Use OTLP/Protobuf Exporter for AMW Endpoint

package.json

@@ -75,8 +75,9 @@
     "@opentelemetry/api-logs": "^0.204.0",
     "@opentelemetry/core": "^2.1.0",
     "@opentelemetry/exporter-logs-otlp-http": "^0.204.0",
-    "@opentelemetry/exporter-metrics-otlp-http": "^0.204.0",
     "@opentelemetry/exporter-trace-otlp-http": "^0.204.0",
+    "@opentelemetry/exporter-metrics-otlp-proto": "^0.204.0",
+    "@opentelemetry/exporter-metrics-otlp-http": "^0.204.0",
     "@opentelemetry/otlp-exporter-base": "^0.204.0",
     "@opentelemetry/resources": "^2.1.0",
     "@opentelemetry/sdk-logs": "^0.204.0",

src/agent/aksLoader.ts

@@ -8,7 +8,8 @@ import { FileWriter } from "./diagnostics/writers/fileWriter";
 import { StatusLogger } from "./diagnostics/statusLogger";
 import { AgentLoader } from "./agentLoader";
 import { InstrumentationOptions } from '../types';
-import { OTLPMetricExporter } from "@opentelemetry/exporter-metrics-otlp-http";
+import { OTLPMetricExporter as OTLPProtoMetricExporter } from "@opentelemetry/exporter-metrics-otlp-proto";
+import { OTLPMetricExporter as OTLPHttpMetricExporter } from "@opentelemetry/exporter-metrics-otlp-http";
 import { MetricReader, PeriodicExportingMetricReader } from "@opentelemetry/sdk-metrics";
 import { OTLP_METRIC_EXPORTER_EXPORT_INTERVAL } from './types';
 
@@ -62,7 +63,17 @@ export class AKSLoader extends AgentLoader {
                     (process.env.OTEL_EXPORTER_OTLP_ENDPOINT || process.env.OTEL_EXPORTER_OTLP_METRICS_ENDPOINT)
                 ) {
                     try {
-                        const otlpExporter = new OTLPMetricExporter();
+                        // Determine which exporter to use based on protocol setting
+                        const protocol = process.env.OTEL_EXPORTER_OTLP_METRICS_PROTOCOL || 
+                                       process.env.OTEL_EXPORTER_OTLP_PROTOCOL;
+
+                        let otlpExporter;
+                        if (protocol === 'http/json') {
+                            otlpExporter = new OTLPHttpMetricExporter();
+                        } else {
+                            // Use protobuf for 'http/protobuf', 'grpc', or any other value
+                            otlpExporter = new OTLPProtoMetricExporter();
+                        }
 
                         const otlpMetricReader = new PeriodicExportingMetricReader({
                             exporter: otlpExporter,

test/unitTests/agent/aksLoader.tests.ts

@@ -183,4 +183,33 @@ describe("agent/AKSLoader", () => {
         );
         assert.equal(azureMonitorExporters.length, 1, "Should have exactly one Azure Monitor metric exporter");
     });
+
+    it("constructor creates OTLP protobuf exporter when OTEL_EXPORTER_OTLP_METRICS_PROTOCOL is set to http/protobuf", () => {
+        const env = {
+            ["APPLICATIONINSIGHTS_CONNECTION_STRING"]: "InstrumentationKey=1aa11111-bbbb-1ccc-8ddd-eeeeffff3333",
+            ["OTEL_METRICS_EXPORTER"]: "otlp",
+            ["OTEL_EXPORTER_OTLP_ENDPOINT"]: "http://localhost:4317",
+            ["OTEL_EXPORTER_OTLP_METRICS_PROTOCOL"]: "http/protobuf"
+        };
+        process.env = env;
+
+        const agent = new AKSLoader();
+
+        // Verify that metricReaders were added to the options
+        const options = (agent as any)._options;
+        assert.ok(options.metricReaders, "metricReaders should be present in options");
+        assert.equal(options.metricReaders.length, 1, "Should have exactly one metric reader");
+
+        // Verify the metric reader is a PeriodicExportingMetricReader
+        const metricReader = options.metricReaders[0];
+        assert.equal(metricReader.constructor.name, "PeriodicExportingMetricReader", "Should be a PeriodicExportingMetricReader");
+
+        // Verify the exporter is an OTLP protobuf exporter
+        const exporter = (metricReader as any)._exporter;
+        assert.equal(exporter.constructor.name, "OTLPMetricExporter", "Should be an OTLPMetricExporter");
+
+        // Verify that it's the protobuf version by checking if it was imported from the proto package
+        // The protobuf exporter should have different internal structure than the HTTP exporter
+        assert.ok(exporter, "Protobuf exporter should exist");
+    });
 });