From 90ad02bf626b885a5dd8967894e2eafc953bdf92 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Wed, 14 Sep 2016 16:00:40 +0200 Subject: Enable HTTP/2 support The binary cache store can now use HTTP/2 to do lookups. This is much more efficient than HTTP/1.1 due to multiplexing: we can issue many requests in parallel over a single TCP connection. Thus it's no longer necessary to use a bunch of concurrent TCP connections (25 by default). For example, downloading 802 .narinfo files from https://cache.nixos.org/, using a single TCP connection, takes 11.8s with HTTP/1.1, but only 0.61s with HTTP/2. This did require a fairly substantial rewrite of the Downloader class to use the curl multi interface, because otherwise curl wouldn't be able to do multiplexing for us. As a bonus, we get connection reuse even with HTTP/1.1. All downloads are now handled by a single worker thread. Clients call Downloader::enqueueDownload() to tell the worker thread to start the download, getting a std::future to the result. --- src/libstore/builtins.cc | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'src/libstore/builtins.cc') diff --git a/src/libstore/builtins.cc b/src/libstore/builtins.cc index d3194a905..a30f30906 100644 --- a/src/libstore/builtins.cc +++ b/src/libstore/builtins.cc @@ -17,13 +17,15 @@ void builtinFetchurl(const BasicDerivation & drv) auto fetch = [&](const string & url) { /* No need to do TLS verification, because we check the hash of the result anyway. */ - DownloadOptions options; - options.verifyTLS = false; + DownloadRequest request(url); + request.verifyTLS = false; /* Show a progress indicator, even though stderr is not a tty. */ - options.showProgress = DownloadOptions::yes; + request.showProgress = DownloadRequest::yes; - auto data = makeDownloader()->download(url, options); + /* Note: have to use a fresh downloader here because we're in + a forked process. */ + auto data = makeDownloader()->download(request); assert(data.data); return data.data; -- cgit v1.2.3