Event Hooks Reference

Event Hooks Reference

Event hooks are outbound calls from Kong Gateway. With event hooks, the Kong Gateway can communicate with target services or resources, letting the target know that an event was triggered. When an event is triggered in Kong, it calls a URL with information about that event. Event hooks add a layer of configuration for subscribing to worker events using the admin interface. Worker events are integrated into Kong Gateway to communicate within the gateway context. For example, when an entity is created, the Kong Gateway fires an event with information about the entity. Parts of the Kong Gateway codebase can subscribe to these events, then process the events using callbacks.

In Kong Gateway, these callbacks can be defined using one fo the following “handlers”:

webhook: Makes a JSON POST request to a provided URL with the event data as a payload. Useful for building a middle tier integration (your own webhook that receives Kong hooks). Specific headers can be configured for the request.
webhook-custom: Fully configurable request. Useful for building a direct integration with a service (for example, a Slack webhook). Because it’s fully configurable, it’s more complex to configure. It supports templating on a configurable body, a configurable form payload, and headers.
log: This handler, which requires no configuration, logs the event and the content of the payload into the Kong Gateway logs. If using hybrid mode, the crud and dao:crud sources will log on the control plane logs and the balancer and rate-limiting-advanced sources will log on the data plane logs.
lambda: This handler runs specified Lua code after an event is triggered.

Note: Event hooks do not work with Konnect Cloud yet.

List all event hooks

Endpoint

/event-hooks

Response

{
    "data": [
        {
            "config": {
                "body": null,
                "body_format": true,
                "headers": {
                    "content-type": "application/json"
                },
                "headers_format": false,
                "method": "POST",
                "payload": {
                    "text": "Admin account \`{{ entity.username }}\` {{ operation}}d; email address set to \`{{ entity.email }}\`"
                },
                "payload_format": true,
                "secret": null,
                "ssl_verify": false,
                "url": "https://hooks.slack.com/services/foo/bar/baz"
            },
            "created_at": 1627588552,
            "event": "admins",
            "handler": "webhook-custom",
            "id": "937df175-3db2-4e6d-8aa1-d95c94a76089",
            "on_change": null,
            "snooze": null,
            "source": "crud"
        },
        {
            "config": {
                "headers": {},
                "secret": null,
                "ssl_verify": false,
                "url": "https://webhook.site/a1b2c3-d4e5-g6h7-i8j9-k1l2m3n4o5p6"
            },
            "created_at": 1627581575,
            "event": "consumers",
            "handler": "webhook",
            "id": "c57340ab-9fed-40fd-bb7e-1cef8d37c2df",
            "on_change": null,
            "snooze": null,
            "source": "crud"
        },
        {
            "config": {
                "functions": [
                    "return function (data, event, source, pid)\n  local user = data.entity.username\n  error(\"Event hook on consumer \" .. user .. \"\")\nend\n"
                ]
            },
            "created_at": 1627595513,
            "event": "consumers",
            "handler": "lambda",
            "id": "c9fdd58d-5416-4d3a-9467-51e5cfe4ca0e",
            "on_change": null,
            "snooze": null,
            "source": "crud"
        }
    ],
    "next": null
}

List all sources

Sources are the actions that trigger the event hook. The /sources JSON output follows the following pattern:

1st level = The source, which is the action that triggers the event hook.
2nd level = The event, which is the Kong entity the event hook will listen to for events.
3rd level = The available template parameters for use in webhook-custom payloads.

For instance, in the example below balancer is the source, health is the event, and upstream_id, ip, port, hostname, and health are the available template parameters.

Endpoint

/event-hooks/sources/

Response

{
    "data": {
        "balancer": {
            "health": {
                "fields": [
                    "upstream_id",
                    "ip",
                    "port",
                    "hostname",
                    "health"
                ]
            }
        },
        "crud": {
            "acls": {
                "fields": [
                    "operation",
                    "entity",
                    "old_entity",
                    "schema"
                ]
            },
            . . .
        "rate-limiting-advanced": {
            "rate-limit-exceeded": {
                "description": "Run an event when a rate limit has been exceeded",
                "fields": [
                    "consumer",
                    "ip",
                    "service",
                    "rate",
                    "limit",
                    "window"
                ],
                "unique": [
                    "consumer",
                    "ip",
                    "service"
                ]
            }
        }
    }
}

Note: The response has been shortened because it is too long to include in its entirety. The ellipsis in the center of the response represents the missing content.

List all events for a source

Events are the Kong entities the event hook will listen to for events. With this endpoint you can list all of the events associated with a particular source.

/event-hooks/sources/{source}/

The following response lists all of the events for the dao:crud source.

Response

{
    "data": {
        "create": {
            "fields": [
                "operation",
                "entity",
                "old_entity",
                "schema"
            ]
        },
        "delete": {
            "fields": [
                "operation",
                "entity",
                "old_entity",
                "schema"
            ]
        },
        "update": {
            "fields": [
                "operation",
                "entity",
                "old_entity",
                "schema"
            ]
        }
    }
}

Add a webhook

Endpoint

/event-hooks

Request Body

Attribute	Description
`event` optional	A string describing the Kong entity the event hook will listen to for events.
`handler` required	A string describing one of four handler options: webhook, webhook-custom, log, or lambda.
`source` required	A string describing the action that triggers the event hook.
`snooze` optional	An optional integer describing the time in seconds to delay an event trigger to avoid spamming an integration.
`on_change` optional	An optional boolean indicating whether to trigger an event when key parts of a payload have changed.
`config.url` required	The URL the JSON POST request is made to with the event data as the payload.
`config.headers` optional	An object defining additional HTTP headers to send in the webhook request, for example `{“X-Custom-Header”: “My Value”}`.
`config.secret` optional	An optional string used to sign the remote webhook for remote verification. When set, Kong will sign the body of the event hook with HMAC-SHA1 and include it in a header, `x-kong-signature`, to the remote endpoint.
`config.ssl_verify` optional	A boolean indicating whether to verify the SSL certificate of the remote HTTPS server where the event hook will be sent. The default is `false`.

Response

{
    "config": {
        "headers": {},
        "secret": null,
        "ssl_verify": false,
        "url": "https://webhook.site/a1b2c3-d4e5-g6h7-i8j9-k1l2m3n4o5p6"
    },
    "created_at": 1627581575,
    "event": "consumers",
    "handler": "webhook",
    "id": "c57340ab-9fed-40fd-bb7e-1cef8d37c2df",
    "on_change": null,
    "snooze": null,
    "source": "crud"
}

Add a custom webhook

Endpoint

/event-hooks

Request Body

Attribute	Description
`event` optional	A string describing the Kong entity the event-hook will listen to for events.
`handler` required	A string describing one of four handler options: webhook, webhook-custom, log, or lambda.
`source` required	A string describing the action that triggers the event hook.
`snooze` optional	An optional integer describing the time in seconds to delay an event trigger to avoid spamming an integration.
`on_change` optional	An optional boolean indicating whether to trigger an event when key parts of a payload have changed.
`config.url` required	The URL the JSON POST request is made to with the event data as the payload.
`config.method` required	The HTTP method used to create the custom webhook.
`config.payload` optional	An object that includes key/value pairs that describe the configurable payload body. Supports templating. The full list of available template parameters can be found in the `/sources` API output, under the `fields` JSON object.
`config.payload_format` optional	A optional boolean (defaults to `true`) indicating whether to format the `config.payload` with resty templating. When set to `false`, the payload is sent as a raw object.
`config.body` optional	An optional string sent in the remote request.
`config.body_format` optional	An optional boolean (defaults to `true`) indicating whether to format the `config.body` with resty templating. When set to `false`, the body is sent as a raw object. To see all the available parameters defined for a specific `source`, check the source fields displayed by the `/event-hooks/source` endpoint.
`config.headers`	An object defining additional HTTP headers to send in the webhook request, for example `{“Content-type”: “application/json”, “X-Custom-Header”: “My Value”}`.
`config.headers_format` optional	An optional boolean (defaults to `false`) indicating whether to format the `config.headers` with resty templating. When set to `true`, the `config.headers` value will be treated as a template. To see all the available parameters defined for a specific `source`, check the source fields displayed by the `/event-hooks/sources` endpoint.
`config.secret` optional	An optional string used to sign the remote webhook for remote verification. When set, Kong will sign the body of the event hook with HMAC-SHA1 and include it in a header, `x-kong-signature`, to the remote endpoint.
`config.ssl_verify` optional	A boolean indicating whether to verify the SSL certificate of the remote HTTPS server where the event hook will be sent. The default value is `false`.

Response

{
    "config": {
        "body": null,
        "body_format": true,
        "headers": {
            "content-type": "application/json"
        },
        "headers_format": false,
        "method": "POST",
        "payload": {
            "text": "Admin account `` d; email address set to ``"
        },
        "payload_format": true,
        "secret": null,
        "ssl_verify": false,
        "url": "https://hooks.slack.com/services/foo/bar/baz"
    },
    "created_at": 1627588552,
    "event": "admins",
    "handler": "webhook-custom",
    "id": "937df175-3db2-4e6d-8aa1-d95c94a76089",
    "on_change": null,
    "snooze": null,
    "source": "crud"
}

Add a log event hook

Endpoint

/event-hooks

Request Body

Attribute	Description
`event` optional	A string describing the Kong entity the event hook will listen to for events.
`handler` required	A string describing one of four handler options: webhook, webhook-custom, log, or lambda.
`source` required	A string describing the action that triggers the event hook.
`snooze` optional	An optional integer describing the time in seconds to delay an event trigger to avoid spamming an integration.
`on_change` optional	An optional boolean indicating whether to trigger an event when key parts of a payload have changed.

Response

{
  "config": {},
  "on_change": null,
  "created_at": 1627346155,
  "snooze": null,
  "id": "13a16f91-68b6-4384-97f7-d02763a551ac",
  "handler": "log",
  "source": "crud",
  "event": "routes"
}

Add a lambda event hook

Endpoint

/event-hooks

Request Body

Attribute	Description
`event` optional	A string describing the Kong entity the event hook will listen to for events.
`handler` required	A string describing one of four handler options: webhook, webhook-custom, log, or lambda.
`source` required	A string describing the action that triggers the event hook.
`snooze` optional	An optional integer describing the time in seconds to delay an event trigger to avoid spamming an integration.
`on_change` optional	An optional boolean indicating whether to trigger an event when key parts of a payload have changed.
`config.functions` required	An array of Lua code functions to execute on the event hook.

Response

{
    "config": {
        "functions": [
            "return function (data, event, source, pid)\n  local user = data.entity.username\n  error(\"Event hook on consumer \" .. user .. \"\")\nend\n"
        ]
    },
    "created_at": 1627595513,
    "event": "consumers",
    "handler": "lambda",
    "id": "c9fdd58d-5416-4d3a-9467-51e5cfe4ca0e",
    "on_change": null,
    "snooze": null,
    "source": "crud"
}

Test an event hook

It’s useful to manually trigger an event hook without provoking the event to be triggered. For instance, you might want to test the integration, or see if your hook’s service is receiving a payload from Kong.

POST any data to /event-hooks/:id-of-hook/test, and the /test endpoint executes the with the provided data as the event payload.

Endpoint

/event-hooks/{event-hook-id}/test

Response

{
    "data": {
        "consumer": {
            "username": "Jane Austen"
        },
        "event": "consumers",
        "source": "crud"
    },
    "result": {
        "body": "",
        "headers": {
            "Cache-Control": "no-cache, private",
            "Content-Type": "text/plain; charset=UTF-8",
            "Date": "Fri, 30 Jul 2021 16:07:09 GMT",
            "Server": "nginx/1.14.2",
            "Transfer-Encoding": "chunked",
            "Vary": "Accept-Encoding",
            "X-Request-Id": "f1e703a5-d22c-435c-8d5d-bc9c561ead4a",
            "X-Token-Id": "1cc1c53b-f613-467f-a5c9-20d276405104"
        },
        "status": 200
    }
}

Ping a webhook event hook

Endpoint

/event-hooks/{event-hook-id}/ping

Response

{
  "source": "kong:event_hooks",
  "event_hooks": {
    "source": "crud",
    "id": "c57340ab-9fed-40fd-bb7e-1cef8d37c2df",
    "on_change": null,
    "event": "consumers",
    "handler": "webhook",
    "created_at": 1627581575,
    "config": {
      "headers": {
        "content-type": "application/json"
      },
      "ssl_verify": false,
      "url": "https://webhook.site/a1b2c3-d4e5-g6h7-i8j9-k1l2m3n4o5p6",
      "secret": null
    },
    "snooze": null
  },
  "event": "ping"
}