Use cache instead of downloading file each time

This is particularly useful if internet is down.

Cargo.lock

@@ -937,6 +937,7 @@ dependencies = [
  "reqwest",
  "tempfile",
  "tokio",
+ "tracing",
 ]
 
 [[package]]

libraries/extensions/download/Cargo.toml

@@ -11,3 +11,4 @@ eyre = "0.6.8"
 tempfile = "3.3.0"
 reqwest = "0.11.12"
 tokio = { version = "1.17.0" }
+tracing = "0.1.36"

libraries/extensions/download/src/lib.rs

@@ -3,11 +3,17 @@ use eyre::Context;
 use std::os::unix::prelude::PermissionsExt;
 use std::path::Path;
 use tokio::io::AsyncWriteExt;
+use tracing::log::warn;
 
 pub async fn download_file<T>(url: T, target_path: &Path) -> Result<(), eyre::ErrReport>
 where
     T: reqwest::IntoUrl + std::fmt::Display + Copy,
 {
+    if target_path.exists() {
+        warn!("Using cache: {:?}", target_path.to_str());
+        return Ok(());
+    }
+
     if let Some(parent) = target_path.parent() {
         tokio::fs::create_dir_all(parent)
             .await