Crate docker_env

docker-env

docker-env is a minimal utility crate for reading environment variables and Docker-style secrets in containerised Rust applications.

This crate is designed for use in Docker, Kubernetes, and other container environments where secrets may be injected as file-based mounts rather than plain environment variables.

Features

• Typed access to environment variables (get_env<T>, get_env_or, etc.).
• Support for secret files via the _FILE suffix convention.
• Graceful fallbacks with optional, default, or required values.
• Logs errors using the tracing crate.

Docker Secret Convention

When a variable has a secret counterpart (e.g., DATABASE_PASSWORD), Docker often mounts the secret as a file and sets an accompanying environment variable with the _FILE suffix:

DATABASE_PASSWORD_FILE=/run/secrets/db_password

Calling:

let password: String = docker_env::get_env("DATABASE_PASSWORD", true).unwrap();

will cause docker-env to read the contents of the file at /run/secrets/db_password instead of the plain DATABASE_PASSWORD variable.

Example

use docker_env::{get_env, get_env_or, get_env_or_panic};

let db_url: String = get_env_or_panic("DATABASE_URL", false);
let port: u16 = get_env_or("PORT", 8080, false);
let api_key: String = get_env("API_KEY", true).unwrap();

When to Use

Use this crate when your app:

• Runs in a Docker or Kubernetes environment
• Uses file-based secrets via /run/secrets/ or similar
• Requires simple, typed configuration with error logging

Modules

prelude

Commonly used imports for convenience.

Functions

get_env

Reads an environment variable.

get_env_or

Reads an environment variable and returns its value if it exists; otherwise, the default value is returned.

get_env_or_default

Reads an environment variable and returns its value if it exists; otherwise, the default value is returned.

get_env_or_panic

Reads an environment variable and returns its value if it exists; otherwise, this function will panic.

get_secret

Reads an environment variable containing the path to a Docker secret file.