[exporter/loadbalancing] Set a placeholder endpoint (#31411)

This is a backport of the original issue, #31381

Signed-off-by: Juraci Paixão Kröhling <juraci@kroehling.de>

.chloggen/lb-exporter-dummy-endpoint.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: loadbalancingexporter
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Fixes a bug where the endpoint become required, despite not being used by the load balancing exporter.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [31371]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

exporter/loadbalancingexporter/factory.go

@@ -32,6 +32,7 @@ func NewFactory() exporter.Factory {
 func createDefaultConfig() component.Config {
 	otlpFactory := otlpexporter.NewFactory()
 	otlpDefaultCfg := otlpFactory.CreateDefaultConfig().(*otlpexporter.Config)
+	otlpDefaultCfg.Endpoint = "placeholder"
 
 	return &Config{
 		Protocol: Protocol{

exporter/loadbalancingexporter/factory_test.go

@@ -46,3 +46,15 @@ func TestLogExporterGetsCreatedWithValidConfiguration(t *testing.T) {
 	assert.NoError(t, err)
 	assert.NotNil(t, exp)
 }
+
+func TestOTLPConfigIsValid(t *testing.T) {
+	// prepare
+	factory := NewFactory()
+	defaultCfg := factory.CreateDefaultConfig().(*Config)
+
+	// test
+	otlpCfg := defaultCfg.Protocol.OTLP
+
+	// verify
+	assert.NoError(t, otlpCfg.Validate())
+}