refactor(outgoing_webhooks): raise errors in the analytics pipeline in case of API client errors or non-2xx responses

[SanchithHegde]

Type of Change

• Bugfix
• New feature
• Enhancement
• Refactoring
• Dependency updates
• Documentation
• CI/CD

Description

This PR refactors the outgoing webhooks logic to raise errors to the analytics pipeline (involving Kafka and ClickHouse) in case the webhook was not at all sent due to API client errors, or if the merchant server returns a non-2xx HTTP response.

This was done in two steps:

1. First, the success and error handling closures were moved out as functions within the outgoing webhooks module.
2. Then, the error handling functions were updated to return errors.

Since it's easier to follow along when reviewing one commit at a time, I'd suggest the reviewers to do the same.

Motivation and Context

This fixes a bug where failed webhook deliveries were falsely displayed as successful on the control center, since the analytics pipeline had no information that an error had occurred.

How did you test it?

With a local Kafka and ClickHouse setup:

1. In case of successful deliveries, the is_error field must be false and error field must not be populated in the Kafka and ClickHouse events:

   Kafke:
   

   ClickHouse:
   

2. In case of failed webhook deliveries due to errors where no HTTP response was involved (non-existent domain name, some configuration issues with the client, etc.), the is_error field must be true and the error field must be populated with CallToMerchantFailed:

   Kafka:
   

   ClickHouse:
   

3. In case of failed webhook deliveries due to the merchant server returning a non-2xx HTTP status code, the is_error field must be true and the error field must be populated with NotReceivedByMerchant:

   Kafka:
   

   ClickHouse:
   

Checklist

• I formatted the code cargo +nightly fmt --all
• I addressed lints thrown by cargo clippy
• I reviewed the submitted code
• I added unit tests for my changes where possible