Add ability to optionally clone an api.Client's headers (#12117)

api/client.go

@@ -125,6 +125,9 @@ type Config struct {
 
 	// SRVLookup enables the client to lookup the host through DNS SRV lookup
 	SRVLookup bool
+
+	// CloneHeaders ensures that the source client's headers are copied to its clone.
+	CloneHeaders bool
 }
 
 // TLSConfig contains the parameters needed to configure TLS on the HTTP client
@@ -504,6 +507,7 @@ func (c *Client) CloneConfig() *Config {
 	newConfig.Limiter = c.config.Limiter
 	newConfig.OutputCurlString = c.config.OutputCurlString
 	newConfig.SRVLookup = c.config.SRVLookup
+	newConfig.CloneHeaders = c.config.CloneHeaders
 
 	// we specifically want a _copy_ of the client here, not a pointer to the original one
 	newClient := *c.config.HttpClient
@@ -809,6 +813,26 @@ func (c *Client) SetLogger(logger retryablehttp.LeveledLogger) {
 	c.config.Logger = logger
 }
 
+// SetCloneHeaders to allow headers to be copied whenever the client is cloned.
+func (c *Client) SetCloneHeaders(cloneHeaders bool) {
+	c.modifyLock.Lock()
+	defer c.modifyLock.Unlock()
+	c.config.modifyLock.Lock()
+	defer c.config.modifyLock.Unlock()
+
+	c.config.CloneHeaders = cloneHeaders
+}
+
+// CloneHeaders gets the configured CloneHeaders value.
+func (c *Client) CloneHeaders() bool {
+	c.modifyLock.RLock()
+	defer c.modifyLock.RUnlock()
+	c.config.modifyLock.RLock()
+	defer c.config.modifyLock.RUnlock()
+
+	return c.config.CloneHeaders
+}
+
 // Clone creates a new client with the same configuration. Note that the same
 // underlying http.Client is used; modifying the client from more than one
 // goroutine at once may not be safe, so modify the client as needed and then
@@ -839,12 +863,17 @@ func (c *Client) Clone() (*Client, error) {
 		OutputCurlString: config.OutputCurlString,
 		AgentAddress:     config.AgentAddress,
 		SRVLookup:        config.SRVLookup,
+		CloneHeaders:     config.CloneHeaders,
 	}
 	client, err := NewClient(newConfig)
 	if err != nil {
 		return nil, err
 	}
 
+	if config.CloneHeaders {
+		client.SetHeaders(c.Headers().Clone())
+	}
+
 	return client, nil
 }
 

api/client_test.go

@@ -9,6 +9,7 @@ import (
 	"net/http"
 	"net/url"
 	"os"
+	"reflect"
 	"strings"
 	"testing"
 	"time"
@@ -409,7 +410,32 @@ func TestClientNonTransportRoundTripper(t *testing.T) {
 }
 
 func TestClone(t *testing.T) {
-	client1, err := NewClient(DefaultConfig())
+	type fields struct {
+	}
+	tests := []struct {
+		name    string
+		config  *Config
+		headers *http.Header
+	}{
+		{
+			name:   "default",
+			config: DefaultConfig(),
+		},
+		{
+			name: "cloneHeaders",
+			config: &Config{
+				CloneHeaders: true,
+			},
+			headers: &http.Header{
+				"X-foo": []string{"bar"},
+				"X-baz": []string{"qux"},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			client1, err := NewClient(tt.config)
 			if err != nil {
 				t.Fatalf("NewClient failed: %v", err)
 			}
@@ -435,6 +461,10 @@ func TestClone(t *testing.T) {
 			client1.SetOutputCurlString(true)
 			client1.SetSRVLookup(true)
 
+			if tt.headers != nil {
+				client1.SetHeaders(*tt.headers)
+			}
+
 			client2, err := client1.Clone()
 			if err != nil {
 				t.Fatalf("Clone failed: %v", err)
@@ -467,6 +497,21 @@ func TestClone(t *testing.T) {
 			if client1.SRVLookup() != client2.SRVLookup() {
 				t.Fatalf("SRVLookup doesn't match: %v vs %v", client1.SRVLookup(), client2.SRVLookup())
 			}
+			if tt.config.CloneHeaders {
+				if !reflect.DeepEqual(client1.Headers(), client2.Headers()) {
+					t.Fatalf("Headers() don't match: %v vs %v", client1.Headers(), client2.Headers())
+				}
+				if client1.config.CloneHeaders != client2.config.CloneHeaders {
+					t.Fatalf("config.CloneHeaders doesn't match: %v vs %v", client1.config.CloneHeaders, client2.config.CloneHeaders)
+				}
+				if tt.headers != nil {
+					if !reflect.DeepEqual(*tt.headers, client2.Headers()) {
+						t.Fatalf("expected headers %v, actual %v", *tt.headers, client2.Headers())
+					}
+				}
+			}
+		})
+	}
 }
 
 func TestSetHeadersRaceSafe(t *testing.T) {

changelog/12117.txt

@@ -0,0 +1,3 @@
+```release-note:improvement
+api: Allow cloning `api.Client` HTTP headers via `api.Config.CloneHeaders` or `api.Client.SetCloneHeaders`.
+```