feat: 🎸 add frontend gray plugin (#1120)

Co-authored-by: Kent Dong <ch3cho@qq.com>

plugins/wasm-go/extensions/frontend-gray/main.go

@@ -0,0 +1,78 @@
+package main
+
+import (
+	"github.com/alibaba/higress/plugins/wasm-go/extensions/frontend-gray/config"
+	"github.com/alibaba/higress/plugins/wasm-go/extensions/frontend-gray/util"
+
+	"github.com/alibaba/higress/plugins/wasm-go/pkg/wrapper"
+	"github.com/higress-group/proxy-wasm-go-sdk/proxywasm"
+	"github.com/higress-group/proxy-wasm-go-sdk/proxywasm/types"
+	"github.com/tidwall/gjson"
+)
+
+func main() {
+	wrapper.SetCtx(
+		"frontend-gray",
+		wrapper.ParseConfigBy(parseConfig),
+		wrapper.ProcessRequestHeadersBy(onHttpRequestHeaders),
+	)
+}
+
+func parseConfig(json gjson.Result, grayConfig *config.GrayConfig, log wrapper.Log) error {
+	// 解析json 为GrayConfig
+	config.JsonToGrayConfig(json, grayConfig)
+	return nil
+}
+
+// FilterGrayRule 过滤灰度规则
+func FilterGrayRule(grayConfig *config.GrayConfig, grayKeyValue string, log wrapper.Log) *config.GrayDeployments {
+	for _, grayDeployment := range grayConfig.GrayDeployments {
+		if !grayDeployment.Enabled {
+			// 跳过Enabled=false
+			continue
+		}
+		grayRule := util.GetRule(grayConfig.Rules, grayDeployment.Name)
+		// 首先：先校验用户名单ID
+		if grayRule.GrayKeyValue != nil && len(grayRule.GrayKeyValue) > 0 && grayKeyValue != "" {
+			if util.Contains(grayRule.GrayKeyValue, grayKeyValue) {
+				log.Infof("x-mse-tag: %s, grayKeyValue: %s", grayDeployment.Version, grayKeyValue)
+				return grayDeployment
+			}
+		}
+		//	第二：校验Cookie中的 GrayTagKey
+		if grayRule.GrayTagKey != "" && grayRule.GrayTagValue != nil && len(grayRule.GrayTagValue) > 0 {
+			cookieStr, _ := proxywasm.GetHttpRequestHeader("cookie")
+			grayTagValue := util.GetValueByCookie(cookieStr, grayRule.GrayTagKey)
+			if util.Contains(grayRule.GrayTagValue, grayTagValue) {
+				log.Infof("x-mse-tag: %s, grayTag: %s=%s", grayDeployment.Version, grayRule.GrayTagKey, grayTagValue)
+				return grayDeployment
+			}
+		}
+	}
+	log.Infof("x-mse-tag: %s, grayKeyValue: %s", grayConfig.BaseDeployment.Version, grayKeyValue)
+	return nil
+}
+
+func onHttpRequestHeaders(ctx wrapper.HttpContext, grayConfig config.GrayConfig, log wrapper.Log) types.Action {
+	// 优先从cookie中获取，如果拿不到再从header中获取
+	cookieStr, _ := proxywasm.GetHttpRequestHeader("cookie")
+	grayHeaderKey, _ := proxywasm.GetHttpRequestHeader(grayConfig.GrayKey)
+	grayKeyValue := util.GetValueByCookie(cookieStr, grayConfig.GrayKey)
+	proxywasm.RemoveHttpRequestHeader("Accept-Encoding")
+	// 优先从Cookie中获取，否则从header中获取
+	if grayKeyValue == "" {
+		grayKeyValue = grayHeaderKey
+	}
+	// 如果有子key, 尝试从子key中获取值
+	if grayConfig.GraySubKey != "" {
+		subKeyValue := util.GetBySubKey(grayKeyValue, grayConfig.GraySubKey)
+		if subKeyValue != "" {
+			grayKeyValue = subKeyValue
+		}
+	}
+	grayDeployment := FilterGrayRule(&grayConfig, grayKeyValue, log)
+	if grayDeployment != nil {
+		proxywasm.AddHttpRequestHeader("x-mse-tag", grayDeployment.Version)
+	}
+	return types.ActionContinue
+}