docker_image resource: properly handle registries in image strings (#2356)

When supplying a docker image that contains a registry with a port number,
such as `localhost:5000/chef/inspec:1.46.3`, the docker_image resource
was unable to locate the image in question due to incorrect parsing
of the repository and tag.

Signed-off-by: Adam Leff <adam@leff.co>

lib/resources/docker_image.rb

@@ -63,25 +63,19 @@ module Inspec::Resources
     private
 
     def sanitize_options(opts)
-      if !opts[:image].nil?
+      opts.merge!(parse_components_from_image(opts[:image]))
-        if !opts[:image].index(':').nil?
-          repo, tag = opts[:image].split(':')
-        else
-          opts[:repo] = opts[:image]
-          opts[:image] = nil
-        end
-        opts[:repo] ||= repo
-        opts[:tag] ||= tag
-      end
-
-      if !opts[:id].nil?
-        if opts[:id].index(':').nil?
-          opts[:id] = 'sha256:' + opts[:id]
-        end
-      end
 
+      # assume a "latest" tag if we don't have one
       opts[:tag] ||= 'latest'
-      opts[:image] ||= "#{opts[:repo]}:#{opts[:tag]}" unless opts[:repo].nil?
+
+      # if the ID isn't nil and doesn't contain a hash indicator (indicated by the presence
+      # of a colon, which separates the indicator from the actual hash), we assume it's sha256.
+      opts[:id] = 'sha256:' + opts[:id] unless opts[:id].nil? || opts[:id].include?(':')
+
+      # Assemble/reassemble the image from the repo and tag
+      opts[:image] = "#{opts[:repo]}:#{opts[:tag]}" unless opts[:repo].nil?
+
+      # return the santized opts back to the caller
       opts
     end
 
@@ -92,5 +86,39 @@ module Inspec::Resources
         (repository == opts[:repo] && tag == opts[:tag]) || (!id.nil? && !opts[:id].nil? && (id == opts[:id] || id.start_with?(opts[:id])))
       }
     end
+
+    def parse_components_from_image(image_string)
+      # if the user did not supply an image string, they likely supplied individual
+      # option parameters, such as repo and tag. Return empty data back to the caller.
+      return {} if image_string.nil?
+
+      first_colon = image_string.index(':') || -1
+      first_slash = image_string.index('/') || -1
+
+      if image_string.count(':') == 2
+        # If there are two colons in the image string, it contains a repo-with-port and a tag.
+        # example: localhost:5000/chef/inspec:1.46.3
+        partitioned_string = image_string.rpartition(':')
+        repo = partitioned_string.first
+        tag = partitioned_string.last
+      elsif image_string.count(':') == 1 && first_colon < first_slash
+        # If there's one colon in the image string, and it comes before a forward-slash,
+        # it contains a repo-with-port but no tag.
+        # example: localhost:5000/ubuntu
+        repo = image_string
+        tag = nil
+      else
+        # If there's one colon in the image string and it doesn't preceed a slash, or if
+        # there is no colon at all, then it separates the repo from the tag, if there is a tag.
+        # example: chef/inspec:1.46.3
+        # example: chef/inspec
+        # example: ubuntu:14.04
+        repo, tag = image_string.split(':')
+      end
+
+      # return the repo and tag parsed from the string, which can be merged into
+      # the rest of the user-supplied options
+      { repo: repo, tag: tag }
+    end
   end
 end

test/unit/resources/docker_image_test.rb

@@ -19,4 +19,53 @@ describe 'Inspec::Resources::DockerImage' do
       resource.to_s.must_equal 'Docker Image alpine:latest'
     end
   end
+
+  describe '#parse_components_from_image' do
+    let(:resource) { load_resource('docker_image', 'alpine') }
+    let(:parsed)   { resource.send(:parse_components_from_image, image_string) }
+
+    describe 'a nil image string' do
+      let(:image_string) { nil }
+
+      it 'returns an empty hash' do
+        parsed.must_equal({})
+      end
+    end
+
+    describe 'an image string containing a simple repo' do
+      let(:image_string) { 'chef/inspec' }
+
+      it 'returns correct data' do
+        parsed[:repo].must_equal 'chef/inspec'
+        parsed[:tag].must_be_nil
+      end
+    end
+
+    describe 'parses an image string containing a repo with a port number' do
+      let(:image_string) { 'localhost:5000/chef/inspec' }
+
+      it 'returns correct data' do
+        parsed[:repo].must_equal 'localhost:5000/chef/inspec'
+        parsed[:tag].must_be_nil
+      end
+    end
+
+    describe 'parses an image string containing a repo with a tag' do
+      let(:image_string) { 'chef/inspec:1.46.3' }
+
+      it 'returns correct data' do
+        parsed[:repo].must_equal 'chef/inspec'
+        parsed[:tag].must_equal '1.46.3'
+      end
+    end
+
+    describe 'parses an image string containing a repo with a port number and a tag' do
+      let(:image_string) { 'localhost:5000/chef/inspec:1.46.3' }
+
+      it 'returns correct data' do
+        parsed[:repo].must_equal 'localhost:5000/chef/inspec'
+        parsed[:tag].must_equal '1.46.3'
+      end
+    end
+  end
 end