Add scripts/import-rubygem to generate morphologies for RubyGemssam/ruby-using-gems

This generates a stratum and a set of chunk morphologies for integrating
a given RubyGem project into Baserock. It uses the 'bundler' Gem to
collate the list dependencies. This means that it works for any Gem that
has a "Gemfile", and will also honour the "Gemfile.lock" file created by
Bundler if the file exists.

It requires the new 'rubygem' build mode.

1 files changed, 189 insertions, 0 deletions

diff --git a/scripts/import-rubygem b/scripts/import-rubygem
new file mode 100755
index 00000000..6b869a7d
--- /dev/null
+++ b/scripts/import-rubygem
@@ -0,0 +1,189 @@
+#!/usr/bin/env ruby
+#
+# Create a stratum to integrate a Ruby project in Baserock, using RubyGems
+#
+# Copyright (C) 2014  Codethink Limited
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+require 'bundler'
+require 'optparse'
+require 'yaml'
+
+BASEROCK_RUBY_VERSION = '2.0.0'
+
+def parse_options(arguments)
+    # No options so far ..
+    opts = OptionParser.new
+
+    opts.banner = "Usage: import-ruby PROJECT_DIR OUTPUT_DIR"
+    opts.separator ""
+    opts.separator "This tool reads the Gemfile and optionally the " +
+                   "Gemfile.lock from a Ruby project "
+    opts.separator "source tree in PROJECT_DIR. It outputs a stratum " +
+                   "morphology and a set of chunk "
+    opts.separator "morphology files to OUTPUT_DIR."
+
+    parsed_arguments = opts.parse!(arguments)
+
+    if parsed_arguments.length != 2 then
+        STDERR.puts opts.help
+        exit 1
+    end
+
+    parsed_arguments
+end
+
+def get_project_name(project_dir_name)
+    # One Git repo can produce any number of Gems, or none, so it's hard to
+    # work out a project name that way. Instead, use the repo name :)
+    project_name = File.basename(project_dir_name)
+end
+
+def load_gemfile()
+    # Load and parse the Gemfile and, if found, the Gemfile.lock file.
+    definition = Bundler::Definition.build(
+        'Gemfile', 'Gemfile.lock', update=false)
+end
+
+def get_all_specs_for_project(dir_name)
+    Dir.chdir(dir_name) { begin
+        load_gemfile.specs
+    rescue Bundler::GemNotFound
+        # If we're missing some Gem info, try remotely resolving. This is very
+        # slow so it's nice if it can be avoided. Perhaps setting up a local
+        # mirror of the necessary specs would avoid this problem. There seems
+        # to be no way to "reset" the Definition instance after the exception,
+        # so we have to call load_gemfile again.
+        STDERR.puts "Resolving definitions remotely (this may take a while!)"
+        load_gemfile.resolve_remotely!
+    rescue Bundler::GemfileNotFound
+        STDERR.puts "Did not find a Gemfile in #{dir_name}."
+        exit
+    end }
+end
+
+def generate_morphs_for_specset(project_name, specs)
+    # Chunk names are the Gem's "full name" (name + version number), so that we
+    # don't break in the rare but possible case that two different versions of
+    # the same Gem are required for something to work. It'd be nicer to only
+    # use the full_name if we detect such a conflict. If we do, at least this
+    # function below can be removed with the much simpler:
+    #   spec.deps.collect |dep| dep.name
+    runtime_depends = proc do |spec|
+        result = []
+        spec.dependencies.each do |dep|
+            next if dep.type == :development
+            found = specs[dep]
+            if found.length != 1
+                raise Exception,
+                    "Unsure which Gem to use for #{dep}, got #{found}"
+            end
+            result << found[0].full_name
+        end
+        result
+    end
+
+    description = 'Automatically generated by import-ruby. This is a ' +
+                  'prototype of a method for integrating RubyGems into ' +
+                  'Baserock.'
+
+    bin_dir = "\"$DESTDIR/$PREFIX/bin\""
+    gem_dir = "\"$DESTDIR/$PREFIX/lib/ruby/gems/#{BASEROCK_RUBY_VERSION}\""
+
+    chunk_morphs = specs.collect do |spec|
+        # There's more splitting to be done, but putting the docs in the
+        # correct artifact is the single biggest win for enabling smaller
+        # system images.
+        split_rules = [
+            {
+                'artifact' => "#{spec.full_name}-doc",
+                'include' => [
+                    "usr/lib/ruby/gems/#{BASEROCK_RUBY_VERSION}/doc/.*"
+                ]
+            }
+        ]
+
+        install_commands = [
+            "mkdir -p #{gem_dir}",
+            "gem install --install-dir #{gem_dir} --bindir #{bin_dir} " +
+                 "--ignore-dependencies --local #{spec.full_name}.gem"
+        ]
+
+        {
+            'name' => spec.full_name,
+            'kind' => 'chunk',
+            'description' => description,
+            'build-system' => 'manual',
+            # FIXME: this is not how we should calculate the URL field!
+            'gem-url' => "http://rubygems.org/downloads/#{spec.full_name}.gem",
+            'products' => split_rules,
+            'install-commands' => install_commands
+        }
+    end
+
+    chunks = specs.collect do |spec|
+        {
+            'name' => spec.full_name,
+            'description' => description,
+            # This is a dummy value; there is no repo for these chunks.
+            # The 'repo' field should perhaps become optional!
+            'repo' => 'baserock:baserock/definitions',
+            'ref' => 'master',
+            'morph' => File.join(project_name, spec.full_name + '.morph'),
+            # Runtime depends must be present at "build" (Gem install) time.
+            'build-depends' => runtime_depends.call(spec),
+            # This feature is not in morph.git master yet
+            'build-mode' => 'rubygem',
+        }
+    end
+
+    stratum_morph = {
+        'name' => project_name,
+        'kind' => 'stratum',
+        'description' => description,
+        'build-depends' => [
+            { 'morph' => 'ruby' }
+        ],
+        'chunks' => chunks,
+    }
+
+    return [stratum_morph] + chunk_morphs
+end
+
+def write_morphs(morphs, project_name, target_dir_name)
+    target_dir_name = File.join(target_dir_name, project_name)
+    FileUtils.makedirs(target_dir_name)
+    Dir.chdir(target_dir_name) do
+        morphs.each do |morph|
+            morph_filename = morph['name'] + '.morph'
+            File.open(morph_filename, 'w') do |file|
+                file.write(YAML.dump(morph))
+            end
+        end
+    end
+end
+
+def run
+    project_dir_name, target_dir_name = parse_options(ARGV)
+
+    project_name = get_project_name(project_dir_name)
+    specset = get_all_specs_for_project(project_dir_name)
+
+    morphs = generate_morphs_for_specset(project_name, specset)
+
+    write_morphs(morphs, project_name, target_dir_name)
+end
+
+run