• Queue Restructuring: The ngx_http_cache_purge_process_queue function was successfully restructured to dequeue the item under the lock and process the directory walk outside of it.

• Vary_Aware Fix: ngx_http_cache_purge_invalidate_node was added to safely update shm state, preventing stale memory accounting when deleting variant files.

• Live Reload Config: ngx_http_cache_purge_init_shm_zone now correctly locks and propagates new batch_size, throttle_ms, and max_size configurations without dropping the old queue.

• Data Types & Races: The size variable in ngx_http_cache_purge_queue_s was changed from ngx_atomic_t to ngx_uint_t. A size snapshot (hash) is now captured inside the mutex in ngx_http_cache_purge_enqueue to safely log the count.

• C89 / GNU89 Compliance: Mid-scope variables like deleted, i, and caches were moved to the top of their respective blocks in the various handler functions.

• Refactoring & Cleanup: The magic number 6 was replaced with NGX_CACHE_PURGE_KEY_HDR_OFFSET. Redundant variables (resp_tmpl_len, len) were removed from send_response. A NULL check for cplcf->conf was added to the access handler. Response size globals were marked const.

• Configuration Script: The config file shebang was updated to #!/bin/sh, and writing to $NGX_AUTOCONF_ERR was replaced with standard echo output.

• Tests: "TEST 15" covering the vary_aware purge path was successfully added to t/basic.t.

Bug Fixes

• Time Unit Parsing (cache_purge_throttle_ms): Resolved an issue where bare integers were incorrectly interpreted as seconds instead of milliseconds by the NGINX configuration parser.

• Directive Context & Inheritance (cache_purge_response_type):

  • Fixed a bug that allowed duplicate directives in http and server contexts to silently overwrite each other without error.

  • Resolved a flawed context guard that prevented the directive from being correctly recognized in certain scopes.

  • Corrected the Content-Type inheritance so that settings at the http level properly propagate down to server and location blocks.

• Code Quality:

  • Fixed a typo in internal macros (renamed NGX_REPONSE_TYPE_* to NGX_CACHE_PURGE_RESPONSE_TYPE_*).

  • Renamed internal variable resptype to response_type for better maintainability.

Documentation Improvements

• Expanded README.md: Added detailed explanations for cache_purge_throttle_ms behavior and the importance of time suffixes.

• Corrected Contexts: Updated the documentation to reflect that cache_purge_response_type is valid in http, server, and location contexts.

• Performance Tuning: Updated the configuration examples and the "Throughput ceiling" formula to clarify how millisecond values impact purge rates.

Asynchronous Purging and Memory Optimization

Major release. Contains breaking internal changes.
Review the updated README before upgrading.

Background Queue System

• Implemented asynchronous purge processing to avoid blocking request workers.
• Added shared memory queue that persists across worker restarts.
• Configurable throttling to limit CPU and I/O impact under purge load.
• Queue flood protection via size limits and per-item timeouts.

Memory Management

• Fixed critical memory leak in partial purge: allocations were incorrectly
  made from the ngx_cycle pool instead of the request pool.
• Eliminated per-file heap allocations; switched to stack-based buffers.
• Introduced batch processing and hash-based deduplication to reduce
  redundant filesystem I/O.

Security

• Added path traversal protection to all file operations.
• Ensured proper file handle cleanup on all exit paths.
• NOTE: Restrict purge endpoints with allow/deny directives or an auth layer.

Logging

• Unified log prefix "ngx_cache_purge:" across all error and debug messages.
• Added debug-level logging for enqueue, dedup, background walk, and delete paths.
• Silent error paths (shm exhaustion, access denied, cache miss) now emit
  proper log entries at the correct severity level.

Infrastructure

• Migrated CI from Travis CI to GitHub Actions.
• Test matrix covers NGINX 1.20 through 1.29 on Ubuntu 20.04 and 24.04.
• Replaced legacy .t test files with a Dockerized test suite.
• Added Makefile for local builds.

• nginx 1.29.4 changed ngx_http_proxy_loc_conf_t structure which caused segfault on purge request. #52 by @arekm

Full Changelog: 2.5.5...2.5.6

What's Changed

• Fix segfault when using same-location syntax with variable cache zones #50 @dvershinin

Full Changelog: 2.5.4...2.5.5

What's Changed

• Fix memory leak when using partial (wildcard) keys. by @TaylanUB in #46

Full Changelog: 2.5.3...2.5.4

a84b0f3 Fix race-condition with two parallel PURGE (#42)

a984849 Update structs for nginx 1.19.4+ and 1.21.0+ (#41)

340da7f empty key check: it coredumps when cache key is empty, Tuğrul Topuz
e60093f purge report calloc fix: Report template has not cache file path but it's length is use in buffer memory allocation, Tuğrul Topuz

a6df03c empty key check: it coredumps when cache key is empty, Tuğrul Topuz