Add a tool for grabbing and parsing prometheus metrics

pkg/metrics/metrics_grabber.go

@@ -0,0 +1,136 @@
+/*
+Copyright 2015 The Kubernetes Authors 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 metrics
+
+import (
+	"fmt"
+	"strings"
+
+	"k8s.io/kubernetes/pkg/api"
+	client "k8s.io/kubernetes/pkg/client/unversioned"
+	"k8s.io/kubernetes/pkg/master/ports"
+	"k8s.io/kubernetes/pkg/util/sets"
+
+	"github.com/golang/glog"
+)
+
+type MetricsCollection struct {
+	ApiServerMetrics         ApiServerMetrics
+	ControllerManagerMetrics ControllerManagerMetrics
+	KubeletMetrics           map[string]KubeletMetrics
+	SchedulerMetrics         SchedulerMetrics
+}
+
+type MetricsGrabber struct {
+	client                    *client.Client
+	grabFromApiServer         bool
+	grabFromControllerManager bool
+	grabFromKubelets          bool
+	grabFromScheduler         bool
+	kubeletPort               int
+	masterName                string
+	registeredMaster          bool
+}
+
+// TODO: find a better way of figuring out if given node is a registered master.
+func isMasterNode(node *api.Node) bool {
+	return strings.HasSuffix(node.Name, "master")
+}
+
+func NewMetricsGrabber(c *client.Client, kubelets bool, scheduler bool, controllers bool, apiServer bool) (*MetricsGrabber, error) {
+	kubeletPort := 0
+	registeredMaster := false
+	masterName := ""
+	nodeList, err := c.Nodes().List(api.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+	if len(nodeList.Items) < 1 {
+		glog.Warning("Can't find any Nodes in the API server to grab metrics from")
+	}
+	for _, node := range nodeList.Items {
+		if isMasterNode(&node) {
+			registeredMaster = true
+			masterName = node.Name
+		} else {
+			// We assume that all Kubelets run on the same port, except possibly Master's Kubelet.
+			// This will need to get change if assumption is prover wrong.
+			kubeletPort = node.Status.DaemonEndpoints.KubeletEndpoint.Port
+		}
+	}
+	if !registeredMaster {
+		scheduler = false
+		controllers = false
+		glog.Warningf("Master node is not registered. Grabbing metrics from Scheduler and ControllerManager is disabled.")
+	}
+
+	return &MetricsGrabber{
+		client:                    c,
+		grabFromApiServer:         apiServer,
+		grabFromControllerManager: controllers,
+		grabFromKubelets:          kubelets,
+		grabFromScheduler:         scheduler,
+		kubeletPort:               kubeletPort,
+		masterName:                masterName,
+		registeredMaster:          registeredMaster,
+	}, nil
+}
+
+func (g *MetricsGrabber) GrabFromKubelet(nodeName string, unknownMetrics sets.String) (KubeletMetrics, error) {
+	if g.kubeletPort == 0 {
+		return KubeletMetrics{}, fmt.Errorf("MetricsGrabber wasn't able to find Kubelet port during startup. Skipping Kubelet's metrics gathering.")
+	}
+	output, err := g.getMetricsFromNode(nodeName)
+	if err != nil {
+		return KubeletMetrics{}, err
+	}
+	return parseKubeletMetrics(output, unknownMetrics)
+}
+
+func (g *MetricsGrabber) GrabFromScheduler(unknownMetrics sets.String) (SchedulerMetrics, error) {
+	if !g.registeredMaster {
+		return SchedulerMetrics{}, fmt.Errorf("Master's Kubelet is not registered. Skipping Scheduler's metrics gathering.")
+	}
+	output, err := g.getMetricsFromPod(fmt.Sprintf("%v-%v", "kube-scheduler", g.masterName), api.NamespaceSystem, ports.SchedulerPort)
+	if err != nil {
+		return SchedulerMetrics{}, err
+	}
+	return parseSchedulerMetrics(output, unknownMetrics)
+}
+
+func (g *MetricsGrabber) GrabFromControllerManager(unknownMetrics sets.String) (ControllerManagerMetrics, error) {
+	if !g.registeredMaster {
+		return ControllerManagerMetrics{}, fmt.Errorf("Master's Kubelet is not registered. Skipping ControllerManager's metrics gathering.")
+	}
+	output, err := g.getMetricsFromPod(fmt.Sprintf("%v-%v", "kube-controller-manager", g.masterName), api.NamespaceSystem, ports.ControllerManagerPort)
+	if err != nil {
+		return ControllerManagerMetrics{}, err
+	}
+	return parseControllerManagerMetrics(output, unknownMetrics)
+}
+
+func (g *MetricsGrabber) GrabFromApiServer(unknownMetrics sets.String) (ApiServerMetrics, error) {
+	output, err := g.getMetricsFromApiServer()
+	if err != nil {
+		return ApiServerMetrics{}, nil
+	}
+	return parseApiServerMetrics(output, unknownMetrics)
+}
+
+func (g *MetricsGrabber) Grab(unknownMetrics sets.String) (MetricsCollection, error) {
+	return MetricsCollection{}, nil
+}