rsyslog-module

rsyslog_module

This skill captures the essential technical patterns for authoring and maintaining rsyslog modules (plugins/contrib).

Quick Start

1. Locking: Follow the "Belt and Suspenders" rule (assert() + if).
2. State: pData (shared) vs WID (per-worker).
3. Boilerplate: Use BEGINmodInit, CODESTARTmodInit, etc.
   • Resource: See Common Snippets for boilerplate code.

Detailed Instructions

1. Concurrency & Locking

Rsyslog v8 has a high-concurrency worker model.

• Shared State (pData): Mutable state shared across workers MUST be protected by a mutex in pData.
• Per-Worker State (WID): Never share wrkrInstanceData_t.
• Belt and Suspenders:

  assert(pData != NULL);
  if (pData == NULL) {
      // Handle error gracefully
  }
  

• Headers: Every output module should have a "Concurrency & Locking" header block.

2. Module Lifecycle

Every module must implement and register standard entry points:

• modInit(): Initialize static data and registry interfaces.
• modExit(): Finalize and cleanup.
• beginTransaction() / commitTransaction(): For efficient batch-based output.

3. Metadata Consistency

• Location: MODULE_METADATA.yaml in the module directory.
• Synchronization: Keep doc/ai/module_map.yaml in sync with locking and concurrency changes.

4. Build Configuration

• Update plugins/Makefile.am and configure.ac when adding new modules.
• Test Registration: Follow the "Define at Top, Distribute Unconditionally, Register Conditionally" pattern in tests/Makefile.am. See the rsyslog_test skill for details. This is critical for make distcheck validity.
• Use MODULE_TYPE(eMOD_OUT) and other macros from runtime/module-template.h.

Related Skills

• rsyslog_build: For compiling the module.
• rsyslog_test: For creating module-specific smoke tests.
• rsyslog_doc: For documentation requirements.