HH Pegasus Helper

When there is a restaurant or package change, the Cloudflare cache must be cleared to reflect these changes on the website. This process involves sending an event to Kafka, which instructs `hh-pegasus-helper` to clear the cache.

Process Overview

1. Event Trigger: A change in the restaurant/package triggers an event. 2. Kafka Event: The event is sent to Kafka. 3. Cache Clearing: hh-pegasus-helper receives the event and adds it to the BullMQ queue. 4. Execution: The cache clearing is executed by a BullMQ worker.

Monitoring

You can monitor the status of the cache clearing process on the BullMQ dashboard.

Production:

Staging:

Caveat (Need BE Support)

Issue 1:

When a package is changed, the cache is not purged for the following API endpoint: GET /api/v5/restaurant_packages.json?locale=en&restaurant_id=2151 This is because the query string cannot be used to purge the cache. Purging by prefix would result in purging all caches with the same prefix /api/v5/restaurant_packages.json, which is not desirable.

Proposed Solution

To address this issue, the backend can add tags to the Cache-Tag HTTP response header from the origin web server. This will enable cache purging by tags. Example:

Cache-Tag:package_1,package_2,package_3

For more information, refer to the Cloudflare documentation on purging cache by tags.

Issue 2

The API https://hungryhub.com/api/v5/restaurant_packages/27517.json is always being bypassed by Cloudflare. This might be due to the Cache-Control header settings: Cache-Control: max-age=0, private, must-revalidate. Is this behavior expected?

Production Deployment

Branch: main Env:

apiVersion: v1
kind: ConfigMap
metadata:
  name: hh-pegasus-helper-config
data:
  NODE_ENV: production
  FASTIFY_PORT: '5000'
  FASTIFY_HOST: '0.0.0.0'
  REDIS_HOST: <same as hh-search production>
  REDIS_PASSWORD: <same as hh-search production>
  REDIS_PORT: <same as hh-search production>
  REDIS_TLS: 'false'
  KAFKA_BROKER_LIST: kafka-hh-production.a.aivencloud.com:25942
  KAFKA_SECURITY_PROTOCOL: ssl
  KAFKA_GROUP_ID: hh-pegasus-helper-group-id
  ROLLBAR_ACCESS_TOKEN: 9927e741c87641bda3f8cd42f2534ef8
  ROLLBAR_ENABLED: 'true'
  WEB_DOMAIN: web.hungryhub.com
  API_DOMAIN: hungryhub.com/api/v5
  CLOUDFLARE_API: https://api.cloudflare.com/client/v4
  CLOUDFLARE_TOKEN: x3d5TBPsq7bYBjWpEeBhPguhjXbR4XcARUHOQ-x2
  CLOUDFLARE_ZONE_ID: 104b9a2a601c57619abee0706a54b28a

I think for Redis can use the same server as hh-search, what do you think?

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