Script Routing Rules

Script Routing Rules

Script routing provides maximum flexibility for traffic management. All traffic will dynamically execute a rule script before performing load balancing selection, and the available address subset is determined based on the script execution results.

Script routing only affects consumers and only supports application-level management. Therefore, the key must be set to the consumer application name. The script syntax supports multiple languages. Taking the Dubbo Java SDK as an example, the script syntax supports Javascript, Groovy, Kotlin, etc. For specific limitations, refer to the implementation of each language.

Since script routing can dynamically load and execute remote code, there are potential security risks. Ensure that the script rules run in a secure sandbox before enabling script routing.

configVersion: v3.0
key: demo-provider
type: javascript
enabled: true
script: |
  (function route(invokers,invocation,context) {
      var result = new java.util.ArrayList(invokers.size());
      for (i = 0; i < invokers.size(); i ++) {
          if ("10.20.3.3".equals(invokers.get(i).getUrl().getHost())) {
              result.add(invokers.get(i));
          }
      }
      return result;
  } (invokers, invocation, context));

ScriptRule

The main body of the script routing rule. It defines the target consumer application for which the script rule is effective, the traffic filtering script, and behaviors in specific scenarios.

Field	Type	Description	Required
configVersion	string	The version of the script rule definition, currently available version is `v3.0`	Yes
key	string	The identifier of the target application that this rule is about to apply to.	Yes
type	string	The script language used to define `script`.	Yes
enabled	bool	Whether to enable this rule or not, set `enabled:false` to disable this rule.	Yes
script	string	The script definition used to filter dubbo provider instances.	Yes
force	bool	The behavior when the instance subset is empty after routing. `true` means return no provider exception while `false` means ignore this rule.	No

Script

script is the main body of the script routing rule, and its type is a string with a specific structure, depending on the script language specified by type.

The following is an example of a script rule with type: javascript:

(function route(invokers,invocation,context) {
      var result = new java.util.ArrayList(invokers.size());
      for (i = 0; i < invokers.size(); i ++) {
          if ("10.20.3.3".equals(invokers.get(i).getUrl().getHost())) {
              result.add(invokers.get(i));
          }
      }
      return result;
  } (invokers, invocation, context));

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Last modified September 30, 2024: Update & Translate Overview Docs (#3040) (d37ebceaea7)