From c3c67abd3421fe70de11e4fbbf13ebe699254222 Mon Sep 17 00:00:00 2001
From: Rafael Roquetto <rafael.roquetto@grafana.com>
Date: Thu, 27 Feb 2025 17:56:58 -0600
Subject: [PATCH] Generalise endpoint resolution func

---
 pkg/export/otel/common.go      | 16 +++++++++++++
 pkg/export/otel/common_test.go | 42 ++++++++++++++++++++++++++++++++++
 pkg/export/otel/metrics.go     | 14 +-----------
 pkg/export/otel/traces.go      | 14 +-----------
 4 files changed, 60 insertions(+), 26 deletions(-)

diff --git a/pkg/export/otel/common.go b/pkg/export/otel/common.go
index fdc70aa66..22ce14861 100644
--- a/pkg/export/otel/common.go
+++ b/pkg/export/otel/common.go
@@ -404,3 +404,19 @@ func ResourceAttrsFromEnv(svc *svc.Attrs) []attribute.KeyValue {
 	parseOTELEnvVar(svc, envResourceAttrs, apply)
 	return otelResourceAttrs
 }
+
+func ResolveOTLPEndpoint(endpoint, common string, grafana *GrafanaOTLP) (string, bool) {
+	if endpoint != "" {
+		return endpoint, false
+	}
+
+	if common != "" {
+		return common, true
+	}
+
+	if grafana != nil && grafana.CloudZone != "" && grafana.Endpoint() != "" {
+		return grafana.Endpoint(), true
+	}
+
+	return "", false
+}
diff --git a/pkg/export/otel/common_test.go b/pkg/export/otel/common_test.go
index e748cdb25..c51e129f6 100644
--- a/pkg/export/otel/common_test.go
+++ b/pkg/export/otel/common_test.go
@@ -186,3 +186,45 @@ func TestParseOTELEnvVar_nil(t *testing.T) {
 
 	assert.True(t, reflect.DeepEqual(actual, map[string]string{}))
 }
+
+func TestResolveOTLPEndpoint(t *testing.T) {
+	grafana1 := GrafanaOTLP{
+		CloudZone: "foo",
+	}
+
+	const grafanaEndpoint = "https://otlp-gateway-foo.grafana.net/otlp"
+
+	grafana2 := GrafanaOTLP{}
+
+	type expected struct {
+		e      string
+		common bool
+	}
+
+	type testCase struct {
+		endpoint string
+		common   string
+		grafana  *GrafanaOTLP
+		expected expected
+	}
+
+	testCases := []testCase{
+		{endpoint: "e1", common: "c1", grafana: nil, expected: expected{e: "e1", common: false}},
+		{endpoint: "e1", common: "", grafana: nil, expected: expected{e: "e1", common: false}},
+		{endpoint: "", common: "c1", grafana: nil, expected: expected{e: "c1", common: true}},
+		{endpoint: "", common: "", grafana: nil, expected: expected{e: "", common: false}},
+		{endpoint: "e1", common: "c1", grafana: &grafana1, expected: expected{e: "e1", common: false}},
+		{endpoint: "", common: "c1", grafana: &grafana1, expected: expected{e: "c1", common: true}},
+		{endpoint: "", common: "", grafana: &grafana1, expected: expected{e: grafanaEndpoint, common: true}},
+		{endpoint: "", common: "", grafana: &grafana2, expected: expected{e: "", common: false}},
+	}
+
+	for _, tc := range testCases {
+		t.Run(fmt.Sprint(tc), func(t *testing.T) {
+			ep, common := ResolveOTLPEndpoint(tc.endpoint, tc.common, tc.grafana)
+
+			assert.Equal(t, ep, tc.expected.e)
+			assert.Equal(t, common, tc.expected.common)
+		})
+	}
+}
diff --git a/pkg/export/otel/metrics.go b/pkg/export/otel/metrics.go
index c6f1eeb36..7928183a6 100644
--- a/pkg/export/otel/metrics.go
+++ b/pkg/export/otel/metrics.go
@@ -146,19 +146,7 @@ func (m *MetricsConfig) GuessProtocol() Protocol {
 }
 
 func (m *MetricsConfig) OTLPMetricsEndpoint() (string, bool) {
-	isCommon := false
-	endpoint := m.MetricsEndpoint
-	if endpoint == "" {
-		endpoint = m.CommonEndpoint
-		if endpoint == "" && m.Grafana != nil && m.Grafana.CloudZone != "" {
-			endpoint = m.Grafana.Endpoint()
-		}
-		if endpoint != "" {
-			isCommon = true
-		}
-	}
-
-	return endpoint, isCommon
+	return ResolveOTLPEndpoint(m.MetricsEndpoint, m.CommonEndpoint, m.Grafana)
 }
 
 // EndpointEnabled specifies that the OTEL metrics node is enabled if and only if
diff --git a/pkg/export/otel/traces.go b/pkg/export/otel/traces.go
index e8c7245e7..df7a180c3 100644
--- a/pkg/export/otel/traces.go
+++ b/pkg/export/otel/traces.go
@@ -115,19 +115,7 @@ func (m *TracesConfig) GetProtocol() Protocol {
 }
 
 func (m *TracesConfig) OTLPTracesEndpoint() (string, bool) {
-	endpoint := m.TracesEndpoint
-	isCommon := false
-	if endpoint == "" {
-		endpoint = m.CommonEndpoint
-		if endpoint == "" && m.Grafana != nil && m.Grafana.CloudZone != "" {
-			endpoint = m.Grafana.Endpoint()
-		}
-		if endpoint != "" {
-			isCommon = true
-		}
-	}
-
-	return endpoint, isCommon
+	return ResolveOTLPEndpoint(m.TracesEndpoint, m.CommonEndpoint, m.Grafana)
 }
 
 func (m *TracesConfig) guessProtocol() Protocol {