consul/website/source/docs/agent/http/session.html.markdown

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---
layout: "docs"
page_title: "Sessions (HTTP)"
sidebar_current: "docs-agent-http-sessions"
description: >
The Session endpoints are used to create, destroy, and query sessions.
---
# Session HTTP Endpoint
The Session endpoints are used to create, destroy, and query sessions.
The following endpoints are supported:
* [`/v1/session/create`](#session_create): Creates a new session
* [`/v1/session/destroy/<session>`](#session_destroy): Destroys a given session
* [`/v1/session/info/<session>`](#session_info): Queries a given session
* [`/v1/session/node/<node>`](#session_node): Lists sessions belonging to a node
* [`/v1/session/list`](#session_list): Lists all active sessions
* [`/v1/session/renew`](#session_renew): Renews a TTL-based session
All of the read session endpoints support blocking queries and all consistency modes.
### <a name="session_create"></a> /v1/session/create
The create endpoint is used to initialize a new session.
There is more documentation on sessions [here](/docs/internals/sessions.html).
Sessions must be associated with a node and may be associated with any number of checks.
The create endpoint expects a JSON request body to be PUT. The request
body must look like:
```javascript
{
"LockDelay": "15s",
"Name": "my-service-lock",
"Node": "foobar",
"Checks": ["a", "b", "c"],
"Behavior": "release",
"TTL": "0s"
}
```
None of the fields are mandatory, and in fact no body needs to be PUT
if the defaults are to be used.
By default, the agent's local datacenter is used; another datacenter
can be specified using the "?dc=" query parameter. However, it is not recommended
to use cross-datacenter sessions.
`LockDelay` field can be specified as a duration string using a "s" suffix for
seconds. The default is 15s. This value can also be a numeric value. Small values are
treated as seconds while larger values are assumed to be nanoseconds.
<QUESTION: I don't see anywhere in the code to substantiate this. If this is true, how do we define small and large values? We need to give people some boundaries. QUESTION>
`Node` must refer to a node that is already registered, if specified. By default,
the agent's own node name is used.
`Name` can be used to provide a human-readable name for the Session.
`Checks` is used to provide a list of associated health checks. It is highly recommended
that, if you override this list, you include the default "serfHealthCheck".
`Behavior` can be set to either `release` or `delete`. This controls
the behavior when a session is invalidated. By default, this is `release`,
causing any locks that are held to be released. Changing this to `delete`
causes any locks that are held to be deleted. `delete is useful for creating ephemeral
key/value entries.
The `TTL` field is a duration string, and like `LockDelay` it can use "s" as
a suffix for seconds. If specified, it must be between 10s and 3600s currently.
When provided, the session is invalidated if it is not renewed before the TTL
expires. See the [session internals page](/docs/internals/session.html) for more
documentation of this feature.
The return code is 200 on success and returns the ID of the created session:
```javascript
{
"ID": "adf4238a-882b-9ddc-4a9d-5b6758e4159e"
}
```
### <a name="session_destroy"></a> /v1/session/destroy/\<session\>
The destroy endpoint is hit with a PUT and destroys the given session.
By default, the local datacenter is used, but the "?dc=" query parameter
can be used to specify the datacenter.
The session being destroyed must be provided on the path.
The return code is 200 on success.
### <a name="session_info"></a> /v1/session/info/\<session\>
This endpoint is hit with a GET and returns the requested session information
within a given datacenter. By default, the datacenter of the agent is queried;
however, the dc can be provided using the "?dc=" query parameter.
The session being queried must be provided on the path.
It returns a JSON body like this:
```javascript
[
{
"LockDelay": 1.5e+10,
"Checks": [
"serfHealth"
],
"Node": "foobar",
"ID": "adf4238a-882b-9ddc-4a9d-5b6758e4159e",
"CreateIndex": 1086449
}
]
```
If the session is not found, null is returned instead of a JSON list.
This endpoint supports blocking queries and all consistency modes.
### <a name="session_node"></a> /v1/session/node/\<node\>
This endpoint is hit with a GET and returns the active sessions
for a given node and datacenter. By default, the datacenter of the agent is queried;
however, the dc can be provided using the "?dc=" query parameter.
The node being queried must be provided on the path.
It returns a JSON body like this:
```javascript
[
{
"LockDelay": 1.5e+10,
"Checks": [
"serfHealth"
],
"Node": "foobar",
"ID": "adf4238a-882b-9ddc-4a9d-5b6758e4159e",
"CreateIndex": 1086449
},
...
]
```
This endpoint supports blocking queries and all consistency modes.
### <a name="session_list"></a> /v1/session/list
This endpoint is hit with a GET and returns the active sessions
for a given datacenter. By default, the datacenter of the agent is queried;
however, the dc can be provided using the "?dc=" query parameter.
It returns a JSON body like this:
```javascript
[
{
"LockDelay": 1.5e+10,
"Checks": [
"serfHealth"
],
"Node": "foobar",
"ID": "adf4238a-882b-9ddc-4a9d-5b6758e4159e",
"CreateIndex": 1086449
},
...
]
```
This endpoint supports blocking queries and all consistency modes.
### <a name="session_renew"></a> /v1/session/renew/\<session\>
The renew endpoint is hit with a PUT and renews the given session.
This is used with sessions that have a TTL, and it extends the
expiration by the TTL. By default, the local datacenter is used, but the "?dc="
query parameter can be used to specify the datacenter.
The session being renewed must be provided on the path.
The return code is 200 on success and a JSON body like this:
```javascript
[
{
"LockDelay": 1.5e+10,
"Checks": [
"serfHealth"
],
"Node": "foobar",
"ID": "adf4238a-882b-9ddc-4a9d-5b6758e4159e",
"CreateIndex": 1086449
"Behavior": "release",
"TTL": "15s"
}
]
```
The response body includes the current session.
Note: Consul MAY return a TTL value higher than the one specified during session creation.
This indicates the server is under high load and is requesting clients renew less
often.