Creating and using a mongodb Client

mongo_requests_c.rs

/** This is not compiler ready
   from cargo.toml:
   dependencies.mongodb]
    version = "2.0.0"
    default-features = false
    features = ["sync"]
    **/

use mongodb::{bson::Bson, bson::doc, bson::Document, options::ClientOptions, options::FindOptions, sync::Client, sync::Collection};
use mongodb::options::AggregateOptions;
use rocket::fairing::{AdHoc};

/**
    fn init() -   Establish a persistent connection to the database
      note that the password to the mongodb atlas account is passed in from the environment
      For this project the synchronous mongodb driver is used.  This is because init() is called by stage which can not be an
      async function.  The connection to mongodb with the async driver has to be called from an async function
**/
fn init() -> Option<Client> {
    let pwd: &'static str = env!("PWD");
    let connect_string = format!("{}{}{}", "mongodb+srv://rust:", pwd, "@mflix.beal2.mongodb.net/sample_restaurants?retryWrites=true&w=majority");
    let mut client_options =
        ClientOptions::parse(&connect_string).unwrap();
    // Manually set an option
    let duration: Duration = Duration::new(60, 0);
    client_options.app_name = Some("Rust Demo".to_string());
    client_options.connect_timeout = Some(duration);
    // Get a handle to the cluster
    let client: Result<Client, mongodb::error::Error> = Client::with_options(client_options);
    match client {
        Ok(my_client) =>{
            let ping = my_client
                .database("admin")
                .run_command(doc! {"ping": 1}, None).unwrap();
            println!( "{}", ping);
            Some(my_client)
        },
        Err(_) => Option::None
    }
}


/**
  Think of stage as your entry point.
   The function can not be async and this is where you define your routes (end-points)
**/
pub  fn stage() -> AdHoc {
    println!("{}", "loading mongo");
    let client = init().unwrap();
    let mbox = Box::new( client );
  AdHoc::on_ignite("mongodb", |rocket| async {
      rocket.manage( mbox ).mount("/mongo", routes![neighborhoods, restaurants,restaurants_docs, cuisines])
  })
}