taskd

A tasker-like daemon designed to execute things based on other things.

This is a pre-alpha hack and is full of sprintf and glorious potential buffer overruns.

High-level overview

taskd uses SQLite for storage of profiles, tasks, variables, and several internal states (balanced between disk and memory tables as appropriate).

Lua is used for execution and currently loads all default libs. Lua is modified to GET and SET variables into an in-memory SQLite table.

A simple plugin API is provided to GET/SET these variables, and to allow adding additional script functions in the future.

Like Tasker, the taskd execution engine is based around defining Profiles and Tasks.

Tasks

A task has a name, description, and a Lua script to be run. For example you might have a task called "Lights On" that contains the script:

os.execute("lights_on.py")

and a similar one for "Lights Off".

Profiles

Profiles define a context for when tasks should be run. A profile has several modes (defined in profiles.h):

• PROFILES_CONDITION_ALWAYS In this mode, the tick_task will run every "tick".

• PROFILES_CONDITION_CUSTOM In this mode, the script defined in the condition_custom column will be run every "tick". If the condition is met, the profile becomes ACTIVE and the enter_task is run. The tick_task is then run for each tick after this. Finally, when the condition is no longer true, the exit_task is run.

• PROFILES_CONDITION_VARIABLE_CHANGED In this mode, the tick_task is run when a variable is updated that matches the condition_custom column.

An example profile to turn off the lights when watching a movie might look like:

return MEDIA_ISPLAYING == "1"

The enter_task for this would be Lights Off, and the exit_task for this would be Lights On.

Plugins

p_core

The core plugin will provide some very basic variables for scripts to use. Currently this is some device info and date/time info. See p_core.c for more.

p_httpapi

The httpapi plugin provides a very basic web server using libmicrohttpd that outputs JSON along with a basic web UI (at http://127.0.0.1:8080/index.html). Currently the functionality is limited to:

http://127.0.0.1:8080/variables?key=VAR and http://127.0.0.1:8080/variables?key=VAR&value=new%20value

This will be extended to allow introspecting all data and manipulating profiles/tasks.

p_replicate

The replicate plugin listens to variable changes and if a TASKD_REPLICATE_HOST option is provided (e.g. http://remote:8080) all variable values will be replicated to this remote instance.

Useful to run a local taskd with special plugins and replicate these to a hub elsewhere for processing.

p_x11

Sets X11_IDLE to how many seconds the current display has been idle (using the XScreenSaver extension).

Installing

Clone this repo, make sure you have the following installed:

• lua5.1 (5.2 will NOT work currently)
• sqlite3
• libmicrohttpd if you want to build the httpapi
• libjansson (tested with 2.7) if you want to build the httpapi
• libcurl if you want to build p_replicate

Simply run make taskd, and make <plugin name> (for each plugin listed above). If need be modify run_taskd.sh and run chmod +x run_taskd.sh.

Finally if all goes well you should be able to ./run_taskd.sh.

Usage

There is a basic web UI available at http://127.0.0.1:8080/index.html by default. Some functionality is still missing so use of the sqlite3 command line may be useful.