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limit-count.md

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Summary

Name

Limit request rate by a fixed number of requests in a given time window.

Attributes

Name Requirement Description
count required the specified number of requests threshold.
time_window required the time window in seconds before the request count is reset.
key required the user specified key to limit the rate. Here is fully key list: "remote_addr", "server_addr", "http_x_real_ip", "http_x_forwarded_for".
rejected_code optional The HTTP status code returned when the request exceeds the threshold is rejected, default 503.
policy optional The rate-limiting policies to use for retrieving and incrementing the limits. Available values are local(the counters will be stored locally in-memory on the node, default value) and redis(counters are stored on a Redis server and will be shared across the nodes, usually used it to do the global speed limit).
redis_host optional When using the redis policy, this property specifies the address of the Redis server.
redis_port optional When using the redis policy, this property specifies the port of the Redis server. The default port is 6379.
redis_password optional When using the redis policy, this property specifies the password of the Redis server.
redis_timeout optional When using the redis policy, this property specifies the timeout in milliseconds of any command submitted to the Redis server. The default timeout is 1000 ms(1 second).

Key can be customized by the user, only need to modify a line of code of the plug-in to complete. It is a security consideration that is not open in the plugin.

How To Enable

Here's an example, enable the limit count plugin on the specified route:

curl -i http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "uri": "/index.html",
    "plugins": {
        "limit-count": {
            "count": 2,
            "time_window": 60,
            "rejected_code": 503,
            "key": "remote_addr"
        }
    },
    "upstream": {
        "type": "roundrobin",
        "nodes": {
            "39.97.63.215:80": 1
        }
    }
}'

You can open dashboard with a browser: http://127.0.0.1:9080/apisix/dashboard/, to complete the above operation through the web interface, first add a route: Add a router.

Then add limit-count plugin: Add limit-count plugin.

If you need a cluster-level precision traffic limit, then we can do it with the redis server. The rate limit of the traffic will be shared between different APISIX nodes to limit the rate of cluster traffic.

Here is the example:

curl -i http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "uri": "/index.html",
    "plugins": {
        "limit-count": {
            "count": 2,
            "time_window": 60,
            "rejected_code": 503,
            "key": "remote_addr",
            "policy": "redis",
            "redis_host": "127.0.0.1",
            "redis_port": 6379,
            "redis_password": "password",
            "redis_timeout": 1001
        }
    },
    "upstream": {
        "type": "roundrobin",
        "nodes": {
            "39.97.63.215:80": 1
        }
    }
}'

Test Plugin

The above configuration limits access to only 2 times in 60 seconds. The first two visits will be normally:

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

The response header contains X-RateLimit-Limit and X-RateLimit-Remaining, which mean the total number of requests and the remaining number of requests that can be sent:

HTTP/1.1 200 OK
Content-Type: text/html
Content-Length: 13175
Connection: keep-alive
X-RateLimit-Limit: 2
X-RateLimit-Remaining: 0
Server: APISIX web server

When you visit for the third time, you will receive a response with the 503 HTTP 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>

This means that the limit count plugin is in effect.

Disable Plugin

When you want to disable the limit count 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",
    "upstream": {
        "type": "roundrobin",
        "nodes": {
            "39.97.63.215:80": 1
        }
    }
}'

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