Fix failure to start CNS when setting WireserverIP

cns/configuration/configuration.go

@@ -3,8 +3,12 @@ package configuration
 
 import (
 	"encoding/json"
+	"net"
+	"net/url"
 	"os"
 	"path/filepath"
+	"strconv"
+	"strings"
 
 	"github.com/Azure/azure-container-networking/cns"
 	"github.com/Azure/azure-container-networking/cns/logger"
@@ -105,6 +109,53 @@ func getConfigFilePath(cmdLineConfigPath string) (string, error) {
 	return configpath, nil
 }
 
+type NMAgentConfig struct {
+	Host   string
+	Port   uint16
+	UseTLS bool
+}
+
+func (c *CNSConfig) NMAgentConfig() (NMAgentConfig, error) {
+	host := "168.63.129.16" // wireserver's IP
+
+	if c.WireserverIP != "" {
+		host = c.WireserverIP
+	}
+
+	if strings.Contains(host, "http") {
+		parts, err := url.Parse(host)
+		if err != nil {
+			return NMAgentConfig{}, errors.Wrap(err, "parsing WireserverIP as URL")
+		}
+		host = parts.Host
+	}
+
+	// create an NMAgent Client based on provided configuration
+	if strings.Contains(host, ":") {
+		host, prt, err := net.SplitHostPort(host) //nolint:govet // it's fine to shadow err here
+		if err != nil {
+			return NMAgentConfig{}, errors.Wrap(err, "splitting wireserver IP into host port")
+		}
+
+		port, err := strconv.ParseUint(prt, 10, 16) //nolint:gomnd // obvious from ParseUint docs
+		if err != nil {
+			return NMAgentConfig{}, errors.Wrap(err, "parsing wireserver port value as uint16")
+		}
+
+		return NMAgentConfig{
+			Host: host,
+			Port: uint16(port),
+		}, nil
+	}
+
+	return NMAgentConfig{
+		Host: host,
+
+		// nolint:gomnd // there's no benefit to constantizing a well-known port
+		Port: 80,
+	}, nil
+}
+
 // ReadConfig returns a CNS config from file or an error.
 func ReadConfig(cmdLineConfigPath string) (*CNSConfig, error) {
 	configpath, err := getConfigFilePath(cmdLineConfigPath)

cns/configuration/configuration_test.go

@@ -6,6 +6,7 @@ import (
 	"testing"
 
 	"github.com/Azure/azure-container-networking/common"
+	"github.com/google/go-cmp/cmp"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -258,3 +259,99 @@ func TestSetCNSConfigDefaults(t *testing.T) {
 		})
 	}
 }
+
+func TestNMAgentConfig(t *testing.T) {
+	tests := []struct {
+		name      string
+		conf      CNSConfig
+		exp       NMAgentConfig
+		shouldErr bool
+	}{
+		{
+			"empty",
+			CNSConfig{
+				WireserverIP: "",
+			},
+			NMAgentConfig{
+				Host: "168.63.129.16",
+				Port: 80,
+			},
+			false,
+		},
+		{
+			"ip",
+			CNSConfig{
+				WireserverIP: "127.0.0.1",
+			},
+			NMAgentConfig{
+				Host: "127.0.0.1",
+				Port: 80,
+			},
+			false,
+		},
+		{
+			"ipport",
+			CNSConfig{
+				WireserverIP: "127.0.0.1:8080",
+			},
+			NMAgentConfig{
+				Host: "127.0.0.1",
+				Port: 8080,
+			},
+			false,
+		},
+		{
+			"scheme",
+			CNSConfig{
+				WireserverIP: "http://127.0.0.1:8080",
+			},
+			NMAgentConfig{
+				Host: "127.0.0.1",
+				Port: 8080,
+			},
+			false,
+		},
+		{
+			"invalid URL",
+			CNSConfig{
+				WireserverIP: "a string containing \"http\" with an invalid character: \x7F",
+			},
+			NMAgentConfig{},
+			true,
+		},
+		{
+			"invalid host:port",
+			CNSConfig{
+				WireserverIP: "way:too:many:colons",
+			},
+			NMAgentConfig{},
+			true,
+		},
+		{
+			"too big for a uint16 port",
+			CNSConfig{
+				WireserverIP: "127.0.0.1:4815162342",
+			},
+			NMAgentConfig{},
+			true,
+		},
+	}
+
+	for _, test := range tests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			got, err := test.conf.NMAgentConfig()
+			if err != nil && !test.shouldErr {
+				t.Fatal("unexpected error fetching nmagent config: err:", err)
+			}
+
+			if err == nil && test.shouldErr {
+				t.Fatal("expected error fetching nmagent config but received none")
+			}
+
+			if !cmp.Equal(got, test.exp) {
+				t.Error("received config differs from expectation: diff:", cmp.Diff(got, test.exp))
+			}
+		})
+	}
+}

cns/service/main.go

@@ -8,7 +8,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"net"
 	"net/http"
 	"net/http/pprof"
 	"os"
@@ -512,32 +511,13 @@ func main() {
 	z, _ := zap.NewProduction()
 	go healthserver.Start(z, cnsconfig.MetricsBindAddress)
 
-	nmaConfig := nmagent.Config{
-		Host: "168.63.129.16", // wireserver
-
-		// nolint:gomnd // there's no benefit to constantizing a well-known port
-		Port: 80,
-	}
-
-	// create an NMAgent Client based on provided configuration
-	if cnsconfig.WireserverIP != "" {
-		host, prt, err := net.SplitHostPort(cnsconfig.WireserverIP) //nolint:govet // it's fine to shadow err here
-		if err != nil {
-			logger.Errorf("[Azure CNS] Invalid IP for Wireserver: %q: %s", cnsconfig.WireserverIP, err.Error())
-			return
-		}
-
-		port, err := strconv.ParseUint(prt, 10, 16) //nolint:gomnd // obvious from ParseUint docs
-		if err != nil {
-			logger.Errorf("[Azure CNS] Invalid port value for Wireserver: %q: %s", cnsconfig.WireserverIP, err.Error())
-			return
-		}
-
-		nmaConfig.Host = host
-		nmaConfig.Port = uint16(port)
+	nmaConfig, err := cnsconfig.NMAgentConfig()
+	if err != nil {
+		logger.Errorf("[Azure CNS] Failed to produce NMAgent config from supplied configuration: %v", err)
+		return
 	}
 
-	nmaClient, err := nmagent.NewClient(nmaConfig)
+	nmaClient, err := nmagent.NewClient(nmagent.Config(nmaConfig))
 	if err != nil {
 		logger.Errorf("[Azure CNS] Failed to start nmagent client due to error: %v", err)
 		return