chore(cmd,util): replace use of io/ioutil (#1530)

Fixes https://togithub.com/googleapis/gapic-showcase/issues/1526

cmd/gapic-showcase/compliance_suite_errors_test.go

@@ -16,7 +16,7 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"strings"
 	"testing"
@@ -291,7 +291,7 @@ func checkExpectedFailure(t *testing.T, verb, url, requestBody, failure, errorPr
 		return
 	}
 
-	body, err := ioutil.ReadAll(httpResponse.Body)
+	body, err := io.ReadAll(httpResponse.Body)
 	httpResponse.Body.Close()
 	if err != nil {
 		t.Fatalf("%s could not read response body: %s", errorPrefix, err)

cmd/gapic-showcase/compliance_suite_test.go

@@ -16,10 +16,11 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
+	"os"
 	"path/filepath"
 	"runtime"
 	"strings"
@@ -108,7 +109,7 @@ func TestComplianceSuite(t *testing.T) {
 
 				// Unmarshal httpResponse body, interpreted as JSON.
 				// should do this.
-				responseBody, err := ioutil.ReadAll(httpResponse.Body)
+				responseBody, err := io.ReadAll(httpResponse.Body)
 				httpResponse.Body.Close()
 				if err != nil {
 					t.Errorf("%s could not read httpResponse body: %s", errorPrefix, err)
@@ -427,7 +428,7 @@ func loadComplianceSuiteFile() (err error) {
 	// Locate, load
 	_, thisFile, _, _ := runtime.Caller(0)
 	complianceSuiteFileName = filepath.Join(filepath.Dir(thisFile), "../../schema/google/showcase/v1beta1/compliance_suite.json")
-	complianceSuiteJSON, err = ioutil.ReadFile(complianceSuiteFileName)
+	complianceSuiteJSON, err = os.ReadFile(complianceSuiteFileName)
 	if err != nil {
 		return fmt.Errorf("could not open suite file %q", complianceSuiteFileName)
 	}

cmd/gapic-showcase/endpoint.go

@@ -19,10 +19,10 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"fmt"
-	"io/ioutil"
 	"log"
 	"net"
 	"net/http"
+	"os"
 	"strings"
 	"sync"
 
@@ -228,7 +228,7 @@ func newEndpointGRPC(lis net.Listener, config RuntimeConfig, backend *services.B
 			log.Fatalf("Failed to load server TLS cert/key with error:%v", err)
 		}
 
-		cert, err := ioutil.ReadFile(config.tlsCaCert)
+		cert, err := os.ReadFile(config.tlsCaCert)
 		if err != nil {
 			log.Fatalf("Failed to load root CA cert file with error:%v", err)
 		}

cmd/gapic-showcase/endpoint_test.go

@@ -15,7 +15,7 @@
 package main
 
 import (
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"net/http/httptest"
@@ -195,7 +195,7 @@ func TestRESTCalls(t *testing.T) {
 			continue
 		}
 
-		body, err := ioutil.ReadAll(response.Body)
+		body, err := io.ReadAll(response.Body)
 		response.Body.Close()
 		if err != nil {
 			jsonOptions.Restore()

util/compile_protos.go

@@ -16,7 +16,6 @@ package util
 
 import (
 	"fmt"
-	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -39,7 +38,7 @@ func CompileProtos(version string) {
 		log.Fatalf("Error: unable to get working dir: %+v", err)
 	}
 
-	outDir, err := ioutil.TempDir(os.TempDir(), "gapic-showcase")
+	outDir, err := os.MkdirTemp(os.TempDir(), "gapic-showcase")
 	if err != nil {
 		log.Fatalf("Error: unable to create a temporary dir: %+v\n", err)
 	}

util/genrest/goviewcreator_test.go

@@ -15,7 +15,7 @@
 package genrest
 
 import (
-	"io/ioutil"
+	"os"
 	"reflect"
 	"testing"
 
@@ -144,7 +144,7 @@ func TestConstructStreamingServer(t *testing.T) {
 		actualSources += helperSources[key].Contents() + "\n"
 	}
 
-	expectedSources, err := ioutil.ReadFile("testdata/TestConstructServerStreamer.go.baseline")
+	expectedSources, err := os.ReadFile("testdata/TestConstructServerStreamer.go.baseline")
 	if err != nil {
 		t.Fatalf("could not load file: %s", err)
 	}

util/genrest/protomodelcreator.go

@@ -16,7 +16,6 @@ package genrest
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 
 	"cloud.google.com/go/iam/apiv1/iampb"
@@ -182,7 +181,7 @@ func GetServiceConfig() (*serviceconfig.Service, error) {
 	// hard-coding this location isn't terrible.
 	serviceConfigPath := "schema/google/showcase/v1beta1/showcase_v1beta1.yaml"
 
-	y, err := ioutil.ReadFile(serviceConfigPath)
+	y, err := os.ReadFile(serviceConfigPath)
 	if err != nil {
 		cwd, _ := os.Getwd()
 		return nil, fmt.Errorf("error reading service config %q (cwd==%q): %v", serviceConfigPath, cwd, err)

util/genrest/resttools/checkrequestformat.go

@@ -18,7 +18,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"strconv"
 	"strings"
@@ -45,7 +44,7 @@ func CheckRequestFormat(jsonReader io.Reader, request *http.Request, message pro
 		return err
 	}
 
-	jsonBytes, err := ioutil.ReadAll(jsonReader)
+	jsonBytes, err := io.ReadAll(jsonReader)
 	if err != nil {
 		return err
 	}