S3BinaryCacheStore: Support compression of narinfo and log files

You can now set the store parameter "text-compression=br" to compress
textual files in the binary cache (i.e. narinfo and logs) using
Brotli. This sets the Content-Encoding header; the extension of
compressed files is unchanged.

You can separately specify the compression of log files using
"log-compression=br". This is useful when you don't want to compress
narinfo files for backward compatibility.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/libstore/binary-cache-store.cc b/src/libstore/binary-cache-store.cc
index 120345b267..804e3f6aa1 100644
--- a/src/libstore/binary-cache-store.cc
+++ b/src/libstore/binary-cache-store.cc
@@ -250,6 +250,7 @@ void BinaryCacheStore::addToStore(const ValidPathInfo & info, const ref<std::str
     narInfo->url = "nar/" + printHash32(narInfo->fileHash) + ".nar"
         + (compression == "xz" ? ".xz" :
            compression == "bzip2" ? ".bz2" :
+           compression == "br" ? ".br" :
            "");
     if (repair || !fileExists(narInfo->url)) {
         stats.narWrite++;