Env Convert

A convenience library for dealing with environment variables, handling basic type conversions and default values.

Getting values

get_default_env_var takes the environment variable name and the default value as a string if it does not exist. It returns an EnvVar that can be converted into a Result with the conversion type. You can then use that result to detect if the conversion happened successfully.

get_env_var takes the environment variable name and returns a Result<EnvVar,std::env::VarError>.

let max_connections_result: Result<u32,_> = get_default_env_var("MAX_DB_CONNECTIONS", "5").into();
let max_connections = max_connections_result.expect("MAX_DB_CONNECTIONS must be an integer");

let env_result: Result<String,_> = get_env_var("DEFAULT_GREETING").expect("DEFAULT_GREETING is required").into();

// You can also convert strings directly
let default_greeting: String = get_default_env_var("DEFAULT_GREETING", "hello").into();

Conversions

The following conversions are implemented in this library:

• String
• Unsigned and signed 8 through 128 bit, and arch (i8, u16, usize...)
• Floats (f32, f64)

To implement your own, you can implement the From<EnvVar> trait for Result<YourType, EnvVarConversionError>.

Versions

Until this reaches version 1, I will make an attempt to keep the API stable but no guarantees. After that this library will follow semantic versioning.