Event Bus

The internal Event Bus (pkg/eventbus/eventbus.go) provides asynchronous, non-blocking message routing across RUSEON Core subsystems.

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Event Schema

Every event emitted across the bus implements the Event struct:

type Event struct {
    ID          string                 `json:"id"`
    TimestampMs int64                  `json:"timestamp_ms"`
    Topic       string                 `json:"topic"`
    CameraID    string                 `json:"camera_id,omitempty"`
    Data        map[string]interface{} `json:"data,omitempty"`
}

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Official Event Topics

Topic	Trigger Condition	Payload Keys (Data)
camera_online	RTSP client connected and receiving video frames.	id
camera_offline	RTSP stream dropped or failed to connect.	id, error
archive_segment_ready	1-hour or stopped fMP4 recording finalized on disk.	camera_id, file, duration
recording_failed	Filesystem write error occurred during recording.	camera_id, error
storage_warning	Disk storage utilization exceeded 90% threshold.	used_percent, path

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Sequential Consistency & Worker Pools

To prevent race conditions (such as a camera_offline event overtaking a preceding camera_online event), RUSEON Core uses consistent hashing (FNV-1a) on CameraID:

• Events for the same camera are always routed to the same dedicated worker goroutine.
• Default worker pool size: 4 workers, each with a channel buffer of 1,000 events.

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Backpressure & Drop Policy

The Event Bus enforces a strict Drop-Newest backpressure policy:

• If a worker queue is saturated (e.g., slow HTTP webhook endpoints), incoming events for that worker are dropped to safeguard video streaming and recording.
• All drops increment the ruseon_eventbus_drops_total Prometheus counter.