OAS Validation | Kong Docs

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Validate HTTP requests and responses based on an API Specification. Supports both Swagger v2 and OpenAPI v3 specifications JSON request and response bodies, with support for schema definitions described using JSON Schema draft v4. For JSON Schema draft 4 type schemas, see the JSON Schema documentation for details on the format and examples.

In Kong Gateway versions 3.1.0.0-3.1.1.1, this plugin is not enabled by default. Upgrade to 3.1.1.2, or manually enable the plugin.

Tutorial

This example tutorial steps you through ensuring an API request conforms to the associated API specification. This example uses the sample Petstore spec.

Create a service called Petstore-Service:

 curl -X POST http://<admin-hostname>:8001/services/ \
     --data name='Petstore-Service' \
     --data url='https://petstore.swagger.io/v2'

Create a wildcard route called Petstore-Route:

 curl -X POST http://<admin-hostname>:8001/services/Petstore-Service/routes \
     --data name='Petstore-Route' \
     --data paths='/.*'

Enable the Validation plugin on the service you configured:

 curl -X POST http://<admin-hostname>:8001/services/Petstore-Service/plugins \
     --data name='oas-validation' \
     --data config.api_spec='<copy contents of https://petstore.swagger.io/v2/swagger.json here>' \
     --data config.verbose_response=true

Test the Validation plugin. The request resource expects a status query parameter, which is missing from the following request:

 curl -X GET "http://<proxy-host>:8000/pet/findByStatus" \
   -H "accept: application/json"

The response includes a verbose error response, since we have enabled this option in the plugin configuration:

 HTTP/1.1 400 Bad Request
 Content-Length: 106
 Content-Type: application/json; charset=utf-8
 Date: Tue, 03 May 2022 20:45:00 GMT
 Server: kong/2.8.0.0-internal-preview-enterprise-edition
 X-Kong-Response-Latency: 2

 {
   "message": "query 'status' validation failed with error: 'required parameter value not found in request'"
 }

Event hooks

Event hooks are outbound calls from Kong Gateway. With event hooks, Kong Gateway can communicate with target services or resources, letting the target know that an event was triggered. Refer to the event hooks example documentation for more information on event hooks.

For the Validation plugin, event hook events can be enabled when a Validation fails for all request parameters, that is URI, Header, & Query parameters and Request body, and/or for Response body from the Upstream Service.

Add an event hook for the Validation plugin:

curl -i -X POST http://{HOSTNAME}:8001/event-hooks \
  -d source=oas-validation \
  -d event=validation-failed \
  -d handler=webhook \
  -d config.url={WEBHOOK_URL}

Response:

HTTP/1.1 201 Created
..

{
    "config": {
        "headers": {},
        "url": {WEBHOOK_URL},
        "ssl_verify": false,
        "secret": null
    },
    "id": "3fe43989-6cf1-4936-bd5d-b7774ca52ad8",
    "source": "oas-validation",
    "event": "validation-failed",
    "handler": "webhook",
    "snooze": null,
    "on_change": null,
    "created_at": 1649732398
 }

Force a validation failure to a service or route to which the Validation plugin is applied. The Webhook URL will receive a response with JSON payload.

The following is an example JSON response which includes the forwarded IP address, service, consumer, and and error message:

 {
 "ip": "10.0.2.2",
 "source": "oas-validation",
 "err": "query 'status' validation failed with error: 'required parameter value not found in request'",
 "event": "validation-failed",
 "service": {
     "ws_id": "7eebecc0-064e-4890-99cf-0c816280a68e",
     "enabled": true,
     "retries": 5,
     "read_timeout": 60000,
     "protocol": "https",
     "id": "6792ec72-67b2-4960-96b1-e7564dda3178",
     "connect_timeout": 60000,
     "name": "petstore-service",
     "port": 443,
     "host": "petstore.swagger.io",
     "updated_at": 1649391578,
     "path": "/v2/",
     "write_timeout": 60000,
     "created_at": 1647993371
 },
 "consumer": {}
 }

Next OAS Validation Configuration