Conditional Routing Rules
Conditional routing rules forward requests that meet specific conditions to a subset of destination instances. The rules match the request parameters of incoming traffic, and requests that meet the matching criteria are forwarded to a subset that contains a specific list of instance addresses.
Here is an example of a conditional routing rule.
Based on the following example rule, all invocations of the getComment method in the org.apache.dubbo.samples.CommentService service will be forwarded to a subset of addresses marked with region=Hangzhou.
configVersion: v3.0
scope: service
force: true
runtime: true
enabled: true
key: org.apache.dubbo.samples.CommentService
conditions:
- method=getComment => region=Hangzhou
You can refer to specific example code for conditional routing here.
ConditionRule
The body of a conditional routing rule defines the target service or application on which the routing rule will take effect, the traffic filtering conditions, and the behaviors in certain specific scenarios.
| Field | Type | Description | Required |
|---|---|---|---|
| configVersion | string | The version of the condition rule definition, currently available version is v3.0 | Yes |
| scope | string | Supports service and application scope rules. | Yes |
| key | string | The identifier of the target service or application that this rule is about to apply to. - If scope:serviceis set, then keyshould be specified as the Dubbo service key that this rule targets to control.- If scope:application is set, then keyshould be specified as the name of the application that this rule targets to control, application should always be a Dubbo Consumer. | Yes |
| enabled | bool | Whether enable this rule or not, set enabled:false to disable this rule. | Yes |
| conditions | string[] | The condition routing rule definition of this configuration. Check Condition for details | 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 |
| runtime | bool | Whether run routing rule for every rpc invocation or use routing cache if available. | No |
Condition
The Condition serves as the body of a conditional routing rule and is of type string with a composite structure, such as method=getComment => region=Hangzhou. Here:
- The conditions before the
=>symbol indicate the request parameter matching conditions. The specifiedmatching conditionsare compared with the consumer’s request context (URL) or even method parameters. When the consumer satisfies the matching conditions, the address subset filtering rules following the conditions will be applied to the consumer. - The conditions after the
=>symbol represent the address subset filtering conditions. The specifiedfiltering conditionsare compared with the provider instance addresses (URLs). The consumer can only access instances that meet the filtering conditions, ensuring that traffic is only sent to the subset of addresses that meet the conditions.- If the matching conditions are empty, it means the rule applies to all requests, for example:
=> status != staging - If the filtering conditions are empty, it denies access from the corresponding requests, for example:
application = product =>
- If the matching conditions are empty, it means the rule applies to all requests, for example:
Matching/Filtering Conditions
Parameter Support
- Service invocation context, such as interface, method, group, version, etc.
- Request context, such as attachments[key] = value.
- Method parameters, such as arguments[0] = tom.
- Fields in the URL itself, such as protocol, host, port, etc.
- Additional parameters on the URL, such as application, organization, etc.
- Supports developer-defined extensions.
Condition Support
- The equal sign (=) represents “match,” for example: method = getComment.
- The not-equal sign (!=) represents “not match,” for example: method != getComment.
Value Support
- Multiple values separated by commas (,), for example: host != 10.20.153.10,10.20.153.11.
- Ending with an asterisk () denotes wildcard matching, for example: host != 10.20..
- Starting with a dollar sign ($) indicates referencing consumer parameters, for example: region = $region.
- Integer value ranges, for example: userId = 1~100, userId = 101~.
- Supports developer-defined extensions.
