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unable to access webrepl when main script is running
Posted: Fri Oct 30, 2020 4:30 pm
by MrRobot
So I have a data logger running in a infinite loop with a few sensors attached to my Pyboard D.
I want to be able to access the repl using webrepl.
I'm only able to access webrepl when no code is being executed. webrepl won't let me log in if code is running.
Due to the nature of my application I can't stop the infinite loop remotely, as the device is in a waterproof case.
I can see in this thread that someone uses a callback timer :
viewtopic.php?f=2&t=7416&p=42743&hilit=webrepl#p42743
But I'm unsure how to implement it for my project.
Essentially my code is this :
Code: Select all
While True:
sampleInstruments()
sendData()
So is there anywhere I can put a callback or give me a chance to log in to webrepl?
Any help would be greatly appreciated
Re: unable to access webrepl when main script is running
Posted: Sat Oct 31, 2020 1:29 am
by MostlyHarmless
It appears that such a busy loop will block all the polling background services, like uftpd, utelnetserver and webrepl. Inserting a small sleep_ms into it will give them time to react:
Code: Select all
import utime
while True:
utime.sleep_ms(20)
That said I haven't found a way to deliver a KeyboardInterrupt (^C) when using the in-browser terminal (term.js). It just disconnects with the main program still running. I don't have that problem with telnet and utelnetserver.
Regards, Jan
Re: unable to access webrepl when main script is running
Posted: Thu Nov 05, 2020 4:33 pm
by MrRobot
Hi I've tried putting in a small sleep in every loop.
But until I kill the main process running I can't access the webrepl.
I can only enter a password, it won't accept it
Please help me if you can
Re: unable to access webrepl when main script is running
Posted: Thu Nov 05, 2020 6:46 pm
by davef
On a ESP32 I have also had inconsistent access. At one stage I thought I was corrupting the filesystem when I accessed WebREPL at random times so I tried this in the main processing block:
Code: Select all
# stop the program here
for x in range(10):
seconds_left = 10 - x
print('you have ' + str(seconds_left) + ' seconds left to hit Ctrl C to stop the program')
utime.sleep(1)
print('times-up!!')
It "seemed" better.
Then trying to track down random resets I removed:
Code: Select all
nic=network.WLAN(network.AP_IF)
nic.active(1)
as suggested elsewhere before running my datalog program. I think that has crippled access through WebREPL, but until I sort out my main problem I'll keep using rshell via USB. I couldn't find a definitive statement on the pre-conditions for WebREPL.
Good luck!
Re: unable to access webrepl when main script is running
Posted: Thu Nov 05, 2020 7:04 pm
by MostlyHarmless
MrRobot wrote: ↑Thu Nov 05, 2020 4:33 pm
Hi I've tried putting in a small sleep in every loop.
But until I kill the main process running I can't access the webrepl.
I can only enter a password, it won't accept it
Please help me if you can
Have you actually tried it with a 20ms sleep?
Jan
Re: unable to access webrepl when main script is running
Posted: Fri Nov 06, 2020 8:31 am
by Roberthh
When main code is running with some sleep statements in it, I can access the device though webrepl. Obviously I get not REPL prompt, since the main code is running. But at least the same output (if any) as the one one USB.
Re: unable to access webrepl when main script is running
Posted: Fri Nov 06, 2020 9:24 am
by MrRobot
I've found a way to access the webrepl using a timer callback like this:
Code: Select all
timer = Timer(-1)
timer.init(period=1, mode=Timer.ONE_SHOT, callback=preSleep)
for countdown in range(20,0,-1):
print('Sleeping in ',countdown)
time.sleep(1)
machine.deepsleep(sleepTime)
and my callback function is just this:
Code: Select all
def preSleep(timer):
print('Giving a user a chance to connect')
input()
So essentially the user has 20 seconds to connect before the system sleeps.
It's not exactly elegant but it does allow me to login to the webrepl.
But unfortunately I can't stop the main thread running.
Can anyone think of a way of doing this?
I tried putting a machine.soft_reset() after the input() but nothing works so far
Re: unable to access webrepl when main script is running
Posted: Fri Nov 06, 2020 10:59 am
by MrRobot
So putting an input() statement works but hangs the entire device.
So it's not a real solution to the problem.
My project is a data logger that is located in a Marine environment,
so having the pyboard D accessible by Wi-Fi would be hugely beneficial.
Otherwise to access the device I need to open the case (which is risky when you're on a boat)
Re: unable to access webrepl when main script is running
Posted: Fri Nov 06, 2020 5:52 pm
by davef
Some more input after spending a day trying to get my datalogger working on ESP32 and a ESP8266 platforms. Access doesn't seem to be a problem for me so I describe my infinite loop timings.
The main loop runs about once every 500-600ms flashing a heartbeat LED. Then every minute goes to a process loop that has one 750ms delay to read 1-wire sensors and another 750ms delay so that I only get one loop execution for that minute.
I don't have any problems issuing a Ctrl C in WebREPL, updating files and doing a Ctrl D to get it running again. As mentioned before I try to do that during a 10 second pause in the "process loop", as I didn't want to do a Ctrl C during file reads and writes (paranoid).
Do you have some specific program execution timings?
Re: unable to access webrepl when main script is running
Posted: Sat Nov 07, 2020 12:40 am
by MostlyHarmless
750ms to read sensors sounds like a lot. Can you give more details on that?
Jan