streamling plugin basics — Agent Skill

A streamling plugin is an independently compiled cdylib loaded at runtime via a stable ABI (abi_stable). A plugin crate can register any mix of six component kinds: source, transform, sink, preprocessor, UDF, and side output. This skill covers the crate skeleton, registration, the lifecycle every component shares, and the cross-cutting utilities (options, metrics, state, async runtime, errors). For the per-kind trait patterns, see the sibling skills.

Read this first, then jump to the specific skill:

• streamling-source-plugin
• streamling-sink-plugin
• streamling-transform-plugin
• streamling-udf-plugin — custom SQL functions (DataFusion UDFs).
• streamling-advanced-plugins — preprocessor, UDF, side output, multi-plugin crate, low-level FFI.

Crate setup

A plugin is a Cargo crate compiled to cdylib (+ rlib so tests work) that depends on streamling-plugin.