Rust: Redis のデータを削除 (Delete)

$ tree -L 2
.
├── Cargo.lock
├── Cargo.toml
├── src
│   └── main.rs
└── target
    └── debug

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

#

[dependencies.redis]
version = "*"

[dependencies]
tokio = { version = "0.2", features = ["full"] }
serde = { version = "1.0", features = ["derive"] }
serde_json = "1.0"

// --------------------------------------------------------------------
/*
    redis_delete/src/main.rs

                    Jul/22/2020
*/
// --------------------------------------------------------------------
use std::env;
extern crate redis;
use redis::{Commands};

// --------------------------------------------------------------------
fn main() -> Result<(), Box<dyn std::error::Error>>  {
    eprintln! ("*** 開始 ***");

    let args: Vec<_> = env::args().collect();
    let key_in = &args[1];
    eprintln! ("{}",key_in);

    let client = redis::Client::open("redis://localhost/").expect("url error");
    let mut conn = client.get_connection().expect("connect error");


//  let key_in = "t1853";

    let result: i32 = conn.del(key_in).unwrap();
    println!("削除結果: 1 => 成功, 0 => 失敗");
    println!("del result for myKey: {}", result);


    eprintln! ("*** 終了 ***");

    Ok(())
}

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

cargo build

cargo run t1856