Use a Docker socket proxy

Put a dedicated socket proxy between Sablier and /var/run/docker.sock, so Sablier reaches only the Docker API endpoints it actually needs.

# compose.yml
services:
  socket-proxy:
    image: lscr.io/linuxserver/socket-proxy:latest
    environment:
      - CONTAINERS=1
      - EVENTS=1
      - VERSION=1
      - POST=1
      - AUTH=0
      - SECRETS=0
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock:ro
    networks:
      - socket-proxy

  sablier:
    image: sablierapp/sablier:1.15.0
    command:
      - start
      - --provider.name=docker
    environment:
      - DOCKER_HOST=tcp://socket-proxy:2375
    depends_on:
      - socket-proxy
    networks:
      - socket-proxy
      - public

  whoami:
    image: acouvreur/whoami:v1.10.2
    labels:
      - "sablier.enable=true"
      - "sablier.group=whoami"
    networks:
      - public

networks:
  socket-proxy:
    internal: true
  public:

Sablier reaches the Docker API only through the proxy. Requests to blocked endpoints (for example /images) receive an HTTP 403 Forbidden.

Mounting /var/run/docker.sock directly into the Sablier container grants it full, unrestricted root-level access to the Docker daemon. You can instead put a dedicated socket proxy between Sablier and the socket, allowing only the API endpoints Sablier actually needs. If Sablier were ever compromised, the blast radius is limited to that handful of endpoints.

When to use it

Use this to enforce least-privilege access to the Docker API instead of exposing the raw socket to Sablier.

How it works

Sablier talks to the proxy over TCP via DOCKER_HOST=tcp://socket-proxy:2375; only the proxy mounts the socket, on an internal network unreachable from outside the host. Sablier needs these endpoints:

Environment variable	Endpoint(s)	Why Sablier needs it
`CONTAINERS=1`	`GET /containers/*`	List and inspect managed containers
`EVENTS=1`	`GET /events`	Subscribe to the Docker event stream
`VERSION=1`	`GET /version`	Initial connection check on startup
`POST=1`	`POST /containers/*`	Start, stop, and wait for containers

POST=1 is required because Sablier calls POST /containers/{id}/wait after stopping a container, and the proxy has no ALLOW_WAIT flag to cover it: the ALLOW_START / ALLOW_STOP flags are not enough. The scope stays bounded by CONTAINERS=1, so all other resource groups (/images, /networks, /volumes, and others) remain blocked.

See the runnable example.