Module chirpstack 

Reading what a ChirpStack network server publishes about the devices it hears.

A gateway hands packets to a network server, and the server hands what they carried to the application: decrypted, deduplicated across gateways, and tagged with the device it came from. ChirpStack publishes that on MQTT, one event per uplink, on application/{application id}/device/{dev eui}/event/up, as the JSON form of its integration.UplinkEvent message. UplinkEvent::from_json reads it into plain fields, so a program that feeds a dashboard or a store needs to know nothing about the message definitions.

Two things about the JSON are worth knowing, both from protobuf’s JSON mapping rather than from ChirpStack. Every name is camelCase, so f_port arrives as fPort. And a field at its default value is left out, so the first uplink after a join has no fCnt, and an uplink without ADR has no adr; they read here as zero and false.

The layout follows ChirpStack v4’s api/proto/integration/integration.proto and the example on its integration events documentation page, and the ChirpStack interop job reads a live server’s events with it.

Examples

A soil probe’s reading as ChirpStack publishes it, in the layout its integration events documentation shows. The payload arrives decrypted and in base64, MjEuNQ== being the text 21.5:

use pamoja_gateway::chirpstack::UplinkEvent;

let json = r#"{
    "deduplicationId": "3ac7e3c4-4401-4b8d-9386-a5c902f9202d",
    "time": "2026-07-18T09:34:15.775023242+00:00",
    "deviceInfo": {
        "applicationId": "17c82e96-be03-4f38-aef3-f83d48582d97",
        "deviceName": "soil probe, north bed",
        "devEui": "70b3d57ed0001234"
    },
    "devAddr": "26011bda",
    "dr": 5,
    "fPort": 2,
    "data": "MjEuNQ==",
    "rxInfo": [{ "gatewayId": "b827ebfffe010203", "rssi": -36, "snr": 10.5 }],
    "txInfo": { "frequency": 868100000 }
}"#;

let event = UplinkEvent::from_json(json)?;
assert_eq!(event.dev_eui.to_hex(), "70b3d57ed0001234");
assert_eq!(event.fport, Some(2));
assert_eq!(event.data, b"21.5");
assert_eq!(event.fcnt, 0, "left out of the JSON because it is zero");
assert_eq!(event.best_reception().map(|heard| heard.rssi_dbm), Some(-36));

Structs

Reception

One gateway’s reception of an uplink.

UplinkEvent

An uplink as a ChirpStack server published it.

Enums

EventError

Why a message is not an uplink event.

Constants

UPLINK_TOPIC

The topic filter for every uplink event of every application on a server.

Functions

uplink_topic

Returns the topic filter for one application’s uplink events.