fix: use a docker container to check for open tcp port

This will allow to dockerize compose in the future and makes
it more portable. Indeed, the containers are not always reachable
from the host.

bin/compose

@@ -695,19 +695,26 @@ wait_docker_ip() {
 }
 export -f wait_docker_ip
 
-
+DEFAULT_BASH_IMAGE=${DEFAULT_BASH_IMAGE:-docker.0k.io/bash}
 wait_for_tcp_port() {
-    local host_port=$1 timeout=30 start=$SECONDS
+    local network=$1 host_port=$2 timeout=20
     verb "Trying to connect to $host_port"
+    docker run --rm -i --network "$network" "$DEFAULT_BASH_IMAGE" <<EOF
+    start=\$SECONDS
     while true; do
         timeout 1 bash -c "</dev/tcp/${host_port/://}" >/dev/null 2>&1 && break
         sleep 0.2
-        if [ "$((SECONDS - start))" -gt "$timeout" ]; then
-            err "${RED}timeout error${NORMAL}(${timeout}s):"\
-                "Could not connect to $host_port."
-            return 1
+        if [ "\$((SECONDS - start))" -gt "$timeout" ]; then
+            exit 1
         fi
     done
+    exit 0
+EOF
+    if [ "$?" == 1 ]; then
+        err "${RED}timeout error${NORMAL}(${timeout}s):"\
+            "Could not connect to $host_port."
+        return 1
+    fi
     return 0
 }
 export -f wait_for_tcp_port
@@ -726,7 +733,7 @@ wait_for_docker_ip() {
     while read-0 port; do
         IFS="/" read port type <<<"$port"
         [ "$type" == "tcp" ] || continue
-        wait_for_tcp_port "$DOCKER_IP:${port}" || return 17
+        wait_for_tcp_port "$DOCKER_NETWORK" "$DOCKER_IP:${port}" || return 17
         verb "Port $DOCKER_IP:${port} checked open."
     done < <(image_exposed_ports_0 "$container_id")