From fa7f0d6d07bdbedd06904d52bd111e58cb3d64c9 Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Sun, 16 Feb 2025 20:01:03 -0500
Subject: [PATCH] Allow setting `ssh://` pipe size

Exposed for Hydra. We could make it fancier but with (a) new store
settings (b) switch to `ssh-ng://` both in the works, it doesn't seem
worth it.

(cherry picked from commit 94a7c34b2f8285650e3130e5dc6ff5333eaa6dc8)
---
 src/libstore/legacy-ssh-store.cc | 3 +++
 src/libstore/legacy-ssh-store.hh | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/src/libstore/legacy-ssh-store.cc b/src/libstore/legacy-ssh-store.cc
index 3f62794ef..3849f088d 100644
--- a/src/libstore/legacy-ssh-store.cc
+++ b/src/libstore/legacy-ssh-store.cc
@@ -70,6 +70,9 @@ ref<LegacySSHStore::Connection> LegacySSHStore::openConnection()
         command.push_back(remoteStore.get());
     }
     conn->sshConn = master.startCommand(std::move(command), std::list{extraSshArgs});
+    if (connPipeSize) {
+        conn->sshConn->trySetBufferSize(*connPipeSize);
+    }
     conn->to = FdSink(conn->sshConn->in.get());
     conn->from = FdSource(conn->sshConn->out.get());
 
diff --git a/src/libstore/legacy-ssh-store.hh b/src/libstore/legacy-ssh-store.hh
index 2444a7a66..92aa4ae56 100644
--- a/src/libstore/legacy-ssh-store.hh
+++ b/src/libstore/legacy-ssh-store.hh
@@ -30,6 +30,11 @@ struct LegacySSHStoreConfig : virtual CommonSSHStoreConfig
      */
     Strings extraSshArgs = {};
 
+    /**
+     * Exposed for hydra
+     */
+    std::optional<size_t> connPipeSize;
+
     const std::string name() override { return "SSH Store"; }
 
     static std::set<std::string> uriSchemes() { return {"ssh"}; }