Issue #449 API endpoint for Peer Monitor metrics

Support the new endpoint for later metrics in `rest/api/client`

Support the new method created in `rest/api/client` in
ipfs-cluster-ctl. i.e. `ipfs-cluster-ctl health metrics <name>` would
show the peers and the last list of metrics logged for each as returned
by the Peer Monitor, in a friendly way.

License: MIT
Signed-off-by: Kishan Mohanbhai Sagathiya <kishansagathiya@gmail.com>

api/rest/client/client.go

@@ -103,6 +103,10 @@ type Client interface {
 	// GetConnectGraph returns an ipfs-cluster connection graph.  The
 	// serialized version, strings instead of pids, is returned
 	GetConnectGraph() (api.ConnectGraphSerial, error)
+
+	// PeerMonitorLatestMetrics returns a map with the latest metrics of matching name
+	// for the current cluster peers.
+	PeerMonitorLatestMetrics(name string) ([]api.Metric, error)
 }
 
 // Config allows to configure the parameters to connect

api/rest/client/methods.go

@@ -204,6 +204,14 @@ func (c *defaultClient) GetConnectGraph() (api.ConnectGraphSerial, error) {
 	return graphS, err
 }
 
+// PeerMonitorLatestMetrics returns a map with the latest metrics of matching name
+// for the current cluster peers.
+func (c *defaultClient) PeerMonitorLatestMetrics(name string) ([]api.Metric, error) {
+	var metrics []api.Metric
+	err := c.do("GET", fmt.Sprintf("/health/metrics/%s", name), nil, nil, &metrics)
+	return metrics, err
+}
+
 // WaitFor is a utility function that allows for a caller to wait for a
 // paticular status for a CID (as defined by StatusFilterParams).
 // It returns the final status for that CID and an error, if there was.

cmd/ipfs-cluster-ctl/formatters.go

@@ -24,6 +24,9 @@ func jsonFormatObject(resp interface{}) {
 		jsonFormatPrint(resp.(api.AddedOutput))
 	case api.Version:
 		jsonFormatPrint(resp.(api.Version))
+	case api.Metric:
+		serial := resp.(api.Metric)
+		textFormatPrintMetric(&serial)
 	case api.Error:
 		jsonFormatPrint(resp.(api.Error))
 	case []api.ID:
@@ -51,6 +54,9 @@ func jsonFormatObject(resp interface{}) {
 	case []api.AddedOutput:
 		serials := resp.([]api.AddedOutput)
 		jsonFormatPrint(serials)
+	case []api.Metric:
+		serials := resp.([]api.Metric)
+		jsonFormatPrint(serials)
 	default:
 		checkErr("", errors.New("unsupported type returned"))
 	}
@@ -84,6 +90,9 @@ func textFormatObject(resp interface{}) {
 	case api.Error:
 		serial := resp.(api.Error)
 		textFormatPrintError(&serial)
+	case api.Metric:
+		serial := resp.(api.Metric)
+		textFormatPrintMetric(&serial)
 	case []api.ID:
 		for _, item := range resp.([]api.ID) {
 			textFormatObject(item)
@@ -100,6 +109,10 @@ func textFormatObject(resp interface{}) {
 		for _, item := range resp.([]api.AddedOutput) {
 			textFormatObject(item)
 		}
+	case []api.Metric:
+		for _, item := range resp.([]api.Metric) {
+			textFormatObject(item)
+		}
 	default:
 		checkErr("", errors.New("unsupported type returned"))
 	}
@@ -202,6 +215,15 @@ func textFormatPrintAddedOutput(obj *api.AddedOutput) {
 	fmt.Printf("added %s %s\n", obj.Cid, obj.Name)
 }
 
+func textFormatPrintMetric(obj *api.Metric) {
+	fmt.Printf("{\n")
+	fmt.Printf("	Peer:   %s\n", (obj.Peer).String())
+	fmt.Printf("	Value:  %s\n", obj.Value)
+	fmt.Printf("	Expire: %d\n", obj.Expire)
+	fmt.Printf("	Expire: %t\n", obj.Valid)
+	fmt.Printf("}\n")
+}
+
 func textFormatPrintError(obj *api.Error) {
 	fmt.Printf("An error occurred:\n")
 	fmt.Printf("  Code: %d\n", obj.Code)

cmd/ipfs-cluster-ctl/main.go

@@ -762,6 +762,20 @@ graph of the connections.  Output is a dot file encoding the cluster's connectio
 						return nil
 					},
 				},
+				{
+					Name:  "metrics",
+					Usage: "Get latest metrics of matching name for the current cluster peers.",
+					Description: `
+This command would show the peers and the last list of metrics logged for each as
+returned by the Peer Monitor, in a friendly way.
+`,
+					ArgsUsage: "Metric name",
+					Action: func(c *cli.Context) error {
+						resp, cerr := globalClient.PeerMonitorLatestMetrics(c.Args().First())
+						formatResponse(c, resp, cerr)
+						return nil
+					},
+				},
 			},
 		},
 		{