Add Zstandard compression support and update tests #12201

JakeChampion · 2025-04-18T08:08:38Z

This pull request adds full support for the zstd (Zstandard) compression algorithm throughout Apache Traffic Server, including build system integration, compression plugin support, Accept-Encoding header normalization, and test coverage.

Key Features

Build system and dependencies:

Add CMake support for finding zstd library with new Findzstd.cmake
Update Docker build files to include libzstd-dev package
Add TS_HAS_ZSTD feature flag for conditional compilation

Core compression support:

Extend compress plugin to support zstd compression alongside gzip and brotli
Add zstd stream handling structures and functions
Update compression configuration to include zstd in supported algorithms list

Accept-Encoding header normalization:

Extend proxy.config.http.normalize_ae configuration to support values 4 and 5 for zstd normalization
Update HTTP transaction cache matching to handle zstd encoding

API and infrastructure:

Add TS_HTTP_VALUE_ZSTD and TS_HTTP_LEN_ZSTD constants
Update MIME field handling to recognize zstd encoding
Add zstd support to traffic_layout feature detection

Improved cache matching:

Fix Accept-Encoding quality calculation logic in HTTP transaction cache
Replace multiplicative quality combining with minimum quality selection
Remove problematic gzip-specific fallback logic that caused cache inconsistencies
Ensure proper cache behavior for all compression algorithms

Test Coverage

Comprehensive compress plugin tests covering zstd compression scenarios
Accept-Encoding normalization tests for all zstd combinations
Updated golden files to include zstd compression test results
New compress3.config for zstd-specific plugin configuration
Test all combinations of zstd, br, and gzip in various scenarios
Cache matching tests demonstrate correct behavior without workarounds

Standards Compliance

The implementation follows RFC 8878 standards for zstd compression and maintains backward compatibility with existing gzip and brotli compression functionality. All tests pass and the feature is properly integrated with existing caching and content negotiation mechanisms.

Configuration

New normalization modes:

proxy.config.http.normalize_ae = 4: Prioritize zstd, fallback to br then gzip
proxy.config.http.normalize_ae = 5: Support all combinations of zstd, br, and gzip

Benefits

Improved compression ratios compared to gzip
Better performance than brotli for compression speed
Reduced bandwidth usage and faster page loads
Seamless integration with existing ATS infrastructure

masaori335 · 2025-04-18T23:27:12Z

[approve ci]

JakeChampion · 2025-04-19T14:24:43Z

@masaori335 do you know which files I need to modify to install zstd on the osx used in the Jenkins job?

masaori335 · 2025-04-20T23:09:28Z

We need to ask @ezelkow1 to install the package in the osx env, I guess.

However, this PR has #if HAVE_ZSTD_F check, why it's failing?

JakeChampion · 2025-04-22T07:52:23Z

We need to ask @ezelkow1 to install the package in the osx env, I guess.

However, this PR has #if HAVE_ZSTD_F check, why it's failing?

thank you, _F was a mistake, it was meant to be _H

JakeChampion · 2025-04-22T11:20:27Z

Looks like all the FreeBSD machines for CI are offline

shukitchan

Really appreciate it if you can please add some documentation to the changes.

Thanks.

plugins/compress/compress.cc

cmcfarlen · 2025-04-28T16:51:36Z

Hi! This doesn't compile for me. I added a line to include/tscore/ink_config.cmake.in so HAVE_ZSTD_H would be truthy for the CPP macros. This lit up that code, but then there were several compiler errors:

/Users/cmcfarlen/projects/oss/trafficserver/plugins/compress/compress.cc:203:9: error: no member named 'zstd_ctx' in 'Data'; did you mean 'zstd_cctx'?
  203 |   data->zstd_ctx = nullptr;
      |         ^~~~~~~~
      |         zstd_cctx
/Users/cmcfarlen/projects/oss/trafficserver/plugins/compress/misc.h:93:14: note: 'zstd_cctx' declared here
   93 |   ZSTD_CCtx *zstd_cctx;
      |              ^
/Users/cmcfarlen/projects/oss/trafficserver/plugins/compress/compress.cc:206:11: error: no member named 'zstd_ctx' in 'Data'; did you mean 'zstd_cctx'?
  206 |     data->zstd_ctx = ZSTD_createCCtx();
      |           ^~~~~~~~
      |           zstd_cctx
/Users/cmcfarlen/projects/oss/trafficserver/plugins/compress/misc.h:93:14: note: 'zstd_cctx' declared here
   93 |   ZSTD_CCtx *zstd_cctx;
      |              ^
/Users/cmcfarlen/projects/oss/trafficserver/plugins/compress/compress.cc:207:16: error: no member named 'zstd_ctx' in 'Data'; did you mean 'zstd_cctx'?
  207 |     if (!data->zstd_ctx) {
      |                ^~~~~~~~
      |                zstd_cctx
/Users/cmcfarlen/projects/oss/trafficserver/plugins/compress/misc.h:93:14: note: 'zstd_cctx' declared here
   93 |   ZSTD_CCtx *zstd_cctx;
      |              ^

Please include this patch in your PR to enable the ZSTD code. Thanks!

diff --git a/include/tscore/ink_config.h.cmake.in b/include/tscore/ink_config.h.cmake.in
index 634ed94c3..7da0771fd 100644
--- a/include/tscore/ink_config.h.cmake.in
+++ b/include/tscore/ink_config.h.cmake.in
@@ -184,3 +184,5 @@ const int DEFAULT_STACKSIZE = @DEFAULT_STACK_SIZE@;
 #cmakedefine YAMLCPP_LIB_VERSION "@YAMLCPP_LIB_VERSION@"

 #cmakedefine01 TS_HAS_CRIPTS
+
+#cmakedefine HAVE_ZSTD_H 1

cmcfarlen

Please patch ink_config.h and resolve compiler issues.

plugins/compress/compress.cc

bryancall · 2025-07-14T22:44:30Z

[approve ci autest]

JakeChampion · 2025-07-15T01:18:27Z

@bryancall i think this is ready to review now 🙏

This patch adds full support for the zstd (Zstandard) compression algorithm throughout Apache Traffic Server, including build system integration, compression plugin support, Accept-Encoding header normalization, and comprehensive test coverage. Build system and dependencies: - Add CMake support for finding zstd library with new Findzstd.cmake - Update Docker build files to include libzstd-dev package - Add TS_HAS_ZSTD feature flag for conditional compilation Core compression support: - Extend compress plugin to support zstd compression alongside gzip and brotli - Add zstd stream handling structures and functions - Update compression configuration to include zstd in supported algorithms list - Add zstd compression type constant and related infrastructure Accept-Encoding header normalization: - Extend proxy.config.http.normalize_ae configuration to support values 4 and 5 for zstd normalization - Add zstd support to header normalization logic with proper priority handling (zstd > br > gzip) - Update HTTP transaction cache matching to handle zstd encoding - Add zstd token to header parsing infrastructure API and infrastructure: - Add TS_HTTP_VALUE_ZSTD and TS_HTTP_LEN_ZSTD constants - Update MIME field handling to recognize zstd encoding - Add zstd support to traffic_layout feature detection Test coverage: - Expand compress plugin tests to cover zstd compression scenarios - Add zstd test cases to Accept-Encoding normalization tests - Update golden files to include zstd compression test results - Add new compress3.config for zstd-specific plugin configuration - Test all combinations of zstd, br, and gzip in various scenarios The implementation follows RFC 8878 standards for zstd compression and maintains backward compatibility with existing gzip and brotli compression functionality. All tests pass and the feature is properly integrated with the existing caching and content negotiation mechanisms.

This patch fixes the Accept-Encoding quality calculation logic in the HTTP transaction cache and updates test files to reflect the corrected behavior, removing workarounds for previously broken cache matching. Cache quality calculation improvements: - Replace multiplicative quality combining with minimum quality selection for multiple content encodings - Simplify wildcard matching to return quality directly - Remove gzip-specific fallback logic that bypassed normal quality calculation and caused inconsistent cache behavior Test updates for corrected behavior: - Remove NOTICE comments describing broken cache matching behavior - Update test expectations to match correct cache responses instead of workaround responses - Fix cache hit/miss expectations for multi-encoding scenarios - Add missing Content-Encoding headers in server responses - Update response identifiers to match the actual cached alternates Specific test corrections: - "br, compress, gzip" now correctly matches "Br-Gzip-Accept-Encoding" instead of falling back to "Gzip-Accept-Encoding" - "zstd, compress, gzip" now correctly matches "Zstd-Gzip-Accept-Encoding" instead of falling back to "Gzip-Accept-Encoding" - "zstd, gzip;q=0.8" now correctly matches "Zstd-Gzip-Accept-Encoding" instead of falling back to "Gzip-Accept-Encoding" - Individual encoding requests now create proper cache alternates instead of incorrectly matching empty encoding alternates The previous multiplicative quality calculation (q_a * q_b) was causing unexpectedly low quality scores and incorrect cache alternate selection. The new minimum quality approach ensures that multi-encoding responses are properly cached and matched according to HTTP content negotiation standards. All test cases now pass without workarounds and demonstrate correct cache behavior for all compression algorithms (gzip, brotli, zstd) across various Accept-Encoding

- Add support for configurable compression levels per host: * gzip-compression-level (1-9, default 6) * brotli-compression-level (0-11, default 6) * brotli-lgwin (10-24, default 16) * zstd-compression-level (1-22, default 12) This enables fine-tuning compression performance vs. speed trade-offs on a per-host basis

JakeChampion force-pushed the zstd branch from 6ffb6ae to 1a113fc Compare April 18, 2025 09:49

JakeChampion marked this pull request as ready for review April 18, 2025 18:34

masaori335 assigned masaori335 and JakeChampion and unassigned masaori335 Apr 18, 2025

masaori335 self-requested a review April 18, 2025 23:25

masaori335 added the compress compress plugin label Apr 18, 2025

masaori335 added this to the 10.2.0 milestone Apr 18, 2025

cmcfarlen self-requested a review April 21, 2025 22:23

JakeChampion force-pushed the zstd branch 2 times, most recently from 0167bf5 to 74cd8b5 Compare April 22, 2025 07:51

JakeChampion force-pushed the zstd branch 4 times, most recently from 308032c to c598282 Compare April 22, 2025 10:12

JakeChampion mentioned this pull request Apr 23, 2025

Add Zstandard compression support to the compress plugin #12211

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shukitchan requested changes Apr 23, 2025

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JakeChampion commented Apr 23, 2025

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plugins/compress/compress.cc Outdated Show resolved Hide resolved

bryancall added the New Feature label Apr 23, 2025

bryancall added this to ATS v10.1.x Apr 23, 2025

cmcfarlen requested changes Apr 28, 2025

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JakeChampion force-pushed the zstd branch 3 times, most recently from 4b8603e to 72c0dbf Compare May 28, 2025 19:48

JakeChampion force-pushed the zstd branch from 7f4f01b to 797b41d Compare July 15, 2025 00:33

JakeChampion force-pushed the zstd branch 11 times, most recently from 6a9110b to 6c3f2ca Compare July 15, 2025 17:06

JakeChampion added 3 commits July 15, 2025 21:19

Fix case sensitivity in ZSTD package find command

eda7c29

JakeChampion force-pushed the zstd branch 3 times, most recently from 107214f to 1a4fc19 Compare July 15, 2025 21:19

Add ZSTD version output to compile-time features

21e27bf

JakeChampion force-pushed the zstd branch from 1a4fc19 to 21e27bf Compare July 15, 2025 21:20

JakeChampion added 3 commits July 15, 2025 23:52

Add ZSTD support to Accept-Encoding and Content-Encoding headers

2a2acf6

Add ZSTD length definition to HTTP value initialization

536f920

Update ZSTD compression level from 6 to 10 for improved performance

9a5432d

JakeChampion force-pushed the zstd branch from a84f4b4 to 9a5432d Compare July 16, 2025 00:36

JakeChampion and others added 4 commits July 16, 2025 09:39

Update compress.gold

d94321d

Update compress.gold

729fbac

Merge branch 'master' into zstd

4bf0c10

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Key Features

Build system and dependencies:

Core compression support:

Accept-Encoding header normalization:

API and infrastructure:

Improved cache matching:

Test Coverage

Standards Compliance

Configuration

Benefits

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