simplify the gem build/release process (#7)

Since we're not distributing a pre-built binary, we don't need Docker to
prepare a build environment. Since we're not doing anything with Java
(yet), we can get rid of those commented parts. And we can use the
Gem::Package API to verify that a gem is signed.

Author: jamis

Rakefile

@@ -1,9 +1,34 @@
 require 'bundler'
 require 'bundler/gem_tasks'
-require 'rake/extensiontask'
+require 'rubygems/package'
+require 'rubygems/security/policies'
 
+def signed_gem?(path_to_gem)
+  Gem::Package.new(path_to_gem, Gem::Security::HighSecurity).verify
+  true
+rescue Gem::Security::Exception => e
+  false
+end
+
+desc 'Compiles the libmongocrypt library'
 task :compile do
-  chdir "ext/libmongocrypt" do
-    ruby "extconf.rb"
+  chdir 'ext/libmongocrypt' do
+    ruby 'extconf.rb'
+  end
+end
+
+desc 'Verifies that all built gems in pkg/ are valid'
+task :verify do
+  gems = Dir['pkg/*.gem']
+  if gems.empty?
+    puts 'There are no gems in pkg/ to verify'
+  else
+    gems.each do |gem|
+      if signed_gem?(gem)
+        puts "#{gem} is signed"
+      else
+        abort "#{gem} is not signed"
+      end
+    end
   end
 end

release.sh

@@ -17,32 +17,14 @@ VERSION=`ruby -Ilib -r$VERSION_REQUIRE -e "puts $VERSION_CONSTANT_NAME"`
 echo "Releasing $NAME $VERSION"
 echo
 
-for variant in mri; do
-  docker build -f release/$variant/Dockerfile -t $RELEASE_NAME-$variant .
-
-  docker kill $RELEASE_NAME-$variant || true
-  docker container rm $RELEASE_NAME-$variant || true
-
-  docker run -d --name $RELEASE_NAME-$variant -it $RELEASE_NAME-$variant
-
-  docker exec $RELEASE_NAME-$variant /app/release/$variant/build.sh
-
-  if test $variant = jruby; then
-    docker cp $RELEASE_NAME-$variant:/app/pkg/$NAME-$VERSION-java.gem .
-  else
-    docker cp $RELEASE_NAME-$variant:/app/pkg/$NAME-$VERSION.gem .
-  fi
-
-  docker kill $RELEASE_NAME-$variant
-done
+./release/mri/build.sh
+cp pkg/$NAME-$VERSION.gem .
 
 echo
 echo Built: $NAME-$VERSION.gem
-#echo Built: $NAME-$VERSION-java.gem
 echo
 
 git tag -a v$VERSION -m "Tagging release: $VERSION"
 git push origin v$VERSION
 
 gem push $NAME-$VERSION.gem
-#gem push $NAME-$VERSION-java.gem

release/mri/Dockerfile

@@ -6,5 +6,4 @@ rm -f *.lock
 rm -f *.gem pkg/*.gem
 # Uses bundler gem tasks, outputs the built gem file to pkg subdir.
 bundle install
-bundle exec rake build
-/app/release/verify-signature.sh pkg/*.gem
+bundle exec rake build verify