All the rules can be queried or modified in memory and these modifications take effects immediately. Sentinel also provides APIs for you to define your own rules.

Rule definitions

There are 3 kinds of rules: flow rules, degradation rules, and system rules.

1.Flow Rules

Flow Rule has the following fields：

Field Description Default value
resource resource name
count thredshold
grade depends on QPS or concurrency(active thread count) QPS
limitApp whether to count on callers no
strategy count on the resource itself, or on the related resource(refResource)，or on entry resource(refResource) resource itself
controlBehavior how to act after block criteria are met. To block immediately, or wait in a queue, or slow warm up block immediatley

Multiple rules can be applied to one resource.

2.Degradation RulesDegrade has the following fields：

Field Description Default value
resource resource name
count thredshold
grade down grade o RT or qps RT
timeWindow timewindow when degradation happens
  • System Protection Rules

    Query active rules

Run the following command to query current active rules：

curl http://localhost:8719/getRules?type=? ,type=flow

If the type is flow, it will return all flow rules in JSON format; if the type is degrade, it will return all degradation rules in JSON format; and if the type is system, it will return system rules.

Modify rules

You can modify the following rules via the following command：

curl http://localhost:8719/setRules?type=<XXXX>&data=<DATA&gt;

Data is the rules in JSON format.

Customize your persistent rules

All the rules' configuration above are stored in memory, which means that rules will be lost if the application restart. We can implement DataSource to define persist rule logic.

  • Via Nacos. You can refer to [TODO] for the sample file.
  • Via SQL, Git, You can refer to [TODO] for the sample file.
  • Via Dashboard, You can refer to [TODO] for the sample file.
  • Via File

原文: https://github.com/alibaba/Sentinel/wiki/Dynamic-Rule-Configuration