A lightweight Go bridge that receives IVS events from a Dahua NVR over HTTP and publishes them to Home Assistant via MQTT discovery.

Each camera automatically gets four HA binary sensors: tripwire vehicle, tripwire human, intrusion vehicle, intrusion human.

• Single static binary — no runtime dependencies, no Python, no pip. Just scp and run.
• MQTT discovery — binary sensors auto-register in HA on startup. No manual YAML sensor definitions needed.
• Auto-off — the bridge publishes OFF after a configurable delay (off_delay), so HA dashboards show real-time detection state without manual reset. The timer resets on every incoming event, even if anti-dither suppresses it.
• Anti-dither — suppress repeated MQTT publishes per camera/rule within a configurable time window to reduce noise, while still extending the OFF timer on every event.
• Last Will & Testament — HA marks sensors as unavailable if the bridge crashes or loses connection.
• IP allowlist — optionally restrict which IPs can send events (e.g., NVR VLAN only).
• Rotating logs — automatic log rotation (5 x 5 MB).
• Monitoring — /health and /stats endpoints for uptime and metrics.
• Security hardened — ships with a locked-down systemd unit (read-only filesystem, no capabilities, restricted syscalls).

Dahua NVR ──HTTP POST──> dahua2mqtt ──MQTT──> Home Assistant
                         (Go binary)          (binary_sensor.*)

1. NVR sends an IVS event to http://<bridge>:<port>/cgi-bin/NotifyEvent.
2. The bridge validates and extracts camera name, event type, and object class.
3. If anti-dither passes, an MQTT message (ON) is published to the matching sensor topic. Either way, the OFF timer resets.
4. After off_delay seconds of inactivity, the bridge publishes OFF.

• Go 1.24+ (build only — the compiled binary has no dependencies)

go build -ldflags="-s -w" -o dahua2mqtt .

Cross-compile for a remote Linux server:

GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go build -ldflags="-s -w" -o dahua2mqtt .

Create user and directories:

sudo useradd -r -s /sbin/nologin dahua
sudo mkdir -p /opt/dahua2mqtt /etc/dahua2mqtt /var/log/dahua2mqtt
sudo chown dahua:dahua /var/log/dahua2mqtt

Deploy binary, config, and service:

sudo cp dahua2mqtt /opt/dahua2mqtt/
sudo chmod 755 /opt/dahua2mqtt/dahua2mqtt
sudo cp config.example.yaml /etc/dahua2mqtt/config.yaml  # edit before starting
sudo chown root:dahua /etc/dahua2mqtt/config.yaml
sudo chmod 640 /etc/dahua2mqtt/config.yaml
sudo cp dahua2mqtt.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable --now dahua2mqtt

Verify:

curl http://localhost:8080/health
# {"mqtt_connected":true,"status":"ok"}

curl http://localhost:8080/stats
# {"version":"2.1.0","events_received":0,"mqtt_connected":true,...}

A simple unprivileged LXC (1 vCPU, 64 MB RAM, 4 GB disk) is more than sufficient. The Go binary uses ~5-10 MB of memory at runtime.

The bridge reads /etc/dahua2mqtt/config.yaml by default (override with CONFIG_FILE env var). All keys can also be overridden via uppercase env vars.

See config.example.yaml for a complete example.

cameras:
  - cam1
  - cam2

List every camera name prefix that appears in your IVS rule names. Four binary sensors are created per camera.

The bridge determines whether a detection is vehicle or human by:

1. Checking the event payload fields: Data.Object.ObjectType, Data.Object.Type, Data.Objects[].ObjectType, Data.Objects[].Type.
2. Falling back to the IVS rule name convention:
   • _c_ or segment c → vehicle
   • _h_ or segment h → human
   • _ch_ or segment ch → both
3. If neither yields a result, both vehicle and human sensors are triggered.

Recognized aliases: human, person → human; vehicle, car, motor vehicle, motorvehicle → vehicle.

On your NVR, under Network → Alarm Center:

1. Enable the checkbox.
2. Set Protocol Type to HTTP.
3. Set Server Address to this bridge's IP (e.g. 192.168.1.10).
4. Set Port to 8080 (or whatever you configured).
5. Hit Apply.

Then, for each rule under Event → Alarm Center:

1. Enable Report Alarm.
2. Set Report Alarm to HTTP.
3. Tick Event.

Dahua NVR does not send channel IDs through the Alarm Center interface. Use the rule name to encode camera identity and object type:

• cam1_r1_h_trip → camera 1, rule 1, human, tripwire
• cam2_r1_ch_intrusion → camera 2, rule 1, car + human, intrusion
• cam1_r1_c_trip → camera 1, rule 1, vehicle, tripwire

The first segment (before the first _) is used as the camera name and must match an entry in the cameras list.

GET /health
{"status": "ok", "mqtt_connected": true}

GET /stats
{
  "version": "2.1.0",
  "events_received": 145,
  "events_anti_dithered": 3,
  "events_ignored": 2,
  "mqtt_publish_ok": 140,
  "mqtt_publish_fail": 0,
  "mqtt_connected": true,
  "uptime_seconds": 3600,
  "uptime_formatted": "1h 0m",
  "config": {
    "anti_dither": 5,
    "off_delay": 10,
    "cameras": ["cam1", "cam2"]
  }
}

GET /
dahua2mqtt 2.1.0

Removing a camera from cameras: and restarting the service stops new events for it but leaves the old retained MQTT discovery and state messages on the broker — Home Assistant will keep showing those sensors as "ghosts". Use the included script to clear them:

./reset_sensors.sh purge BROKER_IP <removed-cam-name> [-u user] [-P pass]

The same script supports a reset mode that publishes OFF to a sensor's state topic (without clearing it) — handy when a sensor is stuck ON and you want HA to see OFF immediately.

• Do NOT expose this bridge to the internet.
• Use allowed_ips to restrict to your NVR's IP.
• When using trust_proxy: true behind a reverse proxy on a non-private IP, populate trusted_proxies with the proxy's IP. Otherwise only loopback and RFC1918/ULA addresses are trusted to inject X-Forwarded-For.
• Allow outbound traffic only to your MQTT broker.
• The systemd unit enforces: read-only filesystem, no capabilities, restricted syscalls, no home directory access, private /tmp.

MIT