Traefik docker 配置基于路径的路由并重写

Question

2-day-old newbie to traefik, needing help with what istm is a basic first docker provider config in traefik v2...

I've tried searching through the docs, but just can't figure out how to do what I'm after.

I'd like to have docker containers like

• app1
• app2
• app3

And have these accessed through traefik via the urls

• http://app.mydomain.com/app1
• http://app.mydomain.com/app2
• http://app.mydomain.com/app3

However the apps themselves don't like these extra paths, so I'd like strip the prefix from the access paths so the apps don't see them.

If I access http://app.mydomain.com/app2/foo I'd like container app2 to get the request http://{container.ip.addr}}/foo

As a repro, the config I do know partially works is having the following in my traefik docker-compose.yml :

version: "3"
services:
  traefik:
    image: "traefik:v2.5.4"
    command:
      - --entrypoints.web.address=:80
      - --providers.docker=true
      - --api
      - --api.insecure=true
      - --api.dashboard=true
      - --providers.file.directory=/etc/traefik/dynamic
      - --providers.docker.defaultRule=Host(`app.mydomain.com`) && PathPrefix(`/{{ index .Labels "com.docker.compose.service" }}`)
    ports:
      - "80:80"
      - "8080:8080"
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock:ro"

  app1:
    image: containous/whoami:v1.3.0
  app2:
    image: containous/whoami:v1.3.0
  app3:
    image: containous/whoami:v1.3.0

Having added 127.0.0.1 app.mydomain.com to \etc\hosts , doing a curl to http://app.mydomain.com/app{1,2,3}/foo this routes to the correct service, but the request path they receive is /app1/foo , /app2/foo , /app3/foo whereas I'd like them all to get /foo .

I feel like I'd like to be able to add the following to the command line params in the docker-compose:

--providers.docker.middleware.default-stripprefix.stripprefix.prefixes=`/{{ index .Labels "com.docker.compose.service" }}`

but it doesnt work (error: command traefik error: failed to decode configuration from flags: field not found, node: middleware )

I can't find any docs that indicate what the correct commandline param(s) might be.

I'm thinking it might need to be in a dynamic config file (I've seen that too messing with tls config, but want to keep all that out of the repro at this stage.) but again can't seem to find what the correct config would be for a default middleware.

I can find lots of refs (and get it working) where I have to specify it in labels on each container, but I'd prefer just to default this out with one-time entries in the traefik config itself.

I've been bashing my head against this for 2 days now. I've tried searching the docs site, this community and the googleverse but without luck. It seems like such a "101" config to me: :-)

Please would someone help me not only solve my issue but optionally teach me how I could have found the solution myself in the docs site. I've seen plenty of mentions of the doc site being good, but they seem quite sparse to me for v2.

Answer 1

Ok, so I'll post the answer I went with in case anyone finds this and wants to know.

The middleware needs to be defined in a Traefik dynamic config file.

This can then be referred to in the endpoint specification in the static configuration file.

Once I needed a separate file for dynamic config, I decided to also use a file for the static config rather than command line args.

So the 3-file solution is:

docker-compose.yml

version: "3"
services:
  traefik:
    image: "traefik:v2.5.4"
    ports:
      - "80:80"
      - "8080:8080"
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock:ro"
      - "{path}/traefik.yml:/etc/traefik/traefik.yml:ro"
      - "{path}/dynamic.yml:/etc/traefik/dynamic.yml:ro"

  app1:
    image: containous/whoami:v1.3.0
  app2:
    image: containous/whoami:v1.3.0
  app3:
    image: containous/whoami:v1.3.0

traefik.yml

api:
  insecure: true
  dashboard: true
providers:
  docker:
    defaultRule: "Host(`app.mydomain.com`) && PathPrefix(`/{{ index .Labels \"com.docker.compose.service\" }}`)"
  file:
    filename: "/etc/traefik/dynamic.yml"
entrypoints:
  web:
    address: ":80"
    http:
      middlewares:
        - root-stripprefix@file

dynamic.yml

http:
  middlewares:
    root-stripprefix:
      stripPrefixRegex:
        regex:
          - "/[^/]+"

The dynamic configuration specifies a StripPrefix middleware - I've actually used StripPrefixRegex to grab whatever is in the first part of the path without having to specify it.

This middleware is then associated with the web endpoint so it applies to everything using it.

This solves the issue fairly simply but it was quite a journey of understanding the Traefik docs and config system before being able to get there. I've written up the journey in more detail in this post should more detail be wanted.

An extra note on real-world inter-container connectivity...

Also note that in a more real-world example with separate docker-compose files, it's necessary to allow the traefik and app containers to communicate by connecting to the same network by appending details to each docker-compose file such as:

service:
  app1:
...
    networks:
      - proxy
networks:
  proxy:
    external: true
    name: proxy

After first creating the network with the one-time command docker network create proxy .

Again I've written the thinking on this up in more detail - see this post .

Hope this helps someone save at least some of the days I've spent on this.