Running Graylog behind Traefik - reverse-proxy

Question

I have been using Traefik as a reverse proxy for several containers managed through docker compose. It has been working well but I'm having some difficulty getting graylog running properly behind it.
This config (excerpt of the complete file, removed irrelevant services) works for me
version: '3'
services:
traefik:
image: traefik
command: --docker
networks:
- web
ports:
- "80:80"
- "8080:8080"
- "443:443"
volumes:
- /var/run/docker.sock:/var/run/docker.sock
graylog:
image: graylog/graylog:3.0
environment:
- GRAYLOG_PASSWORD_SECRET=somepasswordpepper
- GRAYLOG_ROOT_PASSWORD_SHA2=somestuffhere
- GRAYLOG_HTTP_BIND_ADDRESS=0.0.0.0:9000
- GRAYLOG_HTTP_EXTERNAL_URI=http://graylog.localhost/
links:
- mongodb:mongo
- elasticsearch
depends_on:
- mongodb
- elasticsearch
networks:
- web
- default
ports:
- 9000:9000
- 1514:1514
- 1514:1514/udp
- 12201:12201
- 12201:12201/udp
labels:
- "traefik.docker.network=web"
- "traefik.web.frontend.rule=Host:graylog.localhost"
- "traefik.protocol=http"
- "traefik.port=9000"
- "traefik.enable=true"
I can then access graylog in my browser at http://graylog.localhost/
The problem occurs because I can't use domains like this in my staging env. What I have had to use is paths rather than domains e.g. the swagger service in my staging env is defined as
swagger:
image: swaggerapi/swagger-ui
environment:
SWAGGER_JSON: /swagger/staging-openapi.yaml
BASE_URL: /swagger
volumes:
- /home/ubuntu/src/carelink_swagger_service:/swagger
networks:
- web
- default
labels:
- "traefik.docker.network=web"
- "traefik.frontend.rule=Host:my.staging.domain.org; PathPrefix: /swagger"
- "traefik.protocol=http"
- "traefik.port=8080"
- "traefik.enable=true"
and I access services like this https://my.staging.domain.org/swagger/
Trying to adopt this approach for graylog
graylog:
image: graylog/graylog:3.0
environment:
- GRAYLOG_PASSWORD_SECRET=somepasswordpepper
- GRAYLOG_ROOT_PASSWORD_SHA2=somestuffhere
- GRAYLOG_HTTP_BIND_ADDRESS=0.0.0.0:9000
- GRAYLOG_HTTP_EXTERNAL_URI=http://localhost/graylog/
links:
- mongodb:mongo
- elasticsearch
depends_on:
- mongodb
- elasticsearch
networks:
- web
- default
ports:
- 9000:9000
- 1514:1514
- 1514:1514/udp
- 12201:12201
- 12201:12201/udp
labels:
- "traefik.docker.network=web"
- "traefik.web.frontend.rule=Host:localhost; PathPrefix: /graylog"
- "traefik.protocol=http"
- "traefik.port=9000"
- "traefik.enable=true"
and I get the following errors
I have gone through this Q/A, similar entries on the graylog forums etc. but I feel like I'm chasing my tail.

Answer 1

It's for Traefik 2.x but I think that you'll manage to convert your rules:
labels:
- "traefik.http.routers.graylog.rule=PathPrefix(`/graylog`)"
- "traefik.http.routers.graylog.middlewares=graylog3#docker,graylog2#docker,graylog#docker"
- "traefik.http.middlewares.graylog3.stripprefix.prefixes=/graylog"
- "traefik.http.middlewares.graylog2.redirectregex.regex=^(.*)/graylog$$"
- "traefik.http.middlewares.graylog2.redirectregex.replacement=$$1/graylog/"
- "traefik.http.middlewares.graylog.replacepathregex.regex=^/graylog/(.*)"
- "traefik.http.middlewares.graylog.replacepathregex.replacement=^/$$1"
- "traefik.http.routers.graylog.service=graylog"
- "traefik.http.services.graylog.loadbalancer.server.port=9000"
- "traefik.docker.network=traefik"