Eliona App for OpenBOS

The OpenBOS app is used to access OpenBOS.

Configuration

The app needs environment variables and database tables for configuration. To edit the database tables the app provides an own API access.

Registration in Eliona

To start and initialize an app in an Eliona environment, the app has to be registered in Eliona. For this, entries in database tables public.eliona_app and public.eliona_store are necessary.

This initialization can be handled by the reset.sql script.

Environment variables

• CONNECTION_STRING: configures the Eliona database. Otherwise, the app can't be initialized and started (e.g. postgres://user:pass@localhost:5432/iot).

• INIT_CONNECTION_STRING: configures the Eliona database for app initialization like creating schema and tables (e.g. postgres://user:pass@localhost:5432/iot). Default is content of CONNECTION_STRING.

• API_ENDPOINT: configures the endpoint to access the Eliona API v2. Otherwise, the app can't be initialized and started. (e.g. http://api-v2:3000/v2)

• API_TOKEN: defines the secret to authenticate the app and access the Eliona API.

• API_SERVER_PORT(optional): define the port the API server listens. The default value is Port 3000.

• LOG_LEVEL(optional): defines the minimum level that should be logged. The default level is info.

References

App API

The app provides its own API to access configuration data and other functions. The full description of the API is defined in the openapi.yaml OpenAPI definition file.

• API Reference shows details of the API

Generation: to generate api server stub see Generation section below.

Eliona assets

This app creates Eliona asset types and attribute sets during initialization.

The data is written for each device, structured into different subtypes of Eliona assets. The following subtypes are defined:

• Info: Static data which provides information about a device like address and firmware info.
• Status: Device status information, like battery level.
• Input: Current values reported by sensors.
• Output: Values that are to be passed back to the provider.

Continuous asset creation

Assets for all devices connected to the OpenBOS edge are created automatically when the configuration is added.

To select which assets to create, a filter could be specified in config. The schema of the filter is defined in the openapi.yaml file.

Possible filter parameters are defined in the structs in broker.go and marked with eliona:"attribute_name,filterable" field tag.

To avoid conflicts, the Global Asset Identifier is a manufacturer's ID prefixed with asset type name as a namespace.

Tools

Generate API server stub

For the API server the OpenAPI Generator for go-server is used to generate a server stub. The easiest way to generate the server files is to use one of the predefined generation script which use the OpenAPI Generator Docker image.

.\generate-api-server.cmd # Windows
./generate-api-server.sh # Linux

Generate Database access

For the database access SQLBoiler is used. The easiest way to generate the database files is to use one of the predefined generation script which use the SQLBoiler implementation.

.\generate-db.cmd # Windows
./generate-db.sh # Linux

Generate asset type descriptions

For generating asset type descriptions from field-tag-annotated structs, asset-from-struct tool can be used.