Hands-On Microservices with Rust

Reading the configuration file

Our server will expect to find a configuration file in the current working folder with the name microservice.toml. To read a configuration and convert it to the Config struct, we need to find and read this file if it exists. Add the following code to the main function of the server:

let config = File::open("microservice.toml")    .and_then(|mut file| {        let mut buffer = String::new();        file.read_to_string(&mut buffer)?;        Ok(buffer)    })    .and_then(|buffer| {        toml::from_str::<Config>(&buffer)            .map_err(|err| io::Error::new(io::ErrorKind::Other, err))    })    .map_err(|err| {        warn!("Can't read config file: {}", err);    })    .ok();

The preceding code is a chain of method calls that start with the File instance. We use the open method ...