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/executor/api.go

@@ -21,7 +21,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"html"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"strings"
 
@@ -39,7 +39,7 @@ import (
 
 func (executor *Executor) getServiceForFunctionAPI(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
-	body, err := ioutil.ReadAll(r.Body)
+	body, err := io.ReadAll(r.Body)
 	if err != nil {
 		http.Error(w, "Failed to read request", http.StatusInternalServerError)
 		return
@@ -170,7 +170,7 @@ func (executor *Executor) tapServices(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
 	logger := otelUtils.LoggerWithTraceID(ctx, executor.logger)
 
-	body, err := ioutil.ReadAll(r.Body)
+	body, err := io.ReadAll(r.Body)
 	if err != nil {
 		logger.Error("failed to read tap service request", zap.Error(err))
 		http.Error(w, "Failed to read request", http.StatusInternalServerError)
@@ -222,7 +222,7 @@ func (executor *Executor) healthHandler(w http.ResponseWriter, r *http.Request)
 
 func (executor *Executor) unTapService(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
-	body, err := ioutil.ReadAll(r.Body)
+	body, err := io.ReadAll(r.Body)
 	if err != nil {
 		http.Error(w, "Failed to read request", http.StatusInternalServerError)
 		return

pkg/executor/client/client.go

@@ -20,7 +20,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/url"
 	"strings"
@@ -95,7 +95,7 @@ func (c *Client) GetServiceForFunction(ctx context.Context, fn *fv1.Function) (s
 		return "", ferror.MakeErrorFromHTTP(resp)
 	}
 
-	svcName, err := ioutil.ReadAll(resp.Body)
+	svcName, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return "", errors.Wrap(err, "error reading response body from getting service for function")
 	}