Overview
One system,
three pillars
Start here: what EchoMQ is, the one wire it owns, and the three surfaces that fall out of it.
EchoMQ is one Valkey-native job system you own end to end. Its keys, its record fields and its atomic transitions are the protocol; draw the line there and three surfaces fall out of one wire — the Queue that distributes work, the Bus that broadcasts signals and keeps a replayable log, and the Cache that serves reads. This chapter sets the frame: the three pillars, the protocol below the line that makes them polyglot and coherent, the door from Redis Patterns Applied, and what EchoMQ means for the Branded Component System it is the bus of. Three short dives carry it.
The protocol below the line
What makes one wire serve three surfaces, in any language? A line. EchoMQ records its design as a stack: the
bottom layers are the protocol — fixed and shared by everything that speaks it; the top layers
are the runtime's own. L0 is Valkey itself: the scripts are cluster-legal (every key of a
transition hashes to its queue's one slot) and the connector talks to one server; the native module runs on a
standalone server that loads it at start. L1 is the data
layer: which key holds which structure, and the field names. L2 is the set of atomic
transitions that move a record between states, run as Lua scripts by the connector, and for the core job
transitions also as native EMQ.* commands inside the server, bound by the same keys, fields and
replies.
L3 is the executor: the scripted connector loads each script once and runs it by SHA,
reloading on NOSCRIPT; a native client sends the command name and loads nothing.
L4 is the language API a caller invokes. Pick a layer to read its scope and whether it is
shared.
The layer stack · pick a layer
The shared line falls between L2 and L3: below it the protocol is fixed and shared; above it, every runtime writes its own code. That single placement is what lets one wire serve three pillars — and what lets any runtime speak it.
The three orienting dives
Three short dives carry the orientation in a what → why → where arc, before the depth chapters teach the mechanism.
The three pillars
What EchoMQ is — the Queue, the Bus, and the Cache: three surfaces over one wire, and which job each one does.
The protocol below the line
Why it works — the keys, the fields and the transitions are shared and fixed; the language is yours. The line that makes the system polyglot and coherent, on a real key.
The door & the BCS family
Where it lands — the bidirectional Redis-Patterns door, and what owning the queue, the bus, and the cache means for the systems built on them.
Up next — the depth chapters
Read the Protocol next — the substrate the three pillars share. Then take the pillar you need: the Queue, the Bus, the Cache. The Proof chapter shows the system holds: the conformance suite, telemetry and the read plane. Each closes with a hands-on workshop.
The Protocol
The owned keyspace, the record hash, the Lua layer, immutability, the native module.
The Queue
Distribute work: lifecycle, lanes, batches, controls, flows.
The Bus
Broadcast signals: events, the event log, consumer groups, time-travel.
The Cache
Serve reads: cache-aside, single-flight, coherence on the Bus.
References
Sources
- Valkey — Documentation — the BSD-licensed, foundation-governed store EchoMQ is backed by — the substrate of record.
- Redis — EVALSHA — the load-once, run-by-SHA dispatch the scripted executor uses at L3.
- Valkey — Modules Introduction — how a module adds its own commands to the server: the native executor, where each core job transition is one
EMQ.*command. - Valkey — Cluster specification — the
{hashtag}→hash-slot routing the per-queue-hashtag keyspace is built for: every key of a queue on one slot, where a multi-key script is legal. - llmstxt.org — The llms.txt convention — the machine-readable map format the course follows.
Related in this course
- Course home — the full six-chapter map.
- The three pillars — the first dive, what EchoMQ is.
- redis-patterns R0.3 · Patterns become protocol — the near side of the door.
- The Branded Component System — the architecture EchoMQ is the bus and near-cache of.