test(pkg): bring back timeout (#10761)

Signed-off-by: Rudi Grinberg <[email protected]>

<!-- ps-id: d7a9413b-ee57-493f-bc88-5f323386ac42 -->

Author: rgrinberg

test/blackbox-tests/test-cases/pkg/compute-checksums-when-missing.t

@@ -15,6 +15,10 @@ A file that will comprise the package source:
   $ echo "Hello, World!" > foo.txt
 
 Run the server in the background:
+
+We have some really slow tests here
+  $ export DUNE_WEBSERVER_TIMEOUT=10
+
   $ webserver_oneshot --content-file foo.txt --port-file port.txt &
   $ until test -f port.txt; do sleep 0.1; done
   $ PORT=$(cat port.txt)

test/http/http.ml

@@ -36,8 +36,23 @@ module Server = struct
     loop ()
   ;;
 
+  let auto_shutdown_seconds =
+    match Sys.getenv_opt "DUNE_WEBSERVER_TIMEOUT" with
+    | None -> 5.
+    | Some s -> Float.of_string s |> Option.value_exn
+  ;;
+
   let accept t ~f =
-    let descr, _sockaddr = Unix.accept ~cloexec:true t.sock in
+    let descr, _sockaddr =
+      let read_fds, _write_fds, _excpt_fds =
+        Unix.select [ t.sock ] [] [] auto_shutdown_seconds
+      in
+      match read_fds with
+      | _ :: _ -> Unix.accept ~cloexec:true t.sock
+      | [] ->
+        Format.eprintf "Exiting after timeout@.";
+        failwith "timeout"
+    in
     let out = Unix.out_channel_of_descr descr in
     let in_ = Unix.in_channel_of_descr descr in
     let session = in_, out in