Retrieve 0 stats/samples when user asked for zero stats/samples

api/handler.go

@@ -71,6 +71,11 @@ func HandleRequest(m manager.Manager, w http.ResponseWriter, r *http.Request) er
 		log.Printf("Api - Container(%s)", containerName)
 
 		var query info.ContainerInfoRequest
+
+		// If a user does not specify number of stats/samples he wants,
+		// it's 64 by default
+		query.NumStats = 64
+		query.NumSamples = 64
 		decoder := json.NewDecoder(r.Body)
 		err := decoder.Decode(&query)
 		if err != nil && err != io.EOF {

info/container.go

@@ -77,10 +77,10 @@ func (self *ContainerInfoRequest) FillDefaults() *ContainerInfoRequest {
 	if ret == nil {
 		ret = new(ContainerInfoRequest)
 	}
-	if ret.NumStats <= 0 {
+	if ret.NumStats < 0 {
 		ret.NumStats = 1024
 	}
-	if ret.NumSamples <= 0 {
+	if ret.NumSamples < 0 {
 		ret.NumSamples = 1024
 	}
 	if len(ret.CpuUsagePercentiles) == 0 {

storage/influxdb/influxdb.go

@@ -320,6 +320,9 @@ func (self *influxdbStorage) AddStats(ref info.ContainerReference, stats *info.C
 }
 
 func (self *influxdbStorage) RecentStats(containerName string, numStats int) ([]*info.ContainerStats, error) {
+	if numStats == 0 {
+		return nil, nil
+	}
 	// TODO(dengnan): select only columns that we need
 	// TODO(dengnan): escape names
 	query := fmt.Sprintf("select * from %v where %v='%v' and %v='%v'", self.tableName, colContainerName, containerName, colMachineName, self.machineName)
@@ -352,6 +355,9 @@ func (self *influxdbStorage) RecentStats(containerName string, numStats int) ([]
 }
 
 func (self *influxdbStorage) Samples(containerName string, numSamples int) ([]*info.ContainerStatsSample, error) {
+	if numSamples == 0 {
+		return nil, nil
+	}
 	// TODO(dengnan): select only columns that we need
 	// TODO(dengnan): escape names
 	query := fmt.Sprintf("select * from %v where %v='%v' and %v='%v'", self.tableName, colContainerName, containerName, colMachineName, self.machineName)

storage/influxdb/influxdb_test.go

@@ -146,3 +146,13 @@ func TestPercentilesWithoutStats(t *testing.T) {
 	t.SkipNow()
 	runStorageTest(test.StorageDriverTestPercentilesWithoutStats, t)
 }
+
+func TestRetrieveZeroStats(t *testing.T) {
+	t.SkipNow()
+	runStorageTest(test.StorageDriverTestRetrieveZeroRecentStats, t)
+}
+
+func TestRetrieveZeroSamples(t *testing.T) {
+	t.SkipNow()
+	runStorageTest(test.StorageDriverTestRetrieveZeroSamples, t)
+}

storage/memory/memory_test.go

@@ -73,3 +73,11 @@ func TestNoSamples(t *testing.T) {
 func TestPercentilesWithoutStats(t *testing.T) {
 	runStorageTest(test.StorageDriverTestPercentilesWithoutStats, t)
 }
+
+func TestRetrieveZeroStats(t *testing.T) {
+	runStorageTest(test.StorageDriverTestRetrieveZeroRecentStats, t)
+}
+
+func TestRetrieveZeroSamples(t *testing.T) {
+	runStorageTest(test.StorageDriverTestRetrieveZeroSamples, t)
+}

storage/test/storagetests.go

@@ -482,3 +482,61 @@ func StorageDriverTestPercentilesWithoutStats(driver storage.StorageDriver, t *t
 		}
 	}
 }
+
+func StorageDriverTestRetrieveZeroRecentStats(driver storage.StorageDriver, t *testing.T) {
+	defer driver.Close()
+	N := 100
+	memTrace := make([]uint64, N)
+	cpuTrace := make([]uint64, N)
+	for i := 0; i < N; i++ {
+		memTrace[i] = uint64(i + 1)
+		cpuTrace[i] = uint64(1)
+	}
+
+	ref := info.ContainerReference{
+		Name: "container",
+	}
+
+	trace := buildTrace(cpuTrace, memTrace, 1*time.Second)
+
+	for _, stats := range trace {
+		driver.AddStats(ref, stats)
+	}
+
+	recentStats, err := driver.RecentStats(ref.Name, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(recentStats) > 0 {
+		t.Errorf("RecentStats() returns %v stats when requests for 0 stats", len(recentStats))
+	}
+}
+
+func StorageDriverTestRetrieveZeroSamples(driver storage.StorageDriver, t *testing.T) {
+	defer driver.Close()
+	N := 100
+	memTrace := make([]uint64, N)
+	cpuTrace := make([]uint64, N)
+	for i := 0; i < N; i++ {
+		memTrace[i] = uint64(i + 1)
+		cpuTrace[i] = uint64(1)
+	}
+
+	ref := info.ContainerReference{
+		Name: "container",
+	}
+
+	trace := buildTrace(cpuTrace, memTrace, 1*time.Second)
+
+	for _, stats := range trace {
+		driver.AddStats(ref, stats)
+	}
+
+	samples, err := driver.Samples(ref.Name, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(samples) > 0 {
+		t.Errorf("RecentStats() returns %v stats when requests for 0 stats", len(samples))
+	}
+}