logs2s3.go

package main

import (
  "github.com/aws/aws-sdk-go-v2/config"
  "github.com/aws/aws-sdk-go-v2/aws"
  "github.com/aws/aws-sdk-go-v2/service/cloudwatchlogs"
  "github.com/aws/aws-sdk-go-v2/service/s3"
  "context"
  "os"
  "log"
  "fmt"
  "strings"
)

type AppState struct{
  LogGroup string
  Bucket string
  BucketRegion string
}

func initState()(*AppState){
 return &AppState{
    LogGroup: os.Getenv("LOG_GROUP"),
    Bucket: os.Getenv("BUCKET"),
    BucketRegion: os.Getenv("BUCKET_REGION"),
  }
}


func getConfig(ctx context.Context)(aws.Config, error) {
  return config.LoadDefaultConfig(ctx)
}

func (s *AppState)putToBucket(ctx context.Context, cfg aws.Config, key string, body string){
  s3cli:=s3.NewFromConfig(cfg, func(o *s3.Options){
    o.Region=s.BucketRegion
  })
  input:=&s3.PutObjectInput{
    Bucket: &s.Bucket,
    Key: &key,
    Body: strings.NewReader(body),
    ContentType: aws.String("text/plain"),
  }
  res, err:=s3cli.PutObject(ctx, input)
  if err!=nil{
    log.Print(err)
  }else{
    log.Print("etag: ", res.ETag)
  }
}

func main(){
  ctx:=context.Background()
  cfg, err:=getConfig(ctx)
  if err!=nil{
    log.Fatal(err)
  }
  s:=initState()
  cw:=cloudwatchlogs.NewFromConfig(cfg)
  input:=&cloudwatchlogs.DescribeLogStreamsInput{
    Descending: aws.Bool(true),
    LogGroupName: &s.LogGroup,
  }
  streams, err:=cw.DescribeLogStreams(ctx, input)
  if err!=nil{
    log.Fatal(err)
  }
  for _, stream:=range streams.LogStreams{
    streamContents:=""
    eInput:=&cloudwatchlogs.GetLogEventsInput{
      LogStreamName: stream.LogStreamName,
      LogGroupName: &s.LogGroup,
    }
    events, err:=cw.GetLogEvents(ctx, eInput)
    if err!=nil{
      log.Fatal(err)
    }
    for _, event :=range events.Events{
      if *event.Message!=""{
        streamContents+=fmt.Sprintf("%v %v\n", *event.Timestamp, *event.Message)
      }
    }
    if len(events.Events)>0{
      s.putToBucket(ctx, cfg, *stream.LogStreamName, streamContents)
    }
  }
}