Etcd Watch API

openapi: 3.1.0
info:
  title: etcd HTTP Gateway Auth Watch API
  description: The etcd HTTP/JSON gateway translates HTTP requests into gRPC calls, enabling clients without gRPC support to interact with the etcd v3 key-value store. The gateway exposes the full etcd v3 API surface including key-value operations (put, get, delete, range queries), watch streams for change notifications, lease management for TTL-based key expiration, cluster membership management, maintenance operations such as snapshots and defragmentation, and authentication and authorization controls. The gateway is served on port 2379 by default and accepts JSON-encoded request bodies that mirror the protobuf message structures of the underlying gRPC API.
  version: '3.5'
  contact:
    name: etcd Community
    url: https://etcd.io/community/
  termsOfService: https://github.com/etcd-io/etcd/blob/main/LICENSE
servers:
- url: http://{host}:{port}/v3
  description: etcd gRPC Gateway
  variables:
    host:
      default: localhost
    port:
      default: '2379'
security:
- bearerAuth: []
tags:
- name: Watch
  description: Watch operations for streaming key change notifications
paths:
  /watch:
    post:
      operationId: watchEvents
      summary: Etcd Watch for key change events
      description: Opens a streaming watch connection to receive notifications of key-value changes in the etcd cluster. Clients send WatchCreateRequest messages to subscribe to key ranges and WatchCancelRequest messages to unsubscribe. The server streams WatchResponse messages containing events that describe each key change including the event type (PUT or DELETE) and the updated key-value pair. Watches can be started from a specific revision to receive historical events.
      tags:
      - Watch
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/WatchRequest'
      responses:
        '200':
          description: Watch stream established
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/WatchResponse'
        '400':
          description: Bad request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '401':
          description: Unauthorized - authentication required
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
components:
  schemas:
    WatchResponse:
      type: object
      description: A streaming response from the watch endpoint
      properties:
        header:
          $ref: '#/components/schemas/ResponseHeader'
        watch_id:
          type: string
          description: ID of the watch that generated this response
        created:
          type: boolean
          description: True if this response confirms the creation of a new watch
        canceled:
          type: boolean
          description: True if this response confirms the cancellation of a watch
        compact_revision:
          type: string
          description: Set when a watch is canceled because the requested start revision has been compacted
        cancel_reason:
          type: string
          description: Reason the watch was canceled
        fragment:
          type: boolean
          description: True if this is a fragment of a larger watch response
        events:
          type: array
          description: List of events in this watch response
          items:
            $ref: '#/components/schemas/WatchEvent'
    WatchRequest:
      type: object
      description: A watch stream request that can create or cancel watches
      properties:
        create_request:
          $ref: '#/components/schemas/WatchCreateRequest'
        cancel_request:
          type: object
          description: Request to cancel an existing watch
          properties:
            watch_id:
              type: string
              description: ID of the watch to cancel
    WatchCreateRequest:
      type: object
      description: Request to create a new watch on a key range
      properties:
        key:
          type: string
          description: The key to watch in base64-encoded format
        range_end:
          type: string
          description: The range end for watching multiple keys in base64-encoded format
        start_revision:
          type: string
          description: Revision to start watching from. 0 means the current revision.
        progress_notify:
          type: boolean
          description: When true, sends periodic progress reports even when no events occur
        filters:
          type: array
          description: Event types to filter out from the watch stream
          items:
            type: string
            enum:
            - NOPUT
            - NODELETE
        prev_kv:
          type: boolean
          description: When true, includes the previous key-value pair in DELETE events
        watch_id:
          type: string
          description: User-assigned ID to identify this watch stream
        fragment:
          type: boolean
          description: When true, splits large watch responses into smaller fragments
    WatchEvent:
      type: object
      description: An event describing a change to a key in the etcd cluster
      properties:
        type:
          type: string
          enum:
          - PUT
          - DELETE
          description: Type of the event - PUT for creates/updates, DELETE for deletions
        kv:
          $ref: '#/components/schemas/KeyValue'
        prev_kv:
          $ref: '#/components/schemas/KeyValue'
    Error:
      type: object
      description: Error response from the etcd API
      properties:
        error:
          type: string
          description: Human-readable error message
        code:
          type: integer
          description: gRPC status code for the error
        message:
          type: string
          description: Detailed error message
    ResponseHeader:
      type: object
      description: Header included in every etcd response containing cluster metadata and the revision at which the response was generated.
      properties:
        cluster_id:
          type: string
          description: ID of the etcd cluster
        member_id:
          type: string
          description: ID of the member that generated the response
        revision:
          type: string
          description: Key-value store revision at the time of the response
        raft_term:
          type: string
          description: Raft term at the time of the response
    KeyValue:
      type: object
      description: A key-value pair stored in the etcd cluster. Keys and values are base64-encoded byte strings. The version field is the version of the key, the create_revision is the cluster revision when the key was created, and the mod_revision is the cluster revision when the key was last modified.
      properties:
        key:
          type: string
          description: The key in base64-encoded format
        create_revision:
          type: string
          description: Revision of the etcd cluster when the key was created
        mod_revision:
          type: string
          description: Revision of the etcd cluster when the key was last modified
        version:
          type: string
          description: Version of the key, monotonically increasing for each put on the key
        value:
          type: string
          description: The value in base64-encoded format
        lease:
          type: string
          description: Lease ID attached to the key, or 0 if no lease is attached
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT
      description: JWT token obtained from the /auth/authenticate endpoint. Include in the Authorization header as "Bearer {token}".
externalDocs:
  description: etcd gRPC Gateway Documentation
  url: https://etcd.io/docs/v3.5/dev-guide/api_grpc_gateway/