Merge pull request #699 from vmarmol/collector

Add basic metric structures

collector/collector_manager.go

@@ -18,6 +18,8 @@ import (
 	"fmt"
 	"strings"
 	"time"
+
+	"github.com/google/cadvisor/info/v2"
 )
 
 type collectorManager struct {
@@ -46,17 +48,19 @@ func (cm *collectorManager) RegisterCollector(collector Collector) error {
 	return nil
 }
 
-func (cm *collectorManager) Collect() (time.Time, error) {
+func (cm *collectorManager) Collect() (time.Time, []v2.Metric, error) {
 	var errors []error
 
 	// Collect from all collectors that are ready.
 	var next time.Time
+	var metrics []v2.Metric
 	for _, c := range cm.collectors {
 		if c.nextCollectionTime.Before(time.Now()) {
-			nextCollection, err := c.collector.Collect()
+			nextCollection, newMetrics, err := c.collector.Collect()
 			if err != nil {
 				errors = append(errors, err)
 			}
+			metrics = append(metrics, newMetrics...)
 			c.nextCollectionTime = nextCollection
 		}
 
@@ -66,7 +70,7 @@ func (cm *collectorManager) Collect() (time.Time, error) {
 		}
 	}
 
-	return next, compileErrors(errors)
+	return next, metrics, compileErrors(errors)
 }
 
 // Make an error slice into a single error.

collector/collector_manager_test.go

@@ -18,6 +18,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/google/cadvisor/info/v2"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -27,9 +28,9 @@ type fakeCollector struct {
 	collectedFrom      int
 }
 
-func (fc *fakeCollector) Collect() (time.Time, error) {
+func (fc *fakeCollector) Collect() (time.Time, []v2.Metric, error) {
 	fc.collectedFrom++
-	return fc.nextCollectionTime, fc.err
+	return fc.nextCollectionTime, []v2.Metric{}, fc.err
 }
 
 func (fc *fakeCollector) Name() string {
@@ -53,7 +54,7 @@ func TestCollect(t *testing.T) {
 	assert.NoError(cm.RegisterCollector(f2))
 
 	// First collection, everyone gets collected from.
-	nextTime, err := cm.Collect()
+	nextTime, _, err := cm.Collect()
 	assert.Equal(firstTime, nextTime)
 	assert.NoError(err)
 	assert.Equal(1, f1.collectedFrom)
@@ -62,7 +63,7 @@ func TestCollect(t *testing.T) {
 	f1.nextCollectionTime = time.Now().Add(2 * time.Hour)
 
 	// Second collection, only the one that is ready gets collected from.
-	nextTime, err = cm.Collect()
+	nextTime, _, err = cm.Collect()
 	assert.Equal(secondTime, nextTime)
 	assert.NoError(err)
 	assert.Equal(2, f1.collectedFrom)

collector/fakes.go

@@ -16,6 +16,8 @@ package collector
 
 import (
 	"time"
+
+	"github.com/google/cadvisor/info/v2"
 )
 
 type FakeCollectorManager struct {
@@ -25,7 +27,7 @@ func (fkm *FakeCollectorManager) RegisterCollector(collector Collector) error {
 	return nil
 }
 
-func (fkm *FakeCollectorManager) Collect() (time.Time, error) {
+func (fkm *FakeCollectorManager) Collect() (time.Time, []v2.Metric, error) {
 	var zero time.Time
-	return zero, nil
+	return zero, []v2.Metric{}, nil
 }

collector/types.go

@@ -15,6 +15,7 @@
 package collector
 
 import (
+	"github.com/google/cadvisor/info/v2"
 	"time"
 )
 
@@ -26,7 +27,7 @@ type Collector interface {
 	// Returns the next time this collector should be collected from.
 	// Next collection time is always returned, even when an error occurs.
 	// A collection time of zero means no more collection.
-	Collect() (time.Time, error)
+	Collect() (time.Time, []v2.Metric, error)
 
 	// Name of this collector.
 	Name() string
@@ -41,5 +42,5 @@ type CollectorManager interface {
 	// at which a collector will be ready to collect from.
 	// Next collection time is always returned, even when an error occurs.
 	// A collection time of zero means no more collection.
-	Collect() (time.Time, error)
+	Collect() (time.Time, []v2.Metric, error)
 }

info/v2/metric.go

@@ -0,0 +1,69 @@
+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2
+
+import (
+	"time"
+)
+
+// Type of metric being exported.
+type MetricType string
+
+const (
+	// Instantaneous value. May increase or decrease.
+	MetricGauge MetricType = "gauge"
+
+	// A counter-like value that is only expected to increase.
+	MetricCumulative = "cumulative"
+
+	// Rate over a time period.
+	MetricDelta = "delta"
+)
+
+// An exported metric.
+type Metric struct {
+	// The name of the metric.
+	Name string `json:"name"`
+
+	// Type of the metric.
+	Type MetricType `json:"type"`
+
+	// Metadata associated with this metric.
+	Labels map[string]string
+
+	// Value of the metric. Only one of these values will be
+	// available according to the output type of the metric.
+	// If no values are available, there are no data points.
+	IntPoints   []IntPoint   `json:"int_points,omitempty"`
+	FloatPoints []FloatPoint `json:"float_points,omitempty"`
+}
+
+// An integer metric data point.
+type IntPoint struct {
+	// Time at which the metric was queried
+	Timestamp time.Time `json:"timestamp"`
+
+	// The value of the metric at this point.
+	Value int64 `json:"value"`
+}
+
+// A float metric data point.
+type FloatPoint struct {
+	// Time at which the metric was queried
+	Timestamp time.Time `json:"timestamp"`
+
+	// The value of the metric at this point.
+	Value float64 `json:"value"`
+}

manager/container.go

@@ -232,8 +232,9 @@ func (c *containerData) housekeeping() {
 			}
 		}
 
+		// TODO(vmarmol): Export metrics.
 		// Run custom collectors.
-		nextCollectionTime, err := c.collectorManager.Collect()
+		nextCollectionTime, _, err := c.collectorManager.Collect()
 		if err != nil && c.allowErrorLogging() {
 			glog.Warningf("[%s] Collection failed: %v", c.info.Name, err)
 		}