Schema/Metadata API Reference: Event Triggers¶

Table of contents

Introduction
create_event_trigger
delete_event_trigger
redeliver_event
invoke_event_trigger

Introduction¶

Event triggers are used to capture database changes and send them to a configured webhook.

create_event_trigger¶

create_event_trigger is used to create a new event trigger or replace an existing event trigger.

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
    "type" : "create_event_trigger",
    "args" : {
        "name": "sample_trigger",
        "table": {
           "name": "users",
           "schema": "public"
        },
        "webhook": "https://httpbin.org/post",
        "insert": {
            "columns": "*",
            "payload": ["username"]
        },
        "update": {
            "columns": ["username", "real_name"],
            "payload": "*"
        },
        "delete": {
            "columns": "*"
        },
        "headers":[
          {
              "name": "X-Hasura-From-Val",
              "value": "myvalue"
          },
          {
              "name": "X-Hasura-From-Env",
              "value_from_env": "EVENT_WEBHOOK_HEADER"
          }
        ],
        "replace": false
    }
}

Args syntax¶

Key	Required	Schema	Description
name	true	TriggerName	Name of the event trigger
table	true	QualifiedTable	Object with table name and schema
webhook	false	String	Full url of webhook (*)
webhook_from_env	false	String	Environment variable name of webhook (must exist at boot time) (*)
insert	false	OperationSpec	Specification for insert operation
update	false	OperationSpec	Specification for update operation
delete	false	OperationSpec	Specification for delete operation
headers	false	[ HeaderFromValue \| HeaderFromEnv ]	List of headers to be sent with the webhook
retry_conf	false	RetryConf	Retry configuration if event delivery fails
replace	false	Boolean	If set to true, the event trigger is replaced with the new definition
enable_manual	false	Boolean	If set to true, the event trigger can be invoked manually

(*) Either webhook or webhook_from_env are required.

delete_event_trigger¶

delete_event_trigger is used to delete an event trigger.

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
    "type" : "delete_event_trigger",
    "args" : {
        "name": "sample_trigger"
    }
}

Args syntax¶

Key	Required	Schema	Description
name	true	TriggerName	Name of the event trigger

redeliver_event¶

redeliver_event is used to redeliver an existing event. For example, if an event is marked as error ( say it did not succeed after retries), you can redeliver it using this API. Note that this will reset the count of retries so far. If the event fails to deliver, it will be retried automatically according to its retry_conf.

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
    "type" : "redeliver_event",
    "args" : {
        "event_id": "ad4f698f-a14e-4a6d-a01b-38cd252dd8bf"
    }
}

Args syntax¶

Key	Required	Schema	Description
event_id	true	String	UUID of the event

invoke_event_trigger¶

invoke_event_trigger is used to invoke an event trigger with custom payload.

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
    "type" : "invoke_event_trigger",
    "args" : {
        "name": "sample_trigger",
        "payload": {}
    }
}

Args syntax¶

Key	Required	Schema	Description
name	true	TriggerName	Name of the event trigger
payload	true	JSON	Some JSON payload to send to trigger

TriggerName¶

String

OperationSpec¶

Key	Required	Schema	Description
columns	true	EventTriggerColumns	List of columns or “*” to listen to changes
payload	false	EventTriggerColumns	List of columns or “*” to send as part of webhook payload

EventTriggerColumns¶

"*" | [PGColumn]

RetryConf¶

Key	required	Schema	Description
num_retries	false	Integer	Number of times to retry delivery. Default: 0
interval_sec	false	Integer	Number of seconds to wait between each retry. Default: 10
timeout_sec	false	Integer	Number of seconds to wait for response before timing out. Default: 60

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