Usage

The ServiceWrapper will resolve all necessary communications with the SystemManager to register your service, resolve dependencies, and inject OTA tuning states. You can access retrieved information and service.yaml configurations through your shell environment. This page highlights where all information is injected.

All injected environment variables injected, are prefixed with ASE_SW_ to avoid interference with an already present environment. The ServiceWrapper will not check if an environment variable is already present.

Static information

After successful registration and dependency resolution, the following environment variables will be injected

Key	Value
ASE_SW_ServiceName	The name of your service, as defined in your service.yaml file and as used to register your service
ASE_SW_ServicePID	The PID used to register your service

For every output defined in your service.yaml, the output name will be part of the key, and the ZMQ address will be the value, as defined below:

Key	Value
ASE_SW_Output_<OUTPUT_NAME>	The ZMQ address defined in the service.yaml for this output

For every tuning option, its value will be injected in the environment based on the parameter name. You can also fetch the type of this parameter to aid parsing the parameter, as defined below:

Key	Value
ASE_SW_TuningParameterValue_<PARAMETER_NAME>	The tuning parameter value at startup
ASE_SW_TuningParameterType_<PARAMETER_NAME>	The tuning parameter type (INT), FLOAT or STRING

Over the Air tuning disabled

The tuning parameter value might change due to a new broadcasted tuning state, but this will not update the environment variable during execution.

Dependency information

The ServiceWrapper will only start your binary or script when all dependencies are resolved. Then, for each dependency name and endpoint name combination it will inject the found ZMQ address, as defined below:

Key	Value
ASE_SW_Dependency_<SERVICE_NAME>_<ENDPOINT_NAME>	The resolved ZMQ address of this service and endpoint combination

Example

To illustrate the created environment variables, we will consider two services: ServiceA and ServiceB, with ServiceB depending on ServiceA. Their service.yaml files ere defined below, together with the created environment variables.

Service A

Configuration

service.yaml

# Service identifying information
name: serviceA
description: empty service

# Depends on no service
dependencies: []

# Outputs images on the "image" endpoint
outputs:
  - name: image
    address: tcp://localhost:4242

# Tuning options
options:
  # proportional gain for PID
  - name: mytuningparam
    type: float
    mutable: false
    default: 0.2 
  - name: cameraBrightness
    type: int
    mutable: false
    default: 200

Environment created by mod-ServiceWrapper

# identifying info
ASE_SW_ServiceName=serviceA
ASE_SW_ServicePID=1234

# outputs
ASE_SW_Output_image=tcp://localhost:4242

# tuning options
ASE_SW_TuningParameterValue_mytuningparam="0.2"
ASE_SW_TuningParameterType_mytuningparam=FLOAT
ASE_SW_TuningParameterValue_cameraBrightness=200
ASE_SW_TuningParameterType_cameraBrightness=INT

# dependencies (none)

Service B

Configuration

service.yaml

# Service identifying information
name: serviceB
description: empty service

# Depends on service A's "image" output
dependencies: 
  - service: serviceA
    output: image

# Exposes no outputs
outputs: []

# Tuning options
options:
  # proportional gain for PID
  - name: imagethreshold
    type: float
    mutable: false
    default: 0.8

Environment created by mod-ServiceWrapper

# identifying info
ASE_SW_ServiceName=serviceB
ASE_SW_ServicePID=5678

# outputs (none)

# tuning options
ASE_SW_TuningParameterValue_imageThreshold="0.8"
ASE_SW_TuningParameterType_imageThreshold=FLOAT

# dependencies
ASE_SW_Dependency_serviceA_image=tcp://localhost:4242