README

DEP(1)

NAME
      dep -- Basic dependency tracking

SYNOPSIS
      dep
      dep add libname [--pre]
      dep rm libname
      dep install

DESCRIPTION
      dep
          Checks that all dependencies are met.

      dep add [gemname]
          Fetches the latest version of `gemname`
          and automatically adds it to your .gems file.

      rm
          Removes the corresponding entry in your .gems file.

      install
          Installs all the missing dependencies for you. An important
          point here is that it simply does a `gem install` for each
          dependency you have. Dep assumes that you use some form of
          sandboxing like gs, rbenv-gemset or RVM gemsets.


INSTALLATION
      $ wget -qO- http://amakawa.org/sh/install.sh | sh

      # or

      $ gem install dep

HISTORY
      dep is actually more of a workflow than a tool. If you think about
      package managers and the problem of dependencies, you can summarize
      what you absolutely need from them in just two points:

      1. When you build an application which relies on 3rd party libraries,
         it's best to explicitly declare the version numbers of these
         libraries.

      2. You can either bundle the specific library version together with
         your application, or you can have a list of versions.

      The first approach is handled by vendoring the library. The second
      approach typically is done using Bundler. But why do you need such
      a complicated tool when all you need is simply listing version numbers?

      We dissected what we were doing and eventually reached the following
      workflow:

      1. We maintain a .gems file for every application which lists the
         libraries and the version numbers.
      2. We omit dependencies of dependencies in that file, the reason being
         is that that should already be handled by the package manager
         (typically rubygems).
      3. Whenever we add a new library, we add the latest version.
      4. When we pull the latest changes, we want to be able to rapidly
         check if the dependencies we have is up to date and matches what
         we just pulled.

      So after doing this workflow manually for a while, we decided to
      build the simplest tool to aid us with our workflow.

      The first point is handled implicitly by dep. You can also specify
      a different file by doing dep -f.

      The second point is more of an implementation detail. We thought about
      doing dependencies, but then, why re-implement something that's already
      done for you by rubygems?

      The third point (and also the one which is most inconvenient), is
      handled by dep add.

      The manual workflow for that would be:

      gem search -r "^ohm$" [--pre] # check and remember the version number
      echo "ohm -v X.x.x" >> .gems

      If you try doing that repeatedly, it will quickly become cumbersome.

      The fourth and final point is handled by typing dep check or simply dep.
      Practically speaking it's just:

      git pull
      dep

      And that's it. The dep command typically happens in 0.2 seconds which
      is something we LOVE.