Connector Delivery

Purpose

Deliver a new RobustMQ connector end-to-end with consistent patterns across:

• metadata struct and validation
• connector runtime implementation
• connector type registration and dispatch wiring
• admin API parsing and validation
• documentation and verification

Use this skill when the user asks: "add/support/implement ".

Input Contract

Collect only missing essentials. If omitted, apply defaults and proceed.

1. Connector type name (s3, kinesis, foo).
2. Direction (default: sink/outbound).
3. Required config fields.
4. MQTT record -> target payload mapping.

Default assumptions

• Direction: sink
• Batch behavior: one send_batch call handles one pulled batch
• Retry/failure policy: reuse existing framework, do not invent per-connector policy
• Serialization: JSON unless target protocol requires specific format

Fast-path command

If user says only "implement X connector", do this without extra questions:

1. Build minimal usable config with strict validation.
2. Implement sink writing with clear, deterministic mapping.
3. Wire all registration points.
4. Update both zh/en API and overview docs.
5. Run targeted cargo check.

Implementation Workflow

1) Metadata Config

Files:

• src/common/metadata-struct/src/connector/config_<type>.rs
• src/common/metadata-struct/src/connector/mod.rs

Requirements:

1. Add config struct with Serialize, Deserialize, Clone, Debug, PartialEq.
2. Add Default with practical defaults.
3. Add validate(&self) -> Result<(), CommonError>:
   • required fields non-empty
   • protocol/URL format checks
   • numeric range checks
   • dependent field pair checks
4. Export module in mod.rs.

Validation style:

• Prefer explicit error messages with exact field names.
• Keep bounds conservative and consistent with existing connectors.

2) ConnectorType Registration

File:

• src/common/metadata-struct/src/connector/connector_type.rs

Required edits:

1. Add CONNECTOR_TYPE_<TYPE> constant.
2. Add enum variant in ConnectorType.
3. Extend as_str().
4. Extend FromStr with default config constructor.
5. Add import for new config type.

Rule: no partial registration. All four points must be updated.

3) Runtime Connector Module

Files:

• src/connector/src/<module>/mod.rs
• optional dependency updates in src/connector/Cargo.toml

Implement ConnectorSink:

• validate(): call config validation
• init_sink(): build client/operator/resource
• send_batch(): convert and send batch
• cleanup_sink(): optional if resource needs shutdown

Mapping rules:

• Keep payload mapping deterministic.
• Preserve important fields (key, headers, tags, timestamp) when reasonable.
• Do not hide conversion loss; if lossy, document it.

Error rules:

• Use CommonError with actionable messages.
• Do not silently swallow target write errors.

4) Runtime Wiring

Files:

• src/connector/src/lib.rs
• src/connector/src/core.rs

Checklist:

• Module exposed in src/connector/src/lib.rs or module tree.
• Startup path can construct the new sink.
• Branching by connector type includes new variant.

5) Admin API Wiring

File:

• src/admin-server/src/mqtt/connector.rs

Required edits:

1. Allow connector type in validate_connector_type.
2. Parse config in parse_connector_type.
3. Ensure validate() is called on decoded config.

6) Failure Strategy Semantics

Never change global semantics while adding a connector.

Must preserve:

• discard: terminal, commit offset.
• discard_after_retry: retry then terminal.
• dead_message_queue:
  • retry first;
  • write DLQ only after retries exhausted;
  • DLQ write failure returns error and continues retry;
  • only terminal-success path should allow offset commit.

7) Documentation Sync

Update all relevant docs when connector is user-facing.

Files:

• docs/zh/RobustMQ-MQTT/Bridge/Overview.md
• docs/en/RobustMQ-MQTT/Bridge/Overview.md
• docs/zh/Api/Connector.md
• docs/en/Api/Connector.md
• Sidebar entries only if adding new pages.

Document:

• connector purpose,
• config schema,
• examples,
• protocol-compatibility notes (if support is via compatible protocol).

8) Validation and Checks

Run after edits:

1. cargo check -p metadata-struct -p connector -p admin-server
2. Lint check for touched Rust files.
3. Confirm no missing match arms for ConnectorType.
4. Confirm docs include type list + config section + example request.

File Matrix (must touch)

• Metadata config: config_<type>.rs
• Metadata mod export: connector/mod.rs
• Connector type enum: connector/connector_type.rs
• Runtime module: src/connector/src/<module>/mod.rs
• Runtime exports/dispatch: src/connector/src/lib.rs, src/connector/src/core.rs
• Admin parse/validate: src/admin-server/src/mqtt/connector.rs
• Docs: zh/en API + zh/en Overview

Output Format

Return concise delivery report:

1. Files changed.
2. Behavior and defaults.
3. Known limitations.
4. Suggested next verification command(s).

Use this completion template:

Implemented `<type>` connector end-to-end.

- Changed files: ...
- Runtime behavior: ...
- Config defaults: ...
- Limitations: ...
- Verify: `cargo check -p metadata-struct -p connector -p admin-server`

Guardrails

• Reuse existing connector patterns before inventing new abstractions.
• Keep changes minimal and localized.
• Preserve backward compatibility for serialized config where possible.
• If protocol/client constraints block implementation, stop and explain blocker with alternatives.

Common Pitfalls

• Added new config file but forgot ConnectorType FromStr branch.
• Added ConnectorType variant but forgot runtime dispatch in core.rs.
• Added runtime module but forgot pub mod export in lib.rs.
• Added code but forgot admin validate_connector_type whitelist.
• Docs updated in one language only.