greglu / dropwizard-cookbook

Chef custom resource for dropwizard applications

dropwizard cookbook

Custom resource for managing dropwizard applications.

Supported Platforms

This cookbook uses the pleaserun gem to auto-detect and generate init scripts. Theoretically any platform supported by the gem is supported by this cookbook.

Known Issues

• CentOS 6 seems to have an issue where pleaserun generates upstart scripts but the chef service resource doesn't pick them up. To work around this issue, set init_platform to sysv on the dropwizard resource.

Resources

dropwizard resource

properties

property	required	default	description
name	true		Name of the application. Implied from resource name.
path	false	/opt/[name]	Path for the application. Will default into /opt with the application name.
user	true		System user for running the application. This resource will manage this user.
group	false		System group for running the application.
jar_file	false	/opt/[name]/[name].jar	Path to your dropwizard application's fat JAR file. It will look into a default path if this isn't set. The default path can be a symlink to your real JAR file, but will depend on your release process. If the JAR file isn't present, then this resource will not manage the service, only create the init scripts.
config_file	false		Path to the dropwizard configuration file. This is required for safe_restart to work, otherwise it will perform regular restarts.
java_bin	false	Output of which java or /usr/bin/java	Specific java command for running the application. Should be set as #{node['java']['home']}/bin/java when using the java cookbook.
jvm_options	false		JVM options with which to start the dropwizard application. Although there are none set by default, it's highly recommended that you at least set the -Xms and -Xmx parameters here for defining the Java heap size.
arguments	false	server	Arguments to pass after the jar file inclusion. See Running Your Service in the dropwizard docs for more info (don't forget to add server!). Note regarding previous version usage: you can omit the config file path from this property and add it to config_file instead.
log_directory	false		Defines a log directory to pass to the pleaserun gem. Note: not all platforms support this property, so check the pleaserun gem for your specific platform.
safe_restart	false	false	Performs a "safe" restart if the configuration validates correctly. See the Safe Restart section below.
init_platform	false		Sets the init platform for the pleaserun gem. Leave this blank to have the gem auto-detect.

:install action

Creates application user, directories, init scripts, and service for the dropwizard application. Check out the Examples section of this README for more information.

:restart action

Restarts the dropwizard application service. This can run in normal or Safe Restart mode (see section below).

:disable action

Disables and stops the dropwizard application service, but makes no other changes.

:delete action

Removes the directories, init scripts and service for the dropwizard application. Will leave the user intact, though.

Examples

Check out this project's test/cookbooks/dw_test directory for an example recipe.

1. Most basic example:

   dropwizard 'application_name' do
     user 'app_user'
   end

   This example will:

   • Create the app_user system user with no login or home directory.
   • Create the /opt/application_name directory, owned by app_user.
   • Create the init scripts (platform dependent) for application_name service.
   • Not start or enable the application_name service since the jar won't be present yet. Don't forget to notify dropwizard[application_name] if this jar ends up being managed by chef as well.

2. Including a dropwizard config and a few other options:

   dropwizard node['your_app']['name'] do
     user 'app_user'
     java_bin "#{node['java']['home']}/bin/java"
     jvm_options '-Xms1g -Xmx1g'
     config_file node['your_app']['config']
   end
   
   template node['your_app']['config'] do
     source 'your_app-config.yml.erb'
     mode 0644
     owner node['your_app']['user']
     group node['your_app']['group']
   
     notifies :restart, "dropwizard[#{node['your_app']['name']}]", :delayed
   end

   Note: It's recommended to restart the service by notifying the dropwizard instead of directly declaring and using the service resource in your recipes. It will handle the safe_restart functionality, if configured.

Safe Restart

Dropwizard has a built-in check command for verifying compatibility between a JAR and configuration file. Setting safe_restart to true will have the dropwizard resource check for compatibility before restarting the service. This prevent restarts from occurring that would cause the service to not come back up.

The safe restart feature will also retry restarts on subsequent chef runs, by checking for the existence of a restart flag (which will get deleted when a restart is successful).