Odd issue, some in-container apps are seeing different file contents on a ro mounted volume.
Volume is a windows folder mounted to the containers as read only (via docker-compose volume directive )
after file update in windows, cat, wc, flask, celery and others see a truncated file with old file contents while less, vi, head and tail see the correct file.
truncated file with old contents means after the change, the file size changed but the contents are the same, so deleting three lines of fifty bytes each in the middle will result in cat/wc/flask/python reading the original file minus 150 bytes from the end.
This is happening on two containers simultaneously.
# wc -l myapp/app.py
# cat myapp/app.py | wc -l
# tail -n 10000 myapp/app.py | wc -l
# diff <(cat myapp/app.py) myapp/app.py
# diff <(cat myapp/app.py) <(tail -n 1000 myapp/app.py)
Files /dev/fd/63 and /dev/fd/62 differ