Add cluster command to show cluster and peer statuses. (#2256)

Signed-off-by: Fahri Yardımcı <f.yardimci06@gmail.com>

Signed-off-by: Fahri Yardımcı <f.yardimci06@gmail.com>

cli/cluster.go

@@ -0,0 +1,43 @@
+// Copyright 2020 Prometheus Team
+// 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 cli
+
+import (
+	"context"
+	"errors"
+
+	"gopkg.in/alecthomas/kingpin.v2"
+
+	"github.com/prometheus/alertmanager/cli/format"
+)
+
+const clusterHelp = `View cluster status and peers.`
+
+// clusterCmd represents the cluster command
+func configureClusterCmd(app *kingpin.Application) {
+	clusterCmd := app.Command("cluster", clusterHelp)
+	clusterCmd.Command("show", clusterHelp).Default().Action(execWithTimeout(showStatus)).PreAction(requireAlertManagerURL)
+}
+
+func showStatus(ctx context.Context, _ *kingpin.ParseContext) error {
+	alertManagerStatus, err := getRemoteAlertmanagerConfigStatus(ctx, alertmanagerURL)
+	if err != nil {
+		return err
+	}
+	formatter, found := format.Formatters[output]
+	if !found {
+		return errors.New("unknown output formatter")
+	}
+	return formatter.FormatClusterStatus(alertManagerStatus.Cluster)
+}

cli/format/format.go

@@ -39,6 +39,7 @@ type Formatter interface {
 	FormatSilences([]models.GettableSilence) error
 	FormatAlerts([]*models.GettableAlert) error
 	FormatConfig(*models.AlertmanagerStatus) error
+	FormatClusterStatus(status *models.ClusterStatus) error
 }
 
 // Formatters is a map of cli argument names to formatter interface object.

cli/format/format_extended.go

@@ -89,6 +89,27 @@ func (formatter *ExtendedFormatter) FormatConfig(status *models.AlertmanagerStat
 	return nil
 }
 
+// FormatClusterStatus formats the cluster status with peers into a readable string.
+func (formatter *ExtendedFormatter) FormatClusterStatus(status *models.ClusterStatus) error {
+	w := tabwriter.NewWriter(formatter.writer, 0, 0, 2, ' ', 0)
+	fmt.Fprintf(w,
+		"Cluster Status:\t%s\nNode Name:\t%s\n\n",
+		*status.Status,
+		status.Name,
+	)
+	fmt.Fprintln(w, "Address\tName")
+	sort.Sort(ByAddress(status.Peers))
+	for _, peer := range status.Peers {
+		fmt.Fprintf(
+			w,
+			"%s\t%s\t\n",
+			*peer.Address,
+			*peer.Name,
+		)
+	}
+	return w.Flush()
+}
+
 func extendedFormatLabels(labels models.LabelSet) string {
 	output := []string{}
 	for name, value := range labels {

cli/format/format_json.go

@@ -47,3 +47,8 @@ func (formatter *JSONFormatter) FormatConfig(status *models.AlertmanagerStatus)
 	enc := json.NewEncoder(formatter.writer)
 	return enc.Encode(status)
 }
+
+func (formatter *JSONFormatter) FormatClusterStatus(status *models.ClusterStatus) error {
+	enc := json.NewEncoder(formatter.writer)
+	return enc.Encode(status)
+}

cli/format/format_simple.go

@@ -75,6 +75,16 @@ func (formatter *SimpleFormatter) FormatConfig(status *models.AlertmanagerStatus
 	return nil
 }
 
+func (formatter *SimpleFormatter) FormatClusterStatus(status *models.ClusterStatus) error {
+	w := tabwriter.NewWriter(formatter.writer, 0, 0, 2, ' ', 0)
+	fmt.Fprintf(w,
+		"Cluster Status:\t%s\nNode Name:\t%s\n",
+		*status.Status,
+		status.Name,
+	)
+	return w.Flush()
+}
+
 func simpleFormatMatchers(matchers models.Matchers) string {
 	output := []string{}
 	for _, matcher := range matchers {

cli/format/sort.go

@@ -14,6 +14,9 @@
 package format
 
 import (
+	"bytes"
+	"net"
+	"strconv"
 	"time"
 
 	"github.com/prometheus/alertmanager/api/v2/models"
@@ -34,3 +37,19 @@ func (s ByStartsAt) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
 func (s ByStartsAt) Less(i, j int) bool {
 	return time.Time(*s[i].StartsAt).Before(time.Time(*s[j].StartsAt))
 }
+
+type ByAddress []*models.PeerStatus
+
+func (s ByAddress) Len() int      { return len(s) }
+func (s ByAddress) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
+func (s ByAddress) Less(i, j int) bool {
+	ip1, port1, _ := net.SplitHostPort(*s[i].Address)
+	ip2, port2, _ := net.SplitHostPort(*s[j].Address)
+	if ip1 == ip2 {
+		p1, _ := strconv.Atoi(port1)
+		p2, _ := strconv.Atoi(port2)
+		return p1 < p2
+	} else {
+		return bytes.Compare(net.ParseIP(ip1), net.ParseIP(ip2)) < 0
+	}
+}

cli/root.go

@@ -111,6 +111,7 @@ func Execute() {
 	configureAlertCmd(app)
 	configureSilenceCmd(app)
 	configureCheckConfigCmd(app)
+	configureClusterCmd(app)
 	configureConfigCmd(app)
 
 	err = resolver.Bind(app, os.Args[1:])