even if migration fail. We can alter this behavior of-course in our sh file.
UPDATE2: The shell-script with migration error code handling will look something like:
#!/bin/bash
bundle exec rake db:migrate
if [ $? -eq 0 ]
then
bundle exec rails $#
else
echo "Failure: migrations failed, please check application logs for more details." >&2
exit 1
fi
This update will prevent server from starting and causing a non zero exit code from the script, which should indicate that this command failed.
I have two rails apps on the same server, let's call them A and B.
I am trying to have app A restart app B via app B's own capistrano task. Unfortunately, even after cd-ing to app B's directory, it is trying to run app A's capistrano instead. Am I missing something?
example code
system("cd /apps/appB/current && pwd && bundle exec cap:restart")
pwd correctly returns the path of appB (/apps/appB/current), however, in there is a traceback for cap:restart. This is because it is still trying to run the cap command in the context of appA, e.g.
/apps/appA/shared/bundle/ruby/1.9.1/gems/capistrano-2.15.4/lib/capistrano/configuration/loading.rb:152:in 'require': cannot load such file -- airbrake/capistrano (LoadError)
from /apps/appA/shared/bundle/ruby/1.9.1/gems/capistrano-2.15.4/lib/capistrano/configuration/loading.rb:152:in 'require'.
I tried without 'bundle exec', and have tried some other ways of making system calls. I also created a bash script in another directory and tried to run it that way.
All methods described exhibit the same behaviour.
Your help would be greatly appreciated =)
You need to use Bundler.with_clean_env to ensure that your subprocess doesn't pick up your current Bundler environment:
Bundler.with_clean_env do
system("cd /apps/appB/current && pwd && bundle exec cap:restart")
end
This is essentially the same problem as Install bundle of gem within other rails application
Since you said your apps are using Unicorn, you can signal from app A to app B (or the other way around).
Read this page: http://unicorn.bogomips.org/SIGNALS.html
The only thing each application needs to know is the pidfile path of the other application. So look at your Unicorn config and see where it's storing that.
You could either read the PID out of that pidfile and kill it from Ruby:
pid = File.read(path_to_other_application_pidfile).chop
Process.kill("USR2", pid)
Or you could use backticks to execute shell commands
`kill -s USR2 \`cat #{path_to_other_application_pidfile}\``
I'm trying to set daily cron job to update my site stats, but it looks like it doesn't work.
Cron entry (for deployer user):
0 0 * * * cd /var/www/my_site/current && rake RAILS_ENV=production stats:update
I'm running ubuntu server, with rbenv.
Any idea what's wrong?
Many times $PATH is defined differently when cron runs compared to when you are working in your own shell. Do "whereis rake" to find the full path to rake and then replace "rake" with its full path. (I am assuming that the "cd" command is working, so I am focusing on whether "rake" is found / running properly.)
Has cron sent you any emails with error messages after you added your command to your crontab?
You might want to run "crontab -l" under the proper user account to make sure that your cron command is actually registered within the crontab, especially if you aren't receiving any emails.
The presence of a Gemfile can also affect the ability to properly run rake. See, for example, Error: "Could not find rake", yet Rake is installed
With my large application, the Rails console takes a while to load up. Is there a way to single commands more easily?
I'd also like to be able to automate stuff, and echo "query" | rails console isn't a great way to do things.
Thoughts?
EDIT: What about a long-running process that I can ping queries to whenever I have need?
There are two main ways to run commands outside console:
Rake task which depends on :environment
rails runner (previously script/runner), eg:
$ rails runner "query"
Both are pretty well documented on the rails guide: https://guides.rubyonrails.org/command_line.html#bin-rails-runner
Both of these methods will still take the same time as a console to fire up, but they are useful for non-interactive tasks.
Just pipe it in:
echo 'puts Article.count' | bundle exec rails c
It should now be a lot faster than when then the question was originally asked, because of Spring. It's not immediate, but still a lot faster than spinning up the whole app. Use this for the fast lane, it should run in under a second (assuming your required command is fast):
echo 'puts Article.count' | spring rails c
If you really want a single long-running process, you could easily do it by creating a controller action that simply runs whatever you POST to it, then send commands to it using curl behind an alias. The action would of course be completely insecure and should be triple-guarded against running anywhere near production, but it would be easy to setup.
Solution: bundle exec command allows us to run an executable script in the specific context of the project's bundle - making all gems specified in the Gemfile available to require in Ruby application. In addition it eventually avoids any conflicts with other versions of rake installed globally.
echo '<command>' | bundle exec rails c
for more information look at the documentation of bundler
example:
configuration_item=$(echo 'ConfigurationManager.getKey("authentication_method")' | bundle exec rails c )
echo $configuration_item
#output:
MFA_authentication
I'm using the latest version of the whenever gem with Rails 3.1.1 for cron tasks. After I used the whenever command on the terminal
whenever -c
to clear the crontab, whenever I type in
crontab -l
whereas it used to say something like "there are no cron tasks" (this is not verbatim) now it just displays a blank space about the size of two empty lines. Also if I have a cron task setup and I type the same command into the terminal again, those two empty lines come up before it shows the cron tasks. I'm sorry if this is a minor issue. Everything appears to be working fine but I just want to make sure I didn't screw anything up that'll come back to haunt me somewhere down the line. Thanks!
You need to change the task in the schedule.rb file which is generated by whenever gem.
After changing your cron task in the schedule.rb you have to update your crontab file and you can use this command to do that :-
whenever --update-crontab f(here f is your application name)
crontab -l is used to see your current crontab file.
Hope it helps