Data Engineering · 22 Apr 2026 · 4 min
Event logs before dashboards
NOBIL separates the history of EV charging events from the latest operational snapshot.
01
A stream has two useful shapes
A current snapshot answers what each charging point looks like now. An append-oriented event log answers how it got there. NOBIL keeps both: periodic snapshots for quick inspection and hourly JSONL files for history and replay.
02
Normalize before storing
WebSocket messages are normalized before they become durable records. That boundary prevents consumers from depending directly on a volatile upstream format and gives downstream analysis a consistent event contract.
03
Observability begins in the pipeline
Lag and duplicate metrics are derived while the stream is processed. Versioned synchronization to GitHub and optional Google Cloud Storage then makes changes inspectable without turning a dashboard into the only source of truth.
Takeaway
What I take from it
Preserve the event history, publish a convenient current view and measure the health of the path between both.