Add Zstandard (zstd) compression support to the compress plugin

- Updated CMakeLists.txt and Dockerfiles to include zstd dependencies.
- Implemented zstd compression in compress.cc and added related functions.
- Enhanced configuration to support zstd as a compression algorithm.
- Updated tests to verify zstd functionality.

Author: JakeChampion

CMakeLists.txt

@@ -338,6 +338,11 @@ set(TS_USE_MALLOC_ALLOCATOR ${ENABLE_MALLOC_ALLOCATOR})
 set(TS_USE_ALLOCATOR_METRICS ${ENABLE_ALLOCATOR_METRICS})
 find_package(ZLIB REQUIRED)
 
+find_package(ZSTD)
+if(ZSTD_FOUND)
+  set(HAVE_ZSTD_H TRUE)
+endif()
+
 # ncurses is used in traffic_top
 find_package(Curses)
 set(HAVE_CURSES_H ${CURSES_HAVE_CURSES_H})

ci/docker/deb/Dockerfile

@@ -55,7 +55,8 @@ RUN apt-get update; apt-get -y dist-upgrade; \
     apt-get -y install libssl-dev libexpat1-dev libpcre3-dev libcap-dev \
     libhwloc-dev libunwind8 libunwind-dev zlib1g-dev \
     tcl-dev tcl8.6-dev libjemalloc-dev libluajit-5.1-dev liblzma-dev \
-    libhiredis-dev libbrotli-dev libncurses-dev libgeoip-dev libmagick++-dev; \
+    libhiredis-dev libbrotli-dev libncurses-dev libgeoip-dev libmagick++-dev \
+    libzstd-dev; \
     # Optional: This is for the OpenSSH server, and Jenkins account + access (comment out if not needed)
     apt-get -y install openssh-server openjdk-8-jre && mkdir /run/sshd; \
     groupadd  -g 665 jenkins && \

ci/docker/yum/Dockerfile

@@ -52,7 +52,7 @@ RUN yum -y update; \
     # Devel packages that ATS needs
     yum -y install openssl-devel expat-devel pcre-devel libcap-devel hwloc-devel libunwind-devel \
     xz-devel libcurl-devel ncurses-devel jemalloc-devel GeoIP-devel luajit-devel brotli-devel \
-    ImageMagick-devel ImageMagick-c++-devel hiredis-devel zlib-devel \
+    ImageMagick-devel ImageMagick-c++-devel hiredis-devel zlib-devel zstd-devel \
     perl-ExtUtils-MakeMaker perl-Digest-SHA perl-URI; \
     # This is for autest stuff
     yum -y install python3 httpd-tools procps-ng nmap-ncat pipenv \

cmake/Findzstd.cmake

@@ -0,0 +1,53 @@
+#######################
+#
+#  Licensed to the Apache Software Foundation (ASF) under one or more contributor license
+#  agreements.  See the NOTICE file distributed with this work for additional information regarding
+#  copyright ownership.  The ASF licenses this file to you under the Apache License, Version 2.0
+#  (the "License"); you may not use this file except in compliance with the License.  You may obtain
+#  a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software distributed under the License
+#  is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+#  or implied. See the License for the specific language governing permissions and limitations under
+#  the License.
+#
+#######################
+
+# Findzstd.cmake
+#
+# This will define the following variables
+#
+#     ZSTD_FOUND
+#     ZSTD_LIBRARY
+#     ZSTD_INCLUDE_DIRS
+#
+# and the following imported target
+#
+#     zstd::zstd
+#
+
+find_path(ZSTD_INCLUDE_DIR NAMES zstd.h)
+
+find_library(ZSTD_LIBRARY_DEBUG NAMES zstdd zstd_staticd)
+find_library(ZSTD_LIBRARY_RELEASE NAMES zstd zstd_static)
+
+mark_as_advanced(ZSTD_LIBRARY ZSTD_INCLUDE_DIR)
+
+include(SelectLibraryConfigurations)
+select_library_configurations(ZSTD)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(ZSTD DEFAULT_MSG ZSTD_LIBRARY ZSTD_INCLUDE_DIR)
+
+if(ZSTD_FOUND)
+  set(ZSTD_INCLUDE_DIRS "${ZSTD_INCLUDE_DIR}")
+endif()
+
+if(ZSTD_FOUND AND NOT TARGET zstd::zstd)
+  add_library(zstd::zstd INTERFACE IMPORTED)
+  target_include_directories(zstd::zstd INTERFACE ${ZSTD_INCLUDE_DIRS})
+  target_link_libraries(zstd::zstd INTERFACE "${ZSTD_LIBRARY}")
+endif()

contrib/docker/ubuntu/noble/Dockerfile

@@ -48,6 +48,7 @@ RUN apt update \
     libpcre3-dev \
     hwloc \
     libbrotli-dev \
+    libzstd-dev \
     luajit \
     libcap-dev \
     libmagick++-dev \

plugins/compress/CMakeLists.txt

@@ -20,5 +20,10 @@ target_link_libraries(compress PRIVATE libswoc::libswoc)
 if(HAVE_BROTLI_ENCODE_H)
   target_link_libraries(compress PRIVATE brotli::brotlienc)
 endif()
+
+if(HAVE_ZSTD_H)
+  target_link_libraries(compress PRIVATE zstd::zstd)
+endif()
+
 verify_global_plugin(compress)
 verify_remap_plugin(compress)

plugins/compress/compress.cc

@@ -1,6 +1,6 @@
 /** @file
 
-  Transforms content using gzip, deflate or brotli
+  Transforms content using gzip, deflate, brotli or zstd
 
   @section license License
 
@@ -23,6 +23,9 @@
 
 #include <cstring>
 #include <zlib.h>
+#if HAVE_ZSTD_H
+#include <zstd.h>
+#endif
 
 #include "ts/apidefs.h"
 #include "tscore/ink_config.h"
@@ -71,6 +74,10 @@ const int BROTLI_COMPRESSION_LEVEL = 6;
 const int BROTLI_LGW               = 16;
 #endif
 
+#if HAVE_ZSTD_H
+const int ZSTD_COMPRESSION_LEVEL = 6;
+#endif
+
 static const char *global_hidden_header_name = nullptr;
 
 static TSMutex compress_config_mutex = nullptr;
@@ -191,6 +198,16 @@ data_alloc(int compression_type, int compression_algorithms)
     data->bstrm.avail_out = 0;
     data->bstrm.total_out = 0;
   }
+#endif
+#if HAVE_ZSTD_H
+  data->zstd_ctx = nullptr;
+  if (compression_type & COMPRESSION_TYPE_ZSTD) {
+    debug("zstd compression. Create Zstd Compression Context.");
+    data->zstd_ctx = ZSTD_createCCtx();
+    if (!data->zstd_ctx) {
+      fatal("Zstd Compression Context Creation Failed");
+    }
+  }
 #endif
   return data;
 }
@@ -212,6 +229,11 @@ data_destroy(Data *data)
 #if HAVE_BROTLI_ENCODE_H
   BrotliEncoderDestroyInstance(data->bstrm.br);
 #endif
+#if HAVE_ZSTD_H
+  if (data->zstd_ctx) {
+    ZSTD_freeCCtx(data->zstd_ctx);
+  }
+#endif
 
   TSfree(data);
 }
@@ -233,6 +255,9 @@ content_encoding_header(TSMBuffer bufp, TSMLoc hdr_loc, const int compression_ty
   } else if (compression_type & COMPRESSION_TYPE_DEFLATE && (algorithm & ALGORITHM_DEFLATE)) {
     value     = TS_HTTP_VALUE_DEFLATE;
     value_len = TS_HTTP_LEN_DEFLATE;
+  } else if (compression_type & COMPRESSION_TYPE_ZSTD && (algorithm & ALGORITHM_ZSTD)) {
+    value     = "zstd";
+    value_len = strlen("zstd");
   }
 
   if (value_len == 0) {
@@ -357,6 +382,16 @@ compress_transform_init(TSCont contp, Data *data)
     data->downstream_vio    = TSVConnWrite(downstream_conn, contp, data->downstream_reader, INT64_MAX);
   }
 
+#if HAVE_ZSTD_H
+  if (data->compression_type & COMPRESSION_TYPE_ZSTD) {
+    zstd_compress_init(data);
+    if (!data->zstd_cctx) {
+      TSError("Failed to create Zstandard compression context");
+      return;
+    }
+  }
+#endif
+
   TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
 }
 
@@ -462,6 +497,40 @@ brotli_transform_one(Data *data, const char *upstream_buffer, int64_t upstream_l
 }
 #endif
 
+#if HAVE_ZSTD_H
+static void
+zstd_compress_init(Data *data)
+{
+  data->zstd_cctx = ZSTD_createCCtx();
+  if (!data->zstd_cctx) {
+    error("Failed to initialize Zstd compression context");
+  }
+}
+
+static void
+zstd_compress_finish(Data *data)
+{
+  if (data->zstd_cctx) {
+    ZSTD_freeCCtx(data->zstd_cctx);
+    data->zstd_cctx = nullptr;
+  }
+}
+
+static void
+zstd_compress_one(Data *data, const char *upstream_buffer, int64_t upstream_length)
+{
+  char   output_buffer[ZSTD_CStreamOutSize()];
+  size_t compressed_size = ZSTD_compressCCtx(data->zstd_cctx, output_buffer, sizeof(output_buffer), upstream_buffer,
+                                             upstream_length, ZSTD_COMPRESSION_LEVEL);
+  if (ZSTD_isError(compressed_size)) {
+    error("Zstd compression failed: %s", ZSTD_getErrorName(compressed_size));
+    return;
+  }
+  TSIOBufferWrite(data->downstream_buffer, output_buffer, compressed_size);
+  data->downstream_length += compressed_size;
+}
+#endif
+
 static void
 compress_transform_one(Data *data, TSIOBufferReader upstream_reader, int amount)
 {
@@ -488,6 +557,11 @@ compress_transform_one(Data *data, TSIOBufferReader upstream_reader, int amount)
     if (data->compression_type & COMPRESSION_TYPE_BROTLI && (data->compression_algorithms & ALGORITHM_BROTLI)) {
       brotli_transform_one(data, upstream_buffer, upstream_length);
     } else
+#endif
+#if HAVE_ZSTD_H
+      if (data->compression_type & COMPRESSION_TYPE_ZSTD && (data->compression_algorithms & ALGORITHM_ZSTD)) {
+      zstd_compress_one(data, upstream_buffer, upstream_length);
+    } else
 #endif
       if ((data->compression_type & (COMPRESSION_TYPE_GZIP | COMPRESSION_TYPE_DEFLATE)) &&
           (data->compression_algorithms & (ALGORITHM_GZIP | ALGORITHM_DEFLATE))) {
@@ -576,6 +650,12 @@ compress_transform_finish(Data *data)
     brotli_transform_finish(data);
     debug("compress_transform_finish: brotli compression finish");
   } else
+#endif
+#if HAVE_ZSTD_H
+    if (data->compression_type & COMPRESSION_TYPE_ZSTD && data->compression_algorithms & ALGORITHM_ZSTD) {
+    zstd_compress_finish(data);
+    debug("compress_transform_finish: zstd compression finish");
+  } else
 #endif
     if ((data->compression_type & (COMPRESSION_TYPE_GZIP | COMPRESSION_TYPE_DEFLATE)) &&
         (data->compression_algorithms & (ALGORITHM_GZIP | ALGORITHM_DEFLATE))) {
@@ -771,6 +851,11 @@ transformable(TSHttpTxn txnp, bool server, HostConfiguration *host_configuration
           compression_acceptable = 1;
         }
         *compress_type |= COMPRESSION_TYPE_GZIP;
+      } else if (strncasecmp(value, "zstd", sizeof("zstd") - 1) == 0) {
+        if (*algorithms & ALGORITHM_ZSTD) {
+          compression_acceptable = 1;
+        }
+        *compress_type |= COMPRESSION_TYPE_ZSTD;
       }
     }
 

plugins/compress/configuration.cc

@@ -229,6 +229,12 @@ HostConfiguration::add_compression_algorithms(string &line)
     string token = extractFirstToken(line, isCommaOrSpace);
     if (token.empty()) {
       break;
+    } else if (token == "zstd") {
+#ifdef HAVE_ZSTD_H
+      compression_algorithms_ |= ALGORITHM_ZSTD;
+#else
+      error("supported-algorithms: zstd support not compiled in.");
+#endif
     } else if (token == "br") {
 #ifdef HAVE_BROTLI_ENCODE_H
       compression_algorithms_ |= ALGORITHM_BROTLI;
@@ -334,6 +340,10 @@ Configuration::Parse(const char *path)
       continue;
     }
 
+    if (strstr(line.c_str(), "zstd")) {
+      current_host_configuration->add_compression_algorithms(line);
+    }
+
     for (;;) {
       string token = extractFirstToken(line, isspace);
 

plugins/compress/configuration.h

@@ -38,7 +38,8 @@ enum CompressionAlgorithm {
   ALGORITHM_DEFAULT = 0,
   ALGORITHM_DEFLATE = 1,
   ALGORITHM_GZIP    = 2,
-  ALGORITHM_BROTLI  = 4 // For bit manipulations
+  ALGORITHM_BROTLI  = 4, // For bit manipulations
+  ALGORITHM_ZSTD    = 8
 };
 
 enum class RangeRequestCtrl : int {

plugins/compress/misc.cc

@@ -84,6 +84,7 @@ normalize_accept_encoding(TSHttpTxn /* txnp ATS_UNUSED */, TSMBuffer reqp, TSMLo
   bool   deflate = false;
   bool   gzip    = false;
   bool   br      = false;
+  bool   zstd    = false;
   // remove the accept encoding field(s),
   // while finding out if gzip or deflate is supported.
   while (field) {
@@ -100,6 +101,8 @@ normalize_accept_encoding(TSHttpTxn /* txnp ATS_UNUSED */, TSMBuffer reqp, TSMLo
           br = true;
         } else if (strcasecmp("deflate", next) == 0) {
           deflate = true;
+        } else if (strcasecmp("zstd", next) == 0) {
+          zstd = true;
         }
       }
     }
@@ -111,9 +114,13 @@ normalize_accept_encoding(TSHttpTxn /* txnp ATS_UNUSED */, TSMBuffer reqp, TSMLo
   }
 
   // append a new accept-encoding field in the header
-  if (deflate || gzip || br) {
+  if (deflate || gzip || br || zstd) {
     TSMimeHdrFieldCreate(reqp, hdr_loc, &field);
     TSMimeHdrFieldNameSet(reqp, hdr_loc, field, TS_MIME_FIELD_ACCEPT_ENCODING, TS_MIME_LEN_ACCEPT_ENCODING);
+    if (zstd) {
+      TSMimeHdrFieldValueStringInsert(reqp, hdr_loc, field, -1, "zstd", strlen("zstd"));
+      info("normalized accept encoding to zstd");
+    }
     if (br) {
       TSMimeHdrFieldValueStringInsert(reqp, hdr_loc, field, -1, "br", strlen("br"));
       info("normalized accept encoding to br");