lint: Enable goconst

goconst finds repeated strings that could be replaced by a constant:
https://github.com/jgautheron/goconst

Part of #217

Signed-off-by: Andrew Seigner <siggy@buoyant.io>

.golangci.yml

@@ -6,6 +6,7 @@ linters:
   enable:
   - deadcode
   - depguard
+  - goconst
   - gofmt
   - golint
   - gosimple
@@ -20,7 +21,6 @@ linters:
   # - dupl
   # - gochecknoglobals
   # - gochecknoinits
-  # - goconst
   # - gocyclo
   # - goimports
   # - gosec

cli/cmd/endpoints.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
-	"errors"
 	"fmt"
 	"os"
 	"sort"
@@ -23,25 +22,24 @@ type endpointsOptions struct {
 	outputFormat string
 }
 
-var (
+const (
 	podHeader = "POD"
 )
 
 // validate performs all validation on the command-line options.
 // It returns the first error encountered, or `nil` if the options are valid.
 func (o *endpointsOptions) validate() error {
-	switch o.outputFormat {
-	case "table", "json", "":
+	if o.outputFormat == tableOutput || o.outputFormat == jsonOutput {
 		return nil
 	}
 
-	return errors.New("--output currently only supports table and json")
+	return fmt.Errorf("--output currently only supports %s and %s", tableOutput, jsonOutput)
 }
 
 func newEndpointsOptions() *endpointsOptions {
 	return &endpointsOptions{
 		namespace:    "",
-		outputFormat: "",
+		outputFormat: tableOutput,
 	}
 }
 
@@ -89,7 +87,7 @@ requests.`,
 	}
 
 	cmd.PersistentFlags().StringVarP(&options.namespace, "namespace", "n", options.namespace, "Namespace of the specified endpoints (default: all namespaces)")
-	cmd.PersistentFlags().StringVarP(&options.outputFormat, "output", "o", options.outputFormat, "Output format; currently only \"table\" and \"json\" are supported (default \"table\")")
+	cmd.PersistentFlags().StringVarP(&options.outputFormat, "output", "o", options.outputFormat, fmt.Sprintf("Output format; one of: \"%s\" or \"%s\"", tableOutput, jsonOutput))
 
 	return cmd
 }
@@ -166,13 +164,13 @@ func writeEndpointsToBuffer(endpoints *pb.EndpointsResponse, w *tabwriter.Writer
 	}
 
 	switch options.outputFormat {
-	case "table", "":
+	case tableOutput:
 		if len(endpointsTables) == 0 {
 			fmt.Fprintln(os.Stderr, "No endpoints found.")
 			os.Exit(0)
 		}
 		printEndpointsTables(endpointsTables, w, options, maxPodLength, maxNamespaceLength)
-	case "json":
+	case jsonOutput:
 		printEndpointsJSON(endpointsTables, w)
 	}
 }

cli/cmd/endpoints_test.go

@@ -24,7 +24,7 @@ func TestEndpoints(t *testing.T) {
 		}, t)
 	})
 
-	options.outputFormat = "json"
+	options.outputFormat = jsonOutput
 	t.Run("Returns endpoints (json)", func(t *testing.T) {
 		testEndpointsCall(endpointsExp{
 			options:    options,
@@ -42,7 +42,7 @@ func TestEndpoints(t *testing.T) {
 		}, t)
 	})
 
-	options.outputFormat = "json"
+	options.outputFormat = jsonOutput
 	t.Run("Returns all namespace endpoints (json)", func(t *testing.T) {
 		testEndpointsCall(endpointsExp{
 			options:    options,

cli/cmd/inject_test.go

@@ -18,6 +18,13 @@ type injectYAML struct {
 	testInjectOptions *injectOptions
 }
 
+func mkFilename(filename string, verbose bool) string {
+	if verbose {
+		return fmt.Sprintf("%s.verbose", filename)
+	}
+	return filename
+}
+
 func testUninjectAndInject(t *testing.T, tc injectYAML) {
 	file, err := os.Open("testdata/" + tc.inputFileName)
 	if err != nil {
@@ -34,10 +41,7 @@ func testUninjectAndInject(t *testing.T, tc injectYAML) {
 	}
 	diffTestdata(t, tc.goldenFileName, output.String())
 
-	reportFileName := tc.reportFileName
-	if verbose {
-		reportFileName += ".verbose"
-	}
+	reportFileName := mkFilename(tc.reportFileName, verbose)
 	diffTestdata(t, reportFileName, report.String())
 }
 
@@ -46,18 +50,18 @@ func TestUninjectAndInject(t *testing.T) {
 	defaultOptions.linkerdVersion = "testinjectversion"
 
 	tlsOptions := newInjectOptions()
-	tlsOptions.linkerdVersion = "testinjectversion"
+	tlsOptions.linkerdVersion = defaultOptions.linkerdVersion
 	tlsOptions.tls = "optional"
 
 	proxyResourceOptions := newInjectOptions()
-	proxyResourceOptions.linkerdVersion = "testinjectversion"
+	proxyResourceOptions.linkerdVersion = defaultOptions.linkerdVersion
 	proxyResourceOptions.proxyCPURequest = "110m"
 	proxyResourceOptions.proxyMemoryRequest = "100Mi"
 	proxyResourceOptions.proxyCPULimit = "160m"
 	proxyResourceOptions.proxyMemoryLimit = "150Mi"
 
 	noInitContainerOptions := newInjectOptions()
-	noInitContainerOptions.linkerdVersion = "testinjectversion"
+	noInitContainerOptions.linkerdVersion = defaultOptions.linkerdVersion
 	noInitContainerOptions.noInitContainer = true
 
 	testCases := []injectYAML{
@@ -212,10 +216,7 @@ func testInjectCmd(t *testing.T, tc injectCmd) {
 		t.Fatalf("Expected no standard output, but got: %s", outBuffer)
 	}
 
-	stdErrGoldenFileName := tc.stdErrGoldenFileName
-	if verbose {
-		stdErrGoldenFileName += ".verbose"
-	}
+	stdErrGoldenFileName := mkFilename(tc.stdErrGoldenFileName, verbose)
 	diffTestdata(t, stdErrGoldenFileName, errBuffer.String())
 }
 
@@ -266,10 +267,7 @@ func testInjectFilePath(t *testing.T, tc injectFilePath) {
 	}
 	diffTestdata(t, tc.expectedFile, actual.String())
 
-	stdErrFile := tc.stdErrFile
-	if verbose {
-		stdErrFile += ".verbose"
-	}
+	stdErrFile := mkFilename(tc.stdErrFile, verbose)
 	diffTestdata(t, stdErrFile, errBuf.String())
 }
 
@@ -288,10 +286,7 @@ func testReadFromFolder(t *testing.T, resourceFolder string, expectedFolder stri
 	expectedFile := filepath.Join(expectedFolder, "injected_nginx_redis.yaml")
 	diffTestdata(t, expectedFile, actual.String())
 
-	stdErrFileName := filepath.Join(expectedFolder, "injected_nginx_redis.stderr")
-	if verbose {
-		stdErrFileName += ".verbose"
-	}
+	stdErrFileName := mkFilename(filepath.Join(expectedFolder, "injected_nginx_redis.stderr"), verbose)
 	diffTestdata(t, stdErrFileName, errBuf.String())
 }
 

cli/cmd/install_test.go

@@ -112,27 +112,27 @@ func TestRender(t *testing.T) {
 	haOptions := newInstallOptions()
 	haOptions.highAvailability = true
 	haConfig, _ := validateAndBuildConfig(haOptions)
-	haConfig.UUID = "deaab91a-f4ab-448a-b7d1-c832a2fa0a60"
+	haConfig.UUID = defaultConfig.UUID
 
 	haWithOverridesOptions := newInstallOptions()
 	haWithOverridesOptions.highAvailability = true
 	haWithOverridesOptions.controllerReplicas = 2
 	haWithOverridesOptions.proxyCPURequest = "400m"
 	haWithOverridesOptions.proxyMemoryRequest = "300Mi"
 	haWithOverridesConfig, _ := validateAndBuildConfig(haWithOverridesOptions)
-	haWithOverridesConfig.UUID = "deaab91a-f4ab-448a-b7d1-c832a2fa0a60"
+	haWithOverridesConfig.UUID = defaultConfig.UUID
 
 	noInitContainerOptions := newInstallOptions()
 	noInitContainerOptions.noInitContainer = true
 	noInitContainerConfig, _ := validateAndBuildConfig(noInitContainerOptions)
-	noInitContainerConfig.UUID = "deaab91a-f4ab-448a-b7d1-c832a2fa0a60"
+	noInitContainerConfig.UUID = defaultConfig.UUID
 
 	noInitContainerWithProxyAutoInjectOptions := newInstallOptions()
 	noInitContainerWithProxyAutoInjectOptions.noInitContainer = true
 	noInitContainerWithProxyAutoInjectOptions.proxyAutoInject = true
 	noInitContainerWithProxyAutoInjectOptions.tls = "optional"
 	noInitContainerWithProxyAutoInjectConfig, _ := validateAndBuildConfig(noInitContainerWithProxyAutoInjectOptions)
-	noInitContainerWithProxyAutoInjectConfig.UUID = "deaab91a-f4ab-448a-b7d1-c832a2fa0a60"
+	noInitContainerWithProxyAutoInjectConfig.UUID = defaultConfig.UUID
 
 	testCases := []struct {
 		config                installConfig

cli/cmd/profile_test.go

@@ -101,9 +101,11 @@ func TestValidateOptions(t *testing.T) {
 		t.Fatalf("validateOptions returned unexpected error: %s (expected: %s) for options: %+v", err, exp, options)
 	}
 
+	serviceName := "service-name"
+
 	options = newProfileOptions()
 	options.template = true
-	options.name = "service-name"
+	options.name = serviceName
 	options.namespace = ""
 	exp = fmt.Errorf("invalid namespace \"%s\": [a DNS-1123 label must consist of lower case alphanumeric characters or '-', and must start and end with an alphanumeric character (e.g. 'my-name',  or '123-abc', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?')]", options.namespace)
 	err = options.validate()
@@ -113,7 +115,7 @@ func TestValidateOptions(t *testing.T) {
 
 	options = newProfileOptions()
 	options.template = true
-	options.name = "service-name"
+	options.name = serviceName
 	options.namespace = "invalid/namespace"
 	exp = fmt.Errorf("invalid namespace \"%s\": [a DNS-1123 label must consist of lower case alphanumeric characters or '-', and must start and end with an alphanumeric character (e.g. 'my-name',  or '123-abc', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?')]", options.namespace)
 	err = options.validate()
@@ -123,7 +125,7 @@ func TestValidateOptions(t *testing.T) {
 
 	options = newProfileOptions()
 	options.template = true
-	options.name = "service-name"
+	options.name = serviceName
 	options.namespace = "7eet-ns"
 	err = options.validate()
 	if err != nil {

cli/cmd/root.go

@@ -2,7 +2,6 @@ package cmd
 
 import (
 	"bytes"
-	"errors"
 	"fmt"
 	"os"
 	"regexp"
@@ -21,6 +20,10 @@ import (
 
 const (
 	defaultNamespace = "linkerd"
+
+	jsonOutput  = "json"
+	tableOutput = "table"
+	wideOutput  = "wide"
 )
 
 var (
@@ -182,23 +185,23 @@ func newStatOptionsBase() *statOptionsBase {
 	return &statOptionsBase{
 		namespace:    "default",
 		timeWindow:   "1m",
-		outputFormat: "",
+		outputFormat: tableOutput,
 	}
 }
 
 func (o *statOptionsBase) validateOutputFormat() error {
 	switch o.outputFormat {
-	case "table", "json", "":
+	case tableOutput, jsonOutput:
 		return nil
 	default:
-		return errors.New("--output currently only supports table and json")
+		return fmt.Errorf("--output currently only supports %s and %s", tableOutput, jsonOutput)
 	}
 }
 
 func renderStats(buffer bytes.Buffer, options *statOptionsBase) string {
 	var out string
 	switch options.outputFormat {
-	case "json":
+	case jsonOutput:
 		out = buffer.String()
 	default:
 		// strip left padding on the first column

cli/cmd/routes.go

@@ -75,7 +75,7 @@ This command will only display traffic which is sent to a service that has a Ser
 	cmd.PersistentFlags().StringVarP(&options.timeWindow, "time-window", "t", options.timeWindow, "Stat window (for example: \"10s\", \"1m\", \"10m\", \"1h\")")
 	cmd.PersistentFlags().StringVar(&options.toResource, "to", options.toResource, "If present, shows outbound stats to the specified resource")
 	cmd.PersistentFlags().StringVar(&options.toNamespace, "to-namespace", options.toNamespace, "Sets the namespace used to lookup the \"--to\" resource; by default the current \"--namespace\" is used")
-	cmd.PersistentFlags().StringVarP(&options.outputFormat, "output", "o", options.outputFormat, "Output format; currently only \"table\" (default), \"wide\", and \"json\" are supported")
+	cmd.PersistentFlags().StringVarP(&options.outputFormat, "output", "o", options.outputFormat, fmt.Sprintf("Output format; one of: \"%s\", \"%s\", or \"%s\"", tableOutput, wideOutput, jsonOutput))
 
 	return cmd
 }
@@ -142,15 +142,15 @@ func writeRouteStatsToBuffer(resp *pb.TopRoutesResponse, w *tabwriter.Writer, op
 	sort.Strings(resources)
 
 	switch options.outputFormat {
-	case "table", "wide", "":
+	case tableOutput, wideOutput:
 		for _, resource := range resources {
 			if len(tables) > 1 {
 				fmt.Fprintf(w, "==> %s <==\t\f", resource)
 			}
 			printRouteTable(tables[resource], w, options)
 			fmt.Fprintln(w)
 		}
-	case "json":
+	case jsonOutput:
 		printRouteJSON(tables, w, options)
 	}
 }
@@ -168,7 +168,7 @@ func printRouteTable(stats []*routeRowStats, w *tabwriter.Writer, options *route
 		fmt.Sprintf(routeTemplate, "ROUTE"),
 		authorityColumn,
 	}
-	outputActual := options.toResource != "" && options.outputFormat == "wide"
+	outputActual := options.toResource != "" && options.outputFormat == wideOutput
 	if outputActual {
 		headers = append(headers, []string{
 			"EFFECTIVE_SUCCESS",
@@ -276,15 +276,15 @@ func printRouteJSON(tables map[string][]*routeRowStats, w *tabwriter.Writer, opt
 
 func (o *routesOptions) validateOutputFormat() error {
 	switch o.outputFormat {
-	case "table", "json", "":
+	case tableOutput, jsonOutput:
 		return nil
-	case "wide":
+	case wideOutput:
 		if o.toResource == "" {
-			return errors.New("wide output is only available when --to is specified")
+			return fmt.Errorf("%s output is only available when --to is specified", wideOutput)
 		}
 		return nil
 	default:
-		return fmt.Errorf("--output currently only supports table, wide, and json")
+		return fmt.Errorf("--output currently only supports %s, %s, and %s", tableOutput, wideOutput, jsonOutput)
 	}
 }
 

cli/cmd/routes_test.go

@@ -24,7 +24,7 @@ func TestRoutes(t *testing.T) {
 		}, t)
 	})
 
-	options.outputFormat = "json"
+	options.outputFormat = jsonOutput
 	t.Run("Returns route stats (json)", func(t *testing.T) {
 		testRoutesCall(routesParamsExp{
 			routes:  []string{"/a", "/b", "/c"},

cli/cmd/stat.go

@@ -162,7 +162,7 @@ If no resource name is specified, displays stats about all resources of the spec
 	cmd.PersistentFlags().StringVar(&options.fromResource, "from", options.fromResource, "If present, restricts outbound stats from the specified resource name")
 	cmd.PersistentFlags().StringVar(&options.fromNamespace, "from-namespace", options.fromNamespace, "Sets the namespace used from lookup the \"--from\" resource; by default the current \"--namespace\" is used")
 	cmd.PersistentFlags().BoolVar(&options.allNamespaces, "all-namespaces", options.allNamespaces, "If present, returns stats across all namespaces, ignoring the \"--namespace\" flag")
-	cmd.PersistentFlags().StringVarP(&options.outputFormat, "output", "o", options.outputFormat, "Output format; currently only \"table\" (default) and \"json\" are supported")
+	cmd.PersistentFlags().StringVarP(&options.outputFormat, "output", "o", options.outputFormat, "Output format; one of: \"table\" or \"json\"")
 
 	return cmd
 }
@@ -279,13 +279,13 @@ func writeStatsToBuffer(rows []*pb.StatTable_PodGroup_Row, w *tabwriter.Writer,
 	}
 
 	switch options.outputFormat {
-	case "table", "wide", "":
+	case tableOutput, wideOutput:
 		if len(statTables) == 0 {
 			fmt.Fprintln(os.Stderr, "No traffic found.")
 			os.Exit(0)
 		}
 		printStatTables(statTables, w, maxNameLength, maxNamespaceLength, options)
-	case "json":
+	case jsonOutput:
 		printStatJSON(statTables, w)
 	}
 }

cli/cmd/stat_test.go

@@ -29,7 +29,7 @@ func TestStat(t *testing.T) {
 		}, t)
 	})
 
-	options.outputFormat = "json"
+	options.outputFormat = jsonOutput
 	t.Run("Returns namespace stats (json)", func(t *testing.T) {
 		testStatCall(paramsExp{
 			counts: &public.PodCounts{
@@ -58,7 +58,7 @@ func TestStat(t *testing.T) {
 		}, t)
 	})
 
-	options.outputFormat = "json"
+	options.outputFormat = jsonOutput
 	t.Run("Returns all namespace stats (json)", func(t *testing.T) {
 		testStatCall(paramsExp{
 			counts: &public.PodCounts{