1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
|
package pipeline
import (
"fmt"
"github.com/colinmarc/hdfs"
"github.com/confluentinc/confluent-kafka-go/kafka"
guuid "github.com/google/uuid"
"os"
"sync"
utils "hdfs-writer/pkg/utils"
)
var slogger = utils.GetLoggerInstance()
// ChannelMap is the global map to store writerNames as key and channels as values.
//var ChannelMap =make(map[string]chan struct{})
var ChannelMap = make(map[string]chan bool)
// Wg is of type WaitGroup ensures all the writers have enough time to cleanup a
var Wg sync.WaitGroup
var writerStr = "writer"
// CreatePipeline initiates the building of a pipeline
func CreatePipeline(kc utils.KafkaConfig, hc utils.HdfsConfig) string {
//pipelineChan := make(chan struct{})
pipelineChan := make(chan bool)
uuid := guuid.New().String()
slogger.Infof(":: Storing writerName and channel in ChannelMap :: ")
writerName := writerStr + "-" + uuid[len(uuid)-4:]
slogger.Infof("::writerName:: %s ", writerName)
ChannelMap[writerName] = pipelineChan
//Every create request shall add 1 to the WaitGroup
Wg.Add(1)
// envoke the go routine to build pipeline
go buildWriterPipeline(kc, hc, writerName, ChannelMap[writerName])
return writerName
}
// buildWriterPipeline builds a pipeline
func buildWriterPipeline(k utils.KafkaConfig, h utils.HdfsConfig, writerName string, sigchan chan bool) {
topics := make([]string, 1)
topics[0] = k.Topic
c, err := kafka.NewConsumer(&kafka.ConfigMap{
"bootstrap.servers": k.Broker,
"broker.address.family": "v4",
"group.id": k.Group,
"session.timeout.ms": 6000,
"auto.offset.reset": "earliest"})
if err != nil {
fmt.Fprintf(os.Stderr, "Failed to create consumer: %s\n", err)
slogger.Info("Failed to create consumer: %s", err.Error())
delete(ChannelMap, writerName)
Wg.Done()
return
}
fmt.Printf("Created Consumer %v\n", c)
err = c.SubscribeTopics(topics, nil)
setUpPipeline := false
var hdfsFileWriter *hdfs.FileWriter
var hdfsFileWriterError error
// HDFS CLIENT CREATION
//client := utils.GetHdfsClientInstance(h.GetHdfsURL())
client := utils.CreateHdfsClient(h.HdfsURL)
for {
select {
case sig := <-sigchan:
defer Wg.Done()
client.Close()
if hdfsFileWriter != nil {
cleanup(hdfsFileWriter)
}
slogger.Infof("\nCaught signal %v: terminating the go-routine of writer :: %s\n", sig, writerName)
close(sigchan)
return
default:
//slogger.Info("Running default option ....")
ev := c.Poll(100)
if ev == nil {
continue
}
//:: BEGIN : Switch between different types of messages that come out of kafka
switch e := ev.(type) {
case *kafka.Message:
slogger.Infof("::: Message on %s\n%s\n", e.TopicPartition, e.Value)
dataStr := string(e.Value)
slogger.Infof("byte array ::: %s", []byte(dataStr))
fileInfo, fileInfoError := client.Stat("/" + k.Topic)
// create file if it doesnt exists already
if fileInfoError != nil {
slogger.Infof("Error::: %s", fileInfoError)
slogger.Infof("Creating file::: %s", "/"+k.Topic)
hdfsFileWriterError = client.CreateEmptyFile("/" + k.Topic)
if hdfsFileWriterError != nil {
slogger.Infof("Creation of empty file ::: %s failed\n Error:: %s",
"/"+k.Topic, hdfsFileWriterError.Error())
continue
}
_ = client.Chmod("/"+k.Topic, 0777)
}
newDataStr := dataStr + "\n"
// file exists case, so just append
hdfsFileWriter, hdfsFileWriterError = client.Append("/" + fileInfo.Name())
if hdfsFileWriterError != nil {
if hdfsFileWriter == nil {
slogger.Infof("hdfsFileWriter is NULL !!")
}
slogger.Infof(":::Appending to file : %s failed:::\nError occured:::%s\n",
"/"+k.Topic, hdfsFileWriterError)
continue
} else {
bytesWritten, error := hdfsFileWriter.Write([]byte(newDataStr))
if bytesWritten > 0 && error == nil {
slogger.Infof("::: Wrote %s to HDFS:::", newDataStr)
slogger.Infof("::: Wrote %d bytes to HDFS:::", bytesWritten)
if setUpPipeline == false {
slogger.Infof(" The pipeline with topic: %s and hdfs url %s is setup,"+
"watching for more messages.. ", k.Topic, h.HdfsURL)
setUpPipeline = true
}
hdfsFileWriter.Close()
} else {
slogger.Info("::: Unable to write to HDFS\n :::Error:: %s", error)
}
}
case kafka.Error:
// Errors should generally be considered
// informational, the client will try to
// automatically recover.
// But in this example we choose to terminate
// the application if all brokers are down.
fmt.Fprintf(os.Stderr, "%% Error: %v: %v\n", e.Code(), e)
if e.Code() == kafka.ErrAllBrokersDown {
return
}
default:
fmt.Printf("Ignored %v\n", e)
} //:: END : Switch between different types of messages that come out of kafka
} // END: select channel
} // END : infinite loop
}
func cleanup(h *hdfs.FileWriter) {
if h != nil {
err := h.Close()
if err != nil {
fmt.Printf(":::Error occured while closing hdfs writer::: \n%s", err.Error())
}
}
fmt.Printf("\n:::Clean up executed ::: \n")
}
// DeletePipeline deletes a writer pipeline
func DeletePipeline(writerName string) {
slogger.Infof("::Writer to be closed:: %s", writerName)
toBeClosedChannel := ChannelMap[writerName]
toBeClosedChannel <- true
// deleting the channel from ChannelMap after closure to
// avoid closing the closed channel
delete(ChannelMap, writerName)
}
|
