lambda-mvp-rst runs Jolt (native Clojure on Chez Scheme, no JVM) on AWS Lambda as a custom runtime, the same provided.al2023 contract that awslabs/aws-lambda-cpp implements for C++. It's a fork of lambda-mvp-jlt that answers one extra question: can a real Rust capability be embedded into the same runtime via jolt-diplomat, a Diplomat-based FFI bridge? Here, the handler builds its JSON response with real Rust (serde_json) instead of hand-assembling a string, since Jolt itself has no JSON library. On top of the shared runtime loop sits that demo handler and a jolt bench tool built to answer a second question: how much does a Lambda invocation actually cost in wall-clock time, cold versus warm, at different memory tiers, on your own AWS account.
Every AWS-touching command in this repo relies entirely on the caller's own aws CLI configuration (AWS_PROFILE/AWS_REGION, or aws configure). Nothing here hardcodes a profile, an account, or a region: clone it, point it at your account, and the same commands that produced this project's own measured numbers will produce yours.
New to the project? Start with Getting started for the offline probe, the Docker build, and your first live deploy. Then read Architecture for how the pieces fit together: the Runtime API loop, the Rust JSON builder, the AL2023 build, and the bench tool.
Want to know how the JSON builder actually works? The Rust JSON builder via jolt-diplomat is the reason this fork exists: why Jolt needed one, what jolt-diplomat generates, and how the vendoring/sync-bindings workflow gets it into both local dev and the Docker build.
Want the Runtime API loop's own design notes? The Runtime API loop covers the poll/execute/respond contract, why the loop itself needs no JSON dependency, and the offline mock that makes runtime-loop changes a two-second local iteration.
Building on Amazon Linux 2023? Building on Amazon Linux 2023 covers the glibc constraint that forces a from-source build, the recipe itself, and the AL2023 packaging gotchas that cost a build round each.
Want to understand or reproduce the cold/warm boot-time story? Cold vs. warm boot is inherited from lambda-mvp-jlt: what jolt bench measures, how to read the table it prints, and the recipe for reproducing a jolt-version comparison against your own account.
Contributing a change? Contributing covers the build, the test commands, and this project's conventions.
| Page | What you'll learn |
|---|---|
| Getting started | Install, offline probe, Docker build, first live deploy |
| Architecture | How the runtime loop, the JSON builder, the build, and the bench tool fit together |
| The Rust JSON builder via jolt-diplomat | Why Jolt needed one, what it generates, and the vendoring workflow |
| The Runtime API loop | The Lambda custom-runtime contract and this project's implementation |
| Building on Amazon Linux 2023 | The glibc constraint, the from-source build recipe, arm64 |
| Cold vs. warm boot | What jolt bench measures and how to reproduce the comparison |
| Contributing | Build, test, and PR conventions |
| Scenario | Pages to read |
|---|---|
| "I want to try this out" | Getting started |
| "I want to understand how it works" | Architecture, then The Rust JSON builder, The Runtime API loop, and Building on Amazon Linux 2023 |
| "I want to measure cold/warm boot time on my own account" | Getting started, then Cold vs. warm boot |
| "I want to contribute a change" | Contributing |
CHANGELOG.md: version history.