edge-agent

Edge Agent

This project contains the Edge Agent.

Application Settings.

The settings to run the Edge Agent may be configured through the appsettings.json file or environment variables.

appsettings.json

The application will read the appsettings.json for configuration. The format is:

{
  "DockerUri": "<docker service uri>",
  "DeviceConnectionString": "<Your IoT Hub Device Connection String>",
  "ConfigSource": "<twin|local>",
  "LocalConfigPath": "<Path to the custom configuration JSON file in 'local' mode>",
  "DockerLoggingDriver":  "<json-file|journald|fluentd|etwlogs|none>",
  "NetworkId": "<Docker network id>",
  "EdgeDeviceHostName": "<Edge device host name>"
}

Environment Variables

ALternatively, you may override the settings in appsettings.json by setting environment variables.

DockerUri

DeviceConnectionString

ConfigSource

LocalConfigPath

DockerLoggingDriver

NetworkId

EdgeDeviceHostName

DockerURI

This is the URI for the docker service. Typically this is "http://localhost:2375" on Windows and "unix:///var/run/docker.sock" on Linux.

DeviceConnectionString

Set to the IoT Hub connection string of the edge device. Needed when ConfigSource is "twin".

ConfigSource

May be set to "twin" or "local". When set to "twin", the edge device twin is used as a configuration source for modules. When set to "local", a file (config.json) is used as a configuration source for modules.

A custom configuration JSON file can be used by bind mounting a directory containing the custom configuration file into the edge agent container and specifying the path to the configuration file in the container using the LocalConfigPath environment variable.

DeviceConnectionString must be set to a device connection string if ConfigSource is set to "twin".

LocalConfigPath

Path to the custom configuration JSON file used as the configuration source in the "local" mode.

DockerLoggingDriver

All modules created by MMA will use this setting to assign a logging driver for the Docker container. See the Docker logger driver documentation for information on each log. Drivers "json-file" (the default logger), and "journald" will be used by MMA.

Our current repository is set up to use the "json-file" option when MMA is running in Windows, and to use "journald" when running on a Linux target.

Using "json-file"

The default option for the docker daemon is "json-file." The Docker service maintains one log per container. Logs are accessed through the docker logs command. Logs are only available for containers that have not been removed.

Using "journald"

The journald logging system is available for all Linux system which support the systemd init system.

On the host machine, get all docker logs by running: journalctl --unit=docker Or get logs per module by running: journalctl -a CONTAINER_NAME=<module-name>

Logs are not available through the docker logs command when using "journald."

Using other logging drivers

The following logging drivers have default options which should work when assigned: "fluentd", "etwlogs", and "none". No testing or validation was done on these logging drivers.

NetworkId

Set to the Docker network you want the modules in the Edge deployment to be a part of. If not provided, it will run under "azure-iot-edge" docker network, which uses docker bridge network drvier.

EdgeDeviceHostName

Set to the host name of the edge device, which will be used by the modules and downstream devices to connect to the EdgeHub.