Added '@botkube commands list' to show all the supported kubectl cmds (…

…#328)

##### ISSUE TYPE
 - Feature Pull Request

##### SUMMARY
Added new botkube command to list all the supported commands, @botkube commands list

Below are the changes
made changes in executor.go to handle newly added command  
added common method in utils.go to format the allowed commands  

Fixes #312

pkg/execute/executor.go

@@ -50,6 +50,9 @@ var (
 	validFilterCommand = map[string]bool{
 		"filters": true,
 	}
+	validInfoCommand = map[string]bool{
+		"commands": true,
+	}
 	validDebugCommands = map[string]bool{
 		"exec":         true,
 		"logs":         true,
@@ -146,6 +149,14 @@ const (
 	FilterDisable FiltersAction = "disable"
 )
 
+// infoAction for options in Info commands
+type infoAction string
+
+// Info command options
+const (
+	infoList infoAction = "list"
+)
+
 func (action FiltersAction) String() string {
 	return string(action)
 }
@@ -210,6 +221,12 @@ func (e *DefaultExecutor) Execute() string {
 	if validFilterCommand[args[0]] {
 		return e.runFilterCommand(args, e.ClusterName, e.IsAuthChannel)
 	}
+
+	//Check if info command
+	if validInfoCommand[args[0]] {
+		return e.runInfoCommand(args, e.IsAuthChannel)
+	}
+
 	if e.IsAuthChannel {
 		return printDefaultMsg(e.Platform)
 	}
@@ -360,6 +377,23 @@ func (e *DefaultExecutor) runFilterCommand(args []string, clusterName string, is
 	return printDefaultMsg(e.Platform)
 }
 
+//runInfoCommand to list allowed commands
+func (e *DefaultExecutor) runInfoCommand(args []string, isAuthChannel bool) string {
+	if isAuthChannel == false {
+		return ""
+	}
+	if len(args) < 2 && args[1] != string(infoList) {
+		return IncompleteCmdMsg
+	}
+	return makeCommandInfoList()
+}
+
+func makeCommandInfoList() string {
+	allowedVerbs := utils.GetStringInYamlFormat("allowed verbs:", utils.AllowedKubectlVerbMap)
+	allowedResources := utils.GetStringInYamlFormat("allowed resources:", utils.AllowedKubectlResourceMap)
+	return allowedVerbs + allowedResources
+}
+
 // Use tabwriter to display string in tabular form
 // https://golang.org/pkg/text/tabwriter
 func makeFiltersList() string {

pkg/utils/utils.go

@@ -20,6 +20,8 @@
 package utils
 
 import (
+	"bytes"
+	"fmt"
 	"os"
 	"regexp"
 	"strconv"
@@ -477,3 +479,15 @@ func GetClusterNameFromKubectlCmd(cmd string) string {
 	}
 	return s
 }
+
+//GetStringInYamlFormat get the formated commands list
+func GetStringInYamlFormat(header string, commands map[string]bool) string {
+	var b bytes.Buffer
+	fmt.Fprintln(&b, header)
+	for k, v := range commands {
+		if v {
+			fmt.Fprintf(&b, "  - %s\n", k)
+		}
+	}
+	return b.String()
+}

pkg/utils/utils_test.go

@@ -20,6 +20,7 @@
 package utils
 
 import (
+	"fmt"
 	"testing"
 )
 
@@ -49,3 +50,15 @@ func TestGetClusterNameFromKubectlCmd(t *testing.T) {
 		}
 	}
 }
+
+func TestGetStringInYamlFormat(t *testing.T) {
+	var header = "allowed verbs"
+	var commands = map[string]bool{
+		"api-versions": true,
+	}
+	expected := fmt.Sprintf(header + "\n  - api-versions\n")
+	got := GetStringInYamlFormat(header, commands)
+	if got != expected {
+		t.Errorf("expected: %v, got: %v", expected, got)
+	}
+}

test/e2e/command/botkube.go

@@ -59,8 +59,29 @@ func (c *context) testBotkubeCommand(t *testing.T) {
 				"ImageTagChecker         true    Checks and adds recommendation if 'latest' image tag is used for container image.\n" +
 				"IngressValidator        true    Checks if services and tls secrets used in ingress specs are available.\n",
 		},
+		"BotKube commands list": {
+			command: "commands list",
+			expected: "allowed verbs:\n" +
+				"  - api-resources\n" +
+				"  - describe\n" +
+				"  - diff\n" +
+				"  - explain\n" +
+				"  - get\n" +
+				"  - logs\n" +
+				"  - api-versions\n" +
+				"  - cluster-info\n" +
+				"  - top\n" +
+				"  - auth\n" +
+				"allowed resources:\n" +
+				"  - nodes\n" +
+				"  - deployments\n" +
+				"  - pods\n" +
+				"  - namespaces\n" +
+				"  - daemonsets\n" +
+				"  - statefulsets\n" +
+				"  - storageclasses\n",
+		},
 	}
-
 	for name, test := range tests {
 		t.Run(name, func(t *testing.T) {
 			if c.TestEnv.Config.Communications.Slack.Enabled {
@@ -80,6 +101,9 @@ func (c *context) testBotkubeCommand(t *testing.T) {
 				case "filters list":
 					fl := compareFilters(strings.Split(test.expected, "\n"), strings.Split(strings.Trim(m.Text, "```"), "\n"))
 					assert.Equal(t, fl, true)
+				case "commands list":
+					cl := compareFilters(strings.Split(test.expected, "\n"), strings.Split(strings.Trim(m.Text, "```"), "\n"))
+					assert.Equal(t, cl, true)
 				default:
 					assert.Equal(t, test.expected, m.Text)
 				}

test/resource_config.yaml

@@ -212,7 +212,8 @@ settings:
       # method which are allowed
       verbs: ["api-resources", "api-versions", "cluster-info", "describe", "diff", "explain", "get", "logs", "top", "auth"]
       # resource configuration which is allowed
-      resources: ["deployments", "pods" , "namespaces", "daemonsets", "statefulsets", "storageclasses", "serviceaccounts"]
+      resources: ["deployments", "pods" , "namespaces", "daemonsets", "statefulsets", "storageclasses", "nodes"]
+
     # set Namespace to execute botkube kubectl commands by default
     defaultNamespace: default
     # Set true to enable commands execution from configured channel only