feat: improve debuggee ids (#1097)

Firebase debuggee ids are now of the form: d-********

Author: mctavish

src/agent/firebase-controller.ts

@@ -133,10 +133,13 @@ export class FirebaseController implements Controller {
 
     // Calculate the debuggee id as the hash of the object.
     // This MUST be consistent across all debuggee instances.
-    this.debuggeeId = crypto
-      .createHash('md5')
+    // TODO: JSON.stringify may provide different strings if labels are added
+    // in different orders.
+    const debuggeeHash = crypto
+      .createHash('sha1')
       .update(JSON.stringify(debuggee))
       .digest('hex');
+    this.debuggeeId = `d-${debuggeeHash.substring(0, 8)}`;
     debuggee.id = this.debuggeeId;
 
     const debuggeeRef = this.db.ref(`cdbg/debuggees/${this.debuggeeId}`);

test/test-firebase-controller.ts

@@ -150,8 +150,9 @@ describe('Firebase Controller', () => {
   describe('register', () => {
     it('should get a debuggeeId', done => {
       const db = new MockDatabase();
-      // Debuggee Id is the md5 hash of the json representation of the debuggee.
-      const debuggeeId = 'e1662bd77f69383284621966af8eb5e9';
+      // Debuggee Id is based on the sha1 hash of the json representation of
+      // the debuggee.
+      const debuggeeId = 'd-b9dbb5e7';
       const controller = new FirebaseController(
         db as {} as firebase.database.Database
       );