github.com/lirm/aeron-go@v0.0.0-20230415210743-920325491dc4/archive/examples/basic_replayed_subscriber/basic_replayed_subscriber.go (about)

     1  // Copyright (C) 2021-2022 Talos, 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  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // An example replayed subscriber
    16  package main
    17  
    18  import (
    19  	"flag"
    20  	"fmt"
    21  	"math"
    22  	"time"
    23  
    24  	"github.com/lirm/aeron-go/aeron"
    25  	"github.com/lirm/aeron-go/aeron/atomic"
    26  	"github.com/lirm/aeron-go/aeron/idlestrategy"
    27  	"github.com/lirm/aeron-go/aeron/logbuffer"
    28  	"github.com/lirm/aeron-go/aeron/logging"
    29  	"github.com/lirm/aeron-go/archive"
    30  	"github.com/lirm/aeron-go/archive/examples"
    31  )
    32  
    33  var logID = "basic_recording_subscriber"
    34  var logger = logging.MustGetLogger(logID)
    35  
    36  func main() {
    37  	flag.Parse()
    38  
    39  	// As per Java example
    40  	sampleChannel := *examples.Config.SampleChannel
    41  	sampleStream := int32(*examples.Config.SampleStream)
    42  	replayStream := sampleStream + 1
    43  	responseStream := sampleStream + 2
    44  
    45  	timeout := time.Duration(time.Millisecond.Nanoseconds() * *examples.Config.DriverTimeout)
    46  	context := aeron.NewContext()
    47  	context.AeronDir(*examples.Config.AeronPrefix)
    48  	context.MediaDriverTimeout(timeout)
    49  
    50  	options := archive.DefaultOptions()
    51  	options.RequestChannel = *examples.Config.RequestChannel
    52  	options.RequestStream = int32(*examples.Config.RequestStream)
    53  	options.ResponseChannel = *examples.Config.ResponseChannel
    54  	options.ResponseStream = responseStream
    55  
    56  	if *examples.Config.Verbose {
    57  		fmt.Printf("Setting loglevel: archive.DEBUG/aeron.INFO\n")
    58  		options.ArchiveLoglevel = logging.DEBUG
    59  		options.AeronLoglevel = logging.DEBUG
    60  		logging.SetLevel(logging.DEBUG, logID)
    61  	} else {
    62  		logging.SetLevel(logging.NOTICE, logID)
    63  	}
    64  
    65  	arch, err := archive.NewArchive(options, context)
    66  	if err != nil {
    67  		logger.Fatalf("Failed to connect to media driver: %s\n", err.Error())
    68  	}
    69  	defer arch.Close()
    70  
    71  	// Enable recording events although the defaults will only log in debug mode
    72  	arch.EnableRecordingEvents()
    73  
    74  	recordingID, err := FindLatestRecording(arch, sampleChannel, sampleStream)
    75  	if err != nil {
    76  		logger.Fatalf(err.Error())
    77  	}
    78  	var position int64
    79  	var length int64 = math.MaxInt64
    80  
    81  	logger.Infof("Start replay of channel:%s, stream:%d, position:%d, length:%d", sampleChannel, replayStream, position, length)
    82  	replaySessionID, err := arch.StartReplay(recordingID, position, length, sampleChannel, replayStream)
    83  	if err != nil {
    84  		logger.Fatalf(err.Error())
    85  	}
    86  
    87  	// Make the channel based upon that recording and subscribe to it
    88  	subChannel, err := archive.AddSessionIdToChannel(sampleChannel, archive.ReplaySessionIdToStreamId(replaySessionID))
    89  	if err != nil {
    90  		logger.Fatalf("AddReplaySessionIdToChannel() failed: %s", err.Error())
    91  	}
    92  
    93  	logger.Infof("Subscribing to channel:%s, stream:%d", subChannel, replayStream)
    94  	subscription, err := arch.AddSubscription(subChannel, replayStream)
    95  	if err != nil {
    96  		logger.Fatal(err)
    97  	}
    98  	defer subscription.Close()
    99  	logger.Infof("Subscription found %v", subscription)
   100  
   101  	counter := 0
   102  	printHandler := func(buffer *atomic.Buffer, offset int32, length int32, header *logbuffer.Header) {
   103  		bytes := buffer.GetBytesArray(offset, length)
   104  		logger.Infof("%s", bytes)
   105  		counter++
   106  	}
   107  
   108  	idleStrategy := idlestrategy.Sleeping{SleepFor: time.Millisecond * 1000}
   109  	for {
   110  		fragmentsRead := subscription.Poll(printHandler, 10)
   111  		arch.RecordingEventsPoll()
   112  
   113  		idleStrategy.Idle(fragmentsRead)
   114  	}
   115  }
   116  
   117  // FindLatestRecording to lookup the last recording
   118  func FindLatestRecording(arch *archive.Archive, channel string, stream int32) (int64, error) {
   119  	descriptors, err := arch.ListRecordingsForUri(0, 100, channel, stream)
   120  
   121  	if err != nil {
   122  		return 0, err
   123  	}
   124  
   125  	if len(descriptors) == 0 {
   126  		return 0, fmt.Errorf("no recordings found")
   127  	}
   128  
   129  	descriptor := descriptors[len(descriptors)-1]
   130  	if descriptor.StopPosition == 0 {
   131  		return 0, fmt.Errorf("recording length zero")
   132  	}
   133  
   134  	// Return the last recordingID
   135  	return descriptor.RecordingId, nil
   136  }