Function TestConcurrency

coderd/files/cache_test.go:198–256

(t *testing.T)

}

func TestConcurrency(t *testing.T) {
	t.Parallel()
	ctx := dbauthz.AsFileReader(t.Context())

	const fileSize = 10
	var fetches atomic.Int64
	reg := prometheus.NewRegistry()

	dbM := dbmock.NewMockStore(gomock.NewController(t))
	dbM.EXPECT().GetFileByID(gomock.Any(), gomock.Any()).DoAndReturn(func(mTx context.Context, fileID uuid.UUID) (database.File, error) {
		fetches.Add(1)
		// Wait long enough before returning to make sure that all the goroutines
		// will be waiting in line, ensuring that no one duplicated a fetch.
		time.Sleep(testutil.IntervalMedium)
		return database.File{
			Data: make([]byte, fileSize),
		}, nil
	}).AnyTimes()

	c := files.New(reg, &coderdtest.FakeAuthorizer{})

	batches := 1000
	groups := make([]*errgroup.Group, 0, batches)
	for range batches {
		groups = append(groups, new(errgroup.Group))
	}

	// Call Acquire with a unique ID per batch, many times per batch, with many
	// batches all in parallel. This is pretty much the worst-case scenario:
	// thousands of concurrent reads, with both warm and cold loads happening.
	batchSize := 10
	for _, g := range groups {
		id := uuid.New()
		for range batchSize {
			g.Go(func() error {
				// We don't bother to Release these references because the Cache will be
				// released at the end of the test anyway.
				_, err := c.Acquire(ctx, dbM, id)
				return err
			})
		}
	}

	for _, g := range groups {
		require.NoError(t, g.Wait())
	}
	require.Equal(t, int64(batches), fetches.Load())

	// Verify all the counts & metrics are correct.
	require.Equal(t, batches, c.Count())
	require.Equal(t, batches*fileSize, promhelp.GaugeValue(t, reg, cachePromMetricName("open_files_size_bytes_current"), nil))
	require.Equal(t, batches*fileSize, promhelp.CounterValue(t, reg, cachePromMetricName("open_files_size_bytes_total"), nil))
	require.Equal(t, batches, promhelp.GaugeValue(t, reg, cachePromMetricName("open_files_current"), nil))
	require.Equal(t, batches, promhelp.CounterValue(t, reg, cachePromMetricName("open_files_total"), nil))
	require.Equal(t, batches*batchSize, promhelp.GaugeValue(t, reg, cachePromMetricName("open_file_refs_current"), nil))
	hit, miss := promhelp.CounterValue(t, reg, cachePromMetricName("open_file_refs_total"), prometheus.Labels{"hit": "false"}),
		promhelp.CounterValue(t, reg, cachePromMetricName("open_file_refs_total"), prometheus.Labels{"hit": "true"})
	require.Equal(t, batches*batchSize, hit+miss)