puppet-wait-for

A Puppet resource type that enables you to wait for certain conditions. You can use shell commands to query arbitrary things and either react on the exit code or match the output of the command against a regular expression.

Warning: By using this module you are leaving the purist Puppet philosophy - this is not really a resource whose state can updated/kept in sync by Puppet. Also, you might be tempted to use this module to work around issues that should be fixed by other means.

That said, there are situations where this might come in handy - for example, when you need to start/stop services in some asynchronous fashion. Puppet's basic assumption is, that when the code to update a resource has finished, then the resource is in the desired state, period. In the real world, this is not always the case, especially if you are doing a lot of things via exec resources and even more if the exec commandforks or kicks off a process which needs some time to come up.

Installation

Either install the latest release from puppet forge:

puppet module install heini-wait_for

Or add to your Puppetfile:

mod 'heini/wait_for'

Usage

Simply add this module to your Puppetfile to make the type available.

Examples

Wait for a Linux sshd service to start:

service { 'logstash':
  ensure => running,
  enable => true,
}

# Wait for the service to really start.
wait_for { 'logstash':
  query             => 'cat /var/log/logstash/logstash-plain.log 2> /dev/null',
  regex             => 'Successfully started Logstash API endpoint',
  polling_frequency => 5,  # Wait up to 2 minutes (24 * 5 seconds).
  max_retries       => 24,
  refreshonly       => true,
}

Wait for a Windows MySQL service to start:

wait_for { 'sc query MySQL5':
  regex => '.*STATE\s*:\s*4\s*RUNNING.*',
}

Wait until a command returns an exit code of 5:

wait_for { 'scp big_file user@remote.com:/tmp':
  exit_code         => 5,   # Handle exit code 5, connection lost.
  polling_frequency => 0.3,
  max_retries       => 5,
}

Just wait for 1 minute:

wait_for { 'a_minute':
  seconds => 60,
}

Execute a command and inject some environment variables (just like 'exec' does).

wait_for { 'env':
  environment => ['FOO=bar', 'BAR=baz'],
  regex       => 'FOO=.*',
}

Use the query namevar:

wait_for { 'without implicit namevar':
  query => 'echo foobar',
  regex => 'foobar',
}

Testing

Make sure you have:

rake
bundler

Install the necessary gems:

bundle install

To run the tests from the root of the source code:

bundle exec rake spec

Release

This module uses Puppet Blacksmith to publish to the Puppet Forge.

Ensure you have these lines in ~/.bash_profile:

export BLACKSMITH_FORGE_URL=https://forgeapi.puppetlabs.com
export BLACKSMITH_FORGE_USERNAME=heini
export BLACKSMITH_FORGE_PASSWORD=xxxxxxxxx

Build the module:

bundle exec rake build

Push to Forge:

bundle exec rake module:push

Clean the pkg dir (otherwise Blacksmith will try to push old copies to Forge next time you run it and it will fail):

bundle exec rake module:clean