Disabling mirroring when primary service is unhealthy

Traefik Traefik v3 (latest)
1

Hi team,
I’d appreciate any help with this. Thank you!

In my traefik configuration, we’re using a request mirroring setting to send a request also to a secondary service. Is there any way to disable the mirroring when the primary service is temporary unavailable?

The reason is, when the primary service is unavailable, traefik responds back to the client with a 503, the clients then retries the request. Unfortunately this retry is mirrored as a new request to the secondary service (to which the mirrored requests go to) and ends up as a duplicate request for each retry.

My configuration looks like this:

http:
  routers:
    https_router:
      entryPoints:
      - websecure
      rule: "PathPrefix(`/`)"
      service: hfs
      tls: {}

  services:
    hfs:
      mirroring:
        service: domain-hf
        maxBodySize: -1
        mirrors:
        - name: cloud-hf
          percent: 100

    domain-hf:
      loadBalancer:
        serversTransport: main
        healthCheck:
          path: /services/collector/health
          interval: "10s"
          timeout: "3s"
        responseForwarding:
          flushInterval: 1s
        passHostHeader: true
        servers:
        - url: "https://domainhf:6088/"

    cloud-hf:
      loadBalancer:
        serversTransport: main
        healthCheck:
          path: /services/collector/health
          interval: "10s"
          timeout: "3s"
        responseForwarding:
          flushInterval: 1s
        passHostHeader: true
        servers:
        - url: "https://cloudhf:5088/"

  serversTransports:
    main:
      insecureSkipVerify: true
      disableHTTP2: true

tls:
  certificates:
    - certFile: /traefik/certs/traefik.crt
      keyFile: /traefik/certs/traefik.key

This is an example log message returned by traefik when the primary service (domain-hf in this case) is unavailable:

172.21.0.5 - - [10/Oct/2024:21:38:16 +0000] "POST /services/collector/event/1.0 HTTP/1.1" 503 20 "-" "Go-http-client/1.1" 22 "https_router@file" "-" 0ms

Any way to prevent this duplication? or prevent mirroring when the primary service is unavailable?

Thank you!

2

Not sure if the mirroring request is happening at the same time, then it would not be possible. Only if it happens after the first request. You could check the source code on Github.

In general that sounds like a feature request for Github. But not sure if this is something that will be implemented, though.