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package processor
import (
"context"
"encoding/json"
"fmt"
"log"
"os"
"os/signal"
"sync"
"syscall"
"time"
"github.com/Baitinq/fs-tracer-backend/lib"
"github.com/jmoiron/sqlx"
"github.com/segmentio/kafka-go"
)
type Processor struct {
kafka_reader *kafka.Reader
db DB
concurrency int
}
func NewProcessor(kafka_reader *kafka.Reader, db *sqlx.DB, concurrency int) Processor {
log.Println("Created processor with concurrency: ", concurrency)
return Processor{
kafka_reader: kafka_reader,
db: NewDB(db),
concurrency: concurrency,
}
}
func (p Processor) ProcessMessages() {
signals := make(chan os.Signal, 1)
signal.Notify(signals, syscall.SIGINT, syscall.SIGKILL)
ctx, cancel := context.WithCancel(context.Background())
// go routine for getting signals asynchronously
go func() {
sig := <-signals
log.Println("Got signal: ", sig)
cancel()
}()
wg := sync.WaitGroup{}
wg.Add(p.concurrency)
for i := 0; i < p.concurrency; i++ {
go func() {
defer wg.Done()
p.process(ctx, cancel)
}()
}
wg.Wait()
if err := p.kafka_reader.Close(); err != nil {
log.Fatal("failed to close reader:", err)
}
}
func (p Processor) process(ctx context.Context, cancel context.CancelFunc) {
for {
m, err := p.kafka_reader.FetchMessage(ctx)
if err != nil {
log.Println("failed to fetch message:", err)
cancel()
break
}
user_id, err := getHeaderValue(m.Headers, "user_id")
if err != nil {
log.Fatal("failed to get user_id from headers:", err)
}
// TODO: Remove after testing
if string(m.Value) == "" {
m.Value = []byte(fmt.Sprintf(`{
"absolute_path": "/home/user/file.txt",
"contents": "Hello, World!",
"timestamp": "%s"
}`, time.Now().Format(time.RFC3339)))
}
err = p.handleMessage(ctx, m, string(user_id))
if err != nil {
log.Println("failed to handle message:", err)
p.handleError(ctx, m, err)
return
}
p.kafka_reader.CommitMessages(ctx, m)
}
}
func (p Processor) handleMessage(ctx context.Context, m kafka.Message, user_id string) error {
fmt.Printf("(%s): message at paritition %d: offset %d: %s = %s, user_id = %s\n", time.Now().String(), m.Partition, m.Offset, string(m.Key), string(m.Value), user_id)
var file lib.File
err := json.Unmarshal(m.Value, &file)
if err != nil {
return err
}
err = p.db.InsertFile(ctx, file, user_id)
if err != nil {
return err
}
return nil
}
func (p Processor) handleError(ctx context.Context, m kafka.Message, err error) {
switch err {
// TODO: If its a recoverable error, don't commit.
default:
p.kafka_reader.CommitMessages(ctx, m)
}
}
func getHeaderValue(headers []kafka.Header, key string) ([]byte, error) {
for _, header := range headers {
if header.Key == key {
return header.Value, nil
}
}
return []byte{}, fmt.Errorf("Header %s not found", key)
}
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