Version: 2.5.1

Selector And Rule Config

Features#

This document will introduce the use of selectors and rules in the Apache ShenYu background management system. For the concept and design of selectors and rules, please refer to Flow Control.

Please refer to the deployment document, choose a way to start shenyu-admin. For example, local deployment. After startup, visit http://localhost:9095, the default username and password are: admin and 123456 .

Selector#

All plugins are displayed in the PluginList, and selectors and rules can be added to each plugin:

For example, add a selector to the divide plugin:

selector detailed explanation：
- Name: create your selector with a distinguish name.
- Type: Choose request matching strategy.
  - custom: Only handle requests that meet the following matching conditions.
  - full: Handle all requests.
- MatchType: Condition combination type.
  - and： Need to meet all conditions.
  - or: Meet any of the conditions.
- Conditions：
  - uri: filter request with uri.
  - header: filter request with request header.
  - query: filter request with query string.
  - ip: filter request with your real ip.
  - host: filter request with your real host.
  - post: not recommend to use.
  - cookie: filter request with cookie.
  - req_method: filter request with request method.
  - condition match:
    - match : fuzzy string matching，recommend to combine with uri，support path-matching.（/test/**).
    - = : matches only if they are equal.
    - regEx : regex matching，match characters in regex expression.
    - contains: when it contains the specified value, it matches.
    - TimeBefore: before the specified time.
    - TimeAfter: after the specified time.
    - exclude: the inverse of the method of match.
    - startsWith: when its prefix is equal to the specified value, it matches. In certain scenarios, match can be replaced (such as /test/ instead of /test/**) for better performance.
    - endsWith: when its suffix is equal to the specified value, it matches.
    - pathPatter: it's an optimized version of match, which has better performance than match, but does not support writing ** in the middle of the path (such as /api/**/xxx).
- Continued: whether the subsequent selector is still executed.
- PrintLogs: it will print the matching log with the open option enabled.
- Enable: whether to enable the plugin.
- Order：the smaller will have high priority to execute among multi-selectors.
- Handler: The operation when the request matches the selector.
the above picture means: when the prefix of the request uri is /http, it will redirect to this service 127.0.0.1:8080.
selector advice : combine uri condition and startsWith prefix（/contextPath/）as the first request filter.
selector(the same for rule) match condition fuzzy string matching rule:
- ? matches one character
- * matches zero or more characters
- ** matches zero or more directories in a path

Rule#

when the request was passed by the selector, then it will be processed by the rule, the final filter.
rule is the final confirmation about how to execute request logically.
rule detailed explanation：
- Name：create your rule with a distinguish name.
- MatchType: you can combine these conditions with 'and' , 'or' operators.
- Conditions：
  - uri: filter request with uri.
  - header: filter request with request header.
  - query: filter request with query string.
  - ip: filter request with your real ip.
  - host: filter request with your real host.
  - post: not recommend to use.
  - cookie: filter request with cookie.
  - req_method: filter request with request method.
  - condition match:
    - match : fuzzy string matching，recommend to combine with uri，support path-matching.（/test/**).
    - = : matches only if they are equal.
    - regEx : regex matching，match characters in regex expression.
    - contains: when it contains the specified value, it matches.
    - TimeBefore: before the specified time.
    - TimeAfter: after the specified time.
    - exclude: Same function as match, flow selection is opposite.
    - startsWith: when its prefix is equal to the specified value, it matches. In certain scenarios, match can be replaced (such as /test/ instead of /test/**) for better performance.
    - endsWith: when its suffix is equal to the specified value, it matches.
    - pathPatter: it's an optimized version of match, which has better performance than match, but does not support writing ** in the middle of the path (such as /api/**/xxx).
- PrintLogs: it will print the matching log with the open option enabled.
- Enable: whether to enable the plugin.
- Order：the smaller will have high priority to execute among multi-rules.
- handle: The operation when the request matches the rule.
above picture means: when the request uri equals to /http/order/save, it will execute based on this rule，load strategy is random.
rule advice: combine uri condition with match the real uri path condition as the final filter.
combine selector means ：when the request uri is /http/order/save, it will be redicted to 127.0.0.1:8080 by random method.

Match Strategy#

Matching mode refers to the matching mode between multiple conditions when a selector or rule is matched. Currently, and and or are supported.

and
and indicates that a selector or rule can be matched only if more than one condition is met.
The example below shows that a request must meet both the condition uri = /http/order/findById and the condition id = 100 to match this rule.
For example, a real request http://localhost:9195/http/order/findById?id=100 satisfies both conditions, this rule can be matched.

or
or indicates that one of the conditions matches a selector or rule.
The example below shows that a request matches this rule if it meets either the condition uri = /http/order/findById or the condition id = 100.
For example, a real request http://localhost:9195/http/order/findById?id=99 satisfies the first condition uri = /http/order/findById, so it can also match this rule.

Condition Parameter Data#

Conditional parameter Settings in selectors and rules are explained again. Suppose the following is a request header for an Http request:

GET http://localhost:9195/http/order/findById?id=100Accept: application/jsonCookie: shenyu=shenyu_cookieMyHeader: custom-header

In ShenYu you can set different conditional parameters to get real data from the request information.

If the condition parameter is uri, then the actual data retrieved is /http/order/findById;
If the condition parameter is header, the field name is MyHeader, then the actual data retrieved is custom-header;
If the condition parameter is query, the field name is id, then the actual data retrieved is 100;
If the condition parameter is ip, then the actual data retrieved is 0:0:0:0:0:0:0:1;
If the condition parameter is host, then the actual data retrieved is 0:0:0:0:0:0:0:1;
If the condition parameter is post, the field name is contextPath, then the actual data retrieved is /http;
If the condition parameter is cookie, the field name is shenyu, then the actual data retrieved is shenyu_cookie;
If the condition parameter is req_method, then the actual data retrieved is GET;

uri(recommended)
- uri matches are based on the uri in the path you requested, and there is almost no change in the front end when accessing the gateway.
- When using match, the principle is the same as SpringMVC fuzzy matching.
- In selectors, it is recommended to use prefixes in URI for matching, while in rules, specific paths are used for matching.
- When using this matching method, fill in the value of the matching field, as shown in the figure /http/**.
header
- The header is matched against the field values in your http request header.
- When using this matching method, you need to fill in the field name and field value. The examples in the figure are MyHeader and custom-header respectively
query
- This matches the query parameters in your uri, such as /test?id=1, then the matching method can be selected.
- When using this matching method, you need to fill in the field name and field value. The examples in the figure are id and 1 respectively.
ip
- This is matched against the http caller's ip.
- Especially in waf plugin, if an ip address is found to be attacked, you can add a matching condition, fill in the ip, deny the ip access.
- If you use nginx proxy before ShenYu, you can get the right ip with refering to parsing-ip-and-host
- When using this matching method, fill in the value of the matching field, as shown in the example 192.168.236.75.

host
- This is matched against the http caller's host.
- Especially in waf plugin, if an host address is found to be attacked, you can add a matching condition, fill in the host, deny the host access.
- If you use nginx proxy before ShenYu, you can get the right ip with refering to parsing-ip-and-host
- When using this matching method, fill in the value of the matching field, as shown in the example localhost.
post
- To get condition parameters from the request context(org.apache.shenyu.plugin.api.context.ShenyuContext), reflection is required to get the value of the field, which is not recommended.
- When using this matching method, the field name and value need to be specified. The examples in the figure are contextPath and /http respectively.

cookie
- This is matched against the Cookie in the http caller's request header as a condition parameter.
- When using this matching method, you need to fill in the field name and field value. The examples in the figure are shenyu and shenyu_cookie respectively.
req_method
- This matches the request form of the http caller, such as GET, POST, etc.
- When using this matching method, fill in the value of the matching field, as shown in the example GET.

For a more in-depth understanding of condition parameter fetching, read the source code, package name is org.apache.shenyu.plugin.base.condition.data:

Condition Parameter	Class
`uri`	`URIParameterData`
`header`	`HeaderParameterData`
`query`	`QueryParameterData`
`ip`	`IpParameterData`
`host`	`HostParameterData`
`post`	`PostParameterData`
`cookie`	`CookieParameterData`
`req_method`	`RequestMethodParameterData`

Condition Match Strategy#

Condition parameters allow you to retrieve the actual data of the request. How the real data matches the conditional data preset by the selector or rule is realized through the condition match strategy.

match
match supports fuzzy matching (/**). Request /http/order/findById will match if your selector condition is set as follows.
=
= means that the requested real data is equal to the preset condition data. If your selector condition is set to request uri equal to /http/order/findById, then request/http/order/findById?id=1 can match it.
regex
regex means that the requested real data can meet the preset condition of the regular expression to match successfully. Suppose your rule conditions are sets as follows: the request parameter contains an id and is a three-digit number. So request /http/order/findById?id=900 will match.
contains
contains means that the requested real data contains the default condition data. Suppose your rule condition is set as follows: request uri contains findById. Request /http/order/findById?id=1 will match.
TimeBefore
TimeBefore indicates that the request time will be matched before the preset condition time. Suppose your rule conditions are sets as follows: request parameters contain date and date is less than 2021-09-26 06:12:10. Request /http/order/findById?id=100&date=2021-09-22 06:12:10 will match.
TimeAfter
TimeAfter indicates that the request time will be matched before the preset condition time. Suppose your rule conditions are sets as follows: request parameters contain date and date is greater than 2021-09-26 06:12:10. Request /http/order/findById?id=100&date=2021-09-22 06:12:10 will match.
exclude
exclude is the inverse of the method of match, and some functions of match are also available, but it is a matching filter. If your selector condition is set as follows, the request /http/order/findById will filter this.
startsWith
startsWith indicates that the prefix of the requested real data is equal to the preset condition data. Suppose your rule conditions are sets as follows: the prefix in the request uri is equal to /http/, the request /http/order/findById?id=1 can be matched.
endsWith
endsWith indicates that the suffix of the requested real data is equal to the preset condition data. Suppose your rule conditions are sets as follows: request uri suffix equals Id. Then the request /http/order/findById?id=1 can be matched.
pathPatter
Like match, pathPatter supports fuzzy matching (/**). If your rule conditions are sets as follows, then the request /http/order/findById can be matched;
Notice: writing ** in the middle of the path (such as /api/**/xxx) is not supported!

If you want to further understand conditions matching strategy, please read the source code, the package name is org.apache.shenyu.plugin.base.condition.judge:

Match Strategy	Class
`match`	`MatchPredicateJudge`
`=`	`EqualsPredicateJudge`
`regex`	`RegexPredicateJudge`
`contains`	`ContainsPredicateJudge`
`TimeBefore`	`TimerBeforePredicateJudge`
`TimeAfter`	`TimerAfterPredicateJudge`
`exclude`	`ExcludePredicateJudge`
`startsWith`	`StartsWithPredicateJudge`
`endsWith`	`EndsWithPredicateJudge`
`pathPatter`	`PathPatternPredicateJudge`

The examples in this article illustrate the use of selectors and rules. The Settings of specific conditions need to be selected according to actual conditions.