Hi, Community,
I have implemented a plug-in related to traffic split, and I want to add the plug-in to apisix. The following is the main information of the plugin: 1. Background After seeing this issue about traffic split plugin #2303(https://github.com/apache/apisix/issues/2303), I think this function is very useful, it can effectively realize the flow control function. Therefore, this inspired me to implement a dynamic upstream plugin. 2. Why do this For details, please see: https://github.com/apache/apisix/issues/2303 Traffic split means that requests need to comply with certain rules in order to reach the designated upstream or a certain node in the upstream. Through this function, gray release, blue-green release and custom routing are realized, which is very useful for reducing downtime in the event of a failure. 3. Design The dynamic upstream plug-in is mainly composed of two parts `match` and `upstreams` to implement the rules of the plugin. `match` is the matching rule of the plugin (the currently supported operations are: ==, ~=, ~~, >, >=, <, <=, in , ip_in). Only after the `match` rule is passed, can the `upstreams` rule in the plugin be reached, otherwise the default upstream is reached. In the `upstreams` rule, `upstream` is the configuration of the plugin upstream, and the `weight` field is the basis for traffic segmentation between upstream services (using the roundrobin algorithm). note: ``` { "Weight": 1 } ``` When the plug-in upstream configuration has only the weight field, it means the default upstream traffic ratio. Example: Grayscale release: The traffic is split according to the weight field value configured in the upstreams part of the plug-in. If `match` is not configured, match is passed by default. Divide the request traffic by 4:1, 4/5 of the traffic hits the upstream of the plugin port of `1981`, and 1/5 of the traffic hits the default upstream of the `1980` port. ``` "plugins": { "dynamic-upstream": { "rules": [ { "upstreams": [ { "upstream": { "name": "upstream_A", "type": "roundrobin", "nodes": { "127.0.0.1:1981":10 } }, "weight": 4 }, { "weight": 1 } ] } ] } }, "upstream": { "type": "roundrobin", "nodes": { "127.0.0.1:1980": 1 } } ``` Blue-green release: All requests hit the upstrean configured by the plugin (when weight is 0, the corresponding upstream is invalid). ``` "plugins": { "dynamic-upstream": { "rules": [ { "match": [ { "vars": [ [ "http_new-release","==","blue" ] ] } ], "upstreams": [ { "upstream": { "name": "upstream_A", "type": "roundrobin", "nodes": { "127.0.0.1:1981":10 } }, "weight": 1 }, { "weight": 0 } ] } ] } }, "upstream": { "type": "roundrobin", "nodes": { "127.0.0.1:1980": 1 } } ``` Custom release: There are multiple conditions in vars, and the relationship between them is `add`. Multiple vars can be configured, then they have an `or` relationship. After the `match` rule is passed, the traffic is divided into 4:2, 2/3 of the traffic hits the plug-in upstream of the `1981` port, and 1/3 of the traffic hits the default upstream of the `1980` port. ``` "plugins": { "dynamic-upstream": { "rules": [ { "match": [ { "vars": [ [ "arg_name","==","jack" ], [ "http_user-id",">=","23" ], [ "http_apisix-key","~~","[a-z]+" ] ] } ], "upstreams": [ { "upstream": { "name": "upstream_A", "type": "roundrobin", "nodes": { "127.0.0.1:1981":10 } }, "weight": 4 }, { “weight”: 2 } ] } ] } }, "upstream": { "type": "roundrobin", "nodes": { "127.0.0.1:1980": 1 } } ``` Note: The vars parameter here can be obtained from the http request header, querystring or nginx variable. The above is a brief introduction to the dynamic upstream plugin. I want to add this plugin to the apisix project, what do you think?
