Hands-On Microservices with Rust

Implementing subcommands

The implementation of subcommands is simple. For the add subcommand, we extract two arguments, USER_ID and ACTIVITY, and use them to create an Activity struct instance. We also get the current time with the Utc::now method and save it to a datetime field of Activity. Finally, we call the add_activity method to add the Activity instance to the MongoDB database:

match matches.subcommand() {    (CMD_ADD, Some(matches)) => {        let user_id = matches.value_of("USER_ID").unwrap().to_owned();        let activity = matches.value_of("ACTIVITY").unwrap().to_owned();        let activity = Activity {            user_id,            activity,            datetime: Utc::now().to_string(),        };        add_activity(&conn, activity)?;    }    (CMD_LIST, _) => {        let list = list_activities(&conn)?; for ...