fix FAAS provider determination when multiple providers are present

Author: baileympearson

src/cmap/handshake/faas_provider.ts

@@ -4,23 +4,23 @@ import type { ClientMetadata } from './client_metadata';
 export type FAASProvider = 'aws' | 'gcp' | 'azure' | 'vercel' | 'none';
 
 export function determineCloudProvider(): FAASProvider {
-  if (process.env.AWS_EXECUTION_ENV || process.env.AWS_LAMBDA_RUNTIME_API) {
-    return 'aws';
-  }
-
-  if (process.env.FUNCTIONS_WORKER_RUNTIME) {
-    return 'azure';
-  }
+  const awsPresent = process.env.AWS_EXECUTION_ENV || process.env.AWS_LAMBDA_RUNTIME_API;
+  const azurePresent = process.env.FUNCTIONS_WORKER_RUNTIME;
+  const gcpPresent = process.env.K_SERVICE || process.env.FUNCTION_NAME;
+  const vercelPresent = process.env.VERCEL;
 
-  if (process.env.K_SERVICE || process.env.FUNCTION_NAME) {
-    return 'gcp';
-  }
+  const numberOfProvidersPresent = [awsPresent, azurePresent, gcpPresent, vercelPresent].filter(
+    identity
+  ).length;
 
-  if (process.env.VERCEL) {
-    return 'vercel';
+  if (numberOfProvidersPresent !== 1) {
+    return 'none';
   }
 
-  return 'none';
+  if (awsPresent) return 'aws';
+  if (azurePresent) return 'azure';
+  if (gcpPresent) return 'gcp';
+  return 'vercel';
 }
 
 function applyAzureMetadata(m: ClientMetadata): ClientMetadata {

test/integration/mongodb-handshake/mongodb-handshake.prose.test.ts

@@ -49,9 +49,7 @@ context('FAAS Environment Prose Tests', function () {
       ]
     },
     {
-      //  TODO - clarify behavior here
-      expectedProvider: 'aws',
-
+      expectedProvider: 'none',
       context: '5. Invalid - multiple providers',
       env: [
         ['AWS_EXECUTION_ENV', 'AWS_Lambda_java8'],
@@ -67,7 +65,6 @@ context('FAAS Environment Prose Tests', function () {
       ]
     },
     {
-      //  TODO - clarify behavior here
       expectedProvider: 'aws',
       context: '7. Invalid - wrong types',
       env: [
@@ -94,7 +91,7 @@ context('FAAS Environment Prose Tests', function () {
       before(`metadata confirmation test for ${name}`, function () {
         expect(determineCloudProvider()).to.equal(
           expectedProvider,
-          'determined the wrong cloud provider based'
+          'determined the wrong cloud provider'
         );
       });
 

test/unit/cmap/handshake/client_metadata.test.ts

@@ -44,7 +44,17 @@ describe('client metadata module', () => {
     });
 
     context('when there is data from multiple cloud providers in the env', () => {
-      it.skip('TODO');
+      before(() => {
+        process.env.AWS_EXECUTION_ENV = 'non-empty-string';
+        process.env.FUNCTIONS_WORKER_RUNTIME = 'non-empty-string';
+      });
+      after(() => {
+        delete process.env.AWS_EXECUTION_ENV;
+        delete process.env.FUNCTIONS_WORKER_RUNTIME;
+      });
+      it('parses no FAAS provider', () => {
+        expect(determineCloudProvider()).to.equal('none');
+      });
     });
   });