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package pipeline
import (
"fmt"
"os"
"github.com/colinmarc/hdfs"
"github.com/confluentinc/confluent-kafka-go/kafka"
utils "hdfs-writer/pkg/utils"
)
// BuildWriterPipeline builds a pipeline
func BuildWriterPipeline(k utils.KafkaConfig, h utils.HdfsConfig, writerName string, sigchan chan struct{}) {
slogger := utils.GetLoggerInstance()
topics := make([]string, 1)
topics[0] = k.GetTopic()
c,err := kafka.NewConsumer(&kafka.ConfigMap{
"bootstrap.servers": k.GetBroker(),
"broker.address.family": "v4",
"group.id": k.GetGroup(),
"session.timeout.ms": 6000,
"auto.offset.reset": "earliest"})
if err != nil {
fmt.Fprintf(os.Stderr, "Failed to create consumer: %s\n", err)
os.Exit(1)
}
fmt.Printf("Created Consumer %v\n", c)
err = c.SubscribeTopics(topics, nil)
run := true
setUpPipeline := false
var hdfsFileWriter *hdfs.FileWriter
var hdfsFileWriterError error
// HDFS CLIENT CREATION
//client := utils.GetHdfsClientInstance(h.GetHdfsURL())
client := utils.CreateHdfsClient(h.GetHdfsURL())
for run==true {
select {
case sig := <-sigchan:
client.Close()
if hdfsFileWriter!=nil{
cleanup(hdfsFileWriter)
}
slogger.Infof("\nCaught signal %v: terminating the go-routine of writer :: %s\n", sig, writerName)
run = false
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.GetTopic())
// create file if it doesnt exists already
if fileInfoError != nil {
slogger.Infof("Error::: %s",fileInfoError)
slogger.Infof("Creating file::: %s", "/"+k.GetTopic())
hdfsFileWriterError = client.CreateEmptyFile("/"+k.GetTopic())
if hdfsFileWriterError !=nil {
slogger.Infof("Creation of empty file ::: %s failed\n Error:: %s",
"/"+k.GetTopic(), hdfsFileWriterError.Error())
panic(fmt.Sprintf("Creation of empty file ::: %s failed", k.GetTopic()))
}
_= client.Chmod("/"+k.GetTopic(), 0777);
}
newDataStr := dataStr + "\n"
// file exists case, so just append
hdfsFileWriter, hdfsFileWriterError = client.Append("/"+fileInfo.Name())
if hdfsFileWriterError != nil || hdfsFileWriter==nil{
if(hdfsFileWriter==nil){
slogger.Infof("hdfsFileWriter is NULL !!")
}
slogger.Infof(":::Appending to file : %s failed:::\nError occured:::%s\n",
"/"+k.GetTopic(),hdfsFileWriterError)
panic(fmt.Sprintf("Appending to file : %s failed", k.GetTopic()))
}
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.GetTopic(), h.GetHdfsURL())
setUpPipeline = true
}
} else {
slogger.Info("::: Unable to write to HDFS\n :::Error:: %s",error)
}
hdfsFileWriter.Close()
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 {
run = false
}
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
fmt.Printf("Closing the consumer")
}
func cleanup(h *hdfs.FileWriter){
if h!=nil{
err := h.Close()
if err!=nil{
fmt.Printf(":::Error occured while closing the hdfs writer::: \n%s", err.Error())
}
}
}
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