From ecaa4cfc1a8823d28708335934a24abdcca3246d Mon Sep 17 00:00:00 2001
From: WolfDan <5377526+WolfDan@users.noreply.github.com>
Date: Tue, 28 Oct 2025 20:00:10 -0500
Subject: [PATCH] limit max connections to server value on http2 connections

---
 lib/finch/pool_manager.ex | 15 +++++++++++++++
 mise.toml                 |  3 +++
 2 files changed, 18 insertions(+)
 create mode 100644 mise.toml

diff --git a/lib/finch/pool_manager.ex b/lib/finch/pool_manager.ex
index 6d8f141..332824d 100644
--- a/lib/finch/pool_manager.ex
+++ b/lib/finch/pool_manager.ex
@@ -143,8 +143,23 @@ defmodule Finch.PoolManager do
     |> Map.get(shp, default)
     |> maybe_drop_tls_options(shp)
     |> maybe_add_hostname(shp)
+    |> maybe_update_count(shp)
   end
 
+  defp maybe_update_count(%{count: count, mod: Finch.HTTP2.Pool} = config, {scheme, host, port}) do
+    with {:ok, conn} <- Mint.HTTP2.connect(scheme, host, port) do
+      max_concurrent_streams =
+        Mint.HTTP2.get_server_setting(conn, :max_concurrent_streams) || count
+
+      count = min(count, max_concurrent_streams)
+      Map.put(config, :count, count)
+    else
+      _ -> config
+    end
+  end
+
+  defp maybe_update_count(config, _), do: config
+
   # Drop TLS options from :conn_opts for default pools with :http scheme,
   # otherwise you will get :badarg error from :gen_tcp
   defp maybe_drop_tls_options(config, {:http, _, _} = _shp) when is_map(config) do
diff --git a/mise.toml b/mise.toml
new file mode 100644
index 0000000..7ddd7a8
--- /dev/null
+++ b/mise.toml
@@ -0,0 +1,3 @@
+[tools]
+elixir = "latest"
+erlang = "latest"