Version: 2.13

limit-req

Description#

limit request rate using the "leaky bucket" method.

Attributes#

Name	Type	Requirement	Default	Valid	Description
rate	integer	required		rate > 0	the specified request rate (number per second) threshold. Requests exceeding this rate (and below `burst`) will get delayed to conform to the rate.
burst	integer	required		burst >= 0	the number of excessive requests per second allowed to be delayed. Requests exceeding this hard limit will get rejected immediately.
key_type	string	optional	"var"	["var", "var_combination"]	the type of key.
key	string	required			the user specified key to limit the rate. If the `key_type` is "var", the key will be treated as a name of variable, like "remote_addr" or "consumer_name". If the `key_type` is "var_combination", the key will be a combination of variables, like "$remote_addr $consumer_name". If the value of the key is empty, `remote_addr` will be set as the default key.
rejected_code	integer	optional	503	[200,...,599]	The HTTP status code returned when the request exceeds the threshold is rejected.
rejected_msg	string	optional		non-empty	The response body returned when the request exceeds the threshold is rejected.
nodelay	boolean	optional	false		If nodelay flag is true, bursted requests will not get delayed
allow_degradation	boolean	optional	false		Whether to enable plugin degradation when the limit-req function is temporarily unavailable. Allow requests to continue when the value is set to true, default false.

Example#

How to enable on the `route` or `service`#

Take route as an example (the use of service is the same method), enable the limit-req plugin on the specified route when setting key_type to var .

curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "methods": ["GET"],
    "uri": "/index.html",
    "plugins": {
        "limit-req": {
            "rate": 1,
            "burst": 2,
            "rejected_code": 503,
            "key_type": "var",
            "key": "remote_addr"
        }
    },
    "upstream": {
        "type": "roundrobin",
        "nodes": {
            "127.0.0.1:9001": 1
        }
    }
}'

Take route as an example (the use of service is the same method), enable the limit-req plugin on the specified route when setting key_type to var_combination .

curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "methods": ["GET"],
    "uri": "/index.html",
    "plugins": {
        "limit-req": {
            "rate": 1,
            "burst": 2,
            "rejected_code": 503,
            "key_type": "var_combination",
            "key": "$consumer_name $remote_addr"
        }
    },
    "upstream": {
        "type": "roundrobin",
        "nodes": {
            "127.0.0.1:9001": 1
        }
    }
}'

You also can complete the above operation through the web interface, first add a route, then add limit-req plugin:

Test Plugin

The above configuration limits the request rate to 1 per second. If it is greater than 1 and less than 3, the delay will be added. If the rate exceeds 3, it will be rejected:

curl -i http://127.0.0.1:9080/index.html

When you exceed, you will receive a response header with a 503 return code:

HTTP/1.1 503 Service Temporarily Unavailable
Content-Type: text/html
Content-Length: 194
Connection: keep-alive
Server: APISIX web server

<html>
<head><title>503 Service Temporarily Unavailable</title></head>
<body>
<center><h1>503 Service Temporarily Unavailable</h1></center>
<hr><center>openresty</center>
</body>
</html>

At the same time, you set the property rejected_msg to "Requests are too frequent, please try again later." , when you exceed, you will receive a response body like below:

HTTP/1.1 503 Service Temporarily Unavailable
Content-Type: text/html
Content-Length: 194
Connection: keep-alive
Server: APISIX web server

{"error_msg":"Requests are too frequent, please try again later."}

This means that the limit req plugin is in effect.

How to enable on the `consumer`#

To enable the limit-req plugin on the consumer, it needs to be used together with the authorization plugin. Here, the key-auth authorization plugin is taken as an example.

Bind the limit-req plugin to the consumer

curl http://127.0.0.1:9080/apisix/admin/consumers -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "username": "consumer_jack",
    "plugins": {
        "key-auth": {
            "key": "auth-jack"
        },
        "limit-req": {
            "rate": 1,
            "burst": 1,
            "rejected_code": 403,
            "key": "consumer_name"
        }
    }
}'

Create a route and enable the key-auth plugin

curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "methods": ["GET"],
    "uri": "/index.html",
    "plugins": {
        "key-auth": {
            "key": "auth-jack"
        }
    },
    "upstream": {
        "type": "roundrobin",
        "nodes": {
            "127.0.0.1:1980": 1
        }
    }
}'

Test Plugin

The value of rate + burst is not exceeded.

curl -i http://127.0.0.1:9080/index.html -H 'apikey: auth-jack'
HTTP/1.1 200 OK
......

When the value of rate + burst is exceeded.

curl -i http://127.0.0.1:9080/index.html -H 'apikey: auth-jack'
HTTP/1.1 403 Forbidden
.....
<html>
<head><title>403 Forbidden</title></head>
<body>
<center><h1>403 Forbidden</h1></center>
<hr><center>openresty</center>
</body>
</html>

Explains that the limit-req plugin tied to consumer has taken effect.

Disable Plugin#

When you want to disable the limit req plugin, it is very simple, you can delete the corresponding json configuration in the plugin configuration, no need to restart the service, it will take effect immediately:

curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "methods": ["GET"],
    "uri": "/index.html",
    "id": 1,
    "plugins": {
    },
    "upstream": {
        "type": "roundrobin",
        "nodes": {
            "127.0.0.1:1980": 1
        }
    }
}'

Remove the limit-req plugin on consumer.

curl http://127.0.0.1:9080/apisix/admin/consumers -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "username": "consumer_jack",
    "plugins": {
        "key-auth": {
            "key": "auth-jack"
        }
    }
}'

The limit req plugin has been disabled now. It works for other plugins.