/**
* Retrieves an environment variable by name, or exits the program with an error message if it is not set.
* This is useful for critical environment variables that must be present for the application to run.
*/pubfnget_critical_env_var(name:&str)-> String{matchstd::env::var(name){Ok(val)=> val,Err(_)=>{panic!("Critical environment variable '{}' is not set", name);}}}