Rheo Livebooks
Section
Welcome. These notebooks are a hands-on tour of Rheo — an embedded Elixir/OTP library for consumer groups over a searchable event log.
You do not need to read HexDocs first. Start with Quickstart, then follow the path that matches what you care about.
How to run
Open this folder from a clone of the repo so notebooks can use the path
dependency ({:rheo, path: ...}). Hex {:rheo, "~> 1.0"} works for
standalone Livebook. Evaluate cells top to bottom.
livebook server notebooks/
# or jump straight in:
livebook server notebooks/quickstart.livemd
# ops surface:
livebook server notebooks/ops.livemd
# real LiveDashboard page via Phoenix Playground:
livebook server notebooks/live_dashboard.livemd
| Notebook | Story |
|---|---|
| Quickstart | From zero to “I published, fetched, and ACKed an event” |
| Concepts & Overview | Why leases, groups, search, replay, and frontiers exist |
| Ops: inventory, lag, DLQ | Inspect APIs — list, health, dead letters |
| LiveDashboard (Playground) | Real Rheo.LiveDashboard.Page via Phoenix Playground |
| GenStage, Flow & Broadway | Rheo owns delivery; pipelines own topology |
| ETS, Mnesia, Mongo, Redis, SQLite, PostgreSQL | Same API, different durability and ops trade-offs |
Docker? Not for Quickstart, Concepts, Ops, LiveDashboard, or Pipelines
(they use ETS). The Backends notebook also runs Mnesia without Docker; Mongo /
Redis need docker compose up -d, Postgres needs RHEO_POSTGRES_URL.
What Rheo is (and is not)
Rheo is not a message broker you deploy beside your app. It is a library you supervise inside the BEAM: streams, groups, leases, and a portable query model backed by a database (or ETS for tests).
Delivery is at-least-once. Handlers should be idempotent on event.id.
v0.10+ adds inspect ops (list_streams, group_info, dead_letters, Mix
tasks, optional LiveDashboard) without a control plane — see
ops.livemd and ADR 027.
v0.9 added optional Redis Streams ({:redix, "~> 1.5"}) with Model C
receipts — same Consumer API as ETS/Mongo/Ecto.
Further reading: Quick Start · Ops · 0.9 → 0.10 migration
