extension mechanism for custom logs and span attributes (#1451)

plugins/wasm-go/pkg/wrapper/utils.go

@@ -0,0 +1,36 @@
+package wrapper
+
+import (
+	"encoding/json"
+
+	"github.com/higress-group/proxy-wasm-go-sdk/proxywasm"
+	"github.com/tidwall/gjson"
+)
+
+func unmarshalStr(marshalledJsonStr string) string {
+	// e.g. "{\"field1\":\"value1\",\"field2\":\"value2\"}"
+	var jsonStr string
+	err := json.Unmarshal([]byte(marshalledJsonStr), &jsonStr)
+	if err != nil {
+		proxywasm.LogErrorf("failed to unmarshal json string, raw string is: %s, err is: %v", marshalledJsonStr, err)
+		return ""
+	}
+	// e.g. {"field1":"value1","field2":"value2"}
+	return jsonStr
+}
+
+func marshalStr(raw string) string {
+	// e.g. {"field1":"value1","field2":"value2"}
+	helper := map[string]string{
+		"placeholder": raw,
+	}
+	marshalledHelper, _ := json.Marshal(helper)
+	marshalledRaw := gjson.GetBytes(marshalledHelper, "placeholder").Raw
+	if len(marshalledRaw) >= 2 {
+		// e.g. {\"field1\":\"value1\",\"field2\":\"value2\"}
+		return marshalledRaw[1 : len(marshalledRaw)-1]
+	} else {
+		proxywasm.LogErrorf("failed to marshal json string, raw string is: %s", raw)
+		return ""
+	}
+}