Redrive Trace Merging Fix (#605)

Account for missing redrive count in Step Functions trace merging. While we expect the context object to always have `Execution.RedriveCount`, some customers context objects don't have this value.

Author: avedmala

src/trace/context/extractors/step-function.spec.ts

@@ -13,7 +13,6 @@ describe("StepFunctionEventTraceExtractor", () => {
         RoleArn:
           "arn:aws:iam::425362996713:role/service-role/StepFunctions-abhinav-activity-state-machine-role-22jpbgl6j",
         StartTime: "2024-12-04T19:38:04.069Z",
-        RedriveCount: 0,
       },
       State: {
         Name: "Lambda Invoke",

src/trace/step-function-service.spec.ts

@@ -109,16 +109,6 @@ describe("StepFunctionContextService", () => {
           },
         },
       ],
-      [
-        "Execution RedriveCount is not a number",
-        {
-          ...legacyStepFunctionEvent,
-          Execution: {
-            ...legacyStepFunctionEvent.Execution,
-            RedriveCount: "0",
-          },
-        },
-      ],
       [
         "State is not defined",
         {

src/trace/step-function-service.ts

@@ -215,7 +215,7 @@ export class StepFunctionContextService {
     if (this.isValidContextObject(event)) {
       return {
         execution_id: event.Execution.Id,
-        redrive_count: event.Execution.RedriveCount.toString(),
+        redrive_count: (event.Execution.RedriveCount ?? "0").toString(),
         state_entered_time: event.State.EnteredTime,
         state_name: event.State.Name,
       };
@@ -228,7 +228,6 @@ export class StepFunctionContextService {
   private isValidContextObject(context: any): boolean {
     return (
       typeof context?.Execution?.Id === "string" &&
-      typeof context?.Execution?.RedriveCount === "number" &&
       typeof context?.State?.EnteredTime === "string" &&
       typeof context?.State?.Name === "string"
     );