In the previous section, we created a new custom type called gitrepo and told Puppet that it takes two parameters, source and path. However, so far we haven't told Puppet how to actually check out the repo—in other words, how to create a specific instance of this type. That's where the provider comes in.
We saw that a type will often have several possible providers. In our example, there is only one sensible way to instantiate a Git repo, so we'll only supply one provider: git. If you were to generalize this type—to just repo, say—it's not hard to imagine creating several different providers depending on the type of repo, for example, git, svn, cvs, and so on.
We'll add the git provider, and create an instance of a gitrepo resource to check that it all works. You'll need Git installed for this to work, but if you're using the Git-based manifest management setup described in Chapter 1, Puppet Infrastructure, we can safely assume that Git is available...