Behaviour when no ESP device connected using esptool as a module (ESPTOOL-980)

[mbastida123]

Operating System

Debian GNU/Linux 12 (bookworm)

Esptool Version

esptool==4.8.1

Python Version

Python 3.11.2

Full Esptool Command Line that Was Run

No response

Esptool Output

I'm making a script on python to program some ESP devices via a GUI.

The line:

    esp= esptool.get_default_connected_device(serial_list=['/dev/ttyUSB1'], 
                                                                port=None, 
                                                                connect_attempts=1, 
                                                                initial_baud=921600)

Correctly returns an instance if the ESP device is connected.

However, if there is no ESP device attached to the ESP-PROG the function timeouts and raises FatalError.

This is totally expected behaviour.

The problem is that when this happens the serial port is not correctly closed and so if get_default_connected_device() is placed inside a loop the following calls to said function will never work. Even if you connect an ESP device.
/dev/ttyUSB1 failed to connect: Could not open /dev/ttyUSB1, the port is busy or doesn't exist.

I have tried numerous ways to manually close the port. But the serial instance is not available to me.

Is this an issue or am I doing something wrong?

[Dzarda7]

Hi @mbastida123, the esptool as python package can be used with context manager. We recently added the section into the documentation, so you can take a look here. It should ensure that port is properly closed afterwards. Hope it helps.