github.com/pingcap/tiflow@v0.0.0-20240520035814-5bf52d54e205/engine/servermaster/serverutil/watch_executors.go (about)

     1  // Copyright 2022 PingCAP, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package serverutil
    15  
    16  import (
    17  	"context"
    18  	"time"
    19  
    20  	"github.com/pingcap/log"
    21  	"github.com/pingcap/tiflow/engine/model"
    22  	"github.com/pingcap/tiflow/engine/pkg/notifier"
    23  	"github.com/pingcap/tiflow/pkg/errors"
    24  	"github.com/pingcap/tiflow/pkg/logutil"
    25  	"go.uber.org/zap"
    26  )
    27  
    28  // executorWatcher represents an object that can provide a snapshot
    29  // of the executor list followed by a stream of updates to the list.
    30  type executorWatcher interface {
    31  	WatchExecutors(ctx context.Context) (
    32  		snap map[model.ExecutorID]string,
    33  		stream *notifier.Receiver[model.ExecutorStatusChange],
    34  		err error,
    35  	)
    36  }
    37  
    38  // executorInfoUser represents an object that uses the information provides
    39  // by executorWatcher.
    40  type executorInfoUser interface {
    41  	UpdateExecutorList(executors map[model.ExecutorID]string) error
    42  	AddExecutor(executorID model.ExecutorID, addr string) error
    43  	RemoveExecutor(executorID model.ExecutorID) error
    44  }
    45  
    46  // WatchExecutors updates the state of `user` with information provides
    47  // by `watcher`. It blocks until canceled or an error is encountered.
    48  func WatchExecutors(ctx context.Context, watcher executorWatcher, user executorInfoUser) (retErr error) {
    49  	defer func() {
    50  		log.Info("WatchExecutors exited", logutil.ShortError(retErr))
    51  	}()
    52  
    53  	watchStart := time.Now()
    54  	snap, updates, err := watcher.WatchExecutors(ctx)
    55  
    56  	if duration := time.Since(watchStart); duration >= 100*time.Millisecond {
    57  		log.Warn("WatchExecutors took too long",
    58  			zap.Duration("duration", duration),
    59  			zap.Any("snap", snap))
    60  	}
    61  	if err != nil {
    62  		return errors.Annotate(err, "watch executors")
    63  	}
    64  	defer updates.Close()
    65  
    66  	log.Info("update executor list", zap.Any("list", snap))
    67  	if err := user.UpdateExecutorList(snap); err != nil {
    68  		return errors.Annotate(err, "watch executors")
    69  	}
    70  
    71  	for {
    72  		var (
    73  			change model.ExecutorStatusChange
    74  			ok     bool
    75  		)
    76  		select {
    77  		case <-ctx.Done():
    78  			return errors.Trace(ctx.Err())
    79  		case change, ok = <-updates.C:
    80  		}
    81  
    82  		if !ok {
    83  			return errors.ErrExecutorWatcherClosed.GenWithStackByArgs()
    84  		}
    85  		if change.Tp == model.EventExecutorOnline {
    86  			err := user.AddExecutor(change.ID, change.Addr)
    87  			if err != nil {
    88  				if errors.Is(err, errors.ErrExecutorAlreadyExists) {
    89  					log.Warn("unexpected EventExecutorOnline",
    90  						zap.Error(err))
    91  					continue
    92  				}
    93  				return err
    94  			}
    95  			log.Info("add executor",
    96  				zap.String("id", string(change.ID)),
    97  				zap.String("addr", change.Addr))
    98  		} else if change.Tp == model.EventExecutorOffline {
    99  			err := user.RemoveExecutor(change.ID)
   100  			if err != nil {
   101  				if errors.Is(err, errors.ErrExecutorNotFound) || errors.Is(err, errors.ErrTombstoneExecutor) {
   102  					log.Warn("unexpected EventExecutorOffline",
   103  						zap.Error(err))
   104  					continue
   105  				}
   106  				return errors.Annotate(err, "watch executors")
   107  			}
   108  			log.Info("remove executor",
   109  				zap.String("id", string(change.ID)))
   110  		} else {
   111  			log.Panic("unknown ExecutorStatusChange type",
   112  				zap.Any("change", change))
   113  		}
   114  	}
   115  }