From 1a9e5f31a8d6906cfd756cefb8fd9f6a9f027ade Mon Sep 17 00:00:00 2001
From: Marcos Oliveira <marcosvm@gmail.com>
Date: Sat, 20 Oct 2018 00:38:45 -0700
Subject: [PATCH 1/4] add pagination for jobs in the data layer

---
 lib/elixir_bench/benchmarks/benchmarks.ex | 20 ++++++++++++++-
 test/elixir_bench/jobs/jobs_test.exs      | 31 +++++++++++++++++++++++
 2 files changed, 50 insertions(+), 1 deletion(-)
 create mode 100644 test/elixir_bench/jobs/jobs_test.exs

diff --git a/lib/elixir_bench/benchmarks/benchmarks.ex b/lib/elixir_bench/benchmarks/benchmarks.ex
index 9b6bba3..0f800b1 100644
--- a/lib/elixir_bench/benchmarks/benchmarks.ex
+++ b/lib/elixir_bench/benchmarks/benchmarks.ex
@@ -7,6 +7,9 @@ defmodule ElixirBench.Benchmarks do
   alias ElixirBench.Github
   alias ElixirBench.Benchmarks.{Benchmark, Measurement, Job, Runner, Config}
 
+  @jobs_default_limit 10
+  @jobs_max_limit 50
+
   def data() do
     Dataloader.Ecto.new(Repo, query: &query/2)
   end
@@ -69,8 +72,23 @@ defmodule ElixirBench.Benchmarks do
     Repo.all(from(j in Job, where: j.repo_id in ^repo_ids))
   end
 
+  def paginate(query, page, size) do
+    from(query,
+      limit: ^size,
+      offset: ^((page - 1) * size)
+    )
+  end
+
   def list_jobs() do
-    Repo.all(Job)
+    Job
+    |> paginate(1, @jobs_default_limit)
+    |> Repo.all()
+  end
+
+  def list_jobs(page, size) do
+    Job
+    |> paginate(page, size)
+    |> Repo.all()
   end
 
   def get_or_create_job(repo, %{commit_sha: commit_sha} = attrs) do
diff --git a/test/elixir_bench/jobs/jobs_test.exs b/test/elixir_bench/jobs/jobs_test.exs
new file mode 100644
index 0000000..fcc1180
--- /dev/null
+++ b/test/elixir_bench/jobs/jobs_test.exs
@@ -0,0 +1,31 @@
+defmodule ElixirBench.JobsTest do
+  use ElixirBench.DataCase
+  import ElixirBench.Factory
+  alias ElixirBench.Benchmarks
+
+  setup do
+    Enum.each(0..4, fn _ -> insert(:job) end)
+  end
+
+  describe "list_jobs/2" do
+    test "returns 2 jobs for page 1" do
+      jobs = Benchmarks.list_jobs(1, 2)
+      assert length(jobs) == 2
+    end
+
+    test "returns 2 jobs for page 2" do
+      jobs = Benchmarks.list_jobs(2, 2)
+      assert length(jobs) == 2
+    end
+
+    test "returns 1 job for page 3" do
+      jobs = Benchmarks.list_jobs(3, 2)
+      assert length(jobs) == 1
+    end
+
+    test "without page returns all 5 jobs" do
+      jobs = Benchmarks.list_jobs()
+      assert length(jobs) == 5
+    end
+  end
+end

From e39dbe355e12160a4212f3aa78045b467e6c4881 Mon Sep 17 00:00:00 2001
From: Marcos Oliveira <marcosvm@gmail.com>
Date: Sat, 20 Oct 2018 00:57:29 -0700
Subject: [PATCH 2/4] limit jobs page size to jobs_max_limit

---
 lib/elixir_bench/benchmarks/benchmarks.ex | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/elixir_bench/benchmarks/benchmarks.ex b/lib/elixir_bench/benchmarks/benchmarks.ex
index 0f800b1..c71c988 100644
--- a/lib/elixir_bench/benchmarks/benchmarks.ex
+++ b/lib/elixir_bench/benchmarks/benchmarks.ex
@@ -86,6 +86,8 @@ defmodule ElixirBench.Benchmarks do
   end
 
   def list_jobs(page, size) do
+    size = if size < @jobs_max_limit, do: size, else: @jobs_max_limit
+
     Job
     |> paginate(page, size)
     |> Repo.all()

From 0f52f4d8ed81fb54dd6590f4fba900ecef015ab8 Mon Sep 17 00:00:00 2001
From: Marcos Oliveira <marcosvm@gmail.com>
Date: Sat, 20 Oct 2018 01:28:15 -0700
Subject: [PATCH 3/4] fix formatting

---
 lib/elixir_bench/benchmarks/benchmarks.ex | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/elixir_bench/benchmarks/benchmarks.ex b/lib/elixir_bench/benchmarks/benchmarks.ex
index c71c988..a4748e7 100644
--- a/lib/elixir_bench/benchmarks/benchmarks.ex
+++ b/lib/elixir_bench/benchmarks/benchmarks.ex
@@ -73,7 +73,8 @@ defmodule ElixirBench.Benchmarks do
   end
 
   def paginate(query, page, size) do
-    from(query,
+    from(
+      query,
       limit: ^size,
       offset: ^((page - 1) * size)
     )

From cc56d9e7a078c7aa66514d56a82a4f3956749a29 Mon Sep 17 00:00:00 2001
From: Marcos Oliveira <marcosvm@gmail.com>
Date: Sat, 20 Oct 2018 23:28:01 -0700
Subject: [PATCH 4/4] add page number and page size to the schema

---
 lib/elixir_bench_web/schema.ex | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/elixir_bench_web/schema.ex b/lib/elixir_bench_web/schema.ex
index b74c2ee..a75e371 100644
--- a/lib/elixir_bench_web/schema.ex
+++ b/lib/elixir_bench_web/schema.ex
@@ -43,8 +43,11 @@ defmodule ElixirBenchWeb.Schema do
     end
 
     field :jobs, list_of(:job) do
-      resolve(fn _, _ ->
-        {:ok, Benchmarks.list_jobs()}
+      arg(:page, :integer, default_value: 1)
+      arg(:size, :integer, default_value: 10)
+
+      resolve(fn %{page: page_num, size: page_size}, _ ->
+        {:ok, Benchmarks.list_jobs(page_num, page_size)}
       end)
     end