Running in development mode:
$ python tbprocessd.py
Installing (on Raspberry Pi):
$ sudo python setup.py install
$ sudo cp tbprocessd.service /etc/init.d
This installs the binary tbprocessd and the utility scripts (tbopen and tbtail).
1. “tbprocessd runs the home screen”
------------------------------------------------
Λ
┌─────────────────┐ ╱ ╲
│ │ logs ╱ ╲
│ tbprocessd │──────────▶╳ UDP ╳
│ │ ╲ ╱
└─────────────────┘ ╲ ╱
│ ▲ V
│ │
│ │
starts │ │ logs (stdout, stderr)
│ │
│ │
▼ │
┌─────────────────┐
│ │
│ Home screen │
│ │
└─────────────────┘
On startup, tbprocessd starts the home screen, which is defined by the HOME_APP variable. This
is configured in the upstart.conf, the current value is /apps/home. If the home screen crashes,
tbprocessd will relaunch it.
2. “Home screen tells tbprocessd to open an app”
-------------------------------------------------
┌─────────────────┐
│ │
│ tbprocessd │
│ │
└─────────────────┘
▲
│
│ HTTP
└─────────────────────┐
│
│
│
┌─────────────────┐ │
│ │ ┌──────────┐
│ Home screen │─────▶│//tbopen//│
│ │ └──────────┘
└─────────────────┘
The home screen tells tbprocessd to start an app using the tbopen script. The command would be
something like $ tbopen /apps/weather.
3. “tbprocessd starts the new app”
-------------------------------------------------
Λ
┌─────────────────┐ ╱ ╲
│ │ logs ╱ ╲
│ tbprocessd │──────────▶╳ UDP ╳
│ │ ╲ ╱
└─────────────────┘ ╲ ╱
│ ▲ V
│ │
│ └──────────┐
starts │ │ logs (stdout, stderr)
└────────┐ │
│ │
\ / ▼ │
┌──────\───/──────┐ ┌─────────────────┐
│ \ / │ │ │
│ Home /creen │ │ Weather app │
│ / \ │ │ │
└──────/───\──────┘ └─────────────────┘
/ \
Home screen is killed and the new app is started. When tbprocessd is given a path to start, it will
try to launch /apps/weather, or if this is not a binary, it will try /apps/weather/main, and if
this does not exist, it will try python /apps/weather/main.py.
Logs from the new process can be accessed by running tbtail. This is going to be useful for Tide,
but might also be useful when testing the home screen.
When the weather app exits, Home Screen will be launched again.
If you want to run without installing you just need to set the HOME_APP variable to whatever you want tbprocessd to run by default. Example terminal session:
$ export HOME_APP=../tbhome
$ python tbprocessd.py &
$ ./tbtail
...
^C
$ ./tbopen ../example_app
$ ./tbtail
This will run the app at ../tbhome, reboot it if it crashes, and run the example_app, if this crashes or exits, return to the home screen.