- Add general way for source plugins to add flags specific to that

  plugin. For now, only 'gem' uses this.
- Add flag --gem-bin-path to install a gem's executables to a specific
  place. Some folks like /usr/bin, so, package puppet with bins there:
  * fpm -s gem -t deb --gem-bin-path /usr/bin puppet

  The original implementation for this bin-path flag was by lassizci.
  #27

bin/fpm

@@ -8,11 +8,15 @@ require "erb"
 
 $: << "#{File.dirname(__FILE__)}/../lib"
 require "fpm"
+require "fpm/flags"
 
 def main(args)
   settings = OpenStruct.new
   settings.exclude = []
 
+  # Source-specific settings/flags go here.
+  settings.source = {}
+
   # Maintainer scripts - https://github.com/jordansissel/fpm/issues/18
   settings.scripts ||= {} 
 
@@ -125,6 +129,9 @@ def main(args)
     end # --url
   end # OptionParser
 
+  # Add extra flags.
+  FPM::Source::Gem.flags(FPM::Flags.new(opts, "gem", "gem source only"), settings)
+
   opts.parse!(args)
 
   ok = true

lib/fpm/builder.rb

@@ -41,7 +41,8 @@ def initialize(settings, paths=[])
       :maintainer => settings.maintainer,
       :provides => [],
       :description => settings.description,
-      :url => settings.url
+      :url => settings.url,
+      :settings => settings.source
     )
 
     @edit = !!settings.edit

lib/fpm/flags.rb

@@ -0,0 +1,20 @@
+require "fpm/namespace"
+
+class FPM::Flags
+  def initialize(opts, flag_prefix, help_prefix)
+    @opts = opts
+    @flag_prefix = flag_prefix
+    @help_prefix = help_prefix
+  end # def initialize
+
+  def on(*args, &block)
+    fixed_args = args.collect do |arg|
+      if arg =~ /^--/
+        "--#{@flag_prefix}-#{arg.gsub(/^--/, "")}" 
+      else
+        "(#{@help_prefix}) #{arg}"
+      end
+    end
+    @opts.on(*fixed_args, &block)
+  end # def on
+end # class FPM::Flags

lib/fpm/source/gem.rb

@@ -5,6 +5,13 @@
 require "fileutils"
 
 class FPM::Source::Gem < FPM::Source
+  def self.flags(opts, settings)
+    opts.on("--bin-path DIRECTORY",
+            "The directory to install gem executables") do |path|
+      settings.source[:bin_path] = path
+    end
+  end # def flags
+
   def get_source(params)
     gem = @paths.first
     looks_like_name_re = /^[A-Za-z0-9_-]+$/
@@ -102,17 +109,26 @@ def make_tarball!(tar_path, builddir)
     if self[:prefix]
       installdir = "#{tmpdir}/#{self[:prefix]}"
       # TODO(sissel): Overwriting @paths is bad mojo and confusing...
+      # Maybe we shouldn't?
       @paths = [ self[:prefix] ]
     else
-      installdir = "#{tmpdir}/#{::Gem::dir}"
+      installdir = File.join(tmpdir, ::Gem::dir)
       @paths = [ ::Gem::dir ]
     end
+
     ::FileUtils.mkdir_p(installdir)
     args = ["gem", "install", "--quiet", "--no-ri", "--no-rdoc",
-       "--install-dir", installdir, "--ignore-dependencies", gem]
+       "--install-dir", installdir, "--ignore-dependencies"]
+    if self[:settings][:bin_path]
+      args += ["--bindir", File.join(tmpdir, self[:settings][:bin_path])]
+      @paths << self[:settings][:bin_path]
+    end
+
+    args << gem
     system(*args)
 
-    tar(tar_path, ".#{@paths.first}", tmpdir)
+    # make paths relative  (/foo becomes ./foo)
+    tar(tar_path, @paths.collect {|p| ".#{p}"}, tmpdir)
     FileUtils.rm_r(tmpdir)
 
     # TODO(sissel): Make a helper method.