动态配置规则

动态配置规则

动态配置规则 (ConfigurationRule) 是 Dubbo 设计的在无需重启应用的情况下，动态调整 RPC 调用行为的一种能力，也称为动态覆盖规则，因为它是通过在运行态覆盖 Dubbo 实例或者 Dubbo 实例中 URL 地址的各种参数值，实现改变 RPC 调用行为的能力。

使用动态配置规则，有以下几条关键信息值得注意：

设置规则生效过滤条件。 配置规则支持一系列的过滤条件，用来限定规则只对符合特定条件的服务、应用或实例才生效。
设置规则生效范围。 一个 rpc 服务有服务发起方（消费者）和服务处理方（提供者）两个角色，对某一个服务定义的规则，可以具体到限制是对消费者还是提供者生效。
选择规则管理粒度。 Dubbo 支持从服务和应用两个粒度来管理和下发规则。

以下一个应用级别的配置示例，配置生效后，shop-detail 应用下提供的所有服务都将启用 accesslog，对 shop-detail 部署的所有实例生效。

configVersion: v3.0
scope: application
key: shop-detail
configs:
  - side: provider
    parameters:
      accesslog: 'true'

以下是一个服务级别的配置示例，key: org.apache.dubbo.samples.UserService 和 side: consumer 说明这条配置对所有正在消费 UserService 的 Dubbo 实例生效，在调用失败后都执行 4 次重试。match 条件进一步限制了消费端的范围，限定为只对应用名为 shop-frontend 的这个消费端应用生效。

configVersion: v3.0
scope: service
key: org.apache.dubbo.samples.UserService
configs:
  - match:
      application:
        oneof:
          - exact: shop-frontend
    side: consumer
    parameters:
      retries: '4'

ConfigurationRule

配置规则主体，定义要设置的目标服务或应用、具体的规则配置。具体配置规则 (configs) 可以设置多条。

Field	Type	Description	Required
configVersion	string	The version of the configuration rule definition, currently available version is `v3.0`	Yes
scope	string	Supports `service` and `application` scope configurations.	Yes
key	string	The identifier of the target service or application that this rule is about to apply to. - If `scope:service`is set, then `key`should be specified as the Dubbo service key that this rule targets to control. - If `scope:application` is set, then `key`should be specified as the name of the application that this rule targets to control.	Yes
enabled	bool	Whether enable this rule or not, set `enabled:false` to disable this rule.	Yes
configs	Config[]	The `match condition` and `configuration` of this rule.	Yes

Config

具体的规则配置定义，包含生效端 (consumer 或 provider) 和过滤条件。

Field	Type	Description	Required
side	string	Especially useful when `scope:service`is set. - `side: provider`means this Config will only take effect on the provider instances of the service key. - `side:consumer`means this Config will only take effect on the consumer instances of the service key	Yes
parameters	map<string, string>	The keys and values this rule aims to change.	Yes
match	MatchCondition	A set of criterion to be met in order for the rule/config to be applied to the Dubbo instance.	No
enabled	bool	Whether enable this Config or not, will use the value in ConfigurationRule if not set	No
~~addresses~~	~~string[]~~	~~replaced with address in MatchCondition~~	No
~~providerAddresses~~	~~string[]~~	~~not supported anymore~~	No
~~services~~	~~string[]~~	~~replaced with service in MatchCondition~~	No
~~applications~~	~~string[]~~	~~replaced with application in MatchCondition~~	No

MatchCondition

过滤条件，用来设置规则对哪个服务 (service)、应用 (application)、实例 (address)，或者包含哪些参数 (param) 的实例生效。

Field	Type	Description	Required
address	StringMatch	The instance address matching condition for this config rule to take effect. - xact: “value” for exact string match - prefix: “value” for prefix-based match - regex: “value” for RE2 style regex-based match (https://github.com/google/re2/wiki/Syntax)).	No
service	StringMatch (oneof)	The service matching condition for this config rule to take effect. Effective when `scope: application` is set. - exact: “value” for exact string match - prefix: “value” for prefix-based match - regex: “value” for RE2 style regex-based match (https://github.com/google/re2/wiki/Syntax)).	No
application	StringMatch (oneof)	The application matching condition for this config rule to take effect. Effective when `scope: service` is set. - exact: “value” for exact string match - prefix: “value” for prefix-based match - regex: “value” for RE2 style regex-based match (https://github.com/google/re2/wiki/Syntax)).	No
param	ParamCondition[]	The Dubbo url keys and values matching condition for this config rule to take effect.	No

ParamCondition

定义实例参数 (param) 过滤条件，对应到 Dubbo URL 地址参数。

Field	Type	Description	Required
key	string	The name of the key in the Dubbo url address.	Yes
value	StringMatch (oneof)	The matching condition for the value in the Dubbo url address.	Yes

StringMatch

Field	Type	Description	Required
exact	string (oneof)	exact string match	No
prefix	string (oneof)	prefix-based match	No
regex	string (oneof)	RE2 style regex-based match (https://github.com/google/re2/wiki/Syntax)).	No

最后修改 September 13, 2024: Refactor website structure (#2860) (1a4b998f54b)