feat(prune): add prune files feature

This feature allows you to specify the n latest backups to keep in the
bucket.

main.go

@@ -1,7 +1,9 @@
 package main
 
 import (
+	"backup-tool/pruner"
 	"backup-tool/uploader"
+	"flag"
 	"github.com/joho/godotenv"
 	"log"
 	"os"
@@ -11,13 +13,22 @@ const (
 	ENDPOINT = "s3.us-west-004.backblazeb2.com"
 )
 
+var skipUpload bool
+var keepNum int
+
+func init() {
+	flag.BoolVar(&skipUpload, "skip-upload", false, "do not upload file to S3/Backblaze")
+	flag.IntVar(&keepNum, "keep-backups", 7, "number of backups to keep; 0 to keep all")
+}
+
 func main() {
+	flag.Parse()
 	err := godotenv.Load()
 	if err != nil {
 		log.Fatalf("error loading .env file: (%s)", err.Error())
 	}
 
-	if len(os.Args) < 2 {
+	if len(os.Args) < 2 && !skipUpload {
 		log.Fatalln("missing filename parameter")
 	}
 
@@ -26,8 +37,14 @@ func main() {
 		log.Fatalln("missing or empty BUCKET_NAME")
 	}
 
-	err = uploader.UploadFile(bucketName, ENDPOINT, os.Args[1])
-	if err != nil {
-		log.Fatalln(err.Error())
+	if !skipUpload {
+		err = uploader.UploadFile(bucketName, ENDPOINT, os.Args[1])
+		if err != nil {
+			log.Fatalln(err.Error())
+		}
+	}
+
+	if keepNum > 0 {
+		err = pruner.PruneFiles(bucketName, ENDPOINT, keepNum)
 	}
 }