open-consul/website/source/api/event.html.md

layout	page_title	sidebar_current	description
api	Events - HTTP API	api-event	The /event endpoints fire new events and to query the available events in Consul.

Event HTTP Endpoint

The /event endpoints fire new events and to query the available events in Consul.

Fire Event

This endpoint triggers a new user event.

Method	Path	Produces
PUT	/event/fire/:name	application/json

The table below shows this endpoint's support for blocking queries, consistency modes, agent caching, and required ACLs.

Blocking Queries	Consistency Modes	Agent Caching	ACL Required
NO	none	none	event:write

Parameters

• name (string: <required>) - Specifies the name of the event to fire. This is specified as part of the URL. This name must not start with an underscore, since those are reserved for Consul internally.

• dc (string: "") - Specifies the datacenter to query. This will default to the datacenter of the agent being queried. This is specified as part of the URL as a query parameter.

• node (string: "") - Specifies a regular expression to filter by node name. This is specified as part of the URL as a query parameter.

• service (string: "") - Specifies a regular expression to filter by service name. This is specified as part of the URL as a query parameter.

• tag (string: "") - Specifies a regular expression to filter by tag. This is specified as part of the URL as a query parameter.

Sample Payload

The body contents are opaque to Consul and become the "payload" that is passed onto the receiver of the event.

Lorem ipsum dolor sit amet, consectetur adipisicing elit...

Sample Request

$ curl \
    --request PUT \
    --data @payload \
    http://127.0.0.1:8500/v1/event/fire/my-event

Sample Response

{
  "ID": "b54fe110-7af5-cafc-d1fb-afc8ba432b1c",
  "Name": "deploy",
  "Payload": null,
  "NodeFilter": "",
  "ServiceFilter": "",
  "TagFilter": "",
  "Version": 1,
  "LTime": 0
}

• ID is a unique identifier the newly fired event

List Events

This endpoint returns the most recent events (up to 256) known by the agent. As a consequence of how the event command works, each agent may have a different view of the events. Events are broadcast using the gossip protocol, so they have no global ordering nor do they make a promise of delivery.

Method	Path	Produces
GET	/event/list	application/json

The table below shows this endpoint's support for blocking queries, consistency modes, agent caching, and required ACLs.

Blocking Queries	Consistency Modes	Agent Caching	ACL Required
YES	none	none	event:read

Parameters

• name (string: <required>) - Specifies the name of the event to filter. This is specified as part of the URL as a query parameter.

• node (string: "") - Specifies a regular expression to filter by node name. This is specified as part of the URL as a query parameter.

• service (string: "") - Specifies a regular expression to filter by service name. This is specified as part of the URL as a query parameter.

• tag (string: "") - Specifies a regular expression to filter by tag. This is specified as part of the URL as a query parameter.

Sample Request

$ curl \
    http://127.0.0.1:8500/v1/event/list

Sample Response

[
  {
    "ID": "b54fe110-7af5-cafc-d1fb-afc8ba432b1c",
    "Name": "deploy",
    "Payload": "MTYwOTAzMA==",
    "NodeFilter": "",
    "ServiceFilter": "",
    "TagFilter": "",
    "Version": 1,
    "LTime": 19
  }
]

Caveat

The semantics of this endpoint's blocking queries are slightly different. Most blocking queries provide a monotonic index and block until a newer index is available. This can be supported as a consequence of the total ordering of the consensus protocol. With gossip, there is no ordering, and instead X-Consul-Index maps to the newest event that matches the query.

In practice, this means the index is only useful when used against a single agent and has no meaning globally. Because Consul defines the index as being opaque, clients should not be expecting a natural ordering either.