ADR-0017: DSL YAML Key Naming Convention

Date: 2026-06-09 Status: Accepted Issues: rc-co1

Decision

All YAML DSL step keys and field names use snake_case. No camelCase, no kebab-case, no PascalCase.

Rule

1. YAML step keys (set_header, wire_tap, poll_enrich, etc.) are snake_case.
2. YAML field names inside step structs (timeout_ms, cache_ttl_secs, etc.) are snake_case.
3. serde(rename = "...") is only allowed for Rust reserved words (loop, while, type, etc.).
4. EIP pattern names in prose/docs/comments ("pollEnrich", "wireTap") remain as-is — they reference the pattern, not the YAML key.

Rationale

Before this ADR, pollEnrich had a serde(rename = "pollEnrich") that forced camelCase for one step key while all ~30 other step keys (set_header, set_body, wire_tap, stream_cache, convert_body_to, load_balance, dynamic_router, routing_slip, recipient_list, etc.) were already snake_case. This was an inconsistency that broke the established pattern.

Consequences

• The YAML key for poll-enrich is poll_enrich (not pollEnrich).
• Existing YAML route files using pollEnrich must update to poll_enrich.
• Future DSL additions follow snake_case by default (Rust field naming already enforces this via serde default behavior).

Amendment (2026-06-26)

The snake_case rule applies to both YAML and JSON DSL keys. The original wording said "DSL YAML" because YAML was the only authoring format at the time (2026-06-09); JSON inherited the rule silently via the shared RouteDsl* AST (crates/camel-dsl/src/route_ast.rs).

ADR-0026 (JSON Canonical Route Authoring Format) formalizes JSON as a first-class authoring format. To remove ambiguity, this amendment makes explicit that:

• All DSL keys (step keys AND field names) are snake_case regardless of whether the user authors routes in YAML or JSON.
• serde(rename = "...") policy (Rule 3) is unchanged.
• EIP pattern names in prose/docs/comments (Rule 4) remain as-is.

No behavior change. Existing JSON route files already follow this rule; the amendment is a documentation clarification.

Referenced by: ADR-0026.