refactor into uploader module

This will probably just morph further into a "bucket" module for
uploading, listing, deleting, etc.

main.go

@@ -1,90 +1,33 @@
 package main
 
 import (
-	"context"
+	"backup-tool/uploader"
 	"github.com/joho/godotenv"
 	"log"
 	"os"
-
-	"github.com/minio/minio-go/v7"
-	"github.com/minio/minio-go/v7/pkg/credentials"
 )
 
 const (
-	ENDPOINT   = "s3.us-west-004.backblazeb2.com"
-	BUCKETNAME = "ducimon-db-backups"
+	ENDPOINT = "s3.us-west-004.backblazeb2.com"
 )
 
 func main() {
-
-	ctx := context.Background()
-	accessKeyID, secretAccessKey := getCredentials()
-	client := createClient(accessKeyID, secretAccessKey)
-	verifyBucket(client, ctx)
-	absolutePath, basename := validateUploadFile()
-
-	_, err := client.FPutObject(ctx, BUCKETNAME, "test", absolutePath, minio.PutObjectOptions{})
-	if err != nil {
-		log.Fatalln(err)
-	}
-
-	log.Printf("upload of %s complete\n", basename)
-}
-
-func validateUploadFile() (string, string) {
-	if len(os.Args) < 2 {
-		log.Fatalln("upload file not specified")
-	}
-
-	file, err := os.Stat(os.Args[1])
-	if err != nil {
-		log.Fatalln(err)
-	}
-
-	if file.IsDir() {
-		log.Fatalln("upload of directories is not supported")
-	}
-
-	return os.Args[1], file.Name()
-}
-
-func verifyBucket(client *minio.Client, ctx context.Context) {
-	exists, err := client.BucketExists(ctx, BUCKETNAME)
-	if err != nil {
-		log.Fatalln(err)
-	}
-
-	if !exists {
-		log.Fatalf("bucket %s does not exist\n", BUCKETNAME)
-	}
-}
-
-func createClient(accessKeyID string, secretAccessKey string) *minio.Client {
-	// Initialize minio client object.
-	minioClient, err := minio.New(ENDPOINT, &minio.Options{
-		Creds:  credentials.NewStaticV4(accessKeyID, secretAccessKey, ""),
-		Secure: true,
-	})
-	if err != nil {
-		log.Fatalln(err)
-	}
-
-	return minioClient
-}
-
-func getCredentials() (string, string) {
-	// get credentials from env vars
 	err := godotenv.Load()
 	if err != nil {
 		log.Fatalf("error loading .env file: (%s)", err.Error())
 	}
-	keyName := os.Getenv("KEY_ID")
-	if keyName == "" {
-		log.Fatal("missing or empty KEY_ID")
+
+	if len(os.Args) < 2 {
+		log.Fatalln("missing filename parameter")
 	}
-	applicationKey := os.Getenv("APPLICATION_KEY")
-	if applicationKey == "" {
-		log.Fatal("missing or empty APPLICATION_KEY")
+
+	bucketName := os.Getenv("BUCKET_NAME")
+	if bucketName == "" {
+		log.Fatalln("missing or empty BUCKET_NAME")
+	}
+
+	err = uploader.UploadFile(bucketName, ENDPOINT, os.Args[1])
+	if err != nil {
+		log.Fatalln(err.Error())
 	}
-	return keyName, applicationKey
 }

uploader/uploader.go

@@ -0,0 +1,92 @@
+package uploader
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"github.com/minio/minio-go/v7"
+	"github.com/minio/minio-go/v7/pkg/credentials"
+	"log"
+	"os"
+)
+
+func UploadFile(bucketName, endpoint, fileName string) error {
+
+	ctx := context.Background()
+	accessKeyID, secretAccessKey, err := getCredentials()
+	if err != nil {
+		return (err)
+	}
+	client, err := createClient(accessKeyID, secretAccessKey, endpoint)
+	if err != nil {
+		return (err)
+	}
+	err = verifyBucket(client, ctx, bucketName)
+	if err != nil {
+		return err
+	}
+	absolutePath, basename, err := validateUploadFile(fileName)
+	if err != nil {
+		return err
+	}
+
+	_, err = client.FPutObject(ctx, bucketName, basename, absolutePath, minio.PutObjectOptions{})
+	if err != nil {
+		return err
+	}
+
+	log.Printf("upload of %s complete\n", basename)
+	return nil
+}
+
+func validateUploadFile(fileName string) (string, string, error) {
+	file, err := os.Stat(fileName)
+	if err != nil {
+		return "", "", err
+	}
+
+	if file.IsDir() {
+		return "", "", errors.New("upload of directories is not supported")
+	}
+
+	return fileName, file.Name(), nil
+}
+
+func verifyBucket(client *minio.Client, ctx context.Context, bucketName string) error {
+	exists, err := client.BucketExists(ctx, bucketName)
+	if err != nil {
+		return err
+	}
+
+	if !exists {
+		return errors.New(fmt.Sprintf("bucket %s does not exist\n", bucketName))
+	}
+
+	return nil
+}
+
+func createClient(accessKeyID, secretAccessKey, endpoint string) (*minio.Client, error) {
+	// Initialize minio client object.
+	minioClient, err := minio.New(endpoint, &minio.Options{
+		Creds:  credentials.NewStaticV4(accessKeyID, secretAccessKey, ""),
+		Secure: true,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return minioClient, nil
+}
+
+func getCredentials() (string, string, error) {
+	// get credentials from env vars
+	keyName := os.Getenv("KEY_ID")
+	if keyName == "" {
+		return "", "", errors.New("missing or empty KEY_ID")
+	}
+	applicationKey := os.Getenv("APPLICATION_KEY")
+	if applicationKey == "" {
+		return "", "", errors.New("missing or empty APPLICATION_KEY")
+	}
+	return keyName, applicationKey, nil
+}