124 lines
3.1 KiB
Go
124 lines
3.1 KiB
Go
/**
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package realis
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import (
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"encoding/json"
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"fmt"
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"strconv"
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"strings"
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"time"
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"github.com/pkg/errors"
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"github.com/samuel/go-zookeeper/zk"
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)
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type Endpoint struct {
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Host string `json:"host"`
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Port int `json:"port"`
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}
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type ServiceInstance struct {
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Service Endpoint `json:"serviceEndpoint"`
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AdditionalEndpoints map[string]Endpoint `json:"additionalEndpoints"`
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Status string `json:"status"`
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}
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type NoopLogger struct{}
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func (NoopLogger) Printf(format string, a ...interface{}) {
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}
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// Loads leader from ZK endpoint.
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func LeaderFromZK(cluster Cluster) (string, error) {
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var err error
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var zkurl string
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duration := defaultBackoff.Duration
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for i := 0; i < defaultBackoff.Steps; i++ {
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if i != 0 {
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adjusted := duration
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if defaultBackoff.Jitter > 0.0 {
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adjusted = Jitter(duration, defaultBackoff.Jitter)
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}
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fmt.Println(" sleeping for: ", adjusted)
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time.Sleep(adjusted)
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duration = time.Duration(float64(duration) * defaultBackoff.Factor)
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}
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if zkurl, err = leaderFromZK(cluster); err == nil {
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return zkurl, err
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}
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if err != nil {
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fmt.Println("error in LeaderFromZK: ", err)
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}
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}
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return "", err
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}
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func leaderFromZK(cluster Cluster) (string, error) {
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endpoints := strings.Split(cluster.ZK, ",")
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//TODO (rdelvalle): When enabling debugging, change logger here
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c, _, err := zk.Connect(endpoints, time.Second*10, func(c *zk.Conn) { c.SetLogger(NoopLogger{}) })
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if err != nil {
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return "", errors.Wrap(err, "Failed to connect to Zookeeper at "+cluster.ZK)
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}
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defer c.Close()
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children, _, _, err := c.ChildrenW(cluster.SchedZKPath)
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if err != nil {
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return "", errors.Wrapf(err, "Path %s doesn't exist on Zookeeper ", cluster.SchedZKPath)
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}
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serviceInst := new(ServiceInstance)
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for _, child := range children {
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// Only the leader will start with member_
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if strings.HasPrefix(child, "member_") {
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data, _, err := c.Get(cluster.SchedZKPath + "/" + child)
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if err != nil {
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return "", errors.Wrap(err, "Error fetching contents of leader")
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}
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err = json.Unmarshal([]byte(data), serviceInst)
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if err != nil {
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return "", errors.Wrap(err, "Unable to unmarshall contents of leader")
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}
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// Should only be one endpoint
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if len(serviceInst.AdditionalEndpoints) > 1 {
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fmt.Errorf("Ambiguous end points schemes")
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}
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var scheme, host, port string
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for k, v := range serviceInst.AdditionalEndpoints {
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scheme = k
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host = v.Host
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port = strconv.Itoa(v.Port)
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}
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return scheme + "://" + host + ":" + port, nil
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}
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}
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return "", errors.New("No leader found")
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}
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