Allow to configure read/write buffer sizes for http Client (#1447)

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

config/confighttp/confighttp.go

@@ -32,6 +32,12 @@ type HTTPClientSettings struct {
 	// TLSSetting struct exposes TLS client configuration.
 	TLSSetting configtls.TLSClientSetting `mapstructure:",squash"`
 
+	// ReadBufferSize for HTTP client. See http.Transport.ReadBufferSize.
+	ReadBufferSize int `mapstructure:"read_buffer_size"`
+
+	// WriteBufferSize for HTTP client. See http.Transport.WriteBufferSize.
+	WriteBufferSize int `mapstructure:"write_buffer_size"`
+
 	// Timeout parameter configures `http.Client.Timeout`.
 	Timeout time.Duration `mapstructure:"timeout,omitempty"`
 }
@@ -45,6 +51,12 @@ func (hcs *HTTPClientSettings) ToClient() (*http.Client, error) {
 	if tlsCfg != nil {
 		transport.TLSClientConfig = tlsCfg
 	}
+	if hcs.ReadBufferSize > 0 {
+		transport.ReadBufferSize = hcs.ReadBufferSize
+	}
+	if hcs.WriteBufferSize > 0 {
+		transport.WriteBufferSize = hcs.WriteBufferSize
+	}
 	return &http.Client{
 		Transport: transport,
 		Timeout:   hcs.Timeout,

config/confighttp/confighttp_test.go

@@ -28,6 +28,22 @@ import (
 	"go.opentelemetry.io/collector/config/configtls"
 )
 
+func TestAllHTTPClientSettings(t *testing.T) {
+	hcs := &HTTPClientSettings{
+		Endpoint: "localhost:1234",
+		TLSSetting: configtls.TLSClientSetting{
+			Insecure: false,
+		},
+		ReadBufferSize:  1024,
+		WriteBufferSize: 512,
+	}
+	client, err := hcs.ToClient()
+	assert.NoError(t, err)
+	transport := client.Transport.(*http.Transport)
+	assert.EqualValues(t, 1024, transport.ReadBufferSize)
+	assert.EqualValues(t, 512, transport.WriteBufferSize)
+}
+
 func TestHTTPClientSettingsError(t *testing.T) {
 	tests := []struct {
 		settings HTTPClientSettings

exporter/zipkinexporter/README.md

@@ -11,6 +11,8 @@ The following settings can be optionally configured:
 
 - `defaultservicename` (default = <missing service name>): What to name services missing this information.
 - `timeout` (default = 5s): How long to wait until the connection is close.
+- `read_buffer_size` (default = 0): ReadBufferSize for HTTP client.
+- `write_buffer_size` (default = 512 * 1024): WriteBufferSize for HTTP client.
 
 Example:
 

exporter/zipkinexporter/factory.go

@@ -55,6 +55,8 @@ func (f *Factory) CreateDefaultConfig() configmodels.Exporter {
 		},
 		HTTPClientSettings: confighttp.HTTPClientSettings{
 			Timeout: defaultTimeout,
+			// We almost read 0 bytes, so no need to tune ReadBufferSize.
+			WriteBufferSize: 512 * 1024,
 		},
 		Format:             defaultFormat,
 		DefaultServiceName: defaultServiceName,