How do I enable logging for the Reqwest client?

To enable logging for the Reqwest client in Rust, you can use the log crate in conjunction with an appropriate logging implementation such as env_logger. The log crate provides a logging facade that allows different libraries to use logging without having to depend on a specific logging implementation.

Here's a step-by-step guide on setting it up:

1. Add the necessary dependencies to your Cargo.toml file:

[dependencies]
reqwest = "0.11"
log = "0.4"
env_logger = "0.9"

Make sure you use the latest versions of the crates by checking crates.io.

1. Initialize the env_logger in your main function (or wherever your application starts):

fn main() {
    // Initialize the logger
    env_logger::init();

    // Rest of your code...
}

1. Set the appropriate environment variable to control the log level. For example, to enable info-level logging for all crates, you can run your application with:

RUST_LOG=info cargo run

To enable debug-level logging for only the Reqwest crate, you can use:

RUST_LOG=reqwest=debug cargo run

1. Within your application, you can then use the log crate's macros (error!, warn!, info!, debug!, trace!) to log messages at different levels. Since you're interested in enabling logging for the Reqwest client, you don't need to add these macros explicitly for Reqwest's internal logging, but you can use them for your application's logging.

Here is an example of how to make a GET request with Reqwest with logging enabled:

use log::info;
use reqwest;
use std::error::Error;

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    // Initialize the logger
    env_logger::init();

    // Create a Reqwest client
    let client = reqwest::Client::new();

    // Make a GET request
    let response = client.get("https://httpbin.org/get").send().await?;

    // Log the response status
    info!("Response status: {}", response.status());

    // Print the response text
    let response_text = response.text().await?;
    println!("Response text: {}", response_text);

    Ok(())
}

When you run your application with the appropriate RUST_LOG environment variable set, you should see logs from Reqwest detailing the HTTP request process. The env_logger can be further configured with a more complex log filter syntax to include or exclude logs from specific modules or with specific levels. More details can be found in the env_logger documentation: https://docs.rs/env_logger/.