From 0d2bf7acf994ba331d6f72c746721b354931be76 Mon Sep 17 00:00:00 2001
From: Solene Rapenne <solene@perso.pw>
Date: Fri, 19 Aug 2022 12:40:22 +0200
Subject: [PATCH] add a nix.conf option to set a download speed limit

---
 src/libstore/filetransfer.cc | 3 +++
 src/libstore/globals.hh      | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/src/libstore/filetransfer.cc b/src/libstore/filetransfer.cc
index 8454ad7d2..252403cb5 100644
--- a/src/libstore/filetransfer.cc
+++ b/src/libstore/filetransfer.cc
@@ -308,6 +308,9 @@ struct curlFileTransfer : public FileTransfer
 
             curl_easy_setopt(req, CURLOPT_HTTPHEADER, requestHeaders);
 
+            if (settings.downloadSpeed.get() > 0)
+                curl_easy_setopt(req, CURLOPT_MAX_RECV_SPEED_LARGE, (curl_off_t) (settings.downloadSpeed.get() * 1024));
+
             if (request.head)
                 curl_easy_setopt(req, CURLOPT_NOBODY, 1);
 
diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh
index d7f351166..ca8fc6d5f 100644
--- a/src/libstore/globals.hh
+++ b/src/libstore/globals.hh
@@ -746,6 +746,13 @@ public:
               /nix/store/xfghy8ixrhz3kyy6p724iv3cxji088dx-bash-4.4-p23`.
         )"};
 
+    Setting<unsigned int> downloadSpeed {
+        this, 0, "download-speed",
+        R"(
+          Specify the maxium transfer rate in kilobytes per second you want
+          nix to use for download.
+        )"};
+
     Setting<std::string> netrcFile{
         this, fmt("%s/%s", nixConfDir, "netrc"), "netrc-file",
         R"(