private TransportConfig resolveTransportConfig() throws InvalidConfigurationException {
        boolean installed = DockerMachineClient.instance().isInstalled();
        Preconditions.checkArgument(
            installed,
            "docker-machine executable was not found on PATH (" + Arrays.toString(CommandLine.getSystemPath()) + ")"
        );

        Optional<String> machineNameOptional = DockerMachineClient.instance().getDefaultMachine();
        Preconditions.checkArgument(
            machineNameOptional.isPresent(),
            "docker-machine is installed but no default machine could be found"
        );
        String machineName = machineNameOptional.get();

        log.info("Found docker-machine, and will use machine named {}", machineName);

        DockerMachineClient.instance().ensureMachineRunning(machineName);

        String dockerDaemonUrl = DockerMachineClient.instance().getDockerDaemonUrl(machineName);

        log.info("Docker daemon URL for docker machine {} is {}", machineName, dockerDaemonUrl);

        return TransportConfig
            .builder()
            .dockerHost(URI.create(dockerDaemonUrl))
            .sslConfig(
                new LocalDirectorySSLConfig(
                    Paths.get(System.getProperty("user.home") + "/.docker/machine/certs/").toString()
                )
            )
            .build();
    }
Use Docker machine (if available on the PATH) to locate a Docker environment.

@deprecated this class is used by the SPI and should not be used directly
core/src/main/java/org/testcontainers/dockerclient/DockerMachineClientProviderStrategy.java