Rust Fibonacci — Multi-Language Lambda Bindings

This project demonstrates how a single Rust function can be shared across multiple programming languages using AWS Lambda. A recursive Fibonacci function written in Rust is exposed to Python, JavaScript, Java, and C# via their respective FFI binding technologies — and compared against each language's pure native implementation.

Architecture

rust-lib/                       ← Shared pure Rust library (fib-core)
├── Cargo.toml
└── src/lib.rs                  ← pub fn fib(n: i64) -> i64

native-lambdas/                 ← Pure native implementations (no Rust)
├── rust/                       ← Rust native (cargo-lambda)
├── python/                     ← Python native
├── javascript/                 ← JavaScript native (ESM)
├── java/                       ← Java native (Maven)
└── csharp/                     ← C# native (.NET 8)

python-binding/                 ← Python + Rust (PyO3 / Maturin)
javascript-binding/             ← JavaScript + Rust (napi-rs)
java-binding/                   ← Java + Rust (JNI)
csharp-binding/                 ← C# + Rust (csbindgen / FFI)

All binding projects reference rust-lib/ via a Cargo path dependency — there is no duplicated Rust code.

Technologies

Binding	Language	FFI Technology	Build Tool
python-binding	Python 3.12	PyO3	Maturin
javascript-binding	Node.js 20	napi-rs	@napi-rs/cli
java-binding	Java 21	JNI	Cargo + Maven
csharp-binding	.NET 8	csbindgen	Cargo + dotnet

Prerequisites

Requirement	Version	Install guide
Rust	stable	rustup.rs
cargo-lambda	latest	cargo-lambda.info
Python	3.12+	python.org
Maturin	latest	maturin.rs
Node.js	20+	nodejs.org
Java JDK	21+	adoptium.net
Maven	3.9+	maven.apache.org
.NET SDK	8.0+	dotnet.microsoft.com
AWS CLI	v2	docs.aws.amazon.com

After installing Rust, install the additional tooling:

cargo install cargo-lambda
pipx install maturin        # or: pip install maturin
npm install -g @napi-rs/cli

AWS Setup

1. Configure AWS credentials

aws configure

2. Set your AWS Account ID

Edit Makefile and update:

ROLE = arn:aws:iam::YOUR_ACCOUNT_ID:role/lambda-basic-execution-role

3. Create the Lambda execution role

make create-role

Deploying to AWS Lambda

First-time creation (all functions)

make deploy-all CREATE=1

Individual deployments

Command	Description
make deploy-lambda-native CREATE=1	Rust native Lambda
make deploy-python-binding CREATE=1	Python + Rust binding
make deploy-js-binding CREATE=1	JavaScript + Rust binding
make deploy-java-binding CREATE=1	Java + Rust binding
make deploy-csharp-binding CREATE=1	C# + Rust binding
make deploy-native-python CREATE=1	Python native Lambda
make deploy-native-js CREATE=1	JavaScript native Lambda
make deploy-native-java CREATE=1	Java native Lambda
make deploy-native-csharp CREATE=1	C# native Lambda

Drop CREATE=1 to update an already-deployed function.

Invoking & Benchmarking

# Invoke all lambdas (natives + bindings) and display benchmark table
make invoke-all

# Only native language lambdas
make invoke-all-natives

# Only Rust-binding lambdas
make invoke-all-bindings

# Individual invocations
make invoke-lambda-native
make invoke-python-binding
make invoke-js-binding
make invoke-java-binding
make invoke-csharp-binding
make invoke-native-python
make invoke-native-js
make invoke-native-java
make invoke-native-csharp

The benchmark table shows two timing columns:

• invocation ms — wall-clock time client-side (includes network + runtime startup)
• fib only ms — pure computation time measured inside the Lambda function

Payload

All Lambda functions expect an API Gateway v2 event with a queryStringParameters.number field (see payload.json):

{
  "queryStringParameters": {
    "number": "33"
  }
}

Cleanup

make clean