open-consul/website/content/api-docs/event.mdx
Jared Kirschner daf5e3ea10 docs: split HTTP API params into sections by type
Path parameters, query parameters, and request body parameters are now shown in
separate sections rather than combined into one general parameters section.
This makes it much easier to understand quickly where a parameter should be
provided.
2022-05-25 14:45:47 -07:00

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---
layout: api
page_title: Events - HTTP API
description: |-
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](/api-docs/features/blocking),
[consistency modes](/api-docs/features/consistency),
[agent caching](/api-docs/features/caching), and
[required ACLs](/api#authentication).
| Blocking Queries | Consistency Modes | Agent Caching | ACL Required |
| ---------------- | ----------------- | ------------- | ------------- |
| `NO` | `none` | `none` | `event:write` |
The corresponding CLI command is [`consul event`](/commands/event).
### Path Parameters
- `name` `(string: <required>)` - Specifies the name of the event to fire.
This name must not start with an underscore,
since those are reserved for Consul internally.
### Query Parameters
- `dc` `(string: "")` - Specifies the datacenter to query. This will default to
the datacenter of the agent being queried.
- `node` `(string: "")` - Specifies a regular expression to filter by node name.
- `service` `(string: "")` - Specifies a regular expression to filter by service name.
- `tag` `(string: "")` - Specifies a regular expression to filter by tag.
### Sample Payload
The body contents are opaque to Consul and become the "payload" that is passed
onto the receiver of the event.
```text
Lorem ipsum dolor sit amet, consectetur adipisicing elit...
```
### Sample Request
```shell-session
$ curl \
--request PUT \
--data @payload \
http://127.0.0.1:8500/v1/event/fire/my-event
```
### Sample Response
```json
{
"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](/commands/event) works, each
agent may have a different view of the events. Events are broadcast using the
[gossip protocol](/docs/architecture/gossip), so they have no global ordering
nor do they make a promise of delivery.
@include 'http_api_results_filtered_by_acls.mdx'
| Method | Path | Produces |
| ------ | ------------- | ------------------ |
| `GET` | `/event/list` | `application/json` |
The table below shows this endpoint's support for
[blocking queries](/api-docs/features/blocking),
[consistency modes](/api-docs/features/consistency),
[agent caching](/api-docs/features/caching), and
[required ACLs](/api#authentication).
| Blocking Queries | Consistency Modes | Agent Caching | ACL Required |
| ---------------- | ----------------- | ------------- | ------------ |
| `YES` | `none` | `none` | `event:read` |
### Query Parameters
- `name` `(string: "")` - Specifies the name of the event to filter.
- `node` `(string: "")` - Specifies a regular expression to filter by node name.
- `service` `(string: "")` - Specifies a regular expression to filter by service name.
- `tag` `(string: "")` - Specifies a regular expression to filter by tag.
### Sample Request
```shell-session
$ curl \
http://127.0.0.1:8500/v1/event/list
```
### Sample Response
```json
[
{
"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](/docs/architecture/consensus). 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.