Use default SumoLogic URL for OpAmp clients

When the OpAmp URL is not explicitly configured, use the default
SumoLogic URL.

pkg/extension/opampextension/opamp_agent.go

@@ -41,6 +41,8 @@ import (
 	"github.com/SumoLogic/sumologic-otel-collector/pkg/extension/sumologicextension"
 )
 
+const DefaultSumoLogicOpAmpURL = "wss://opamp-events.sumologic.com/v1/opamp"
+
 type opampAgent struct {
 	cfg    *Config
 	host   component.Host
@@ -99,6 +101,9 @@ func (o *opampAgent) Start(ctx context.Context, host component.Host) error {
 	}
 
 	o.endpoint = o.cfg.Endpoint
+	if o.endpoint == "" {
+		o.endpoint = DefaultSumoLogicOpAmpURL
+	}
 
 	if o.authExtension == nil {
 		return o.startClient(ctx)
@@ -144,7 +149,7 @@ func (o *opampAgent) Reload(ctx context.Context) error {
 	return o.Start(ctx, o.host)
 }
 
-func (o *opampAgent) startClient(ctx context.Context) error {
+func (o *opampAgent) startSettings() types.StartSettings {
 	settings := types.StartSettings{
 		Header:         o.authHeader,
 		OpAMPServerURL: o.endpoint,
@@ -172,6 +177,16 @@ func (o *opampAgent) startClient(ctx context.Context) error {
 		Capabilities:       o.getAgentCapabilities(),
 	}
 
+	if settings.OpAMPServerURL == "" {
+		settings.OpAMPServerURL = DefaultSumoLogicOpAmpURL
+	}
+
+	return settings
+}
+
+func (o *opampAgent) startClient(ctx context.Context) error {
+	settings := o.startSettings()
+
 	o.logger.Debug("Starting OpAMP client...")
 
 	if err := o.opampClient.Start(ctx, settings); err != nil {

pkg/extension/opampextension/opamp_agent_test.go

@@ -485,3 +485,16 @@ func TestReload(t *testing.T) {
 	assert.NoError(t, o.Start(ctx, componenttest.NewNopHost()))
 	assert.NoError(t, o.Reload(ctx))
 }
+
+func TestDefaultEndpointSetOnStart(t *testing.T) {
+	cfg := createDefaultConfig().(*Config)
+	set := extensiontest.NewNopCreateSettings()
+	o, err := newOpampAgent(cfg, set.Logger, set.BuildInfo, set.Resource)
+	if err != nil {
+		t.Fatal(err)
+	}
+	settings := o.startSettings()
+	if settings.OpAMPServerURL != DefaultSumoLogicOpAmpURL {
+		t.Error("expected unconfigured opamp endpoint to result in default sumo opamp url setting")
+	}
+}