[fetcher] use lz4 encoding

[fetcher] use lz4 encoding
commit_hash:e29504c1f68be2a5d138dbba0ed461b2f2568b97

3 files changed, 67 insertions, 0 deletions

diff --git a/library/cpp/monlib/encode/format.cpp b/library/cpp/monlib/encode/format.cpp
index 63f9932aad2..dbcc2411f46 100644
--- a/library/cpp/monlib/encode/format.cpp
+++ b/library/cpp/monlib/encode/format.cpp
@@ -97,6 +97,21 @@ namespace NMonitoring {
         return CompressionFromHeader(value);
     }
 
+    ECompression FastestCompressionFromAcceptEncodingHeader(TStringBuf value) {
+        if (value.empty()) {
+            return ECompression::UNKNOWN;
+        }
+
+        for (const auto& it : StringSplitter(value).Split(',').SkipEmpty()) {
+            TStringBuf token = StripString(it.Token());
+            if (AsciiEqualsIgnoreCase(token, NFormatContentEncoding::LZ4)) {
+                return ECompression::LZ4;
+            }
+        }
+
+        return CompressionFromAcceptEncodingHeader(value);
+    }
+
     TStringBuf ContentEncodingByCompression(ECompression compression) {
         switch (compression) {
             case ECompression::IDENTITY:
diff --git a/library/cpp/monlib/encode/format.h b/library/cpp/monlib/encode/format.h
index d363945ec3d..08c59e192d9 100644
--- a/library/cpp/monlib/encode/format.h
+++ b/library/cpp/monlib/encode/format.h
@@ -152,6 +152,16 @@ namespace NMonitoring {
     ECompression CompressionFromAcceptEncodingHeader(TStringBuf value);
 
     /**
+     * Matches fasters compression algorithm by the given "Accept-Encoding"
+     * header value. Currently fastest accepted algorithm is lz4. If lz4 is not
+     * found in header fallbacks to CompressionFromAcceptEncodingHeader
+     *
+     * @param value  value of the "Accept-Encoding" header.
+     * @return fastest accepted compression algorithm
+     */
+    ECompression FastestCompressionFromAcceptEncodingHeader(TStringBuf value);
+
+    /**
      * Matches compression algorithm by the given "Content-Encoding" header value.
      *
      * @param value  value of the "Accept-Encoding" header.
diff --git a/library/cpp/monlib/encode/format_ut.cpp b/library/cpp/monlib/encode/format_ut.cpp
index 644a36ee532..92bcddc86bb 100644
--- a/library/cpp/monlib/encode/format_ut.cpp
+++ b/library/cpp/monlib/encode/format_ut.cpp
@@ -122,6 +122,48 @@ Y_UNIT_TEST_SUITE(TFormatTest) {
             ECompression::LZ4);
     }
 
+    Y_UNIT_TEST(FastestAcceptEncodingHeader) {
+        UNIT_ASSERT_EQUAL(
+            FastestCompressionFromAcceptEncodingHeader(""),
+            ECompression::UNKNOWN);
+
+        UNIT_ASSERT_EQUAL(
+            FastestCompressionFromAcceptEncodingHeader("br"),
+            ECompression::UNKNOWN);
+
+        UNIT_ASSERT_EQUAL(
+            FastestCompressionFromAcceptEncodingHeader("identity"),
+            ECompression::IDENTITY);
+
+        UNIT_ASSERT_EQUAL(
+            FastestCompressionFromAcceptEncodingHeader("zlib"),
+            ECompression::ZLIB);
+
+        UNIT_ASSERT_EQUAL(
+            FastestCompressionFromAcceptEncodingHeader("lz4"),
+            ECompression::LZ4);
+
+        UNIT_ASSERT_EQUAL(
+            FastestCompressionFromAcceptEncodingHeader("zstd"),
+            ECompression::ZSTD);
+
+        UNIT_ASSERT_EQUAL(
+            FastestCompressionFromAcceptEncodingHeader("zstd, zlib"),
+            ECompression::ZSTD);
+
+        UNIT_ASSERT_EQUAL(
+            FastestCompressionFromAcceptEncodingHeader(" ,, , zstd , zlib"),
+            ECompression::ZSTD);
+
+        UNIT_ASSERT_EQUAL(
+            FastestCompressionFromAcceptEncodingHeader("br, deflate,lz4, zlib"),
+            ECompression::LZ4);
+
+        UNIT_ASSERT_EQUAL(
+            FastestCompressionFromAcceptEncodingHeader("zstd, zlib, lz4"),
+            ECompression::LZ4);
+    }
+
     Y_UNIT_TEST(CompressionToStrFromStr) {
         const std::array<ECompression, 5> algs = {{
             ECompression::UNKNOWN,