julian
22b1b069df
Initialize CLAUDE.md schema, index, and log; ingest three architecture sources (system overview, Teltonika ingestion design, official Teltonika data-sending protocols) into 7 entity pages, 8 concept pages, and 3 source pages with wikilink cross-references.
41 lines
1.8 KiB
Markdown
41 lines
1.8 KiB
Markdown
---
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title: Redis Streams
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type: entity
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created: 2026-04-30
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updated: 2026-04-30
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sources: [gps-tracking-architecture, teltonika-ingestion-architecture]
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tags: [infrastructure, telemetry-plane, queue]
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---
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# Redis Streams
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The durable in-flight queue between [[tcp-ingestion]] and [[processor]]. Also the transport for Phase 2 outbound commands.
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## What it provides
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- **Buffering** — temporary slowness in [[processor]] does not push back on Ingestion sockets.
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- **Replayability** — Streams retain messages, so a Processor crash does not lose telemetry; consumer-group offsets resume from the last position.
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- **Horizontal scaling** — multiple Processor instances join a consumer group and split load across device IDs.
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## Why Redis (and not Kafka/NATS)
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Sufficient at current scale and adds minimal operational burden. NATS or Kafka are reasonable upgrades when **multi-region durability** or **very high throughput** become real concerns. Until then, Redis is the right choice.
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## Phase 2 usage
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Outbound commands ride on per-instance streams: `commands:outbound:{instance_id}`. Responses ride on `commands:responses`. Redis is the transport; the source of truth for commands is the Directus `commands` collection. See [[phase-2-commands]].
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The connection registry (`connections:registry` hash) and per-instance heartbeats (`instance:heartbeat:{instance_id}` keys with `EX 90`) also live in Redis.
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## Failure mode
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Streams are persisted; restart resumes from disk. Complete Redis loss is recoverable from device retransmits and Processor checkpointing. See [[failure-domains]].
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## Operational note
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**Consumer lag is the canary metric** for the entire telemetry pipeline. Observability dashboards should make it prominent.
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## Deployment
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Internal-only container. Persistence enabled. Never exposed externally.
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