feat(tvix/store): set user-agent for NixHTTPPathInfoService

Change-Id: I8eb74c5a9457b88ab51bd88084591a4c7c5cdbcc
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12849
Reviewed-by: Domen Kožar <domen@cachix.org>
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>

tvix/store/src/lib.rs

@@ -9,6 +9,9 @@ pub mod utils;
 #[cfg(test)]
 mod tests;
 
+// Used as user agent in various HTTP Clients
+const USER_AGENT: &str = concat!(env!("CARGO_PKG_NAME"), "/", env!("CARGO_PKG_VERSION"));
+
 // That's what the rstest_reuse README asks us do, and fails about being unable
 // to find rstest_reuse in crate root.
 #[cfg(test)]

tvix/store/src/pathinfoservice/nix_http.rs

@@ -54,9 +54,14 @@ impl<BS, DS> NixHTTPPathInfoService<BS, DS> {
         Self {
             instance_name,
             base_url,
-            http_client: reqwest_middleware::ClientBuilder::new(reqwest::Client::new())
-                .with(tvix_tracing::propagate::reqwest::tracing_middleware())
-                .build(),
+            http_client: reqwest_middleware::ClientBuilder::new(
+                reqwest::Client::builder()
+                    .user_agent(crate::USER_AGENT)
+                    .build()
+                    .expect("Client::new()"),
+            )
+            .with(tvix_tracing::propagate::reqwest::tracing_middleware())
+            .build(),
             blob_service,
             directory_service,