rsyslog_config

Development

Governs the dual-frontend config architecture (RainerScript + YAML) and enforces parity rules when extending or changing configuration objects.

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rsyslog_config

rsyslog supports two configuration frontends that share a single backend:

RainerScript — parsed by grammar/ (flex/bison), produces cnfobj + nvlst trees.
YAML — parsed by runtime/yamlconf.c (libyaml), produces the same cnfobj + nvlst trees.

Both call cnfDoObj() → module setModCnf() / newActInst() with identical data structures. This means any change to the config layer must be reflected in both frontends.

Quick Start

New config object or statement → update grammar/ and runtime/yamlconf.c.
New module parameter → add YAML smoke test alongside the RainerScript test.
New template modifier or property → update parse_template_sequence() in yamlconf.c.
Changed semantics → update doc/source/configuration/yaml_config.rst and the module .rst.

Detailed Instructions

1. Architecture: one backend, two frontends

rsyslog.conf  ──► grammar/ (flex/bison) ──┐
                                           ├──► cnfobj + nvlst ──► cnfDoObj() ──► module setModCnf()
config.yaml   ──► runtime/yamlconf.c   ──┘

The backend entry point is cnfDoObj() in runtime/conf.c. Both frontends must produce structurally identical nvlst parameter lists for a given object so the module receives the same data regardless of which format the operator chose.

2. Config parity rules

Change	RainerScript	YAML	Test
New global parameter	`grammar/rainerscript.y`	`parse_global()` in yamlconf.c	`yaml-global-*.sh`
New module parameter	module param table	no change needed — nvlst key matches param name	`yaml-<module>-*.sh`
New statement type	grammar rule + action	`build_one_stmt_rs()` in yamlconf.c	`yaml-statements-*.sh`
New block type (ruleset, etc.)	grammar rule	`parse_<type>_sequence()` in yamlconf.c	`yaml-<type>-*.sh`
New template modifier	`template.c` modifier table	`parse_template_sequence()` in yamlconf.c	`yaml-template-*.sh`
New template property option	`template.c`	`parse_template_sequence()` in yamlconf.c	existing template tests

3. Key files

File	Role
`runtime/yamlconf.c`	YAML frontend — all YAML parsing lives here
`runtime/yamlconf.h`	Public API: `yamlconf_load()`
`grammar/rainerscript.y`	RainerScript grammar
`grammar/rainerscript.h`	RainerScript AST types
`runtime/conf.c`	Shared backend: `cnfDoObj()`, `cnfDoCfsysline()`
`runtime/nvlst.c`	Parameter list nodes shared by both frontends
`doc/source/configuration/yaml_config.rst`	User-facing YAML reference

4. Adding a new statement type

RainerScript — add a grammar rule in grammar/rainerscript.y that calls the appropriate runtime function.

YAML — add a branch in build_one_stmt_rs() in runtime/yamlconf.c:

} else if (!strcmp(kname, "mystatement")) {
    /* parse value(s), build nvlst node(s), call runtime function */
}

Test — add or extend a tests/yaml-statements-*.sh that exercises the new statement and verifies observable output.

5. Adding a new template modifier or property option

Modifiers (e.g. uppercase, json, csv) and per-property options (e.g. name, format, onEmpty, position.from, position.to) are decoded in parse_template_sequence() inside yamlconf.c. When template.c gains a new modifier or option, add the matching YAML key there and add a test case to tests/yaml-template-*.sh.

6. YAML test conventions

Name: tests/yaml-<area>-<what>.sh (e.g. yaml-template-list.sh, yaml-global-ratelimit.sh).
Include diag.sh using the POSIX . command and use the standard helpers (startup, injectmsg, wait_queueempty, shutdown_when_empty, wait_shutdown).
Config file: tests/testsuites/<testname>.yaml (.yaml extension triggers the YAML loader).
Verify observable output — don't just check that rsyslog starts; assert that the expected data appears in output files.
Register in tests/Makefile.am under the same conditionals as the module being tested.

7. Documentation

Every config object documented in doc/source/configuration/modules/ or doc/source/reference/parameters/ should include a YAML example alongside the RainerScript example. Update doc/source/configuration/yaml_config.rst when:

A new statement type or global option is added.
Supported template modifiers or property options change.

Related Skills

rsyslog_module: Concurrency and module lifecycle patterns.
rsyslog_test: Testbench conventions and Makefile.am registration.
rsyslog_doc: Documentation structure and Sphinx validation.