Rust match

main.rs

#[macro_use]
extern crate mysql;
extern crate dotenv;

use std::error::Error;
use mysql::Row;
use std::env::var;

struct Lead {
    id: u32,
    source: String,
}

fn main() -> Result<(), Box<dyn Error>> {
    dotenv::dotenv().ok();

    let mut conn = mysql::Conn::new(std::env::var("MYSQL_URL")?)?;
    let mut stmt = conn.prepare(r"select id, source from lead where email = :email and product_id = 312")?;
    let mut rdr = csv::Reader::from_path("data.csv")?;
    let mut wtr = csv::Writer::from_path("output.csv")?;

    for result in rdr.records() {
        let mut record = result?;
        let email = record.get(8).unwrap();

        let qr: Option<Row> = stmt.first_exec(params!{"email" => email})?;
        let lead = qr.map(|row| {
            let (id, source) = mysql::from_row(row);
            Lead { id, source }
        });

        match lead {
            Some(lead) => {
                record.push_field(format!("{}/{}", var("LEAD_BASE_URL")?, lead.id).as_str());
                record.push_field(&lead.source);
            },
            None => {
                record.push_field("Not found");
                record.push_field("N/A");
            },
        };

        wtr.write_record(record.iter());
    }

    wtr.flush();
    Ok(())
}