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//! Defines extracting config variables based on the method to enable testing as well as production use.
//! A good is API views. Wehn when defining an API view function, we can use the `GetConfigVariable` trait to
//! to enable config variables from different sources be applied to the API view function by having the following
//! outline:
//!
//! ```rust
//! use nanoservices_utils::config::GetConfigVariable;
//!
//! pub async fn api_view<T: GetConfigVariable>() {
//! }
//! ```
//! Anything passed into the `api_view` function will be able to get config variables from the source defined by
//! the type of the generic parameter `T`. For example, if we want to get config variables from the environment, we
//! can pass the `EnvConfig` struct as `api_view::<EnvConfig>()`. However, we can implement the `GetConfigVariable`
//! on a random struct for unit testing and pass that struct into the `api_view` function for testing.
//! use nanoservices_utils::config::GetConfigVariable;
//!
//! let _ =
use std::env;
use crate::errors::{
NanoServiceError,
NanoServiceErrorStatus
};
/// Used for extracting config cariables.
pub trait GetConfigVariable {
/// Gets the config variable
///
/// # Arguments
/// * `variable` - The name of the config variable to get
///
/// # Returns
/// * `Result<String, NanoServiceError>` - The result of getting the config variable
fn get_config_variable(variable: String) -> Result<String, NanoServiceError>;
}
/// Defines the struct for getting config variables from the environment
pub struct EnvConfig;
impl GetConfigVariable for EnvConfig {
/// Gets the config variable from the environment
///
/// # Arguments
/// * `variable` - The name of the config variable to get
///
/// # Returns
/// * `Result<String, NanoServiceError>` - The result of getting the config variable
fn get_config_variable(variable: String) -> Result<String, NanoServiceError> {
match env::var(&variable) {
Ok(val) => Ok(val),
Err(_) => Err(
NanoServiceError::new(
format!("{} not found in environment", variable),
NanoServiceErrorStatus::Unknown
)
)
}
}
}