[Solved] How to stop Python oledExp writing to STDOUT/STDERR ?

peter garner 0

This is my second project using Python 2 oledExp and I'm having the same problem as before. When I SSH into the Onion2 and run my script I get this:

./clock.py 
> Setting display to ON
> Initializing display  
> Writing 'Wed 10 Jul 2019' to display
> Writing '08:03 +0100' to display
> Writing 'Local Time BST' to display

and the output also appears on the display, as planned. is there any way that I can stop the above appearing? I just need it to appear on the display. Here is what I've tried so far:

within the script:

old_stderr = sys.stderr
old_stdout = sys.stdout
sys.stderr = open(os.devnull, 'w')
sys.stdout = open(os.devnull, 'w')

and in crontab:

crontab -l
*/1 * * * * /root/clock.py >/dev/null 2>&1
#

and here's the top of the script with a write statement:

oledExp.setDisplayPower(1)
oledExp.driverInit()
oledExp.setBrightness(127)
oledExp.setTextColumns()
oledExp.setDisplayMode(0)
oledExp.setVerbosity(0)
oledExp.clear()
...
oledExp.setCursor(0,0)
oledExp.write("the time is now...")

crispyoz

@peter-garner-0 I think you need move oled.setVerbosity to the top of your code, it seems to default to debug verbosity so it is reporting all of your actions prior to you setting verbosity to Info level. The C library calls OnionPrint inside the OledExp code and this relies upon the verbosity setting.

I haven't tested this on Python but this is the case in C.

peter garner 0

Got it! Thanks for that. I actually had to do it in this order:

oledExp.setVerbosity(-1)
oledExp.driverInit()
oledExp.write("Hello World")

I wasn't expecting to have to set the verbosity before the init but there you go...

Actually, oledExp.setVerbosity() doesn't seem to be mentioned for the Python module, but it makes sense given it's C origins.

crispyoz

@peter-garner-0 the first line in the C code of oledDriverInit is:

onionPrint(ONION_SEVERITY_INFO, "> Initializing display\n");

So you need vernbosity set to < INFO before calling init.