queue file read/write problem

[klaus-hildner]

Very useful and well maintainable code - thank you for sharing. - I have made amendments and run this as a system service and redirect stdout (>) and stderr (2>) to /mnt/ram (a ramdisk in a RasPi to further reduce flash wear) and caught the following error after about an hour of runtime - issue 1:

Traceback (most recent call last):
  File "sds-reader.py", line 229, in <module>
    loop(USBPORT)
  File "sds-reader.py", line 223, in loop
    uploader.postValues(reader.read(60))
  File "sds-reader.py", line 191, in postValues
    self.file_put_contents(filePath2,pickle.dumps(values))
  File "sds-reader.py", line 162, in file_put_contents
    with open(filename,'w') as f:
IOError: [Errno 13] Permission denied: 'pending.30c1.2017-09-01-14-25-09.pickle'

Issue 2: During an http 200 OK posting I get this message that I do not really understand (I have however increased the POST payload):

Posting 33680 bytes -> 200 OK
http-post: error. <type 'exceptions.ValueError'>
upload not ok... there are now 58 entries pending (/mnt/ram/30c1.pickle).

For sensor type SDS011, I had do divide the PM10 and PM2.5 values by 10.

On smartgart.com/pm10, I have started to aggregate the measurements with Yahoo JSON weather data to include weather condition (like rain), wind direction, wind speed, atmospheric pressure for the purpose of monitoring pollution from a nearby waste incineration plant, and in the future perhaps to try to correlate the values (like: if ... more incoming wind, less rain, higher atmospheric pressure ... then ... more PM10 dust).