Avoid job duplication by Github webhooks

Signed-off-by: Tallys Martins <tallysmartins@gmail.com>

lib/elixir_bench/benchmarks/benchmarks.ex

@@ -51,6 +51,16 @@ defmodule ElixirBench.Benchmarks do
     Repo.fetch(where(Job, uuid: ^uuid))
   end
 
+  def fetch_running_job_by_reference(branch_name, commit_sha) do
+    query =
+      Job
+      |> last
+      |> Job.unfinished()
+      |> where(branch_name: ^branch_name, commit_sha: ^commit_sha)
+
+    Repo.fetch(query)
+  end
+
   def list_benchmarks_by_repo_id(repo_ids) do
     Repo.all(from(b in Benchmark, where: b.repo_id in ^repo_ids))
   end
@@ -63,6 +73,18 @@ defmodule ElixirBench.Benchmarks do
     Repo.all(Job)
   end
 
+  def get_or_create_job(repo, attrs) do
+    %{branch_name: branch_name, commit_sha: commit_sha} = attrs
+
+    case fetch_running_job_by_reference(branch_name, commit_sha) do
+      {:ok, job} ->
+        {:ok, job}
+
+      {:error, :not_found} ->
+        create_job(repo, attrs)
+    end
+  end
+
   def create_job(repo, attrs) do
     changeset = Job.create_changeset(%Job{repo_id: repo.id}, attrs)
 

lib/elixir_bench/benchmarks/job.ex

@@ -2,6 +2,7 @@ defmodule ElixirBench.Benchmarks.Job do
   use Ecto.Schema
 
   import Ecto.Changeset
+  import Ecto.Query, only: [from: 1, from: 2]
 
   alias ElixirBench.Repos
   alias ElixirBench.Benchmarks.{Runner, Job, Config}
@@ -66,4 +67,8 @@ defmodule ElixirBench.Benchmarks.Job do
     |> validate_required(@submit_fields)
     |> put_change(:completed_at, DateTime.utc_now())
   end
+
+  def unfinished(query) do
+    from(j in query, where: is_nil(j.completed_at))
+  end
 end

lib/elixir_bench_web/controllers/github/webhooks_controller.ex

@@ -39,7 +39,7 @@ defmodule ElixirBenchWeb.Github.WebHooks do
 
     with {:ok, %Repos.Repo{} = repo} <- Repos.fetch_repo_by_slug(slug),
          {:ok, job} <-
-           Benchmarks.create_job(repo, %{branch_name: branch_name, commit_sha: commit_sha}) do
+           Benchmarks.get_or_create_job(repo, %{branch_name: branch_name, commit_sha: commit_sha}) do
       conn
       |> render(ElixirBenchWeb.JobView, "show.json", job: job, repo: repo)
     else

test/elixir_bench_web/controllers/github/webhooks_controller_test.exs

@@ -52,6 +52,30 @@ defmodule ElixirBenchWeb.Github.WebHooksControllerTest do
       assert 200 = response.status
     end
 
+    # This scenario happens when there is a branch with an open pull request
+    # So Github sends requests for both events, pull request and push.
+    test "not duplicate job for same branch and commit references", context do
+      insert(:repo, @github_repo_attrs)
+      push_params = %{"payload" => push_payload()}
+      pull_request = %{"payload" => pull_request_payload()}
+
+      assert_difference(Job, 1) do
+        {:ok, %{"data" => data}} =
+          context.conn
+          |> set_headers("pull_request")
+          |> post("/hooks/handle", pull_request)
+          |> decode_response_body
+
+        {:ok, %{"data" => ^data}} =
+          context.conn
+          |> set_headers("push")
+          |> post("/hooks/handle", push_params)
+          |> decode_response_body
+      end
+
+      assert %{"branch_name" => "changes", "repo_slug" => "baxterthehacker/public-repo"} = data
+    end
+
     test "not break given unexpected pull request event payload scheme", context do
       insert(:repo, @github_repo_attrs)
       params = %{"payload" => ~s({"data": "some data"})}