fix(azure-iot-common): Fix for Azure#338: Exp backoff retry formula

pierreca · Jul 27, 2018 · 4a036b7 · 4a036b7
1 parent 08f541f
commit 4a036b7
Show file tree

Hide file tree

Showing 2 changed files with 3 additions and 3 deletions.
diff --git a/common/core/src/retry_policy.ts b/common/core/src/retry_policy.ts
@@ -134,7 +134,7 @@ export class ExponentialBackOffWithJitter implements RetryPolicy {
       let minRandomFactor = constants.c * (1 - constants.jd);
       let maxRandomFactor = constants.c * (1 - constants.ju);
       let randomJitter = Math.random() * (maxRandomFactor - minRandomFactor);
-      return Math.min(constants.cMin + (Math.pow(retryCount - 1, 2) - 1) * randomJitter, constants.cMax);
+      return Math.min(constants.cMin + (Math.pow(2, retryCount - 1) - 1) * randomJitter, constants.cMax);
     }
   }
 

diff --git a/common/core/test/_retry_policy_test.js b/common/core/test/_retry_policy_test.js
@@ -38,10 +38,10 @@ describe('RetryPolicy', function () {
         Math.random.restore();
       });
 
-      it('returns \'C\' for the first retry if the first retry is not set to be immediate', function () {
+      it('returns a non-zero value for the first retry if the first retry is not set to be immediate', function () {
         sinon.stub(Math, 'random').returns(0.42);
         var policy = new ExponentialBackOffWithJitter(false);
-        assert.strictEqual(policy.nextRetryTimeout(0, false), 100);
+        assert.isAbove(policy.nextRetryTimeout(0, false), 0);
         Math.random.restore();
       });