The runnable companion to the Coursera course Valkey from Zero (course #11 of the Rust for Data Engineering specialization). Five modules covering caching, sorted-set leaderboards, streams + consumer groups, pipelining + Lua, and operational HA — all built against Valkey 8 from async Rust via redis-rs.

Why Valkey, not Redis — Redis Inc. relicensed Redis 7.4+ under SSPL/RSALv2 in March 2024. The Linux Foundation forked the last permissive version as Valkey (Apache-2.0). The redis crate on crates.io is wire-compatible with both forks, so the Rust client code is identical. Lesson 1.1 acknowledges the lineage explicitly so students searching for "Redis" find the content.

git clone https://github.com/paiml/valkey-from-zero
cd valkey-from-zero
make up          # docker compose up -d (Valkey 8 on 127.0.0.1:6379)
make demo        # cargo run --bin valkey-demo — four runtime contracts
make test        # cargo test --release (lib unit + integration)

make up is idempotent. The container has AOF persistence enabled and a 256 MB LRU eviction cap so the cache lessons (Module 1) and persistence lessons (Module 5.1) have something observable.

One-line install per prerequisite:

curl -fsSL https://get.docker.com | sh           # Docker 24+ for compose.yml
curl -sSf https://sh.rustup.rs | sh              # rustup; rust-toolchain.toml pins 1.95

make up          # start Valkey 8
make demo        # run all four contracts against the live instance
make test        # cargo test --release (4 lib unit + 4 integration tests)
make lint        # cargo clippy --all-targets -- -D warnings
make coverage    # cargo llvm-cov line coverage report
make pmat        # pmat quality-gate (entropy excluded — small-repo artifact)
make down        # docker compose down (keeps the named volume)
make nuke        # docker compose down -v (wipes the AOF data)

The demo binary takes flags via env:

VALKEY_URL=redis://host:6379 cargo run --bin valkey-demo

valkey-from-zero/
├── compose.yml                     # Valkey 8 single-node, AOF on, 256MB LRU cap
├── crates/
│   └── valkey-core/                # connection helper + four named contracts
│       ├── src/lib.rs              # set_get_round_trip / incr_monotonic / set_with_ttl / hash_round_trip
│       ├── src/main.rs             # valkey-demo binary
│       └── tests/integration.rs    # round-trips against the running container
├── contracts/
│   └── valkey-rust-v1.yaml         # provable contracts; lintable via `pv lint contracts/`
├── assets/
│   └── hero.svg                    # README banner
└── .github/workflows/ci.yml        # gate-matrix (1.95 + stable) + Valkey service

The Module-3 streams crate (crates/valkey-streams) and course-capstone CLI (crates/valkey-cli) are scaffolded into the workspace plan but their content lands with the lesson scripts. The single-container compose.yml is enough for Modules 1–4; Module 5's Sentinel + Cluster topology will arrive as compose.cluster.yml alongside Module 5 lessons.

Four named runtime contracts asserted inside the valkey-core demo functions, formalised in contracts/valkey-rust-v1.yaml:

Each contract has a falsification ID (FALSIFY-VALKEY-001..004), an enforcement description, and a Kani harness placeholder in the YAML. A fifth contract — XACK after Postgres commit — is reserved for the Module-3 streams expansion.

Reproduce: make up && make demo && make test && make lint.

Five modules; the companion repo's valkey-core crate underlies Module 1 and will grow as the lessons land:

The course-level capstone is a real-time inventory service that uses every layer: session hashes (M1), trending-products leaderboard (M2), order-pipeline streams (M3), Lua-scripted atomic stock decrement (M4), running against the Sentinel cluster (M5).

PRs that improve fidelity to the course videos, fix data-fetch breakage, or harden the provable contracts are welcome. Before opening a PR:

1. make test && make lint must pass cleanly
2. Coverage gate is cargo llvm-cov --release --workspace ≥ 95% on lib.rs
3. pv lint contracts/ must remain at 0 errors
4. Any new contract goes in both contracts/valkey-rust-v1.yaml and a runtime assert! inside the corresponding demo function

Dual-licensed under MIT or Apache-2.0 at your option (matches the rest of the PAIML Coursera companion repos). See LICENSE-MIT and LICENSE-APACHE.