Hands-On Microservices with Rust

Interaction functions

Since we have a declared structure, we can add functions to work with databases. The first function we will add is add_activity which adds an activity record to a database:

fn add_activity(conn: &Database, activity: Activity) -> Result<(), Error> {    let doc = doc! {        "user_id": activity.user_id,        "activity": activity.activity,        "datetime": activity.datetime,    };    let coll = conn.collection("activities");    coll.insert_one(doc, None).map(drop)}

This function only converts the Activity struct into a BSON document, and does this by extracting fields from a struct and construct BSON document with the same fields. We can derive the Serialize trait for the structure and use automatic serialization, but I used the doc! macro for demonstration ...