Remove ioutil usage

This has been deprecated in Go for some time, in favour of the
io package.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alex@openfaas.com>

gateway/handlers/alerthandler.go

@@ -6,7 +6,7 @@ package handlers
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"math"
 	"net/http"
@@ -27,7 +27,7 @@ func MakeAlertHandler(service scaling.ServiceQuery, defaultNamespace string) htt
 
 		defer r.Body.Close()
 
-		body, err := ioutil.ReadAll(r.Body)
+		body, err := io.ReadAll(r.Body)
 		if err != nil {
 			w.WriteHeader(http.StatusBadRequest)
 			w.Write([]byte("Unable to read alert."))

gateway/handlers/forwarding_proxy_test.go

@@ -6,7 +6,7 @@ package handlers
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/url"
 	"testing"
@@ -33,7 +33,7 @@ func Test_buildUpstreamRequest_Body_Method_Query(t *testing.T) {
 		t.Fail()
 	}
 
-	upstreamBytes, _ := ioutil.ReadAll(upstream.Body)
+	upstreamBytes, _ := io.ReadAll(upstream.Body)
 
 	if string(upstreamBytes) != string(srcBytes) {
 		t.Errorf("Body - want: %s, got: %s", string(upstreamBytes), string(srcBytes))
@@ -212,7 +212,7 @@ func Test_buildUpstreamRequest_WithPathNoQuery(t *testing.T) {
 		t.Fail()
 	}
 
-	upstreamBytes, _ := ioutil.ReadAll(upstream.Body)
+	upstreamBytes, _ := io.ReadAll(upstream.Body)
 
 	if string(upstreamBytes) != string(srcBytes) {
 		t.Errorf("Body - want: %s, got: %s", string(upstreamBytes), string(srcBytes))
@@ -268,7 +268,7 @@ func Test_buildUpstreamRequest_WithNoPathNoQuery(t *testing.T) {
 		t.Fail()
 	}
 
-	upstreamBytes, _ := ioutil.ReadAll(upstream.Body)
+	upstreamBytes, _ := io.ReadAll(upstream.Body)
 
 	if string(upstreamBytes) != string(srcBytes) {
 		t.Errorf("Body - want: %s, got: %s", string(upstreamBytes), string(srcBytes))
@@ -322,7 +322,7 @@ func Test_buildUpstreamRequest_WithPathAndQuery(t *testing.T) {
 		t.Fail()
 	}
 
-	upstreamBytes, _ := ioutil.ReadAll(upstream.Body)
+	upstreamBytes, _ := io.ReadAll(upstream.Body)
 
 	if string(upstreamBytes) != string(srcBytes) {
 		t.Errorf("Body - want: %s, got: %s", string(upstreamBytes), string(srcBytes))

gateway/handlers/logs_test.go

@@ -3,7 +3,7 @@ package handlers
 import (
 	"context"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
@@ -52,7 +52,7 @@ func Test_logsProxyDoesNotLeakGoroutinesWhenProviderClosesConnection(t *testing.
 		t.Fatalf("unexpected error sending log request: %s", err)
 	}
 
-	body, err := ioutil.ReadAll(resp.Body)
+	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		t.Fatalf("unexpected error reading the response body: %s", err)
 	}
@@ -126,7 +126,7 @@ func Test_logsProxyDoesNotLeakGoroutinesWhenClientClosesConnection(t *testing.T)
 	go func() {
 		defer resp.Body.Close()
 		defer close(errCh)
-		_, err := ioutil.ReadAll(resp.Body)
+		_, err := io.ReadAll(resp.Body)
 		errCh <- err
 	}()
 	cancel()

gateway/handlers/queue_proxy.go

@@ -5,7 +5,7 @@ package handlers
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"net/url"
@@ -27,7 +27,7 @@ func MakeQueuedProxy(metrics metrics.MetricOptions, queuer ftypes.RequestQueuer,
 			defer r.Body.Close()
 
 			var err error
-			body, err = ioutil.ReadAll(r.Body)
+			body, err = io.ReadAll(r.Body)
 			if err != nil {
 				http.Error(w, err.Error(), http.StatusBadRequest)
 				return

gateway/metrics/add_metrics.go

@@ -3,7 +3,7 @@ package metrics
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"net/http/httptest"
@@ -28,7 +28,7 @@ func AddMetricsHandler(handler http.HandlerFunc, prometheusQuery PrometheusQuery
 		}
 
 		defer upstreamCall.Body.Close()
-		upstreamBody, _ := ioutil.ReadAll(upstreamCall.Body)
+		upstreamBody, _ := io.ReadAll(upstreamCall.Body)
 
 		if recorder.Code != http.StatusOK {
 			log.Printf("List functions responded with code %d, body: %s",

gateway/metrics/exporter.go

@@ -7,7 +7,7 @@ package metrics
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net"
 	"net/http"
 	"net/url"
@@ -159,7 +159,7 @@ func (e *Exporter) getFunctions(endpointURL url.URL, namespace string) ([]types.
 		return services, err
 	}
 
-	bytesOut, readErr := ioutil.ReadAll(res.Body)
+	bytesOut, readErr := io.ReadAll(res.Body)
 	if readErr != nil {
 		return services, readErr
 	}
@@ -193,7 +193,7 @@ func (e *Exporter) getNamespaces(endpointURL url.URL) ([]string, error) {
 		return namespaces, nil
 	}
 
-	bytesOut, readErr := ioutil.ReadAll(res.Body)
+	bytesOut, readErr := io.ReadAll(res.Body)
 	if readErr != nil {
 		return namespaces, readErr
 	}

gateway/metrics/prometheus_query.go

@@ -3,7 +3,7 @@ package metrics
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 )
 
@@ -44,7 +44,7 @@ func (q PrometheusQuery) Fetch(query string) (*VectorQueryResponse, error) {
 		defer res.Body.Close()
 	}
 
-	bytesOut, readErr := ioutil.ReadAll(res.Body)
+	bytesOut, readErr := io.ReadAll(res.Body)
 	if readErr != nil {
 		return nil, readErr
 	}

gateway/scaling/ranges.go

@@ -3,6 +3,7 @@ package scaling
 import (
 	"bytes"
 	"encoding/json"
+	"io"
 	"io/ioutil"
 	"net/http"
 
@@ -43,7 +44,7 @@ func MakeHorizontalScalingHandler(next http.HandlerFunc) http.HandlerFunc {
 			return
 		}
 
-		body, err := ioutil.ReadAll(r.Body)
+		body, err := io.ReadAll(r.Body)
 		if err != nil {
 			http.Error(w, "Error reading request body", http.StatusBadRequest)
 			return