Deploying Rust Applications

This comprehensive guide covers everything you need to know about deploying Rust applications via Deploy with Git, from simple HTTP servers to complex microservices using Actix-web, Rocket, or Axum.

Overview

Deploy with Git automatically detects Rust applications by looking for:

• Cargo.toml file
• Cargo.lock for dependency locking (optional)
• rust-toolchain.toml or rust-toolchain for version specification (optional)

Basic Rust Deployment

Simple Actix-web API

docker run -d \
  --name actix-api \
  -e GIT_REPO_URL=https://github.com/your-username/actix-api \
  -e APP_PORT=3000 \
  -p 3000:3000 \
  runonflux/orbit:latest

What Happens Automatically

1. Detection: Finds Cargo.toml and identifies as Rust project
2. Version Selection:
   • Checks RUST_VERSION environment variable
   • Checks rust-toolchain.toml channel field
   • Checks rust-toolchain file
   • Falls back to stable channel
3. Runtime Installation:
   • Installs Rust using official rustup installer
   • Sets RUSTUP_HOME to /opt/flux-tools/rustup
   • Sets CARGO_HOME to /opt/flux-tools/cargo
   • Adds cargo bin directory to PATH
4. Dependencies: Runs cargo fetch to download and verify dependencies
5. Build: Compiles optimized release binary with cargo build --release
6. Start: Executes compiled binary from target/release/

Framework-Specific Guides

Actix-web Framework

Actix-web is a powerful, pragmatic, and extremely fast web framework for Rust:

docker run -d \
  --name actix-rest-api \
  -e GIT_REPO_URL=https://github.com/your-username/actix-api \
  -e APP_PORT=3000 \
  -e RUST_VERSION=stable \
  -p 3000:3000 \
  runonflux/orbit:latest

Example main.rs:

use actix_web::{get, web, App, HttpResponse, HttpServer, Responder};
use serde::{Deserialize, Serialize};
use std::env;

#[derive(Serialize, Deserialize)]
struct HealthCheck {
    status: String,
}

#[get("/health")]
async fn health() -> impl Responder {
    HttpResponse::Ok().json(HealthCheck {
        status: "healthy".to_string(),
    })
}

#[actix_web::main]
async fn main() -> std::io::Result<()> {
    let port = env::var("APP_PORT")
        .unwrap_or_else(|_| "3000".to_string())
        .parse::<u16>()
        .expect("APP_PORT must be a valid port number");

    HttpServer::new(|| {
        App::new()
            .service(health)
    })
    .bind(("0.0.0.0", port))?
    .run()
    .await
}

Example Cargo.toml:

[package]
name = "actix-api"
version = "1.0.0"
edition = "2021"

[dependencies]
actix-web = "4"
serde = { version = "1.0", features = ["derive"] }
serde_json = "1.0"

Rocket Framework

Rocket is a web framework for Rust with focus on ease-of-use, expressiveness, and speed:

docker run -d \
  --name rocket-api \
  -e GIT_REPO_URL=https://github.com/your-username/rocket-api \
  -e APP_PORT=3000 \
  -p 3000:3000 \
  runonflux/orbit:latest

Example main.rs:

#[macro_use] extern crate rocket;

use rocket::{State, Config};
use rocket::serde::{Serialize, json::Json};
use std::env;

#[derive(Serialize)]
#[serde(crate = "rocket::serde")]
struct HealthCheck {
    status: String,
}

#[get("/health")]
fn health() -> Json<HealthCheck> {
    Json(HealthCheck {
        status: "healthy".to_string(),
    })
}

#[launch]
fn rocket() -> _ {
    let port = env::var("APP_PORT")
        .unwrap_or_else(|_| "3000".to_string())
        .parse::<u16>()
        .expect("APP_PORT must be a valid port number");

    let config = Config {
        port,
        address: "0.0.0.0".parse().unwrap(),
        ..Config::default()
    };

    rocket::custom(&config)
        .mount("/", routes![health])
}

Axum Framework

Axum is an ergonomic and modular web framework built with Tokio, Tower, and Hyper:

docker run -d \
  --name axum-api \
  -e GIT_REPO_URL=https://github.com/your-username/axum-api \
  -e APP_PORT=3000 \
  -p 3000:3000 \
  runonflux/orbit:latest

Warp Framework

Warp is a super-easy, composable, web server framework for warp speeds:

docker run -d \
  --name warp-api \
  -e GIT_REPO_URL=https://github.com/your-username/warp-api \
  -e APP_PORT=3000 \
  -p 3000:3000 \
  runonflux/orbit:latest

Version Management

Specify Rust Version

Option 1: Environment Variable

docker run -d \
  -e GIT_REPO_URL=https://github.com/your-username/rust-app \
  -e APP_PORT=3000 \
  -e RUST_VERSION=stable \
  -p 3000:3000 \
  runonflux/orbit:latest

Supported values:

• stable - Latest stable release
• nightly - Nightly builds
• beta - Beta channel
• 1.75.0 - Specific version number

Option 2: rust-toolchain.toml File

[toolchain]
channel = "stable"
components = ["rustfmt", "clippy"]

Option 3: rust-toolchain File

stable

Build Optimization

Release Mode

By default, Deploy with Git builds Rust applications in release mode for optimal performance:

# Default: Optimized release build
docker run -d \
  -e GIT_REPO_URL=https://github.com/your-username/rust-app \
  -e APP_PORT=3000 \
  -p 3000:3000 \
  runonflux/orbit:latest

This runs cargo build --release, which:

• Optimizes for speed
• Removes debug symbols
• Takes longer to build but runs faster
• Creates binary in target/release/ directory

Custom Build Command

Override the default build command if needed:

docker run -d \
  -e GIT_REPO_URL=https://github.com/your-username/rust-app \
  -e APP_PORT=3000 \
  -e BUILD_COMMAND="cargo build --release --features production" \
  -p 3000:3000 \
  runonflux/orbit:latest

Environment Variables

Rust-Specific Variables

Variable	Description	Default
RUST_VERSION	Rust channel or version	stable
RUSTFLAGS	Additional compiler flags	-
CARGO_BUILD_JOBS	Parallel build jobs	Auto-detected

Common Application Variables

docker run -d \
  --name rust-api \
  -e GIT_REPO_URL=https://github.com/your-username/rust-api \
  -e APP_PORT=3000 \
  -e RUST_VERSION=stable \
  -e DATABASE_URL=postgres://user:pass@db:5432/mydb \
  -e JWT_SECRET=your-secret-key \
  -e RUST_LOG=info \
  -p 3000:3000 \
  runonflux/orbit:latest

Advanced Scenarios

Monorepo - Deploy Specific Service

docker run -d \
  --name rust-auth-service \
  -e GIT_REPO_URL=https://github.com/your-username/monorepo \
  -e PROJECT_PATH=services/auth \
  -e APP_PORT=3000 \
  -p 3000:3000 \
  runonflux/orbit:latest

Private Repository

docker run -d \
  --name private-rust-api \
  -e GIT_REPO_URL=https://github.com/your-username/private-api \
  -e GIT_TOKEN=ghp_your_personal_access_token \
  -e APP_PORT=3000 \
  -p 3000:3000 \
  runonflux/orbit:latest

With Deployment Hooks

Create pre-deploy.sh in your repository root:

#!/bin/bash
# Run database migrations before deployment
echo "Running database migrations..."
# Your migration logic here

Create post-deploy.sh:

#!/bin/bash
# Warm up cache after deployment
echo "Warming up cache..."
curl http://localhost:$APP_PORT/api/warmup

docker run -d \
  --name rust-api-with-hooks \
  -e GIT_REPO_URL=https://github.com/your-username/rust-api \
  -e APP_PORT=3000 \
  -p 3000:3000 \
  runonflux/orbit:latest

CI/CD Integration

Automatic Deployment with Webhooks

docker run -d \
  --name rust-api \
  -e GIT_REPO_URL=https://github.com/your-username/rust-api \
  -e APP_PORT=3000 \
  -e WEBHOOK_SECRET=my-secret-phrase \
  -p 3000:3000 \
  -p 9001:9001 \
  runonflux/orbit:latest

Configure GitHub Webhook:

• Payload URL: https://your-app-9001.app.runonflux.io/webhook
• Content type: application/json
• Secret: my-secret-phrase
• Events: Just the push event

Polling for Updates

docker run -d \
  --name rust-api \
  -e GIT_REPO_URL=https://github.com/your-username/rust-api \
  -e APP_PORT=3000 \
  -e POLLING_INTERVAL=300 \
  -p 3000:3000 \
  runonflux/orbit:latest

Troubleshooting

Binary Not Found After Build

Problem: "Binary 'my-app' was not created"

Solution: Ensure your Cargo.toml has a valid package name:

[package]
name = "my-app"  # Binary will be named "my-app"
version = "1.0.0"
edition = "2021"

The binary name is derived from the package name in Cargo.toml.

Build Takes Too Long

Problem: Rust build timeout

Solution: Rust builds can be slow, especially first builds. Increase build timeout:

-e BUILD_TIMEOUT=3600  # 60 minutes for large projects

Performance tips:

• Release builds are slower but produce faster binaries
• First build downloads and compiles all dependencies
• Subsequent builds are much faster (cached dependencies)
• Consider using fewer dependencies for faster builds

Port Binding Issues

Problem: Application not accessible

Solution: Ensure your Rust application binds to 0.0.0.0 (not localhost or 127.0.0.1):

// Good: Accessible from outside container
HttpServer::new(|| App::new())
    .bind(("0.0.0.0", port))?
    .run()
    .await

// Bad: Only accessible from inside container
HttpServer::new(|| App::new())
    .bind(("127.0.0.1", port))?
    .run()
    .await

Dependency Compilation Errors

Problem: Cargo build fails with dependency errors

Solution: Check Rust version compatibility. Some crates require specific Rust versions:

# Try with latest stable
-e RUST_VERSION=stable

# Or specific version if crate requires it
-e RUST_VERSION=1.75.0

Performance Tips

1. Release Mode: Always use release builds in production (automatic with Deploy with Git)
2. Static Linking: Rust produces static binaries by default - no runtime dependencies needed
3. Binary Size: Use strip = true in Cargo.toml to reduce binary size:

   [profile.release]
   strip = true
   opt-level = 3
   lto = true

4. Dependency Caching: Dependencies are cached based on Cargo.lock hash - no recompilation if unchanged
5. Health Checks: Implement /health endpoint for faster deployment verification
6. Async Runtime: Use Tokio for async operations - excellent performance characteristics

Example Repository Structure

my-rust-api/
├── Cargo.toml             # Package manifest
├── Cargo.lock             # Dependency lock file
├── rust-toolchain.toml    # Optional: Pin Rust version
├── pre-deploy.sh          # Optional: Pre-deployment hook
├── post-deploy.sh         # Optional: Post-deployment hook
├── src/
│   ├── main.rs           # Application entry point
│   ├── routes/
│   │   ├── mod.rs
│   │   ├── users.rs
│   │   └── auth.rs
│   ├── models/
│   │   ├── mod.rs
│   │   └── user.rs
│   └── middleware/
│       ├── mod.rs
│       └── auth.rs
└── tests/
    └── integration_test.rs

Why Rust?

Rust delivers exceptional performance with memory safety:

• Blazingly Fast: Performance comparable to C/C++
• Memory Safe: No null pointers, no data races
• Zero-Cost Abstractions: High-level features with no runtime overhead
• Concurrent: Fearless concurrency with ownership system
• Reliable: Catch bugs at compile time, not runtime

Perfect for:

• High-performance APIs
• Microservices
• Real-time systems
• WebSocket servers
• Data processing pipelines

Next Steps

• Environment Variables Reference
• Deployment Hooks Guide
• CI/CD Setup
• Troubleshooting