limit-conn
Summary#
Name#
Limiting request concurrency plugin.
Attributes#
| Name | Type | Requirement | Default | Valid | Description |
|---|---|---|---|---|---|
| conn | integer | required | conn > 0 | the maximum number of concurrent requests allowed. Requests exceeding this ratio (and below conn + burst) will get delayed(the latency seconds is configured by default_conn_delay) to conform to this threshold. | |
| burst | integer | required | burst >= 0 | the number of excessive concurrent requests (or connections) allowed to be delayed. | |
| default_conn_delay | number | required | default_conn_delay > 0 | the latency seconds of request when concurrent requests exceeding conn but below (conn + burst). | |
| only_use_default_delay | boolean | optional | false | [true,false] | enable the strict mode of the latency seconds. If you set this option to true, it will run strictly according to the latency seconds you set without additional calculation logic. |
| 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 $consumer_name". If the value of the key is empty, remote_addr will be set as the default key. | ||
| rejected_code | string | optional | 503 | [200,...,599] | the HTTP status code returned when the request exceeds conn + burst will be rejected. |
| rejected_msg | string | optional | non-empty | the response body returned when the request exceeds conn + burst will be rejected. | |
| allow_degradation | boolean | optional | false | Whether to enable plugin degradation when the limit-conn function is temporarily unavailable. Allow requests to continue when the value is set to true, default false. |
How To Enable#
Here's an example, enable the limit-conn plugin on the specified route when setting key_type to var :
curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '{ "methods": ["GET"], "uri": "/index.html", "plugins": { "limit-conn": { "conn": 1, "burst": 0, "default_conn_delay": 0.1, "rejected_code": 503, "key_type": "var", "key": "http_a" } }, "upstream": { "type": "roundrobin", "nodes": { "39.97.63.215:80": 1 } }}'Here's an example, enable the limit-conn plugin on the specified route when setting key_type to var_combination :
curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '{ "methods": ["GET"], "uri": "/index.html", "plugins": { "limit-conn": { "conn": 1, "burst": 0, "default_conn_delay": 0.1, "rejected_code": 503, "key_type": "var_combination", "key": "$consumer_name $remote_addr" } }, "upstream": { "type": "roundrobin", "nodes": { "39.97.63.215:80": 1 } }}'You also can complete the above operation through the web interface, first add a route, then add limit-conn plugin:
Test Plugin#
The parameters of the plugin enabled above indicate that only one concurrent request is allowed. When more than one concurrent request is received, will return 503 directly.
curl -i http://127.0.0.1:9080/index.html?sleep=20 &
curl -i http://127.0.0.1:9080/index.html?sleep=20<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 request concurrency plugin is in effect.
Disable Plugin#
When you want to disable the limit-conn 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": { "39.97.63.215:80": 1 } }}'The limit-conn plugin has been disabled now. It works for other plugins.