langchain/cli/main.py/PlusCommand/_start_and_expose
class PlusCommand:    def _start_and_expose(self, auth_token: Optional[str]) -> None:
        with create_ngrok_config(auth_token=auth_token):
            command = [
                *self.docker_compose_command,
                "-f",
                str(self.docker_compose_file),
                "-f",
                str(self.ngrok_path),
            ]
            subprocess.run(
                [
                    *command,
                    "up",
                    "--pull=always",
                    "--quiet-pull",
                    "--wait",
                ]
            )
        logger.info(
            "ngrok is running. You can view the dashboard at http://0.0.0.0:4040"
        )
        ngrok_url = get_ngrok_url(auth_token)
        logger.info(
            "langchain plus server is running at http://localhost."
            " To connect remotely, set the following environment"
            " variable when running your LangChain application."
        )
        logger.info("\tLANGCHAIN_TRACING_V2=true")
        logger.info(f"\tLANGCHAIN_ENDPOINT={ngrok_url}")
        self._open_browser("http://0.0.0.0:4040")
        self._open_browser("http://localhost")