API Evangelist enhancements for the HAProxy Data Plane API

overlay: 1.0.0
info:
  title: API Evangelist enhancements for the HAProxy Data Plane API
  version: 1.0.0
x-provenance:
  generated: '2026-08-28'
  method: generated
  source: openapi/haproxy-data-plane-api-openapi.yml
  extends: openapi/haproxy-data-plane-api-openapi.yml
  note: >-
    This overlay records API Evangelist's derived enrichment of the harvested HAProxy Data
    Plane API contract. The original Swagger 2.0 document is never mutated. Actions add
    documentation and machine-readable pointers that the upstream spec does not carry:
    the self-hosted base URL shape, the contact/licence identity, the optimistic-concurrency
    and transaction semantics, and links to the artifacts derived from this spec.
actions:
  - target: $.info
    description: >-
      Record where this copy came from and which HAProxy release line it describes.
    update:
      x-harvested-from: https://raw.githubusercontent.com/haproxytech/client-native/master/specification/build/haproxy_spec.yaml
      x-harvested-on: '2026-08-28'
      x-vendor: HAProxy Technologies
      x-product-line: HAProxy Data Plane API 3.4
  - target: $.info
    description: State the licence of the upstream project, which the spec omits.
    update:
      x-license:
        name: Apache-2.0
        url: https://github.com/haproxytech/dataplaneapi/blob/master/LICENSE
  - target: $
    description: >-
      The contract declares no `host`, because the Data Plane API is self-hosted software.
      Record the documented default deployment shape so a client knows what to fill in.
    update:
      x-deployment:
        model: self-hosted
        default_port: 5555
        base_path: /v3
        base_url_template: http://{haproxy-host}:5555/v3
        note: >-
          There is no vendor-operated host. Port and base path are the documented defaults;
          both are configurable via the dataplaneapi --port flag and the URI version.
  - target: $
    description: >-
      Surface the write-safety model at the document level. It is expressed in the spec only
      as two shared query parameters, which is easy to miss.
    update:
      x-write-semantics:
        concurrency: optimistic
        version_parameter: version
        version_read: GET /v3/services/haproxy/configuration/version
        conflict_status: 409
        response_header: Configuration-Version
        transactional: true
        transaction_open: startTransaction
        transaction_commit: commitTransaction
        transaction_rollback: deleteTransaction
        reversible_until: commit
        idempotency_key_header: null
  - target: $
    description: Record the reload signalling that a 202 response implies.
    update:
      x-reload-semantics:
        accepted_status: 202
        header: Reload-ID
        poll: GET /v3/services/haproxy/reloads/{id}
        note: A 202 is not confirmation the change is live.
  - target: $
    description: Link the artifacts derived from this contract.
    update:
      x-api-evangelist-artifacts:
        authentication: authentication/haproxy-authentication.yml
        conventions: conventions/haproxy-conventions.yml
        errors: errors/haproxy-problem-types.yml
        data_model: data-model/haproxy-data-model.yml
        lifecycle: lifecycle/haproxy-lifecycle.yml
        conformance: conformance/haproxy-conformance.yml
        skills: skills/_index.yml
        mcp: mcp/haproxy-mcp.yml
  - target: $.definitions.error
    description: >-
      The error definition carries no guidance on what a caller should do. Record the
      remediation the derived error catalog captures.
    update:
      x-remediation:
        '409': >-
          Re-read the configuration version (or the Configuration-Version response header)
          and replay the write with the fresh value. Do not retry with the same version.
        '429': >-
          Commit or delete open transactions. This 429 is a transaction-concurrency limit,
          not a request-rate limit.
      x-error-catalog: errors/haproxy-problem-types.yml
  - target: $.securityDefinitions.basic_auth
    description: State how the Basic credentials are provisioned.
    update:
      x-credential-source: >-
        Users defined in the HAProxy userlist referenced by the Data Plane API's --userlist
        or --userlist-file flag. There are no API keys, no OAuth flows and no scopes.
  - target: $.parameters.version
    description: Make the concurrency contract explicit on the parameter itself.
    update:
      x-concurrency: optimistic-lock
      x-read-from: GET /v3/services/haproxy/configuration/version
      x-on-mismatch: 409
  - target: $.parameters.transaction_id
    description: Make the reversibility window explicit on the parameter itself.
    update:
      x-reversible-until: commitTransaction
      x-rollback: DELETE /v3/services/haproxy/transactions/{id}