mirror of https://github.com/k3s-io/k3s
135 lines
3.7 KiB
Go
135 lines
3.7 KiB
Go
// Copyright 2017 The etcd Authors
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//
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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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package v3election
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import (
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"context"
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"errors"
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"go.etcd.io/etcd/clientv3"
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"go.etcd.io/etcd/clientv3/concurrency"
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epb "go.etcd.io/etcd/etcdserver/api/v3election/v3electionpb"
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)
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// ErrMissingLeaderKey is returned when election API request
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// is missing the "leader" field.
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var ErrMissingLeaderKey = errors.New(`"leader" field must be provided`)
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type electionServer struct {
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c *clientv3.Client
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}
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func NewElectionServer(c *clientv3.Client) epb.ElectionServer {
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return &electionServer{c}
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}
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func (es *electionServer) Campaign(ctx context.Context, req *epb.CampaignRequest) (*epb.CampaignResponse, error) {
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s, err := es.session(ctx, req.Lease)
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if err != nil {
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return nil, err
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}
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e := concurrency.NewElection(s, string(req.Name))
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if err = e.Campaign(ctx, string(req.Value)); err != nil {
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return nil, err
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}
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return &epb.CampaignResponse{
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Header: e.Header(),
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Leader: &epb.LeaderKey{
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Name: req.Name,
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Key: []byte(e.Key()),
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Rev: e.Rev(),
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Lease: int64(s.Lease()),
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},
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}, nil
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}
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func (es *electionServer) Proclaim(ctx context.Context, req *epb.ProclaimRequest) (*epb.ProclaimResponse, error) {
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if req.Leader == nil {
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return nil, ErrMissingLeaderKey
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}
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s, err := es.session(ctx, req.Leader.Lease)
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if err != nil {
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return nil, err
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}
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e := concurrency.ResumeElection(s, string(req.Leader.Name), string(req.Leader.Key), req.Leader.Rev)
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if err := e.Proclaim(ctx, string(req.Value)); err != nil {
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return nil, err
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}
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return &epb.ProclaimResponse{Header: e.Header()}, nil
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}
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func (es *electionServer) Observe(req *epb.LeaderRequest, stream epb.Election_ObserveServer) error {
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s, err := es.session(stream.Context(), -1)
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if err != nil {
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return err
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}
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e := concurrency.NewElection(s, string(req.Name))
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ch := e.Observe(stream.Context())
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for stream.Context().Err() == nil {
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select {
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case <-stream.Context().Done():
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case resp, ok := <-ch:
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if !ok {
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return nil
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}
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lresp := &epb.LeaderResponse{Header: resp.Header, Kv: resp.Kvs[0]}
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if err := stream.Send(lresp); err != nil {
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return err
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}
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}
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}
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return stream.Context().Err()
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}
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func (es *electionServer) Leader(ctx context.Context, req *epb.LeaderRequest) (*epb.LeaderResponse, error) {
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s, err := es.session(ctx, -1)
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if err != nil {
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return nil, err
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}
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l, lerr := concurrency.NewElection(s, string(req.Name)).Leader(ctx)
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if lerr != nil {
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return nil, lerr
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}
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return &epb.LeaderResponse{Header: l.Header, Kv: l.Kvs[0]}, nil
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}
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func (es *electionServer) Resign(ctx context.Context, req *epb.ResignRequest) (*epb.ResignResponse, error) {
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if req.Leader == nil {
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return nil, ErrMissingLeaderKey
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}
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s, err := es.session(ctx, req.Leader.Lease)
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if err != nil {
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return nil, err
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}
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e := concurrency.ResumeElection(s, string(req.Leader.Name), string(req.Leader.Key), req.Leader.Rev)
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if err := e.Resign(ctx); err != nil {
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return nil, err
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}
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return &epb.ResignResponse{Header: e.Header()}, nil
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}
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func (es *electionServer) session(ctx context.Context, lease int64) (*concurrency.Session, error) {
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s, err := concurrency.NewSession(
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es.c,
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concurrency.WithLease(clientv3.LeaseID(lease)),
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concurrency.WithContext(ctx),
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)
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if err != nil {
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return nil, err
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}
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s.Orphan()
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return s, nil
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}
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