Pywaggle

Added context manager support to Plugin. Users are now encourage to move to the following safer alternative to `plugin.init`:

python
from waggle.plugin import Plugin

with Plugin() as plugin:
do cool stuff here!

* Camera now support file:// URLs allowing local files to be provided in the same way as other URLs / names. For example:

python
for deployment
with Camera("left") as camera:
do work

for testing
with Camera("file://path/to/test.jpg") as camera:
do work


This also allows device input to be specified more uniformly when using args. For example:

sh
pass camera on node
python3 main.py --input left

pass local file
python3 main.py --input file://path/to/test.jpg

This release allows you to manage Camera in your own context . You can now safely do:


with Camera(device) as camera:
frame1 = camera.snapshot()
frame2 = camera.snapshot()
... do something cool with frames ...


This change also fixes the behavior of snapshot returning the same frame when passing Camera a video file.

To maintain resource safety by default, we still support:


camera = Camera(device)

will safely open / close camera
frame1 = camera.snapshot()

will safely open / close camera
frame2 = camera.snapshot()

... do something cool with frames ...


Breaking change: We have dropped the dropframes flag to snapshot. We recommend using the new context approach and manually taking a few snapshots, if needed.

Bug fix: Non-serializable data types were able to throw exceptions silently in the background thread.