diff --git a/app/models/project_services/flowdock_service.rb b/app/models/project_services/flowdock_service.rb
index 4d23a17a545..da01ac1b7cf 100644
--- a/app/models/project_services/flowdock_service.rb
+++ b/app/models/project_services/flowdock_service.rb
@@ -1,5 +1,51 @@
 require "flowdock-git-hook"
 
+# Flow dock depends on Grit to compute the number of commits between two given
+# commits. To make this depend on Gitaly, a monkey patch is applied
+module Flowdock
+  class Git
+    # pass down a Repository all the way down
+    def repo
+      @options[:repo]
+    end
+
+    def config
+      {}
+    end
+
+    def messages
+      Git::Builder.new(repo: repo,
+                       ref: @ref,
+                       before: @from,
+                       after: @to,
+                       commit_url: @commit_url,
+                       branch_url: @branch_url,
+                       diff_url: @diff_url,
+                       repo_url: @repo_url,
+                       repo_name: @repo_name,
+                       permanent_refs: @permanent_refs,
+                       tags: tags
+                      ).to_hashes
+    end
+
+    class Builder
+      def commits
+        @repo.commits_between(@before, @after).map do |commit|
+          {
+            url: @opts[:commit_url] ? @opts[:commit_url] % [commit.sha] : nil,
+            id: commit.sha,
+            message: commit.message,
+            author: {
+              name: commit.author_name,
+              email: commit.author_email
+            }
+          }
+        end
+      end
+    end
+  end
+end
+
 class FlowdockService < Service
   prop_accessor :token
   validates :token, presence: true, if: :activated?
@@ -34,7 +80,7 @@ class FlowdockService < Service
       data[:before],
       data[:after],
       token: token,
-      repo: project.repository.path_to_repo,
+      repo: project.repository,
       repo_url: "#{Gitlab.config.gitlab.url}/#{project.full_path}",
       commit_url: "#{Gitlab.config.gitlab.url}/#{project.full_path}/commit/%s",
       diff_url: "#{Gitlab.config.gitlab.url}/#{project.full_path}/compare/%s...%s"