sbx/docker-tcp:latest

schemaVersion: "3"
displayName: Docker over TCP
description: Serve the sandbox's Docker Engine on TCP port 2375 and publish it on the host's loopback, so a Docker client on the host can run containers inside the sandbox.
version: 0.1.0
kind: mixin
provides:
    - docker-tcp
requires:
    - deb/curl
    - deb/docker-ce
    - deb/jq
    - deb/procps
capabilities:
    - type: com.docker.sandbox/port@1
      config:
        container: 2375
        name: docker-api
    - type: com.docker.sandbox/lifecycle@1
      config:
        startup:
            - command: |
                set -eu
                cfg=/etc/docker/daemon.json
                tcp=tcp://0.0.0.0:2375
                probe() { curl -sf --max-time 2 http://127.0.0.1:2375/_ping >/dev/null 2>&1; }

                command -v dockerd >/dev/null || { echo "docker-tcp: dockerd is not installed in this sandbox" >&2; exit 1; }

                mkdir -p /etc/docker
                [ -s "$cfg" ] || echo '{}' > "$cfg"
                jq --arg tcp "$tcp" '.hosts = (((.hosts // []) + ["unix:///var/run/docker.sock", $tcp]) | unique)' "$cfg" > "$cfg.tmp"
                if [ "$(cat "$cfg")" = "$(cat "$cfg.tmp")" ]; then rm -f "$cfg.tmp"; else mv "$cfg.tmp" "$cfg"; fi

                probe && exit 0

                if pkill -x dockerd; then
                  n=0
                  while pgrep -x dockerd >/dev/null; do
                    n=$((n + 1))
                    [ "$n" -lt 150 ] || { echo "docker-tcp: dockerd did not stop" >&2; exit 1; }
                    sleep 0.2
                  done
                fi
                nohup sh -c 'echo $$ > /var/run/sandboxes-dockerd.pid; exec dockerd >> /var/log/dockerd.log 2>&1' </dev/null >/dev/null 2>&1 &

                n=0
                until probe; do
                  n=$((n + 1))
                  if [ "$n" -ge 60 ]; then
                    echo "docker-tcp: dockerd did not come up on $tcp" >&2
                    tail -n 30 /var/log/dockerd.log >&2
                    exit 1
                  fi
                  sleep 0.5
                done
              description: Make dockerd listen on tcp://0.0.0.0:2375 as well as the unix socket.
              user: root