[Azure Monitor OpenTelemetry] Add support for Azure Functions program…

…ming model v4 (#27161)

### Packages impacted by this PR
@azure/monitor-opentelemetry

Related to
microsoft/ApplicationInsights-node.js#1181

sdk/monitor/monitor-opentelemetry/src/traces/azureFnHook.ts

@@ -18,16 +18,7 @@ export class AzureFunctionsHook {
     try {
       // TODO: Add types files when publicly available
       this._functionsCoreModule = require("@azure/functions-core");
-      // Only v3 of Azure Functions library is supported right now. See matrix of versions here:
-      // https://github.com/Azure/azure-functions-nodejs-library
-      const funcProgModel = this._functionsCoreModule.getProgrammingModel();
-      if (funcProgModel.name === "@azure/functions" && funcProgModel.version.startsWith("3.")) {
-        this._addPreInvocationHook();
-      } else {
-        Logger.getInstance().debug(
-          `AzureFunctionsHook does not support model "${funcProgModel.name}" version "${funcProgModel.version}"`
-        );
-      }
+      this._addPreInvocationHook();
     } catch (error) {
       Logger.getInstance().debug(
         "@azure/functions-core failed to load, not running in Azure Functions"

sdk/monitor/monitor-opentelemetry/test/internal/unit/traces/azureFnHook.test.ts

@@ -55,32 +55,6 @@ describe("Library/AzureFunctionsHook", () => {
       Module.prototype.require = originalRequire;
     });
 
-    it("Hook not added if using not supported programming model", () => {
-      var Module = require("module");
-      var preInvocationCalled = false;
-      Module.prototype.require = function () {
-        if (arguments[0] === "@azure/functions-core") {
-          return {
-            registerHook(name: string) {
-              if (name === "preInvocation") {
-                preInvocationCalled = true;
-              }
-            },
-            getProgrammingModel() {
-              return {
-                name: "@azure/functions",
-                version: "2.x",
-              };
-            },
-          };
-        }
-        return originalRequire.apply(this, arguments);
-      };
-      let azureFnHook = new AzureFunctionsHook();
-      assert.ok(azureFnHook, "azureFnHook");
-      assert.ok(!preInvocationCalled, "preInvocationCalled");
-    });
-
     it("Pre Invokation Hook added if running in Azure Functions and context is propagated", () => {
       let Module = require("module");
       let preInvocationCalled = false;