Allow specifying a command for determining a docker host port

Author: natefoo

lib/galaxy/config/sample/job_conf.sample.yml

@@ -503,6 +503,11 @@ execution:
       # Following command can be used to tweak docker command.
       #docker_cmd: /usr/local/custom_docker/docker
 
+      # Docker containers that expose ports (e.g. Interactive Tools) can
+      # optionally use a command to determine the host port that is exposed. By
+      # default, one is chosen at random (docker run -p <guest_port> ...).
+      #docker_host_port_cmd:
+
       # Following can be used to connect to docker server in different
       # ways (translated as -H argument to docker client).
       #docker_host: unix:///var/run/docker.sock

lib/galaxy/tool_util/deps/container_classes.py

@@ -481,6 +481,7 @@ def containerize_command(self, command: str) -> str:
             set_user=self.prop("set_user", docker_util.DEFAULT_SET_USER),
             run_extra_arguments=self.prop("run_extra_arguments", docker_util.DEFAULT_RUN_EXTRA_ARGUMENTS),
             guest_ports=self.tool_info.guest_ports,
+            host_port_cmd=self.prop("host_port_cmd", None),
             container_name=self.container_name,
             **docker_host_props,
         )

lib/galaxy/tool_util/deps/docker_util.py

@@ -111,6 +111,7 @@ def build_docker_run_command(
     set_user: Optional[str] = DEFAULT_SET_USER,
     host: Optional[str] = DEFAULT_HOST,
     guest_ports: Union[bool, str, List[str]] = False,
+    host_port_cmd: Optional[str] = None,
     container_name: Optional[str] = None,
 ) -> str:
     env_directives = env_directives or []
@@ -129,10 +130,14 @@ def build_docker_run_command(
         # When is True, expose all ports
         command_parts.append("-P")
     elif guest_ports:
+        if host_port_cmd:
+            host_port_cmd = f"$({host_port_cmd}):"
+        else:
+            host_port_cmd = ""
         if not isinstance(guest_ports, list):
             guest_ports = [guest_ports]
         for guest_port in guest_ports:
-            command_parts.extend(["-p", guest_port])
+            command_parts.extend(["-p", f"{host_port_cmd}{guest_port}"])
     if container_name:
         command_parts.extend(["--name", container_name])
     for volume in volumes: