Linux daemon

The Fundamentum Edge daemon is the ready-made way to connect a Linux device to Fundamentum, instead of writing your own MQTT client. It handles provisioning, keys, the MQTTS connection, heartbeats and reboots, and exposes everything else to your application over a local gRPC interface. This page shows you how to install it, provision the device and call its services.

Before you begin

• A Linux device with a Rust toolchain (1.88 or later), protoc, and the OpenSSL development libraries.
• The registry token file and the asset_type_id for your device. See Self-provisioning.
• grpcurl to try the gRPC calls from a shell.

1. Install the daemon

The daemon is published on crates.io as fundamentum-edge-daemon (Apache-2.0):

cargo install fundamentum-edge-daemon

This installs the fundamentum-edge binary.

On a Yocto Linux built with the meta-fundamentum layer, the daemon is already included and listens on the Unix socket /run/fundamentum-edge/grpc.socket.

2. Start the daemon

fundamentum-edge --config /etc/fundamentum-edge/config.toml --state-dir /var/lib/fundamentum-edge

Without options, the daemon uses ./config.toml (created with default values if it doesn't exist), stores its state in the current directory, and serves gRPC on 127.0.0.1:8080. Run it under your init system (for example, a systemd service) so it starts at boot.

Run fundamentum-edge --help for the full list. After an upgrade, fundamentum-edge update-config adds any new fields to your configuration file.

3. Configure it

The main settings in config.toml, with their defaults:

For example, to serve gRPC on a Unix socket:

[grpc.server]
socket = { uds = "/run/fundamentum-edge/grpc.socket" }

4. Provision the device

Until the device is provisioned, Provisioning.Provision is the only gRPC call that works. Use the values from the token file:

grpcurl -plaintext -d '{
    "api_base_url": "https://devices.fundamentum-iot.com",
    "project_id": <project-id>,
    "region_id": 1,
    "registry_id": <registry-id>,
    "serial_number": "<serial-number>",
    "asset_type_id": <asset-type-id>,
    "access_token": "<registry-provisioning-token>"
  }' \
  127.0.0.1:8080 com.fundamentum.edge.v1.Provisioning.Provision

The daemon generates the key pair, registers the device, and writes provisioning.json, rsa_public.pem and rsa_private.pem to the state directory. It then connects over MQTTS on its own.

Over a Unix socket, replace the address with the socket path:

grpcurl -unix -authority localhost -plaintext -d '{}' \
  /run/fundamentum-edge/grpc.socket com.fundamentum.edge.v1.Configuration.Get

5. Call the services from your application

All services live in the com.fundamentum.edge.v1 package. The server also supports gRPC reflection and health checks.

For example, to publish telemetry to the test sub-topic:

grpcurl -plaintext -d '{"sub_topic": "test", "qos": 0, "payload": "SGVsbG8sIFdvcmxkIQ=="}' \
  127.0.0.1:8080 com.fundamentum.edge.v1.Telemetry.Publish

The daemon handles the reboot command itself.

Language bindings

Generated bindings are published as fundamentum-edge-proto:

For other languages, generate client stubs from the .proto files with protoc.

What's next

• Gateways and sub-devices to report for sub-devices through the daemon.
• Port-forwarding agent to turn on remote access.
• Send telemetry, states and heartbeats for what the daemon sends on your behalf.