Using the Thor tasks

Please note that as of Merb 1.0.5, this section is deprecated. Please refer to the information on bundling dependencies

In an app merb.thor will operate on your local ./gems directory. Without this directory (which is automatically created by merb-gen) it will operate on your system gems. In other words, if you use merb.thor outside of your app, you can manage your system gems in the same manner. Preferably you'd use merb:stack:install or merb:dependencies:install with a YAML configuration file.

Also, at all times, check if your config/dependencies.rb versions match your gem versions. Mismatches tend to occur, especially when running from edge.

Finally, 'merb' and 'bin/merb' are identical - both will pickup your local merb-core before starting your application. The latter is just useful if you don't have a system merb install available, during deployment for example.

Maybe one final tip: play around with a fresh merb app to get a feeling of what merb.thor can do. As all operations will happen local to the app, your system gems stay unaffected.

It's considered a best practice to keep merb.thor 'local', for example a new merb app will already have it installed in tasks/merb.thor; generally you shouldn't install it globally using 'thor install'. Having both a local and global merb.thor installed can lead to serious conflicts as their code will be merged.

First off all, see what tasks are available to you: thor -T

If you want to see the extended, more low-level tasks, check out: thor -T –all

Learn how to inspect your application:

thor merb:dependencies:list

This task takes all the same options as merb:dependencies:install, which is useful for knowing what's installed and what's going to be.

To see the actual local gems use:

thor merb:gem:list

Finally, a lot of tasks support a —dry-run option to preview what's going to happen.

If you just want to install your apps basic dependencies, use one of the following:

thor merb:dependencies:install stable

or, if you're more adventurous:

thor merb:dependencies:install edge

Both methods accept —include-dependencies which bundles any subdependencies as well. Add —force to start with a blank slate.

Note that some dependencies can't be inferred automatically, most notably the specific DO adapter you intend to use. In this case, just add the dependency in config/dependencies.rb:

dependency “do_sqlite3”

Alternatively, just install this afterwards, either from stable:

thor merb:gem:install do_sqlite3

or from edge:

thor merb:source:install do_sqlite3

The above should work for any specific gems your app requires, but didn't pickup with merb:dependencies:install - you can check with merb:dependencies:list.

To get a full merb stack, regardless of your app's actual dependencies, you can use the merb:stack tasks, which by default install from stable rubygems:

thor merb:stack:install –force

Add —edge to install from git HEAD, and —include-dependencies to bundle any subdependencies.

If you want full control over your apps dependencies, without infering these from your app automatically, you can always create a config/dependencies.yml file.

thor merb:dependencies:configure

The contents of this file looks similar to this:

- merb-core (= 0.9.8, runtime)
- merb-slices (= 0.9.8, runtime)

You can use this config file by passing the —config option to the merb:dependencies:* tasks, for example, to see the contents:

thor merb:dependencies:list –config

Or more explicitly: thor merb:dependencies:list –config-file path/to/config.yml

This means you can easily define multiple configurations and easily switch between them (just use —force); for edge installs the version requirement will be ignored - this only applies to gems found in one of the git sources. These sources can be configured in config/sources.yml, for example:

merb-core: git://github.com/myfork/merb-core.git
merb-more: git://github.com/myfork/merb-more.git

Listing tasks

To see an overview of the basic tasks run thor -T. Add –all to see all tasks, including the more low-level ones.

Basic tasks

merb:dependencies:*

The Dependencies tasks will install dependencies based on actual application dependencies. For this, the application is queried for any dependencies. All operations will be performed within this context.

List application dependencies.

By default all dependencies are listed, partitioned into system, local and currently missing dependencies. The first argument allows you to filter on any of the partitionings. A second argument can be used to filter on a set of known components, like all merb-more gems for example.