Issue #37: Added multi-cluster support for displaying cluster specific information.

Issue #16: Added cluster-name in kubectl, notifier and ping messages from botkube.

config.yaml

@@ -125,5 +125,3 @@ settings:
   clustername: not-configured
   # Set false to disable kubectl commands execution
   allowkubectl: false
-  # Set true only respond to channel in config
-  checkchannel: false

design/multi-cluster.md

@@ -0,0 +1,51 @@
+# Multi-cluster Support
+
+#### Assumptions
+`@botkube` commands refer to all the commands in the slack bot which currently supports:
+- kubectl
+- notifier
+- ping
+    
+
+### Summary
+Add Multi-cluster support for Botkube, where a single bot can monitor multiple clusters and respond to `@botkube` commands with cluster specific results.
+
+### Motivation
+Currently in multi-cluster scenario, a Slack bot authenticates all the clusters with a same authentication token. Thus running `@botkube` command returns response from all the configured clusters, irrespective of the slack channel or group. For `@botkube` command execution, we need a particular cluster specific output.
+
+### Design
+
+This design approach adds a flag `--cluster-name` to all `@botkube` commands. Use of that flag is optional in a cluster specific channel.
+
+Botkube `Notifier` commands are restricted to a dedicated channel for a cluster only and `--cluster-name` flag is ignored. 
+
+Botkube `ping` command with the `--cluster-name` flag returns `pong` response from the cluster specified in the flag, else you get response from all the clusters. `Ping` command without --cluster-name flag can be used to list all the configured clusters in the slack bot and identify you cluster's name among them.
+
+For `kubectl` commands in a dedicated channel to a cluster, if `--cluster-name` flag is used, it responds with the output for the cluster specified in flag, else it checks if the channel in the request matches the `config.Communications.Slack.Channel` and responds if true else ignores.
+
+For `kubectl` commands in a group, Direct message or channel not dedicated to any cluster, the `--cluster-name` flag is mandatory. The executor checks if the `--cluster-name` flag is present in the request. If yes, it gets the cluster's name from the flag and compares with `c.Settings.ClusterName` from the config file, if it matches then it responds with the required output to the slack bot and if it doesn't match, it ignores the request. And if the `--cluster-name` flag is absent for kubectl commands, it responds to the slack bot saying 'Please specify the cluster-name'. 
+
+For example -
+```sh
+@Botkube get pods --cluster-name={CLUSTER_NAME}
+```
+where,
+`CLUSTER_NAME` is the name of the cluster you want to query.
+
+To get the list of all clusters configured in the slack, you can run the following command in slack.
+
+```sh
+@Botkube ping
+```
+
+##### Workflow
+
+![Multi_Cluster_Design](workflow.png)
+
+
+### Drawbacks
+The `--cluster-name` flag is mandated for kubectl and notifier commands resulting additional overhead.
+
+### Alternatives
+We can add channel specific authentication token or completely dedicate a channel to a particular cluster which requires changes in the slack code.
+

helm/botkube/values.yaml

@@ -140,8 +140,6 @@ config:
     clustername: not-configured
     # Set false to disable kubectl commands execution
     allowkubectl: false
-    # Set true only respond to channel in config
-    checkchannel: false
 
 resources: {}
   # We usually recommend not to specify default resources and to leave this as a conscious

pkg/config/config.go

@@ -49,7 +49,6 @@ type Slack struct {
 type Settings struct {
 	ClusterName  string
 	AllowKubectl bool
-	CheckChannel bool
 }
 
 // New returns new Config

pkg/controller/controller.go

@@ -1,6 +1,7 @@
 package controller
 
 import (
+	"fmt"
 	"os"
 	"os/signal"
 	"strconv"
@@ -20,13 +21,13 @@ import (
 	"k8s.io/client-go/tools/cache"
 )
 
-var startTime time.Time
-
 const (
-	controllerStartMsg = "...and now my watch begins! :crossed_swords:"
-	controllerStopMsg  = "my watch has ended!"
+	controllerStartMsg = "...and now my watch begins for cluster '%s'! :crossed_swords:"
+	controllerStopMsg  = "my watch has ended for cluster '%s'!"
 )
 
+var startTime time.Time
+
 func findNamespace(ns string) string {
 	if ns == "all" {
 		return apiV1.NamespaceAll
@@ -39,7 +40,7 @@ func findNamespace(ns string) string {
 
 // RegisterInformers creates new informer controllers to watch k8s resources
 func RegisterInformers(c *config.Config) {
-	sendMessage(controllerStartMsg)
+	sendMessage(fmt.Sprintf(controllerStartMsg, c.Settings.ClusterName))
 	startTime = time.Now().Local()
 
 	// Get resync period
@@ -127,7 +128,7 @@ func RegisterInformers(c *config.Config) {
 	signal.Notify(sigterm, syscall.SIGTERM)
 	signal.Notify(sigterm, syscall.SIGINT)
 	<-sigterm
-	sendMessage(controllerStopMsg)
+	sendMessage(fmt.Sprintf(controllerStopMsg, c.Settings.ClusterName))
 }
 
 func registerEventHandlers(resourceType string, events []string) (handlerFns cache.ResourceEventHandlerFuncs) {

pkg/execute/executor.go

@@ -1,6 +1,7 @@
 package execute
 
 import (
+	"fmt"
 	"io/ioutil"
 	"os"
 	"os/exec"
@@ -25,19 +26,23 @@ var validKubectlCommands = map[string]bool{
 	"auth":          true,
 }
 
-var validNotifierCommands = map[string]bool{
+var validNotifierCommand = map[string]bool{
 	"notifier": true,
-	"help":     true,
-	"ping":     true,
+}
+var validPingCommand = map[string]bool{
+	"ping": true,
+}
+var validHelpCommand = map[string]bool{
+	"help": true,
 }
 
 var kubectlBinary = "/usr/local/bin/kubectl"
 
 const (
-	notifierStartMsg   = "Brace yourselves, notifications are coming."
-	notifierStopMsg    = "Sure! I won't send you notifications anymore."
+	notifierStartMsg   = "Brace yourselves, notifications are coming from cluster '%s'."
+	notifierStopMsg    = "Sure! I won't send you notifications from cluster '%s' anymore."
 	unsupportedCmdMsg  = "Command not supported. Please run '@BotKube help' to see supported commands."
-	kubectlDisabledMsg = "Sorry, the admin hasn't given me the permission to execute kubectl command."
+	kubectlDisabledMsg = "Sorry, the admin hasn't given me the permission to execute kubectl command on cluster '%s'."
 )
 
 // Executor is an interface for processes to execute commands
@@ -47,15 +52,52 @@ type Executor interface {
 
 // DefaultExecutor is a default implementations of Executor
 type DefaultExecutor struct {
-	Message      string
-	AllowKubectl bool
+	Message       string
+	AllowKubectl  bool
+	ClusterName   string
+	ChannelName   string
+	IsAuthChannel bool
+}
+
+// NotifierAction creates custom type for notifier actions
+type NotifierAction string
+
+// Defines constants for notifier actions
+const (
+	Start      NotifierAction = "start"
+	Stop       NotifierAction = "stop"
+	Status     NotifierAction = "status"
+	ShowConfig NotifierAction = "showconfig"
+)
+
+func (action NotifierAction) String() string {
+	return string(action)
+}
+
+// CommandFlags creates custom type for flags in botkube
+type CommandFlags string
+
+// Defines botkube flags
+const (
+	ClusterFlag    CommandFlags = "--cluster-name"
+	FollowFlag     CommandFlags = "--follow"
+	AbbrFollowFlag CommandFlags = "-f"
+	WatchFlag      CommandFlags = "--watch"
+	AbbrWatchFlag  CommandFlags = "-w"
+)
+
+func (flag CommandFlags) String() string {
+	return string(flag)
 }
 
 // NewDefaultExecutor returns new Executor object
-func NewDefaultExecutor(msg string, allowkubectl bool) Executor {
+func NewDefaultExecutor(msg string, allowkubectl bool, clusterName, channelName string, isAuthChannel bool) Executor {
 	return &DefaultExecutor{
-		Message:      msg,
-		AllowKubectl: allowkubectl,
+		Message:       msg,
+		AllowKubectl:  allowkubectl,
+		ClusterName:   clusterName,
+		ChannelName:   channelName,
+		IsAuthChannel: isAuthChannel,
 	}
 }
 
@@ -64,112 +106,172 @@ func (e *DefaultExecutor) Execute() string {
 	args := strings.Split(e.Message, " ")
 	if validKubectlCommands[args[0]] {
 		if !e.AllowKubectl {
-			return kubectlDisabledMsg
+			return fmt.Sprintf(kubectlDisabledMsg, e.ClusterName)
 		}
-		return runKubectlCommand(args)
+		return runKubectlCommand(args, e.ClusterName, e.IsAuthChannel)
 	}
-	if validNotifierCommands[args[0]] {
-		return runNotifierCommand(args)
+	if validNotifierCommand[args[0]] {
+		return runNotifierCommand(args, e.ClusterName, e.IsAuthChannel)
+	}
+	if validPingCommand[args[0]] {
+		return runPingCommand(args, e.ClusterName)
+	}
+	if validHelpCommand[args[0]] {
+		return printHelp(e.ChannelName)
 	}
 	return unsupportedCmdMsg
 }
 
-func printHelp() string {
-	allowedKubectl := ""
-	for k := range validKubectlCommands {
-		allowedKubectl = allowedKubectl + k + ", "
+func printHelp(channelName string) string {
+	kubecltCmdKeys := make([]string, 0, len(validKubectlCommands))
+	for cmd := range validKubectlCommands {
+		kubecltCmdKeys = append(kubecltCmdKeys, cmd)
 	}
-	helpMsg := "BotKube executes kubectl commands on k8s cluster and returns output.\n" +
-		"Usages:\n" +
-		"    @BotKube <kubectl command without `kubectl` prefix>\n" +
-		"e.g:\n" +
-		"    @BotKube get pods\n" +
-		"    @BotKube logs podname -n namespace\n" +
-		"Allowed kubectl commands:\n" +
-		"    " + allowedKubectl + "\n\n" +
-		"Commands to manage notifier:\n" +
-		"notifier stop          Stop sending k8s event notifications to Slack (started by default)\n" +
-		"notifier start         Start sending k8s event notifications to Slack\n" +
-		"notifier status        Show running status of event notifier\n" +
-		"notifier showconfig    Show BotKube configuration for event notifier\n\n" +
-		"Other Commands:\n" +
-		"help                   Show help\n" +
-		"ping                   Check connection health\n"
-	return helpMsg
+	allowedKubectl := strings.Join(kubecltCmdKeys, ", ")
+	helpMsg := `
+BotKube Help
 
+Usage:
+    @BotKube <kubectl command without kubectl prefix> [--cluster-name <cluster_name>]
+    @BotKube notifier [stop|start|status|showconfig]
+    @BotKube ping [--cluster-name <cluster-name>]
+
+Description:
+
+Kubectl commands:
+	- Executes kubectl commands on k8s cluster and returns output.
+
+	Example:
+	    @BotKube get pods
+	    @BotKube logs podname -n namespace
+	    @BotKube get deployment --cluster-name cluster_name
+
+	Allowed kubectl commands:
+    	%s
+
+Cluster Status:
+	- List all available Kubernetes Clusters and check connection health. 
+	- If flag specified, gives response from the specified cluster.
+
+	Example:
+		@BotKube ping
+		@BotKube ping --cluster-name mycluster
+
+Notifier commands:
+	- Commands to manage notifier (Runs only on configured channel %s).
+
+	Example:
+		@BotKube notifier stop          Stop sending k8s event notifications to Slack
+		@BotKube notifier start         Start sending k8s event notifications to Slack
+		@BotKube notifier status        Show running status of event notifier
+		@BotKube notifier showconfig    Show BotKube configuration for event notifier
+
+Options:
+	--cluster-name                  Get cluster specific response
+`
+	return fmt.Sprintf(helpMsg, allowedKubectl, channelName)
 }
 
 func printDefaultMsg() string {
 	return unsupportedCmdMsg
 }
 
-func runKubectlCommand(args []string) string {
+func runKubectlCommand(args []string, clusterName string, isAuthChannel bool) string {
 	// Use 'default' as a default namespace
 	args = append([]string{"-n", "default"}, args...)
 
 	// Remove unnecessary flags
 	finalArgs := []string{}
-	for _, a := range args {
-		if a == "-f" || strings.HasPrefix(a, "--follow") {
+	checkFlag := false
+	for _, arg := range args {
+		if checkFlag {
+			if arg != clusterName {
+				return ""
+			}
+			checkFlag = false
 			continue
 		}
-		if a == "-w" || strings.HasPrefix(a, "--watch") {
+		if arg == AbbrFollowFlag.String() || strings.HasPrefix(arg, FollowFlag.String()) {
 			continue
 		}
-		finalArgs = append(finalArgs, a)
+		if arg == AbbrWatchFlag.String() || strings.HasPrefix(arg, WatchFlag.String()) {
+			continue
+		}
+		if strings.HasPrefix(arg, ClusterFlag.String()) {
+			if arg == ClusterFlag.String() {
+				checkFlag = true
+			} else if strings.SplitAfterN(arg, ClusterFlag.String()+"=", 2)[1] != clusterName {
+				return ""
+			}
+			isAuthChannel = true
+			continue
+		}
+		finalArgs = append(finalArgs, arg)
+	}
+	if isAuthChannel == false {
+		return ""
 	}
-
 	cmd := exec.Command(kubectlBinary, finalArgs...)
 	out, err := cmd.CombinedOutput()
 	if err != nil {
 		log.Logger.Error("Error in executing kubectl command: ", err)
-		return string(out) + err.Error()
+		return fmt.Sprintf("Cluster: %s\n%s", clusterName, string(out)+err.Error())
 	}
-	return string(out)
+	return fmt.Sprintf("Cluster: %s\n%s", clusterName, string(out))
 }
 
 // TODO: Have a seperate cli which runs bot commands
-func runNotifierCommand(args []string) string {
-	switch len(args) {
-	case 1:
-		if strings.ToLower(args[0]) == "help" {
-			return printHelp()
+func runNotifierCommand(args []string, clusterName string, isAuthChannel bool) string {
+	if isAuthChannel == false {
+		return ""
+	}
+	switch args[1] {
+	case Start.String():
+		config.Notify = true
+		log.Logger.Info("Notifier enabled")
+		return fmt.Sprintf(notifierStartMsg, clusterName)
+	case Stop.String():
+		config.Notify = false
+		log.Logger.Info("Notifier disabled")
+		return fmt.Sprintf(notifierStopMsg, clusterName)
+	case Status.String():
+		if config.Notify == false {
+			return fmt.Sprintf("Notifications are off for cluster '%s'", clusterName)
 		}
-		if strings.ToLower(args[0]) == "ping" {
-			return "pong"
-		}
-	case 2:
-		if args[0] != "notifier" {
-			return printDefaultMsg()
-		}
-		if args[1] == "start" {
-			config.Notify = true
-			log.Logger.Info("Notifier enabled")
-			return notifierStartMsg
-		}
-		if args[1] == "stop" {
-			config.Notify = false
-			log.Logger.Info("Notifier disabled")
-			return notifierStopMsg
-		}
-		if args[1] == "status" {
-			if config.Notify == false {
-				return "stopped"
-			}
-			return "running"
-		}
-		if args[1] == "showconfig" {
-			out, err := showControllerConfig()
-			if err != nil {
-				log.Logger.Error("Error in executing showconfig command: ", err)
-				return "Error in getting configuration!"
-			}
-			return out
+		return fmt.Sprintf("Notifications are on for cluster '%s'", clusterName)
+	case ShowConfig.String():
+		out, err := showControllerConfig()
+		if err != nil {
+			log.Logger.Error("Error in executing showconfig command: ", err)
+			return "Error in getting configuration!"
 		}
+		return fmt.Sprintf("Showing config for cluster '%s'\n\n%s", clusterName, out)
 	}
 	return printDefaultMsg()
 }
 
+func runPingCommand(args []string, clusterName string) string {
+	checkFlag := false
+	for _, arg := range args {
+		if checkFlag {
+			if arg != clusterName {
+				return ""
+			}
+			checkFlag = false
+			continue
+		}
+		if strings.HasPrefix(arg, ClusterFlag.String()) {
+			if arg == ClusterFlag.String() {
+				checkFlag = true
+			} else if strings.SplitAfterN(arg, ClusterFlag.String()+"=", 2)[1] != clusterName {
+				return ""
+			}
+			continue
+		}
+	}
+	return fmt.Sprintf("pong from cluster '%s'", clusterName)
+}
+
 func showControllerConfig() (string, error) {
 	configPath := os.Getenv("CONFIG_PATH")
 	configFile := filepath.Join(configPath, config.ConfigFileName)

pkg/slack/slack.go

@@ -14,14 +14,15 @@ import (
 type Bot struct {
 	Token        string
 	AllowKubectl bool
+	ClusterName  string
 	ChannelName  string
-	CheckChannel bool
 }
 
 // slackMessage contains message details to execute command and send back the result
 type slackMessage struct {
 	ChannelID    string
 	BotID        string
+	MessageType  string
 	InMessage    string
 	OutMessage   string
 	OutMsgLength int
@@ -37,8 +38,8 @@ func NewSlackBot() *Bot {
 	return &Bot{
 		Token:        c.Communications.Slack.Token,
 		AllowKubectl: c.Settings.AllowKubectl,
+		ClusterName:  c.Settings.ClusterName,
 		ChannelName:  c.Communications.Slack.Channel,
-		CheckChannel: c.Settings.CheckChannel,
 	}
 }
 
@@ -55,6 +56,7 @@ func (b *Bot) Start() {
 	go rtm.ManageConnection()
 
 	for msg := range rtm.IncomingEvents {
+		isAuthChannel := false
 		switch ev := msg.Data.(type) {
 		case *slack.ConnectedEvent:
 			logging.Logger.Debug("Connection Info: ", ev.Info)
@@ -73,10 +75,9 @@ func (b *Bot) Start() {
 					if !strings.HasPrefix(ev.Text, "<@"+botID+"> ") {
 						continue
 					}
-					// if config.settings.checkChannel is true
 					// Serve only if current channel is in config
-					if b.CheckChannel && (b.ChannelName != info.Name) {
-						continue
+					if b.ChannelName == info.Name {
+						isAuthChannel = true
 					}
 				}
 			}
@@ -95,7 +96,7 @@ func (b *Bot) Start() {
 				InMessage: inMessage,
 				RTM:       rtm,
 			}
-			sm.HandleMessage(b.AllowKubectl)
+			sm.HandleMessage(b.AllowKubectl, b.ClusterName, b.ChannelName, isAuthChannel)
 
 		case *slack.RTMError:
 			logging.Logger.Errorf("Slack RMT error: %+v", ev.Error())
@@ -108,8 +109,8 @@ func (b *Bot) Start() {
 	}
 }
 
-func (sm *slackMessage) HandleMessage(allowkubectl bool) {
-	e := execute.NewDefaultExecutor(sm.InMessage, allowkubectl)
+func (sm *slackMessage) HandleMessage(allowkubectl bool, clusterName, channelName string, isAuthChannel bool) {
+	e := execute.NewDefaultExecutor(sm.InMessage, allowkubectl, clusterName, channelName, isAuthChannel)
 	sm.OutMessage = e.Execute()
 	sm.OutMsgLength = len(sm.OutMessage)
 	sm.Send()
@@ -141,7 +142,11 @@ func (sm slackMessage) Send() {
 			logging.Logger.Error("Error in uploading file:", err)
 		}
 		return
+	} else if sm.OutMsgLength == 0 {
+		logging.Logger.Info("Invalid request. Dumping the response")
+		return
 	}
+
 	params := slack.PostMessageParameters{
 		AsUser: true,
 	}