Issue #85 - Adding support for a regex tag blacklist

lib/chef/handler/datadog.rb

@@ -57,6 +57,7 @@ def prepare_report_for_datadog
             .with_application_key(config[:application_key])
             .with_tag_prefix(config[:tag_prefix])
             .with_retries(config[:tags_submission_retries])
+            .with_tag_blacklist(config[:tags_blacklist_regex])
 
         # Build the chef event information
         @event =

lib/chef/handler/datadog_chef_tags.rb

@@ -13,6 +13,7 @@ def initialize
     @tag_prefix = 'tag:'
     @retries = 0
     @combined_host_tags = nil
+    @regex_black_list = nil
   end
 
   # set the dogapi client handle
@@ -85,6 +86,11 @@ def with_retries(retries)
     self
   end
 
+  def with_tag_blacklist(tags_blacklist_regex)
+    @regex_black_list = Regexp.new(tags_blacklist_regex, Regexp::IGNORECASE) unless tags_blacklist_regex.nil? || tags_blacklist_regex.empty?
+    self
+  end
+
   # send updated chef run generated tags to Datadog
   def send_update_to_datadog
     tags = combined_host_tags
@@ -135,6 +141,12 @@ def node_env
 
   def node_tags
     return [] unless @node.tags
-    @node.tags.map { |tag| "#{@tag_prefix}#{tag}" }
+    output = @node.tags.map { |tag| "#{@tag_prefix}#{tag}" }
+
+    # No blacklist, return all results
+    return output if @regex_black_list.nil?
+
+    # The blacklist is set, so return the items which are not filtered by it.
+    output.select { |t| !@regex_black_list.match(t) }
   end
 end # end class DatadogChefTags

spec/datadog_spec.rb

@@ -262,6 +262,39 @@
         )).to have_been_made.times(1)
       end
     end
+
+    describe 'when tag blacklist is specified' do
+      it 'does not include the tag(s) specified' do
+        @node.normal.tags = ['allowed_tag', 'not_allowed_tag']
+        @handler.config[:tags_blacklist_regex] = 'not_allowed.*'
+        @handler.run_report_unsafe(@run_status)
+
+        expect(a_request(:put, HOST_TAG_ENDPOINT + @node.name).with(
+          :query => { 'api_key' => @handler.config[:api_key],
+                      'application_key' => @handler.config[:application_key],
+                      'source' => 'chef' },
+          :body => hash_including(:tags => [
+              'env:hostile', 'role:highlander', 'tag:allowed_tag'
+            ]),
+        )).to have_been_made.times(1)
+      end
+    end
+
+    describe 'when tag blacklist is unspecified' do
+      it 'should include all of the tag(s) specified' do
+        @node.normal.tags = ['allowed_tag', 'not_allowed_tag']
+        @handler.run_report_unsafe(@run_status)
+
+        expect(a_request(:put, HOST_TAG_ENDPOINT + @node.name).with(
+          :query => { 'api_key' => @handler.config[:api_key],
+                      'application_key' => @handler.config[:application_key],
+                      'source' => 'chef' },
+          :body => hash_including(:tags => [
+              'env:hostile', 'role:highlander', 'tag:allowed_tag', 'tag:not_allowed_tag'
+            ]),
+        )).to have_been_made.times(1)
+      end
+    end
   end
 
   context 'tags submission retries' do