refactor: move from io/ioutil to io and os package (#2236)

The io/ioutil package has been deprecated as of Go 1.16, see
https://golang.org/doc/go1.16#ioutil. This commit replaces the existing
io/ioutil functions with their new definitions in io and os packages.

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

pkg/mqtrigger/messageQueue/azurequeuestorage/asq.go

@@ -20,7 +20,7 @@ import (
 	"bytes"
 	"encoding/base64"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"os"
 	"regexp"
@@ -354,7 +354,7 @@ func invokeTriggeredFunction(conn AzureStorageConnection, sub *AzureQueueSubscri
 		}
 		defer response.Body.Close()
 
-		body, err := ioutil.ReadAll(response.Body)
+		body, err := io.ReadAll(response.Body)
 		if err != nil {
 			conn.logger.Error("failed to read response body from function invocation", zap.Error(err), zap.String("function_url", sub.functionURL))
 			continue

pkg/mqtrigger/messageQueue/azurequeuestorage/asq_test.go

@@ -17,7 +17,7 @@ package azurequeuestorage
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"os"
@@ -197,7 +197,7 @@ func TestAzureStorageQueuePoisonMessage(t *testing.T) {
 	).Return(
 		&http.Response{
 			StatusCode: http.StatusInternalServerError,
-			Body:       ioutil.NopCloser(strings.NewReader("server error")),
+			Body:       io.NopCloser(strings.NewReader("server error")),
 		},
 		nil,
 	).Once()
@@ -207,7 +207,7 @@ func TestAzureStorageQueuePoisonMessage(t *testing.T) {
 	).Return(
 		&http.Response{
 			StatusCode: http.StatusNotFound,
-			Body:       ioutil.NopCloser(strings.NewReader("not found")),
+			Body:       io.NopCloser(strings.NewReader("not found")),
 		},
 		nil,
 	).Once()
@@ -217,7 +217,7 @@ func TestAzureStorageQueuePoisonMessage(t *testing.T) {
 	).Return(
 		&http.Response{
 			StatusCode: http.StatusBadRequest,
-			Body:       ioutil.NopCloser(strings.NewReader("bad request")),
+			Body:       io.NopCloser(strings.NewReader("bad request")),
 		},
 		nil,
 	).Once()
@@ -227,7 +227,7 @@ func TestAzureStorageQueuePoisonMessage(t *testing.T) {
 	).Return(
 		&http.Response{
 			StatusCode: http.StatusForbidden,
-			Body:       ioutil.NopCloser(strings.NewReader("not authorized")),
+			Body:       io.NopCloser(strings.NewReader("not authorized")),
 		},
 		nil,
 	).Once()
@@ -339,10 +339,10 @@ func TestAzureStorageQueuePoisonMessage(t *testing.T) {
 func httpRequestMatcher(t *testing.T, queue string, responseQueue string, retry string, contentType string, functionName string, body string) func(*http.Request) bool {
 	expectedURL := fmt.Sprintf("%s/fission-function/%s", DummyRouterURL, functionName)
 	return func(req *http.Request) bool {
-		requestBody, err := ioutil.ReadAll(req.Body)
+		requestBody, err := io.ReadAll(req.Body)
 		require.NoError(t, err)
 
-		req.Body = ioutil.NopCloser(strings.NewReader(string(requestBody)))
+		req.Body = io.NopCloser(strings.NewReader(string(requestBody)))
 
 		return queue == req.Header.Get("X-Fission-MQTrigger-Topic") &&
 			responseQueue == req.Header.Get("X-Fission-MQTrigger-RespTopic") &&
@@ -372,7 +372,7 @@ func runAzureStorageQueueTest(t *testing.T, count int, output bool) {
 	// Mock a HTTP client that returns http.StatusOK with "output" for the body
 	httpClient := new(azureHTTPClientMock)
 	httpClient.bodyHandler = func(res *http.Response) {
-		res.Body = ioutil.NopCloser(strings.NewReader(FunctionResponse))
+		res.Body = io.NopCloser(strings.NewReader(FunctionResponse))
 	}
 	httpClient.On(
 		"Do",

pkg/mqtrigger/messageQueue/kafka/kafka.go

@@ -20,14 +20,14 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"os"
 	"regexp"
 	"strconv"
 	"strings"
 
-	sarama "github.com/Shopify/sarama"
+	"github.com/Shopify/sarama"
 	cluster "github.com/bsm/sarama-cluster"
 	"github.com/pkg/errors"
 	"go.uber.org/zap"
@@ -307,7 +307,7 @@ func kafkaMsgHandler(kafka *Kafka, producer sarama.SyncProducer, trigger *fv1.Me
 		return
 	}
 	defer resp.Body.Close()
-	body, err := ioutil.ReadAll(resp.Body)
+	body, err := io.ReadAll(resp.Body)
 
 	kafka.logger.Debug("got response from function invocation",
 		zap.String("function_url", url),

pkg/mqtrigger/messageQueue/nats/nats.go

@@ -19,7 +19,7 @@ package nats
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"os"
 	"strings"
@@ -192,7 +192,7 @@ func msgHandler(nats *Nats, trigger *fv1.MessageQueueTrigger) func(*ns.Msg) {
 
 		defer resp.Body.Close()
 
-		body, bodyErr := ioutil.ReadAll(resp.Body)
+		body, bodyErr := io.ReadAll(resp.Body)
 		if bodyErr != nil {
 			nats.logger.Error("error reading function invocation response",
 				zap.Error(err),