Skip to content

Latest commit

 

History

History
54 lines (47 loc) · 3.21 KB

redis-setup.md

File metadata and controls

54 lines (47 loc) · 3.21 KB

Setup Cache service with Redis Cache

To complete this setup, you need an active Redis server. A good option when deploying on Openshift is using Redis Enterprise Operator provided by Redis (marked as Certified, official Redis Docs here), but any Redis instance should be fine; feel free to chose any deployment method you prefer.

To enable the Cache service in RHDH, you need to add the following configuration to your app-config.yaml:

backend:
  cache:
    store: redis
    connection: redis://user:[email protected]:PORT

The useRedisSets option is no longer supported (from RHDH 1.5).

Use Redis with plugins

The plugins using Redis are Techdocs (production-ready) and Bulk-import (tech preview).

To use Redis with Techdocs, make sure you set the ttl parameter in the Techdocs section of your configuration, or the items won't be cached:

# File: app-config.yaml

techdocs:
  # techdocs.generator is used to configure how documentation sites are generated using MkDocs.
  .
  .
  .
  cache:
    # Represents the number of milliseconds a statically built asset should
    # stay cached. Cache invalidation is handled automatically by the frontend,
    # which compares the build times in cached metadata vs. canonical storage,
    # allowing long TTLs (e.g. 1 month/year)
    ttl: 3600000

    # (Optional) The time (in milliseconds) that the TechDocs backend will wait
    # for a cache service to respond before continuing on as though the cached
    # object was not found (e.g. when the cache service is unavailable). The
    # default value is 1000
    readTimeout: 500

Troubleshooting

The logs will no show any hint of the cache service being running correctly. You can set more verbose logging by passing the enviroment variable LOG_LEVEL=debug to your RHDH instance. You will only see error logs when a cache read is requested by any of the plugins (for example, when opening a Techdocs page). Some examples:

  • if you see errors like: 
    {"level":"\u001b[31merror\u001b[39m","message":"Request failed with status 500 NOAUTH Authentication required","plugin":"techdocs","service":"backstage","span_id":"f2f0499492ded848","timestamp":"2025-02-20 13:37:03","trace_flags":"01","trace_id":"c750094ef56da1412f217c3a2cd01ded","type":"errorHandler"}
    or 
    {"level":"\u001b[31merror\u001b[39m","message":"Failed to create redis cache client WRONGPASS invalid username-password pair","service":"backstage","span_id":"cfaf6a6a2031a34d","timestamp":"2025-02-20 13:27:15","trace_flags":"01","trace_id":"c0196b4be2bb94bba433290d8311d18b","type":"cacheManager"}
    make sure you have setup at least a password for the dafault user (or better, a proper user with the rights to access your Redis database) and that you are providing the correct values in the connection string
  • if you are a using ssl/tls (i.e. rediss://user:[email protected]:PORT), make sure all the certificates are in place and valid; if you are using self-signed certificates, the connection will probably fail to validate the CA; for testing porpuses only, you can set the NODE_TLS_REJECT_UNAUTHORIZED=0 enviromnment variable to overcome this issue