From 5357c57873d98241050859e0bcf2ee26ddf11211 Mon Sep 17 00:00:00 2001
From: Akshay Mankar <akshay@wire.com>
Date: Wed, 20 Dec 2023 09:34:58 +0100
Subject: [PATCH 1/2] http2-manager: Expose a function to allow single use
 connections

---
 libs/http2-manager/src/HTTP2/Client/Manager.hs          | 1 +
 libs/http2-manager/src/HTTP2/Client/Manager/Internal.hs | 9 +++++++++
 2 files changed, 10 insertions(+)

diff --git a/libs/http2-manager/src/HTTP2/Client/Manager.hs b/libs/http2-manager/src/HTTP2/Client/Manager.hs
index 2cf1278061..b163b7fdf0 100644
--- a/libs/http2-manager/src/HTTP2/Client/Manager.hs
+++ b/libs/http2-manager/src/HTTP2/Client/Manager.hs
@@ -11,6 +11,7 @@ module HTTP2.Client.Manager
     defaultHttp2Manager,
     http2ManagerWithSSLCtx,
     withHTTP2Request,
+    withHTTP2RequestOnSingleUseConn,
     connectIfNotAlreadyConnected,
     ConnectionAlreadyClosed (..),
     disconnectTarget,
diff --git a/libs/http2-manager/src/HTTP2/Client/Manager/Internal.hs b/libs/http2-manager/src/HTTP2/Client/Manager/Internal.hs
index 884bc46959..0dd00173c8 100644
--- a/libs/http2-manager/src/HTTP2/Client/Manager/Internal.hs
+++ b/libs/http2-manager/src/HTTP2/Client/Manager/Internal.hs
@@ -165,6 +165,15 @@ withHTTP2Request mgr target req k = do
   conn <- getOrMakeConnection mgr target
   sendRequestWithConnection conn req k
 
+-- | Temporary workaround for https://github.com/kazu-yamamoto/http2/issues/102
+withHTTP2RequestOnSingleUseConn :: Http2Manager -> Target -> HTTP2.Request -> (HTTP2.Response -> IO a) -> IO a
+withHTTP2RequestOnSingleUseConn Http2Manager {..} target req k = do
+  sendReqMVar <- newEmptyMVar
+  thread <- liftIO . async $ startPersistentHTTP2Connection sslContext target cacheLimit sslRemoveTrailingDot tcpConnectionTimeout sendReqMVar
+  let newConn = HTTP2Conn thread (putMVar sendReqMVar CloseConnection) sendReqMVar
+  sendRequestWithConnection newConn req $ \resp -> do
+    k resp <* disconnect newConn
+
 -- | Connects to a server if it is not already connected, useful when making
 -- many concurrent requests. This way the first few requests don't have to fight
 -- for making a connection This way the first few requests don't have to fight

From b7b258cda111063759f2fa94a3b675d49d305e3d Mon Sep 17 00:00:00 2001
From: Akshay Mankar <akshay@wire.com>
Date: Wed, 20 Dec 2023 09:35:28 +0100
Subject: [PATCH 2/2] federator: Do no reuse connections when talking to
 remotes

This comes with performance penalty but its required to get around this bug in
the http2 library: https://github.com/kazu-yamamoto/http2/issues/102
---
 services/federator/src/Federator/Remote.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/services/federator/src/Federator/Remote.hs b/services/federator/src/Federator/Remote.hs
index 21f1443c78..7f1b880dbe 100644
--- a/services/federator/src/Federator/Remote.hs
+++ b/services/federator/src/Federator/Remote.hs
@@ -101,7 +101,7 @@ interpretRemote = interpret $ \case
     resp <- mapError (RemoteError target pathT) . (fromEither @FederatorClientHTTP2Error =<<) . embed $
       Codensity $ \k ->
         E.catches
-          (H2Manager.withHTTP2Request mgr (True, hostname, fromIntegral port) req' (consumeStreamingResponseWith $ k . Right))
+          (H2Manager.withHTTP2RequestOnSingleUseConn mgr (True, hostname, fromIntegral port) req' (consumeStreamingResponseWith $ k . Right))
           [ E.Handler $ k . Left,
             E.Handler $ k . Left . FederatorClientTLSException,
             E.Handler $ k . Left . FederatorClientHTTP2Exception,