File format

VILLASnode currently supports two config file formats:

JSON (recommended)
libconfig

Note: Consider using the villas conf2json command to migrate your old configurations to JSON.

Structure

At the top level, the configuration file consists of these sections:

Examples

VILLASnode comes with a lot of existing configurations which can be used for inspiration: https://git.rwth-aachen.de/acs/public/villas/node/-/tree/master/etc

# Global configuration settings go here
stats = 2
# Webserver / API config
http = {
        port = 8081
}
# Logging
logging = {
        level = "debug
}
# Node definitions
nodes = {
        test_node = {
                in = {
                        signals = {
                                count = 12
                                type = "float"
                        }
                }
        }
}
# Path Mapping
paths = (
        {
                in = "test_node",
                out = "test_node"
        }
)

Tips & Tricks

Use environment variables in your configuration

VILLASnode substitutes any environment variables in you JSON and libconfig configuration files.

To replace environment variables you must use the following syntax within any string value of your config: ${MYENV_VAR}.

Note: Non-string values can currently not be subsituted by environment variables!

Example

nodes = {
        file_node = {
                uri = "${FILE_PATH}"
        }
}

Include other files into your configuration

VILLASnode can include other files into you configuration. This allows you to better structure and reuse parts of your configuration (e.g. the node definitions).

File inclusion is handled via a special key in JSON objects named @include. The value of this key must point to an existing file on your file system.

Note: libconfig supports inclusion of other files out of the box via directives. So this tip is mostly useful for JSON configuration files.

Example

`params.json`

{
  "gain": 1.45,
  "t_dt": 50e-6
}

`nodes.json`

{
  "test_node": {
    "type": "file",
    "in": {
      "signals": {
        "count": 12,
        "type": "float"
      }
    }
  },
  "signal_node": {
    "signal": "random",
    "in": {
      "hooks": [
        {
          "type": "lua",
          "script": "myscript.lua",
          "@include": "params.json"
        }
      ]
    }
  }
}

`experiment1.json`

{
  "nodes":{
    "@include": "nodes.json"
  },
  "paths": [
    {
      "in": "signal_node",
      "out": "test_node"
        }
  ]
}