Merge pull request #4 from dbgeek/poor_mans_tail

feat: tail command

Author: dbgeek

cmd/tail.go

@@ -0,0 +1,65 @@
+package cmd
+
+import (
+	"bytes"
+	"fmt"
+	"time"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/service/s3"
+	"github.com/dbgeek/elblogcat/logcat"
+	"github.com/dbgeek/elblogcat/logworker"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+)
+
+// tailCmd represents the tail command
+var tailCmd = &cobra.Command{
+	Use:   "tail",
+	Short: "Porman tail pool for new accesslogs for default every 1min",
+	Long: `
+`,
+	Run: func(cmd *cobra.Command, args []string) {
+		awsConfiguration := logworker.AWSconfiguration{Region: "eu-west-1"}
+		configuration := logworker.NewConfiguration()
+		accessLogFilter := logworker.NewAccessLogFilter()
+		client := logworker.NewLogWorker(
+			&awsConfiguration,
+			&configuration,
+			&accessLogFilter,
+		)
+		logs := make(chan string, 1)
+
+		client.Tail(logs)
+
+		for v := range logs {
+			buff := &aws.WriteAtBuffer{}
+			key := fmt.Sprintf("%s%s", accessLogFilter.AccesslogPath(configuration.Prefix), v)
+			_, err := client.S3Downloader.Download(buff, &s3.GetObjectInput{
+				Bucket: aws.String(viper.GetString("s3-bucket")),
+				Key:    aws.String(key),
+			})
+			if err != nil {
+				logworker.Logger.Fatalf("Failed to Download key: %v from s3. Got error: %v",
+					key,
+					err)
+			}
+
+			c := logcat.NewRowFilter()
+			b := bytes.NewBuffer(buff.Bytes())
+			a := logcat.Accesslog{
+				Content:     b,
+				RowFilter:   c,
+				PrintFields: viper.GetString("fields"),
+			}
+			a.Cat()
+		}
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(tailCmd)
+	tailCmd.PersistentFlags().Duration("polling-interval", 60*time.Second, "")
+	viper.BindPFlag("polling-interval", tailCmd.PersistentFlags().Lookup("polling-interval"))
+
+}

logworker/logworker.go

@@ -31,8 +31,9 @@ type (
 		Profile string
 	}
 	Configuration struct {
-		Bucket string
-		Prefix string
+		Bucket          string
+		Prefix          string
+		PollingInterval time.Duration
 	}
 	AccessLogFilter struct {
 		matchString    string
@@ -138,6 +139,80 @@ func (l *LogWorker) List() []string {
 	return accessLogs
 }
 
+func (l *LogWorker) Tail(logch chan<- string) {
+	go func() {
+		accessLogFilter := NewAccessLogFilter()
+		consumedAccessLogs := make(map[string]struct{})
+
+		lbAccessLogTimestamp := l.AccessLogFilter.StartTime
+		for t := lbAccessLogTimestamp; t.Before(time.Now().UTC()); t = t.Add(5 * time.Minute) {
+			lbAccessLogTimestamp = t
+			lbAccessLog := fmt.Sprintf("%s_elasticloadbalancing_%s_%s_%s",
+				accessLogFilter.AwsAccountID,
+				accessLogFilter.Region,
+				accessLogFilter.LoadBalancerID,
+				t.Format("20060102T1504Z"),
+			)
+			s3Prefix := filepath.Join(l.AccessLogFilter.AccesslogPath(l.Configuration.Prefix), lbAccessLog)
+			for _, accessLog := range *l.listAccessLogs(s3Prefix) {
+				if _, ok := consumedAccessLogs[accessLog]; !ok {
+					consumedAccessLogs[accessLog] = struct{}{}
+					logch <- accessLog
+				}
+			}
+		}
+
+		poller := time.Tick(l.Configuration.PollingInterval)
+		for now := range poller {
+
+			lbAccessLogTimestamp = lbAccessLogTimestamp.Add(15 * time.Second)
+			lbAccessLog := fmt.Sprintf("%s_elasticloadbalancing_%s_%s_%s",
+				accessLogFilter.AwsAccountID,
+				accessLogFilter.Region,
+				accessLogFilter.LoadBalancerID,
+				now.UTC().Format("20060102T1504Z"),
+			)
+			s3Prefix := filepath.Join(l.AccessLogFilter.AccesslogPath(l.Configuration.Prefix), lbAccessLog)
+			for _, accessLog := range *l.listAccessLogs(s3Prefix) {
+				if _, ok := consumedAccessLogs[accessLog]; !ok {
+					consumedAccessLogs[accessLog] = struct{}{}
+					logch <- accessLog
+				}
+			}
+			for k := range consumedAccessLogs {
+				ts := strings.Split(k, "_")
+				t, _ := time.Parse("20060102T1504Z", ts[4])
+				if t.Before(now.UTC().Add(-2 * time.Minute)) {
+					delete(consumedAccessLogs, k)
+				}
+
+			}
+		}
+	}()
+}
+
+func (l *LogWorker) listAccessLogs(s3Prefix string) *[]string {
+	var al []string
+	input := &s3.ListObjectsV2Input{
+		Bucket:    aws.String(l.Configuration.Bucket),
+		Prefix:    aws.String(s3Prefix),
+		Delimiter: aws.String("/"),
+		MaxKeys:   aws.Int64(200),
+	}
+	err := l.S3.ListObjectsV2Pages(input,
+		func(page *s3.ListObjectsV2Output, lastPage bool) bool {
+			for _, val := range page.Contents {
+				accessLog := strings.Split(*val.Key, "/")[len(strings.Split(*val.Key, "/"))-1]
+				al = append(al, accessLog)
+			}
+			return true
+		})
+	if err != nil {
+		fmt.Println(err)
+	}
+	return &al
+}
+
 func (a *AccessLogFilter) AccesslogPath(prefix string) string {
 	return filepath.Join(prefix, fmt.Sprintf("AWSLogs/%s/elasticloadbalancing/%s/%s/", a.AwsAccountID, a.Region, a.StartTime.Format("2006/01/02"))) + "/"
 
@@ -197,7 +272,8 @@ func NewAccessLogFilter() AccessLogFilter {
 
 func NewConfiguration() Configuration {
 	return Configuration{
-		Bucket: viper.GetString("s3-bucket"),
-		Prefix: viper.GetString("s3-prefix"),
+		Bucket:          viper.GetString("s3-bucket"),
+		Prefix:          viper.GetString("s3-prefix"),
+		PollingInterval: viper.GetDuration("polling-interval"),
 	}
 }