switchy_env

Deterministic environment variable access for testing and simulation.

Features

Standard backend: switchy_env::standard::* reads real environment variables via std::env
Simulator backend: switchy_env::* uses a configurable environment with deterministic defaults when simulator is enabled (default)
Type Safety: Parse environment variables to specific types
Testing: Set/remove variables for testing scenarios

Usage

With default features, switchy_env::* resolves to the simulator backend.

use switchy_env::{var, var_or, var_parse, var_parse_or, var_parse_opt, var_exists, vars};

// Get environment variable
let database_url = var("DATABASE_URL")?;

// Get with default
let port = var_or("PORT", "8080");

// Parse to specific type
let timeout: u64 = var_parse("TIMEOUT")?;

// Parse with default
let max_connections: usize = var_parse_or("MAX_CONNECTIONS", 100);

// Parse optional variable (None if not set, Some(T) if parseable, Err if unparseable)
let debug_level: Option<u32> = var_parse_opt("DEBUG_LEVEL")?;

// Check if variable exists
if var_exists("FEATURE_FLAG") {
    // ...
}

// Get all environment variables
let all_vars = vars();

To force real environment access when both default features are enabled, use the standard module:

use switchy_env::standard::var;

let home = var("HOME")?;

Simulator Features

In simulator mode, you can control environment variables:

use switchy_env::simulator::{set_var, remove_var, clear, reset};

// Set variable for testing
set_var("TEST_VAR", "test_value");

// Remove variable
remove_var("TEST_VAR");

// Clear all variables
clear();

// Reset to defaults
reset();

Cargo Features

std (default): Enable real environment variable access
simulator (default): Enable deterministic simulation mode
fail-on-warnings: Treat warnings as errors

Core Types