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limit-count

Summary#

Name#

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

Attributes#

NameTypeRequirementDefaultValidDescription
countintegerrequiredcount > 0the specified number of requests threshold.
time_windowintegerrequiredtime_window > 0the time window in seconds before the request count is reset.
key_typestringoptional"var"["var", "var_combination", "constant"]the type of key.
keystringoptional"remote_addr"the user specified key to limit the rate. If the key_type is "constant", the key will be treated as a constant. If the key_type is "var", the key will be treated as a name of variable. If the key_type is "var_combination", the key will be a combination of variables. For example, if we use "$remote_addr $consumer_name" as key, plugin will be restricted by two variables which are "remote_addr" and "consumer_name". If the value of the key is empty, remote_addr will be set as the default key.
rejected_codeintegeroptional503[200,...,599]The HTTP status code returned when the request exceeds the threshold is rejected, default 503.
rejected_msgstringoptionalnon-emptyThe response body returned when the request exceeds the threshold is rejected.
policystringoptional"local"["local", "redis", "redis-cluster"]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), redis(counters are stored on a Redis server and will be shared across the nodes, usually use it to do the global speed limit), and redis-cluster which works the same as redis but with redis cluster.
allow_degradationbooleanoptionalfalseWhether to enable plugin degradation when the limit-count function is temporarily unavailable(e.g. redis timeout). Allow requests to continue when the value is set to true, default false.
show_limit_quota_headerbooleanoptionaltrueWhether show X-RateLimit-Limit and X-RateLimit-Remaining (which mean the total number of requests and the remaining number of requests that can be sent) in the response header, default true.
groupstringoptionalnon-emptyRoute configured with the same group will share the same counter
redis_hoststringrequired for redisWhen using the redis policy, this property specifies the address of the Redis server.
redis_portintegeroptional6379[1,...]When using the redis policy, this property specifies the port of the Redis server.
redis_passwordstringoptionalWhen using the redis or redis-cluster policy, this property specifies the password of the Redis server.
redis_databaseintegeroptional0redis_database >= 0When using the redis policy, this property specifies the database you selected of the Redis server, and only for non Redis cluster mode (single instance mode or Redis public cloud service that provides single entry).
redis_timeoutintegeroptional1000[1,...]When using the redis or redis-cluster policy, this property specifies the timeout in milliseconds of any command submitted to the Redis server.
redis_cluster_nodesarrayrequired when policy is redis-clusterWhen using redis-cluster policy,This property is a list of addresses of Redis cluster service nodes (at least two).
redis_cluster_namestringrequired when policy is redis-clusterWhen using redis-cluster policy, this property is the name of Redis cluster service nodes.

How To Enable#

Here's an example, enable the limit count plugin on the specified route when setting key_type to var :

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_type": "var",            "key": "remote_addr"        }    },    "upstream": {        "type": "roundrobin",        "nodes": {            "127.0.0.1:9001": 1        }    }}'

Here's an example, enable the limit count plugin on the specified route when setting key_type to var_combination :

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_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-count plugin: Add limit-count plugin.

It is possible to share the same limit counter across different routes. For example,

curl -i http://127.0.0.1:9080/apisix/admin/services/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '{    "plugins": {        "limit-count": {            "count": 1,            "time_window": 60,            "rejected_code": 503,            "key": "remote_addr",            "group": "services_1#1640140620"        }    },    "upstream": {        "type": "roundrobin",        "nodes": {            "127.0.0.1:1980": 1        }    }}'

Every route which group name is "services_1#1640140620" will share the same count limitation 1 in one minute per remote_addr.

$ curl -i http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '{    "service_id": "1",    "uri": "/hello"}'
$ curl -i http://127.0.0.1:9080/apisix/admin/routes/2 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '{    "service_id": "1",    "uri": "/hello2"}'
$ curl -i http://127.0.0.1:9080/helloHTTP/1.1 200 ...
$ curl -i http://127.0.0.1:9080/hello2HTTP/1.1 503 ...

Note that every limit-count configuration of the same group must be the same. Therefore, once update the configuration, we also need to update the group name.

It is also possible to share the same limit counter in all requests. For example,

curl -i http://127.0.0.1:9080/apisix/admin/services/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '{    "plugins": {        "limit-count": {            "count": 1,            "time_window": 60,            "rejected_code": 503,            "key": "remote_addr",            "key_type": "constant",            "group": "services_1#1640140621"        }    },    "upstream": {        "type": "roundrobin",        "nodes": {            "127.0.0.1:1980": 1        }    }}'

Compared with the previous configuration, we set the key_type to constant. By setting key_type to constant, we don't evaluate the value of key but treat it as a constant.

Now every route which group name is "services_1#1640140621" will share the same count limitation 1 in one minute among all the requests, even these requests are from different remote_addr.

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 if we use single redis policy:

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_database": 1,            "redis_timeout": 1001        }    },    "upstream": {        "type": "roundrobin",        "nodes": {            "127.0.0.1:1980": 1        }    }}'

If using redis-cluster policy:

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-cluster",            "redis_cluster_nodes": [              "127.0.0.1:5000",              "127.0.0.1:5001"            ],            "redis_password": "password",            "redis_cluster_name": "redis-cluster-1"        }    },    "upstream": {        "type": "roundrobin",        "nodes": {            "127.0.0.1:1980": 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 OKContent-Type: text/htmlContent-Length: 13175Connection: keep-aliveX-RateLimit-Limit: 2X-RateLimit-Remaining: 0Server: 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 UnavailableContent-Type: text/htmlContent-Length: 194Connection: keep-aliveServer: 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, if you set the property rejected_msg to "Requests are too frequent, please try again later." , when you visit for the third time, you will receive a response body like below:

HTTP/1.1 503 Service Temporarily UnavailableContent-Type: text/htmlContent-Length: 194Connection: keep-aliveServer: APISIX web server
{"error_msg":"Requests are too frequent, please try again later."}

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": {            "127.0.0.1:1980": 1        }    }}'

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