From f96773e829f3ea1221bd609845c495a94baef6a5 Mon Sep 17 00:00:00 2001
From: Ritchie Vink <ritchie46@gmail.com>
Date: Mon, 12 Feb 2024 08:56:49 -0800
Subject: [PATCH] feat: restrict more cloud interop to semaphore budget
 (#14435)

---
 crates/polars-io/src/cloud/options.rs      | 19 +++++++++------
 crates/polars-io/src/parquet/async_impl.rs | 28 +++++++++++++---------
 2 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/crates/polars-io/src/cloud/options.rs b/crates/polars-io/src/cloud/options.rs
index 5338682d477d..1df835d5d3b0 100644
--- a/crates/polars-io/src/cloud/options.rs
+++ b/crates/polars-io/src/cloud/options.rs
@@ -37,6 +37,8 @@ use smartstring::alias::String as SmartString;
 #[cfg(feature = "cloud")]
 use url::Url;
 
+#[cfg(feature = "aws")]
+use crate::pl_async::with_concurrency_budget;
 #[cfg(feature = "aws")]
 use crate::utils::resolve_homedir;
 
@@ -284,13 +286,16 @@ impl CloudOptions {
                         builder = builder.with_config(AmazonS3ConfigKey::Region, "us-east-1");
                     } else {
                         polars_warn!("'(default_)region' not set; polars will try to get it from bucket\n\nSet the region manually to silence this warning.");
-                        let result = reqwest::Client::builder()
-                            .build()
-                            .unwrap()
-                            .head(format!("https://{bucket}.s3.amazonaws.com"))
-                            .send()
-                            .await
-                            .map_err(to_compute_err)?;
+                        let result = with_concurrency_budget(1, || async {
+                            reqwest::Client::builder()
+                                .build()
+                                .unwrap()
+                                .head(format!("https://{bucket}.s3.amazonaws.com"))
+                                .send()
+                                .await
+                                .map_err(to_compute_err)
+                        })
+                        .await?;
                         if let Some(region) = result.headers().get("x-amz-bucket-region") {
                             let region =
                                 std::str::from_utf8(region.as_bytes()).map_err(to_compute_err)?;
diff --git a/crates/polars-io/src/parquet/async_impl.rs b/crates/polars-io/src/parquet/async_impl.rs
index 49bf30d45087..c13e5a3c46f1 100644
--- a/crates/polars-io/src/parquet/async_impl.rs
+++ b/crates/polars-io/src/parquet/async_impl.rs
@@ -80,14 +80,17 @@ impl ParquetObjectStore {
         if self.length.is_some() {
             return Ok(());
         }
-        self.length = Some(
-            self.store
-                .head(&self.path)
-                .await
-                .map_err(to_compute_err)?
-                .size as u64,
-        );
-        Ok(())
+        with_concurrency_budget(1, || async {
+            self.length = Some(
+                self.store
+                    .head(&self.path)
+                    .await
+                    .map_err(to_compute_err)?
+                    .size as u64,
+            );
+            Ok(())
+        })
+        .await
     }
 
     pub async fn schema(&mut self) -> PolarsResult<ArrowSchemaRef> {
@@ -112,9 +115,12 @@ impl ParquetObjectStore {
         let length = self.length;
         let mut reader = CloudReader::new(length, object_store, path);
 
-        parquet2_read::read_metadata_async(&mut reader)
-            .await
-            .map_err(to_compute_err)
+        with_concurrency_budget(1, || async {
+            parquet2_read::read_metadata_async(&mut reader)
+                .await
+                .map_err(to_compute_err)
+        })
+        .await
     }
 
     /// Fetch and memoize the metadata of the parquet file.