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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package event
import (
"fmt"
"hash/crc32"
"sort"
"github.com/apache/dubbo-go/common"
"github.com/apache/dubbo-go/common/constant"
"github.com/apache/dubbo-go/common/extension"
"github.com/apache/dubbo-go/common/logger"
"github.com/apache/dubbo-go/registry"
)
const defaultRevision = "N/A"
func init() {
extension.AddCustomizers(&exportedServicesRevisionMetadataCustomizer{})
extension.AddCustomizers(&subscribedServicesRevisionMetadataCustomizer{})
}
type exportedServicesRevisionMetadataCustomizer struct {
}
// GetPriority will return 1 so that it will be invoked in front of user defining Customizer
func (e *exportedServicesRevisionMetadataCustomizer) GetPriority() int {
return 1
}
func (e *exportedServicesRevisionMetadataCustomizer) Customize(instance registry.ServiceInstance) {
if err != nil {
logger.Errorf("could not get metadata service", err)
return
}
urls, err := ms.GetExportedURLs(constant.ANY_VALUE, constant.ANY_VALUE, constant.ANY_VALUE, constant.ANY_VALUE)
if err != nil {
logger.Errorf("could not find the exported url", err)
}
revision := resolveRevision(urls)
if len(revision) == 0 {
revision = defaultRevision
}
instance.GetMetadata()[constant.EXPORTED_SERVICES_REVISION_PROPERTY_NAME] = revision
}
type subscribedServicesRevisionMetadataCustomizer struct {
}
// GetPriority will return 2 so that it will be invoked in front of user defining Customizer
func (e *subscribedServicesRevisionMetadataCustomizer) GetPriority() int {
return 2
}
func (e *subscribedServicesRevisionMetadataCustomizer) Customize(instance registry.ServiceInstance) {
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if err != nil {
logger.Errorf("could not get metadata service", err)
return
}
urls, err := ms.GetSubscribedURLs()
if err != nil {
logger.Errorf("could not find the subscribed url", err)
}
revision := resolveRevision(urls)
if len(revision) == 0 {
revision = defaultRevision
}
instance.GetMetadata()[constant.SUBSCRIBED_SERVICES_REVISION_PROPERTY_NAME] = revision
}
// resolveRevision is different from Dubbo because golang doesn't support overload
// so that we could use interface + method name as identifier and ignore the method params
// per my understanding, it's enough because Dubbo actually ignore the url params.
// please refer org.apache.dubbo.common.URL#toParameterString(java.lang.String...)
func resolveRevision(urls []common.URL) string {
if len(urls) == 0 {
return ""
}
candidates := make([]string, 0, len(urls))
for _, u := range urls {
sk := u.GetParam(constant.INTERFACE_KEY, "")
for _, m := range u.Methods {
// methods are part of candidates
candidates = append(candidates, sk+constant.KEY_SEPARATOR+m)
}
// append url params if we need it
}
sort.Sort(sort.StringSlice(candidates))
// it's nearly impossible to be overflow
res := uint64(0)
for _, c := range candidates {
res += uint64(crc32.ChecksumIEEE([]byte(c)))
}
return fmt.Sprint(res)
}