Get Chef to execute a mongodb script after mongodb has started

Question

We're currently using chef to provision our servers and we want our recipe/cookbook to automatically add some data to the mongo database once its installed and running.

This is where we start to run into problems. We were using an execute resource to run the mongo script like this:

execute "install-mongodb-config" do
  command "mongo #{node[:mongodb][:mongo_db_host]}/#{node[:mongodb][:mongo_db]} \"#{node[:mongodb][:mongo_add_config_script]}\""
  action :run
end

This part of the recipe always failed no matter what we tried! I won't get into the details of everything we tried here (unless i need to) but lets just say that i've exhausted all possibilities of subscribes and notifies (i think).

The problem originates from the fact that we are using the mongodb::10gen_repo to install mongodb. The recipe exits when apt-get installs the package and then chef continues on to execute more resourses.

We have tried executing the above resource directly after mongodb::10gen_repo but it doesn't seem like mongodb is available and the mongo shell cannot connect and run the script. The error we see is somewhat like this:

MongoDB shell version: 2.0.2
Thu Sep  6 18:40:45 ReferenceError: setTimeout is not defined mongotest.js:2
failed to load: mongoAddConfig.js

Nothing we have tried has been able to get around this in a nice chef way. The thing that we resorted to was to replace the execute resource with the following:

execute "install-mongodb-config" do
  command "sleep 60; mongo #{node[:mongodb][:mongo_db_host]}/#{node[:mongodb][:mongo_db]} \"#{node[:mongodb][:mongo_add_config_script]}\""
  action :run
end

Which just makes the command sleep for 60 seconds before the mongo script is run. I know this isn't the Right way to do this but it works for now.

Can anyone suggest the Right way to do this? I have a feeling that I will need to talk to the guys that created the mongodb chef script and request a feature!

Answer 1

First of all. Remove this "sleep 60". This can be done by chef: All resources have common attributes and "retries" and "retry_delay" are part of them. So the easiest way would be:

execute "install-mongodb-config" do
  command "mongo some_command"
  action :run
  retries 6
  retry_delay 10
end

If you have more than 2-3 places, where you have to run some command on mongo database, consider creating LWRP, similar to one created in this mongodb cookbook. (Particularly check the libraries/mongodb.rb file). You can hide the logic that waits for the server to respond there.