feat(event-bus): random-delay for 429 and 409 lock errors

[saby1101]

This pull request introduces a new utility function, randomDelay, to improve handling of rate-limiting and lock-conflict scenarios across multiple event consumer implementations. The function is integrated into the Azure Service Bus, GCP Pub/Sub, and RabbitMQ consumer logic, and its maximum delay is configurable via an environment variable.

Utility Enhancements:

• src/event-bus/event-consumer/utils.ts: Added the randomDelay function, which introduces a randomized delay mechanism. The maximum delay can be configured using the EVENT_RANDOMIZED_DELAY_MAX environment variable. [1] [2]

Integration with Event Consumers:

• src/event-bus/event-consumer/azure-servicebus.ts: Imported randomDelay and integrated it into the Azure Service Bus consumer logic to handle rate-limiting and lock-conflict scenarios. [1] [2]
• src/event-bus/event-consumer/gcp-pubsub.ts: Added randomDelay to the GCP Pub/Sub consumer logic for similar scenarios. [1] [2]
• src/event-bus/event-consumer/rabbitmq.ts: Incorporated randomDelay into the RabbitMQ consumer logic for handling rate-limiting and lock-conflict cases. [1] [2]

[Copilot]

Pull Request Overview

This PR adds a randomized delay utility and wires it into all event consumers to improve backoff behavior on rate-limit and lock-conflict errors.

• Introduces randomDelay in utils.ts with a configurable EVENT_RANDOMIZED_DELAY_MAX
• Integrates randomDelay into RabbitMQ, GCP Pub/Sub, and Azure Service Bus consumers for 429/409 responses

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
src/event-bus/event-consumer/utils.ts	Defines RANDOMIZED_DELAY_MAX and randomDelay helper
src/event-bus/event-consumer/rabbitmq.ts	Imports and calls randomDelay() before requeue on 429/409
src/event-bus/event-consumer/gcp-pubsub.ts	Imports and calls randomDelay() before nack on 429/409
src/event-bus/event-consumer/azure-servicebus.ts	Imports and calls randomDelay() before abandon on 429/409

Comments suppressed due to low confidence (6)

src/event-bus/event-consumer/utils.ts:30

• Add a JSDoc comment above randomDelay to describe its purpose, parameters, default behavior, and related environment variable.

export async function randomDelay(max: number = RANDOMIZED_DELAY_MAX) {

src/event-bus/event-consumer/utils.ts:30

• Add unit tests for randomDelay to verify default behavior, custom max values, and edge cases (e.g., zero or very large values).

export async function randomDelay(max: number = RANDOMIZED_DELAY_MAX) {

src/event-bus/event-consumer/utils.ts:30

• [nitpick] Consider renaming the parameter max to maxDelay for clearer intent in the function signature.

export async function randomDelay(max: number = RANDOMIZED_DELAY_MAX) {

src/event-bus/event-consumer/rabbitmq.ts:62

• Add or update integration tests for the RabbitMQ consumer to verify that randomDelay is invoked correctly when handling 429/409 status codes.

await randomDelay();

src/event-bus/event-consumer/gcp-pubsub.ts:124

• Ensure GCP Pub/Sub consumer tests cover the retry path with randomDelay on 429/409 errors.

await randomDelay();

src/event-bus/event-consumer/azure-servicebus.ts:80

• Add coverage for the Azure Service Bus consumer to confirm randomDelay is applied before abandoning messages on lock-conflict or rate-limit errors.

await randomDelay();