Add a flag for antctl to print OVS table names only (#5895)

The flag is `--table-names-only`.
Usage: `antctl get ovsflows --table-names-only`.

Signed-off-by: Lan Luo <luola@vmware.com>

pkg/agent/apiserver/handlers/ovsflows/handler.go

@@ -17,6 +17,7 @@ package ovsflows
 import (
 	"encoding/json"
 	"net/http"
+	"sort"
 	"strconv"
 	"strings"
 
@@ -33,6 +34,7 @@ var (
 	// Use function variables for tests.
 	getFlowTableName = openflow.GetFlowTableName
 	getFlowTableID   = openflow.GetFlowTableID
+	getFlowTableList = openflow.GetTableList
 )
 
 // Response is the response struct of ovsflows command.
@@ -183,6 +185,19 @@ func getNetworkPolicyFlows(aq agentquerier.AgentQuerier, npName, namespace strin
 	return dumpMatchedFlows(aq, flowKeys)
 }
 
+func getTableNames(aq agentquerier.AgentQuerier) []Response {
+	resps := []Response{}
+	names := []string{}
+	for _, t := range getFlowTableList() {
+		names = append(names, t.GetName())
+	}
+	sort.Strings(names)
+	for _, name := range names {
+		resps = append(resps, Response{name})
+	}
+	return resps
+}
+
 // HandleFunc returns the function which can handle API requests to "/ovsflows".
 func HandleFunc(aq agentquerier.AgentQuerier) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
@@ -194,6 +209,20 @@ func HandleFunc(aq agentquerier.AgentQuerier) http.HandlerFunc {
 		namespace := r.URL.Query().Get("namespace")
 		table := r.URL.Query().Get("table")
 		groups := r.URL.Query().Get("groups")
+		tableNamesOnly := r.URL.Query().Has("table-names-only")
+
+		encodeResp := func() {
+			err = json.NewEncoder(w).Encode(resps)
+			if err != nil {
+				w.WriteHeader(http.StatusInternalServerError)
+			}
+		}
+
+		if tableNamesOnly {
+			resps = getTableNames(aq)
+			encodeResp()
+			return
+		}
 
 		if (pod != "" || service != "" || networkPolicy != "") && namespace == "" {
 			http.Error(w, "namespace must be provided", http.StatusBadRequest)
@@ -240,17 +269,14 @@ func HandleFunc(aq agentquerier.AgentQuerier) http.HandlerFunc {
 			return
 		}
 
-		err = json.NewEncoder(w).Encode(resps)
-		if err != nil {
-			w.WriteHeader(http.StatusInternalServerError)
-		}
+		encodeResp()
 	}
 }
 
 var _ common.TableOutput = new(Response)
 
 func (r Response) GetTableHeader() []string {
-	return []string{"FLOW"}
+	return []string{""}
 }
 
 func (r Response) GetTableRow(maxColumnLength int) []string {

pkg/agent/apiserver/handlers/ovsflows/handler_test.go

@@ -240,6 +240,19 @@ func TestTableFlows(t *testing.T) {
 
 }
 
+func TestTableNamesOnly(t *testing.T) {
+	ctrl := gomock.NewController(t)
+	getFlowTableList = mockGetTableList
+	tc := testCase{
+		test:           "Get table names only",
+		query:          "?table-names-only",
+		expectedStatus: http.StatusOK,
+		resps:          []Response{{"table0"}, {"table1"}},
+	}
+	q := aqtest.NewMockAgentQuerier(ctrl)
+	runHTTPTest(t, &tc, q)
+}
+
 func mockGetFlowTableName(id uint8) string {
 	if id == 80 {
 		return "IngressRule"
@@ -254,6 +267,13 @@ func mockGetFlowTableID(tableName string) uint8 {
 	return binding.TableIDAll
 }
 
+func mockGetTableList() []binding.Table {
+	return []binding.Table{
+		binding.NewOFTable(0, "table0", 0, 0, 0),
+		binding.NewOFTable(0, "table1", 0, 0, 0),
+	}
+}
+
 func TestGroups(t *testing.T) {
 	ctrl := gomock.NewController(t)
 	testcases := []struct {

pkg/agent/openflow/pipeline.go

@@ -293,7 +293,7 @@ func GetFlowTableID(tableName string) uint8 {
 func GetTableList() []binding.Table {
 	tables := make([]binding.Table, 0)
 	for _, obj := range tableCache.List() {
-		t := obj.(binding.Table)
+		t := obj.(*Table).ofTable
 		tables = append(tables, t)
 	}
 	return tables

pkg/antctl/antctl.go

@@ -15,7 +15,6 @@
 package antctl
 
 import (
-	"fmt"
 	"reflect"
 
 	"antrea.io/antrea/pkg/agent/apiserver/handlers/agentinfo"
@@ -24,7 +23,6 @@ import (
 	"antrea.io/antrea/pkg/agent/apiserver/handlers/ovsflows"
 	"antrea.io/antrea/pkg/agent/apiserver/handlers/podinterface"
 	"antrea.io/antrea/pkg/agent/apiserver/handlers/serviceexternalip"
-	"antrea.io/antrea/pkg/agent/openflow"
 	fallbackversion "antrea.io/antrea/pkg/antctl/fallback/version"
 	"antrea.io/antrea/pkg/antctl/raw/featuregates"
 	"antrea.io/antrea/pkg/antctl/raw/multicluster"
@@ -370,6 +368,8 @@ $ antctl get podmulticaststats pod -n namespace`,
 			long:    "Dump all the OVS flows or the flows installed for the specified entity.",
 			example: `  Dump all OVS flows
   $ antctl get ovsflows
+  Dump OVS table names only
+  $ antctl get ovsflows --table-names-only
   Dump OVS flows of a local Pod
   $ antctl get ovsflows -p pod1 -n ns1
   Dump OVS flows of a Service
@@ -381,9 +381,7 @@ $ antctl get podmulticaststats pod -n namespace`,
   Dump OVS groups
   $ antctl get ovsflows -G 10,20
   Dump all OVS groups
-  $ antctl get ovsflows -G all
-
-  Antrea OVS Flow Tables:` + generateFlowTableHelpMsg(),
+  $ antctl get ovsflows -G all`,
 			agentEndpoint: &endpoint{
 				nonResourceEndpoint: &nonResourceEndpoint{
 					path: "/ovsflows",
@@ -413,6 +411,11 @@ $ antctl get podmulticaststats pod -n namespace`,
 							usage:     "Comma separated Antrea OVS flow table names or numbers",
 							shorthand: "T",
 						},
+						{
+							name:   "table-names-only",
+							usage:  "Print all Antrea OVS flow table names only, and nothing else",
+							isBool: true,
+						},
 						{
 							name:      "groups",
 							usage:     "Comma separated OVS group IDs. Use 'all' to dump all groups",
@@ -689,11 +692,3 @@ $ antctl get podmulticaststats pod -n namespace`,
 	},
 	codec: scheme.Codecs,
 }
-
-func generateFlowTableHelpMsg() string {
-	msg := ""
-	for _, t := range openflow.GetTableList() {
-		msg += fmt.Sprintf("\n  %d\t%s", uint32(t.GetID()), t.GetName())
-	}
-	return msg
-}

pkg/antctl/command_definition.go

@@ -186,6 +186,7 @@ type flagInfo struct {
 	supportedValues []string
 	arg             bool
 	usage           string
+	isBool          bool
 }
 
 // rawCommand defines a full function cobra.Command which lets developers
@@ -562,13 +563,25 @@ func (cd *commandDefinition) collectFlags(cmd *cobra.Command, args []string) (ma
 					argMap[f.name] = args[0]
 				}
 			} else {
-				vs, err := cmd.Flags().GetString(f.name)
-				if err == nil && len(vs) != 0 {
-					if f.supportedValues != nil && !cd.validateFlagValue(vs, f.supportedValues) {
-						return nil, fmt.Errorf("unsupported value %s for flag %s", vs, f.name)
+				if f.isBool {
+					vs, err := cmd.Flags().GetBool(f.name)
+					if err != nil {
+						return nil, fmt.Errorf("error accessing flag %s for command %s: %v", f.name, cmd.Name(), err)
+					}
+					if vs {
+						argMap[f.name] = ""
+					}
+				} else {
+					vs, err := cmd.Flags().GetString(f.name)
+					if err != nil {
+						return nil, fmt.Errorf("error accessing flag %s for command %s: %v", f.name, cmd.Name(), err)
+					}
+					if err == nil && len(vs) != 0 {
+						if f.supportedValues != nil && !cd.validateFlagValue(vs, f.supportedValues) {
+							return nil, fmt.Errorf("unsupported value %s for flag %s", vs, f.name)
+						}
+						argMap[f.name] = vs
 					}
-					argMap[f.name] = vs
-					continue
 				}
 			}
 		}
@@ -639,18 +652,23 @@ func (cd *commandDefinition) newCommandRunE(c AntctlClient, out io.Writer) func(
 
 // applyFlagsToCommand sets up args and flags for the command.
 func (cd *commandDefinition) applyFlagsToCommand(cmd *cobra.Command) {
-	var hasFlag bool
+	var hasArg bool
 	for _, flag := range cd.getEndpoint().flags() {
 		if flag.arg {
 			cmd.Args = cobra.MaximumNArgs(1)
 			cmd.Use += fmt.Sprintf(" [%s]", flag.name)
 			cmd.Long += fmt.Sprintf("\n\nArgs:\n  %s\t%s", flag.name, flag.usage)
-			hasFlag = true
+			hasArg = true
 		} else {
-			cmd.Flags().StringP(flag.name, flag.shorthand, flag.defaultValue, flag.usage)
+			if flag.isBool {
+				// When the flag is a boolean, the default value will always be false.
+				cmd.Flags().BoolP(flag.name, flag.shorthand, false, flag.usage)
+			} else {
+				cmd.Flags().StringP(flag.name, flag.shorthand, flag.defaultValue, flag.usage)
+			}
 		}
 	}
-	if !hasFlag {
+	if !hasArg {
 		cmd.Args = cobra.NoArgs
 	}
 	if cd.commandGroup == get {

pkg/antctl/command_definition_test.go

@@ -1055,6 +1055,11 @@ func TestCollectFlags(t *testing.T) {
 								usage:        "Comma separated Antrea OVS flow table names or numbers",
 								shorthand:    "T",
 							},
+							{
+								name:   "table-names-only",
+								usage:  "Print all Antrea OVS flow table names only, and nothing else",
+								isBool: true,
+							},
 							{
 								name:         "groups",
 								defaultValue: "Groups",