Rust: 更新 MongoDB 数据

[package]
name = "mongodb_update"
version = "0.1.0"
edition = "2018"


[dependencies]
mongodb = "1.0.0"
tokio = "*"
chrono = "0.4"

// --------------------------------------------------------------------
/*
    mongodb_update/src/main.rs

                    Jul/26/2020
*/
// --------------------------------------------------------------------
use std::env;
use mongodb::{
    bson::doc,
    error::Result,
    Client
};
use chrono::{Local, Date};

#[tokio::main]
async fn main() -> Result<()> {
    eprintln! ("*** 開始 ***");
    let args: Vec<_> = env::args().collect();
    let key_in = &args[1];
    let population_in = &args[2];
    eprintln!("{}",key_in);
    eprintln!("{}",population_in);

    let client =
        Client::with_uri_str("mongodb://localhost:27017").await?;

    let coll = client
        .database("city")
        .collection("saitama");

    let pp_in : i32 = population_in.parse().unwrap();

    let date_mod: Date<Local> = Local::today();
    println!("{}", date_mod);

    let update_result = coll.update_one(
        doc! { "key": key_in },
        doc! {
        "$set": {"population": pp_in, "date_mod": date_mod.to_string()}
        },
        None,
        ).await?;
    println!("Updated {} document", update_result.modified_count);

    eprintln! ("*** 終了 ***");

    Ok(())
}

// --------------------------------------------------------------------

执行

$ cargo run t1163 8235100
    Finished dev [unoptimized + debuginfo] target(s) in 0.14s
     Running `target/debug/mongodb_update t1163 8235100`
*** 開始 ***
t1163
8235100
2020-07-26+09:00
Updated 1 document
*** 終了 ***

快速指南：使用Rust和MongoDB进行启动并运行