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Rust on Miren

Miren auto-detects Rust apps from Cargo.toml, builds them with Cargo, and ships a single release binary at /bin/app on a minimal runtime image — no Dockerfile required.

Let your agent do this

Ask your AI coding agent to "set up this Rust app on Miren" after installing the Miren agent skills. It confirms your binary, checks the server binds 0.0.0.0:$PORT, wires up environment variables, and deploys — using this page as its reference.

Do you need a Dockerfile?​

No. Miren detects Rust from Cargo.toml and runs cargo build --release for you. The default Rust version is 1.83. Provide a Dockerfile.miren only for custom build steps — see Using Dockerfile.miren.

Set up the app​

From your project root:

miren init
miren deploy

Preview what Miren detects — binary name, version, entrypoint — without building:

miren deploy --analyze

Binary name​

Miren reads Cargo.toml to find the binary, then copies it to /bin/app:

  1. Uses the [[bin]] name if specified.
  2. Otherwise uses the package name from [package].

Start command​

Your server must bind to 0.0.0.0 on $PORT — Miren injects PORT and routes traffic to it. Read it with std::env::var("PORT"). Here's a minimal axum server:

use axum::{routing::get, Router};
use std::env;
use tokio::net::TcpListener;

#[tokio::main]
async fn main() {
    let app = Router::new().route("/", get(|| async { "Hello from Rust on Miren!\n" }));
    let port = env::var("PORT").unwrap_or_else(|_| "8080".to_string());
    let listener = TcpListener::bind(format!("0.0.0.0:{port}")).await.unwrap();
    axum::serve(listener, app).await.unwrap();
}

The compiled binary lands at /bin/app, which is the default start command. Use a Procfile only to pass flags or define extra processes:

# Default — run the compiled binary
web: /bin/app

# Background worker
worker: /bin/app --mode worker

Example Cargo.toml​

[package]
name = "myapp"
version = "0.1.0"
edition = "2021"

[dependencies]
axum = "0.7"
tokio = { version = "1", features = ["full"] }

Environment variables​

Set variables with miren env set — -e for plain values, -s for secrets (masked in output and logs):

miren env set -e RUST_LOG=info
miren env set -s DATABASE_URL
miren env set -s API_TOKEN

miren env set -s API_TOKEN (no value) prompts with masked input. You can also declare variables in .miren/app.toml:

[[env]]
key = "DATABASE_URL"
value = ""
required = true
sensitive = true
description = "Postgres connection string"

See App Configuration — Environment Variables.

Agent quick reference​

  • Detection: Cargo.toml in the project
  • Default version: Rust 1.83 (override via [build] version in .miren/app.toml)
  • Build: cargo build --release; binary copied to /bin/app
  • Binary name: [[bin]] name if set, else the [package] name
  • Start command: web: /bin/app (default); bind 0.0.0.0:$PORT via std::env::var("PORT")
  • Env vars: miren env set -e KEY=VALUE, -s for secrets, or [[env]] in app.toml
  • Dockerfile: not needed; add Dockerfile.miren only for custom builds

Next steps​