add ability to explicitly disable logger

Signed-off-by: Bob Callaway <bcallaway@google.com>

pkg/client/options.go

@@ -15,7 +15,9 @@
 package client
 
 import (
+	"log"
 	"net/http"
+	"os"
 
 	"github.com/hashicorp/go-retryablehttp"
 )
@@ -34,10 +36,17 @@ const (
 	DefaultRetryCount = 3
 )
 
+var DefaultLogger retryablehttp.Logger
+
+func init() {
+	DefaultLogger = log.New(os.Stderr, "", log.LstdFlags)
+}
+
 func makeOptions(opts ...Option) *options {
 	o := &options{
 		UserAgent:  "",
 		RetryCount: DefaultRetryCount,
+		Logger:     DefaultLogger,
 	}
 
 	for _, opt := range opts {

pkg/client/options_test.go

@@ -15,34 +15,42 @@
 package client
 
 import (
+	"log"
 	"net/http"
+	"os"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
 )
 
 func TestMakeOptions(t *testing.T) {
+	customLogger := log.New(os.Stdout, "", log.LstdFlags)
+
 	tests := []struct {
 		desc string
 
 		opts []Option
 		want *options
 	}{{
 		desc: "no opts",
-		want: &options{RetryCount: DefaultRetryCount},
+		want: &options{RetryCount: DefaultRetryCount, Logger: DefaultLogger},
 	}, {
 		desc: "WithUserAgent",
 		opts: []Option{WithUserAgent("test user agent")},
-		want: &options{UserAgent: "test user agent", RetryCount: DefaultRetryCount},
+		want: &options{UserAgent: "test user agent", RetryCount: DefaultRetryCount, Logger: DefaultLogger},
 	}, {
 		desc: "WithRetryCount",
 		opts: []Option{WithRetryCount(2)},
-		want: &options{UserAgent: "", RetryCount: 2},
+		want: &options{UserAgent: "", RetryCount: 2, Logger: DefaultLogger},
+	}, {
+		desc: "WithLogger",
+		opts: []Option{WithLogger(customLogger)},
+		want: &options{UserAgent: "", RetryCount: DefaultRetryCount, Logger: customLogger},
 	}}
 	for _, tc := range tests {
 		t.Run(tc.desc, func(t *testing.T) {
 			got := makeOptions(tc.opts...)
-			if d := cmp.Diff(tc.want, got); d != "" {
+			if d := cmp.Diff(tc.want, got, cmp.Comparer(func(a, b *log.Logger) bool { return a == b })); d != "" {
 				t.Errorf("makeOptions(%v) returned unexpected result (-want +got): %s", tc.desc, d)
 			}
 		})

pkg/client/rekor_client.go

@@ -35,9 +35,7 @@ func GetRekorClient(rekorServerURL string, opts ...Option) (*client.Rekor, error
 
 	retryableClient := retryablehttp.NewClient()
 	retryableClient.RetryMax = int(o.RetryCount)
-	if o.Logger != nil {
-		retryableClient.Logger = o.Logger
-	}
+	retryableClient.Logger = o.Logger
 
 	rt := httptransport.NewWithClient(url.Host, client.DefaultBasePath, []string{url.Scheme}, retryableClient.StandardClient())
 	rt.Consumers["application/json"] = runtime.JSONConsumer()