Merge pull request #2 from alphagov/gem-version-comparison

Gem version comparison

Gemfile

@@ -4,6 +4,7 @@ source 'https://rubygems.org'
 
 gem 'octokit'
 gem 'webmock'
+gem 'rake'
 
 group :development, :test do
   gem 'rspec'

Gemfile.lock

@@ -17,6 +17,7 @@ GEM
       faraday (>= 1, < 3)
       sawyer (~> 0.9)
     public_suffix (5.0.3)
+    rake (13.1.0)
     rexml (3.2.6)
     rspec (3.12.0)
       rspec-core (~> 3.12.0)
@@ -45,6 +46,7 @@ PLATFORMS
 
 DEPENDENCIES
   octokit
+  rake
   rspec
   webmock
 

Rakefile

@@ -0,0 +1,7 @@
+require './lib/version_checker'
+
+task default: %w[gem_release_alert]
+
+task :gem_release_alert do
+  VersionChecker.new.print_version_discrepancies
+end

lib/version_checker.rb

@@ -9,22 +9,59 @@ class HttpError < RuntimeError
 end
 
 class VersionChecker
-  def fetch_rubygems_version(gemname)
-    uri = URI("https://rubygems.org/api/v1/gems/#{gemname}.json")
+  def print_version_discrepancies
+    discrepancies_found = false
+
+    fetch_all_govuk_gemspecs.each do |gemspec|
+      rubygems_version = fetch_rubygems_version(gemspec.name)
+      unless gemspec.version == rubygems_version
+        discrepancies_found = true
+        puts "Version mismatch for '#{gemspec.name}':"
+        puts "  Version on RubyGems: #{rubygems_version}"
+        puts "  Version on GitHub: #{gemspec.version}"
+      end
+    end
+
+    unless discrepancies_found
+      puts "No discrepancies found!"
+    end
+  end
+
+  def fetch_all_govuk_gemspecs
+    uri = URI("https://docs.publishing.service.gov.uk/gems.json")
+    res = Net::HTTP.get_response(uri)
+
+    raise HttpError unless res.is_a?(Net::HTTPSuccess)
+
+    JSON.parse(res.body)
+      .map { |gem| fetch_gemspec(gem["app_name"]) }
+      .compact
+  end
+
+  def fetch_rubygems_version(gem_name)
+    uri = URI("https://rubygems.org/api/v1/gems/#{gem_name}.json")
     res = Net::HTTP.get_response(uri)
 
     raise HttpError unless res.is_a?(Net::HTTPSuccess)
 
-    parsed_json = JSON.parse(res.body)
-    parsed_json['version']
+    JSON.parse(res.body)['version']
   end
 
-  def fetch_github_version(gemname)
-    payload = Octokit.contents("alphagov/#{gemname}", path: "lib/#{gemname}/version.rb")
-    Base64.decode64(payload[:content]).split('"')[1]
+  def fetch_gemspec(repo_name)
+    Dir.mktmpdir do |path|
+      Dir.chdir(path) do
+        clone_github_repo(repo_name)
+        gemspecs = Dir.glob("*.gemspec", base: repo_name)
+        if gemspecs.count == 1
+          Gem::Specification::load("#{repo_name}/#{gemspecs.first}")
+        else
+          nil
+        end
+      end
+    end
   end
 
-  def rubygems_and_github_match?(gemname)
-    fetch_rubygems_version(gemname) == fetch_github_version(gemname)
+  def clone_github_repo(name)
+    `git clone --recursive --depth 1 --shallow-submodules git@github.com:alphagov/#{name}.git > /dev/null 2>&1`
   end
 end

spec/example.gemspec

@@ -0,0 +1,7 @@
+Gem::Specification.new do |s|
+  s.name        = 'example'
+  s.version     = "1.2.3"
+  s.authors     = ["Ruby Coder"]
+  s.files       = ["lib/example.rb"]
+  s.summary     = "This is an example!"
+end

spec/version_checker_spec.rb

@@ -4,41 +4,61 @@
 require 'base64'
 
 RSpec.describe VersionChecker do
+  let(:example_gemspec_path) { File.join(__dir__, "example.gemspec") }
+
   it 'fetches version number of a gem from rubygems' do
     stub_rubygems_call('6.0.1')
 
-    expect(subject.fetch_rubygems_version('govuk_app_config')).to eq('6.0.1')
+    expect(subject.fetch_rubygems_version('example')).to eq('6.0.1')
   end
 
   it 'fetches version number of a gem from GitHub' do
-    stub_github_call('9.7.0')
+    stub_github_call
+
+    expect(subject.fetch_gemspec('example').version).to eq('1.2.3')
+  end
+
+  it "fetches gemspecs for all govuk repos" do
+    stub_devdocs_call
+    stub_github_call
 
-    expect(subject.fetch_github_version('govuk_app_config')).to eq('9.7.0')
+    expect(subject.fetch_all_govuk_gemspecs).to eq([Gem::Specification.load(example_gemspec_path)])
   end
 
-  it "compares versions of gems on GitHub and rubygems and it's a match" do
-    stub_github_call('9.7.0')
-    stub_rubygems_call('9.7.0')
+  it "detects when there are no version discrepancies" do
+    stub_devdocs_call
+    stub_github_call
+    stub_rubygems_call('1.2.3')
 
-    expect(subject.rubygems_and_github_match?('govuk_app_config')).to eq(true)
+    expect { subject.print_version_discrepancies }.to output("No discrepancies found!\n").to_stdout
   end
 
-  it "compares versions of gems on GitHub and rubygems and it's not a match" do
-    stub_github_call('9.7.0')
-    stub_rubygems_call('9.7.1')
+  it "detects when there are are version discrepancies" do
+    stub_devdocs_call
+    stub_github_call
+    stub_rubygems_call('1.2.2')
 
-    expect(subject.rubygems_and_github_match?('govuk_app_config')).to eq(false)
+    expect { subject.print_version_discrepancies }.to output(
+      "Version mismatch for 'example':\n  Version on RubyGems: 1.2.2\n  Version on GitHub: 1.2.3\n"
+    ).to_stdout
   end
 
-  def stub_github_call(version)
-    repo = { content: Base64.encode64(%(module GovukAppConfig\n  VERSION = "#{version}".freeze\nend\n)) }
-    stub_request(:get, 'https://api.github.com/repos/alphagov/govuk_app_config/contents/lib/govuk_app_config/version.rb')
-      .to_return(status: 200, body: repo.to_json, headers: { 'Content-Type' => 'application/json' })
+  def stub_github_call
+    allow(subject).to receive(:clone_github_repo) do
+      FileUtils.mkdir "example"
+      FileUtils.cp example_gemspec_path, File.join(Dir.pwd, "example")
+    end
   end
 
   def stub_rubygems_call(version)
     repo = { "version": version }
-    stub_request(:get, 'https://rubygems.org/api/v1/gems/govuk_app_config.json')
+    stub_request(:get, 'https://rubygems.org/api/v1/gems/example.json')
+      .to_return(status: 200, body: repo.to_json, headers: {})
+  end
+
+  def stub_devdocs_call
+    repo = [{ "app_name": "example" }]
+    stub_request(:get, 'https://docs.publishing.service.gov.uk/gems.json')
       .to_return(status: 200, body: repo.to_json, headers: {})
   end
 end