HTTP 500, Found

[bradbeattie]

When I configure Sablier with the blocking strategy with Traefik, the service spins up and returns HTTP 500 with body content "Found". If I then reload again, I get the service in question successfully. I suspect it has something to do with #240 theorizing that Sablier releases the block before Traefik establishes the route.

provider:
  name: docker
  docker:
    strategy: stop
server:
  port: 10000 
  base-path: /
storage:
  file:
sessions:
  default-duration: 5m
logging:
  level: debug
strategy:
  dynamic:
    show-details-by-default: true
    default-theme: ghost
    default-refresh-frequency: 5s
  blocking:
    default-timeout: 30s

Labels on my meilisearch docker compose instance:

    labels:
      - homelan.group=apps
      - traefik.http.routers.meilisearch.rule=Host(`meilisearch.home.lan`)
      - traefik.http.routers.meilisearch.tls=true
      - sablier.enable=true
      - sablier.group=meilisearch-group
      - traefik.http.services.meilisearch.loadbalancer.server.port=7700
      - traefik.http.routers.meilisearch.middlewares=meilisearch-sablier
      - traefik.http.middlewares.meilisearch-sablier.plugin.sablier.endpoint=http://sablier:10000
      - traefik.http.middlewares.meilisearch-sablier.plugin.sablier.group=meilisearch-group
      - traefik.http.middlewares.meilisearch-sablier.plugin.sablier.blocking.timeout=30s
      - traefik.docker.allownonrunning=true

Have I misconfigured obvious here? Dynamic strategy isn't ideal for services that aren't accessed via browsers directly, so I'd really love to get blocking strategy working.

[acouvreur]

Can you print Sablier logs ?

[bradbeattie]

Sablier's logs

sablier-1  | 6:58PM DBG docker/container_list.go:60 listing containers provider=docker strategy=stop options.all=true options.filters="{fields:map[label:map[sablier.enable=true:true]]}"
sablier-1  | 6:58PM DBG docker/container_list.go:70 containers listed provider=docker strategy=stop count=6
sablier-1  | 6:58PM DBG sablier/session_request.go:128 requesting ready session for group group=meilisearch-group duration=20s timeout=30s
sablier-1  | 6:58PM DBG sablier/session_request.go:73 requesting ready session names=[meilisearch-meilisearch-1] duration=20s timeout=30s
sablier-1  | 6:58PM DBG sablier/session_request.go:19 requesting session names=[meilisearch-meilisearch-1] duration=20s
sablier-1  | 6:58PM DBG sablier/instance_request.go:19 request to start instance received instance=meilisearch-meilisearch-1
sablier-1  | 6:58PM DBG docker/container_start.go:20 starting container provider=docker strategy=stop name=meilisearch-meilisearch-1
sablier-1  | 6:58PM DBG docker/container_inspect.go:18 container inspected provider=docker strategy=stop container=meilisearch-meilisearch-1 status=running health=starting
sablier-1  | 6:58PM DBG sablier/instance_request.go:30 request to start instance status completed instance=meilisearch-meilisearch-1 status=not-ready
sablier-1  | 6:58PM DBG sablier/instance_request.go:43 set expiration for instance instance=meilisearch-meilisearch-1 expiration=20s
sablier-1  | 6:58PM DBG docker/container_list.go:60 listing containers provider=docker strategy=stop options.all=true options.filters="{fields:map[label:map[sablier.enable=true:true]]}"
sablier-1  | 6:58PM DBG docker/container_list.go:70 containers listed provider=docker strategy=stop count=6
sablier-1  | 6:58PM DBG docker/container_list.go:60 listing containers provider=docker strategy=stop options.all=true options.filters="{fields:map[label:map[sablier.enable=true:true]]}"
sablier-1  | 6:58PM DBG docker/container_list.go:70 containers listed provider=docker strategy=stop count=6
sablier-1  | 6:58PM DBG docker/container_list.go:60 listing containers provider=docker strategy=stop options.all=true options.filters="{fields:map[label:map[sablier.enable=true:true]]}"
sablier-1  | 6:58PM DBG docker/container_list.go:70 containers listed provider=docker strategy=stop count=6
sablier-1  | 6:58PM DBG sablier/session_request.go:19 requesting session names=[meilisearch-meilisearch-1] duration=20s
sablier-1  | 6:58PM DBG sablier/instance_request.go:35 request to check instance status received instance=meilisearch-meilisearch-1 current_status=not-ready
sablier-1  | 6:58PM DBG docker/container_inspect.go:18 container inspected provider=docker strategy=stop container=meilisearch-meilisearch-1 status=running health=starting
sablier-1  | 6:58PM DBG sablier/instance_request.go:40 request to check instance status completed instance=meilisearch-meilisearch-1 new_status=not-ready
sablier-1  | 6:58PM DBG sablier/instance_request.go:43 set expiration for instance instance=meilisearch-meilisearch-1 expiration=20s
sablier-1  | 6:58PM DBG docker/container_list.go:60 listing containers provider=docker strategy=stop options.all=true options.filters="{fields:map[label:map[sablier.enable=true:true]]}"
sablier-1  | 6:58PM DBG docker/container_list.go:70 containers listed provider=docker strategy=stop count=6
sablier-1  | 6:58PM DBG docker/container_list.go:60 listing containers provider=docker strategy=stop options.all=true options.filters="{fields:map[label:map[sablier.enable=true:true]]}"
sablier-1  | 6:58PM DBG docker/container_list.go:70 containers listed provider=docker strategy=stop count=6
sablier-1  | 6:58PM DBG sablier/session_request.go:19 requesting session names=[meilisearch-meilisearch-1] duration=20s
sablier-1  | 6:58PM DBG sablier/instance_request.go:35 request to check instance status received instance=meilisearch-meilisearch-1 current_status=not-ready
sablier-1  | 6:58PM DBG docker/container_inspect.go:18 container inspected provider=docker strategy=stop container=meilisearch-meilisearch-1 status=running health=healthy
sablier-1  | 6:58PM DBG sablier/instance_request.go:40 request to check instance status completed instance=meilisearch-meilisearch-1 new_status=ready
sablier-1  | 6:58PM DBG sablier/instance_request.go:43 set expiration for instance instance=meilisearch-meilisearch-1 expiration=20s
sablier-1  | 6:58PM DBG slog-gin@v1.18.0/middleware.go:276 Incoming request request.time=2026-03-09T18:58:02.620Z request.method=GET request.host=sablier:10000 request.path=/api/strategies/blocking request.query="group=meilisearch-group&timeout=30s" request.params=map[] request.route=/api/strategies/blocking request.ip=192.168.80.9 request.referer="" request.length=0 response.time=2026-03-09T18:58:12.766Z response.latency=10.145156739s response.status=200 response.length=0 id=be21c50f-cc2b-4e07-bed5-961e4c76bfbf
sablier-1  | 6:58PM DBG docker/container_list.go:60 listing containers provider=docker strategy=stop options.all=true options.filters="{fields:map[label:map[sablier.enable=true:true]]}"
sablier-1  | 6:58PM DBG docker/container_list.go:70 containers listed provider=docker strategy=stop count=6
^C

Meilisearch's logs:

meilisearch-1  | 2026-03-09T18:58:02.768073Z DEBUG meilisearch::personalization: Personalization service disabled
meilisearch-1  | 2026-03-09T18:58:02.768331Z  INFO actix_server::builder: starting 8 workers
meilisearch-1  | 2026-03-09T18:58:02.768358Z  INFO actix_server::server: Actix runtime found; starting in Actix runtime
meilisearch-1  | 2026-03-09T18:58:02.768368Z  INFO actix_server::server: starting service: "actix-web-service-0.0.0.0:7700", workers: 8, listening on: 0.0.0.0:7700
meilisearch-1  | 2026-03-09T18:58:07.804692Z  INFO HTTP request{method=GET host="localhost:7700" route=/health query_parameters= user_agent=curl/8.14.1 status_code=200}: meilisearch: close time.busy=212µs time.idle=12.3µs
^C

Curl's details:

$ curl -v https://meilisearch.home.lan/health
*   Trying 10.0.0.14:443...
* Connected to meilisearch.home.lan (10.0.0.14) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
*  CAfile: /etc/ssl/certs/ca-certificates.crt
*  CApath: /etc/ssl/certs
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.3 (IN), TLS handshake, Encrypted Extensions (8):
* TLSv1.3 (IN), TLS handshake, Certificate (11):
* TLSv1.3 (IN), TLS handshake, CERT verify (15):
* TLSv1.3 (IN), TLS handshake, Finished (20):
* TLSv1.3 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.3 (OUT), TLS handshake, Finished (20):
* SSL connection using TLSv1.3 / TLS_CHACHA20_POLY1305_SHA256
* ALPN, server accepted to use h2
* Server certificate:
*  subject: ...
*  start date: Jul  2 23:05:00 2025 GMT
*  expire date: Jul  2 23:05:00 2026 GMT
*  subjectAltName: host "meilisearch.home.lan" matched cert's "*.home.lan"
*  issuer: ...
*  SSL certificate verify ok.
* Using HTTP2, server supports multi-use
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* Using Stream ID: 1 (easy handle 0x562c28c78bd0)
> GET /health HTTP/2
> Host: meilisearch.home.lan
> user-agent: curl/7.74.0
> accept: */*
> 
* TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):
* Connection state changed (MAX_CONCURRENT_STREAMS == 250)!
...HERE IT HUNG WHILE IT WAITED FOR THE DOCKER CONTAINER TO SPIN UP...
< HTTP/2 500 
< content-length: 5
< date: Mon, 09 Mar 2026 18:58:12 GMT
< 
* Connection #0 to host meilisearch.home.lan left intact
Found

From Meilisearch's perspective, the request replied just fine. I see no HTTP 3XX redirect.

[bradbeattie]

Tried with a much simpler Docker image and confirmed this isn't a Meilisearch specific problem.

[bradbeattie]

In sablierapp/sablier-traefik-plugin@95eb328, I discover - We cannot use [allowEmptyServices](https://doc.traefik.io/traefik/providers/docker/#allowemptyservices) because if you use the [blocking strategy](LINKHERE) you will receive a 503. I suspect this is related to my use of traefik.docker.allownonrunning=true.

https://doc.traefik.io/traefik/reference/routing-configuration/other-providers/docker/ says

When this label is set to true, Traefik will ... Create services with empty backend server lists

My only followup question is then what is meant by "Middleware configuration must be centralized on the Sablier service to remain accessible when services are scaled to 0".

[bradbeattie]

I was able to interpret that and do the following:

$ cat ~/traefik/etc-traefik/files/meilisearch.yml 
http:
  routers:
    meilisearch-router:
      rule: "Host(`meilisearch.home.lan`)"
      entryPoints:
        - websecure
      service: meilisearch-service
      middlewares:
        - meilisearch-sablier
      tls: {}

  middlewares:
    meilisearch-sablier:
      plugin:
        sablier:
          endpoint: "http://sablier:10000"
          group: "meilisearch-group"
          blocking:
            timeout: "30s"

  services:
    meilisearch-service:
      loadBalancer:
        servers:
          - url: "http://meilisearch:7700"

which fixed it.