Benchmarking the Thanos Receiver Handler for a memory leak

receiver_test.go

// Trying to reproduce https://github.com/thanos-io/thanos/issues/3726
// Add this somewhere (at the end) in the pkg/receive/handler_test.go
// Run go test -bench=BenchmarkHandler ./pkg/receive

func BenchmarkHandler(b *testing.B) {
	wreq1 := &prompb.WriteRequest{
		Timeseries: []prompb.TimeSeries{
			{
				Labels: []labelpb.ZLabel{{Name: "foo", Value: "bar"}},
				Samples: []prompb.Sample{
					{Value: 1, Timestamp: 1},
					{Value: 2, Timestamp: 2},
					{Value: 3, Timestamp: 3},
				},
			},
		},
	}

	handlers, _ := newHandlerHashring(
		[]*fakeAppendable{
			{appender: newFakeAppender(nil, nil, nil, nil)},
			{appender: newFakeAppender(nil, nil, nil, nil)},
			{appender: newFakeAppender(nil, nil, nil, nil)},
			{appender: newFakeAppender(nil, nil, nil, nil)},
			{appender: newFakeAppender(nil, nil, nil, nil)},
			{appender: newFakeAppender(nil, nil, nil, nil)},
		},
		3,
	)
	handler := handlers[0]

	server := httptest.NewServer(handler)
	defer server.Close()
	client := &http.Client{}

	b.ReportAllocs()
	b.ResetTimer()

	buf, err := proto.Marshal(wreq1)
	if err != nil {
		b.Fatal(err)
	}

	for i := 0; i < b.N; i++ {
		req, err := http.NewRequest("POST", server.URL+"/api/v1/receive", bytes.NewBuffer(snappy.Encode(nil, buf)))
		if err != nil {
			b.Fatal(err)
		}

		req.Header.Add(handler.options.TenantHeader, "test")
		req.Header.Add("X-Request-ID", fmt.Sprintf("%d", i))

		resp, err := client.Do(req)
		if err != nil {
			b.Fatal(err)
		}
		defer resp.Body.Close()
		if resp.StatusCode/100 != 2 {
			body, _ := ioutil.ReadAll(resp.Body)
			b.Log(string(body))
			b.Fatal("no 200 OK", resp.Status)
		}
	}

}