Merge #609

609: Retry downloading the benchmarks datasets r=Kerollmops a=irevoire

Downloading the benchmarks datasets is failing [more and more](https://github.com/meilisearch/milli/pull/607#pullrequestreview-1076023074) often; thus, instead of fixing the issue, I thought we could retry multiple times.


Co-authored-by: Irevoire <tamo@meilisearch.com>

benchmarks/build.rs

@@ -80,7 +80,7 @@ fn main() -> anyhow::Result<()> {
         }
         let url = format!("{}/{}.{}.gz", BASE_URL, dataset, extension);
         eprintln!("downloading: {}", url);
-        let bytes = download_dataset(url.clone())?;
+        let bytes = retry(|| download_dataset(url.clone()), 10)?;
         eprintln!("{} downloaded successfully", url);
         eprintln!("uncompressing in {}", out_file.display());
         uncompress_in_file(bytes, &out_file)?;
@@ -89,6 +89,15 @@ fn main() -> anyhow::Result<()> {
     Ok(())
 }
 
+fn retry<Ok, Err>(fun: impl Fn() -> Result<Ok, Err>, times: usize) -> Result<Ok, Err> {
+    for _ in 0..times {
+        if let ok @ Ok(_) = fun() {
+            return ok;
+        }
+    }
+    fun()
+}
+
 fn download_dataset<U: IntoUrl>(url: U) -> anyhow::Result<Cursor<Bytes>> {
     let bytes =
         reqwest::blocking::Client::builder().timeout(None).build()?.get(url).send()?.bytes()?;