# Configuration Configuration defines all in **Signal composer** each signals and sources has to be defined in it. At start, configuration will be searched in default binding configuration directory which should be _/var/local/lib/afm/applications/signal-composer/VER/etc/_, VER is the version of **signal composer**. Binding search for a file name as _init-daemon*.json_. Others files could be used to split sections and don't have 1 big fat definitions file. Saying that you have 4 sections to define: - **metadata**: Main parts and the only one that can't be in a separates configuration. This must appears in the main configuration file. - **plugins** (optional): Declare plugins that will be used by *sources* and *signals* for the subscription and composition. - **sources**: Declare **low level** signals sources (eg. low-can, gps, mraa, ...). - **signals**: Declare signals, virtuals and raw. ## Metadata Here we define some metadata about **signal composer** binding. Fields to configure are : - **uid**: self-explanatory - **version** (optional): self-explanatory - **api** (optional): name that the binding will be initialized to and later be accessible by **Application Framework** - **info** (optional): self-explanatory - **require** (optional): list of required external apis. ## Plugins This section is the only which is optional, it is needed if you develop specifics C/C++ plugins to be used with signal-composer. LUA and API consumption does not need plugins. Default path to search for a plugin is in the binding library directory in a subdirectory _plugins_ _/var/local/lib/afm/applications/signal-composer/VER/lib/plugins_. Else you could use the environment variable _CONTROL_PLUGIN_PATH_ with a semicolon separated list of directory. Fields are: - **uid**: Define the plugin name. This is that label that will be used on **sources** and **signals** callbacks. - **ldpath** (optional): path to the plugin directory - **info** (optional): self-explanatory - **basename**: shared library file name **without** the extension. - **files** (optional): list of additionnals files. **ONLY NAME** or part of it, without extension. Don't mix up section object with this key, either one or the other but avoid using both ## Sources A source is a **low level** API that will be consume by the **signal composer** to be able to expose those signals with additionnals treatments, filtering, thinning,... and create new virtuals signals composed with basic raw signals. A source is defined with following fields: - **uid**: An unique identifier name for thatuid source API. - **api**: Name of the source API. - **info** (optional): self-explanatory - **init** (optional): an **action** to take to initialize a source. May you have to call a verb from that API, of create a files etc. - **getSignals** (optional); an **action** to take to get signals from that source. These callback will be used for each signals defined later in the **signals** section. Dedicated arguments for each signal could be defined in **signals**. - **files** (optional): list of additionnals files. **ONLY NAME** or part of it, without extension. Don't mix up section object with this key, either one or the other but avoid using both ## Signals A signal definition could be either a **raw** one or a **virtual** one. A **virtual signal** is a set of existing **raw signals** associated to an **action** on reception which will compute the value of the signal. - **uid**: Unique identifier used inside **signal composer**, used to compose virtual signals. - **event**: specify a **raw signal** coming from **low level** sources. Couldn't be used with **depends** field, only one of them is possible. - **depends**: specify others signals **id** that compose it (eg: heading is composed with longitude+latitude signals.). Couldn't be used with **event** field at same time. - **retention** (optional): retention duration in seconds - **unit** (optional): Unit used to exprime the signal - **frequency** (optional): Frequency maximum at which the signal could be requested or sent. This is a thinning made at **high level** so not best suited for performance. Used **low level** native filtering capabilities when possible. - **getSignalsArgs**: a JSON object used at subscription time. Meant to enabled filtering capabilities at subscription and to be able to customize in general a subcription request by signal if needed. - **onReceived**: an **action** to take when this signal is received! - **files** (optional): list of additionnals files. **ONLY NAME** or part of it, without extension. Don't mix up section object with this key, either one or the other but avoid using both