Reorganize file util functionality (#7848)

* reorganize file util functionality

* fix api test compilation

* fix rebase issue

6 files changed, 532 insertions, 531 deletions

diff --git a/utils/file.go b/utils/file.go
index 6472770a0..13b25bdab 100644
--- a/utils/file.go
+++ b/utils/file.go
@@ -4,372 +4,13 @@
 package utils
 
 import (
-	"bytes"
 	"fmt"
 	"io"
 	"io/ioutil"
-	"net/http"
 	"os"
 	"path/filepath"
-	"strings"
-
-	l4g "github.com/alecthomas/log4go"
-	s3 "github.com/minio/minio-go"
-	"github.com/minio/minio-go/pkg/credentials"
-
-	"github.com/mattermost/mattermost-server/model"
-)
-
-const (
-	TEST_FILE_PATH = "/testfile"
 )
 
-// Similar to s3.New() but allows initialization of signature v2 or signature v4 client.
-// If signV2 input is false, function always returns signature v4.
-//
-// Additionally this function also takes a user defined region, if set
-// disables automatic region lookup.
-func s3New(endpoint, accessKey, secretKey string, secure bool, signV2 bool, region string) (*s3.Client, error) {
-	var creds *credentials.Credentials
-	if signV2 {
-		creds = credentials.NewStatic(accessKey, secretKey, "", credentials.SignatureV2)
-	} else {
-		creds = credentials.NewStatic(accessKey, secretKey, "", credentials.SignatureV4)
-	}
-
-	s3Clnt, err := s3.NewWithCredentials(endpoint, creds, secure, region)
-	if err != nil {
-		return nil, err
-	}
-
-	if *Cfg.FileSettings.AmazonS3Trace {
-		s3Clnt.TraceOn(os.Stdout)
-	}
-
-	return s3Clnt, nil
-}
-
-func TestFileConnection() *model.AppError {
-	if *Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_S3 {
-		endpoint := Cfg.FileSettings.AmazonS3Endpoint
-		accessKey := Cfg.FileSettings.AmazonS3AccessKeyId
-		secretKey := Cfg.FileSettings.AmazonS3SecretAccessKey
-		secure := *Cfg.FileSettings.AmazonS3SSL
-		signV2 := *Cfg.FileSettings.AmazonS3SignV2
-		region := Cfg.FileSettings.AmazonS3Region
-		bucket := Cfg.FileSettings.AmazonS3Bucket
-
-		s3Clnt, err := s3New(endpoint, accessKey, secretKey, secure, signV2, region)
-		if err != nil {
-			return model.NewAppError("TestFileConnection", "Bad connection to S3 or minio.", nil, err.Error(), http.StatusInternalServerError)
-		}
-
-		exists, err := s3Clnt.BucketExists(bucket)
-		if err != nil {
-			return model.NewAppError("TestFileConnection", "Error checking if bucket exists.", nil, err.Error(), http.StatusInternalServerError)
-		}
-
-		if !exists {
-			l4g.Warn("Bucket specified does not exist. Attempting to create...")
-			err := s3Clnt.MakeBucket(bucket, region)
-			if err != nil {
-				l4g.Error("Unable to create bucket.")
-				return model.NewAppError("TestFileConnection", "Unable to create bucket", nil, err.Error(), http.StatusInternalServerError)
-			}
-		}
-		l4g.Info("Connection to S3 or minio is good. Bucket exists.")
-	} else if *Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_LOCAL {
-		f := []byte("testingwrite")
-		if err := writeFileLocally(f, Cfg.FileSettings.Directory+TEST_FILE_PATH); err != nil {
-			return model.NewAppError("TestFileConnection", "Don't have permissions to write to local path specified or other error.", nil, err.Error(), http.StatusInternalServerError)
-		}
-		os.Remove(Cfg.FileSettings.Directory + TEST_FILE_PATH)
-		l4g.Info("Able to write files to local storage.")
-	} else {
-		return model.NewAppError("TestFileConnection", "No file driver selected.", nil, "", http.StatusInternalServerError)
-	}
-
-	return nil
-}
-
-func ReadFile(path string) ([]byte, *model.AppError) {
-	if *Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_S3 {
-		endpoint := Cfg.FileSettings.AmazonS3Endpoint
-		accessKey := Cfg.FileSettings.AmazonS3AccessKeyId
-		secretKey := Cfg.FileSettings.AmazonS3SecretAccessKey
-		secure := *Cfg.FileSettings.AmazonS3SSL
-		signV2 := *Cfg.FileSettings.AmazonS3SignV2
-		region := Cfg.FileSettings.AmazonS3Region
-		s3Clnt, err := s3New(endpoint, accessKey, secretKey, secure, signV2, region)
-		if err != nil {
-			return nil, model.NewAppError("ReadFile", "api.file.read_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-		bucket := Cfg.FileSettings.AmazonS3Bucket
-		minioObject, err := s3Clnt.GetObject(bucket, path)
-		if err != nil {
-			return nil, model.NewAppError("ReadFile", "api.file.read_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-		defer minioObject.Close()
-		if f, err := ioutil.ReadAll(minioObject); err != nil {
-			return nil, model.NewAppError("ReadFile", "api.file.read_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
-		} else {
-			return f, nil
-		}
-	} else if *Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_LOCAL {
-		if f, err := ioutil.ReadFile(Cfg.FileSettings.Directory + path); err != nil {
-			return nil, model.NewAppError("ReadFile", "api.file.read_file.reading_local.app_error", nil, err.Error(), http.StatusInternalServerError)
-		} else {
-			return f, nil
-		}
-	} else {
-		return nil, model.NewAppError("ReadFile", "api.file.read_file.configured.app_error", nil, "", http.StatusNotImplemented)
-	}
-}
-
-func MoveFile(oldPath, newPath string) *model.AppError {
-	if *Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_S3 {
-		endpoint := Cfg.FileSettings.AmazonS3Endpoint
-		accessKey := Cfg.FileSettings.AmazonS3AccessKeyId
-		secretKey := Cfg.FileSettings.AmazonS3SecretAccessKey
-		secure := *Cfg.FileSettings.AmazonS3SSL
-		signV2 := *Cfg.FileSettings.AmazonS3SignV2
-		region := Cfg.FileSettings.AmazonS3Region
-		encrypt := false
-		if *Cfg.FileSettings.AmazonS3SSE && IsLicensed() && *License().Features.Compliance {
-			encrypt = true
-		}
-		s3Clnt, err := s3New(endpoint, accessKey, secretKey, secure, signV2, region)
-		if err != nil {
-			return model.NewAppError("moveFile", "api.file.write_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-		bucket := Cfg.FileSettings.AmazonS3Bucket
-
-		source := s3.NewSourceInfo(bucket, oldPath, nil)
-		destination, err := s3.NewDestinationInfo(bucket, newPath, nil, CopyMetadata(encrypt))
-		if err != nil {
-			return model.NewAppError("moveFile", "api.file.write_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-		if err = s3Clnt.CopyObject(destination, source); err != nil {
-			return model.NewAppError("moveFile", "api.file.move_file.delete_from_s3.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-		if err = s3Clnt.RemoveObject(bucket, oldPath); err != nil {
-			return model.NewAppError("moveFile", "api.file.move_file.delete_from_s3.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-	} else if *Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_LOCAL {
-		if err := os.MkdirAll(filepath.Dir(Cfg.FileSettings.Directory+newPath), 0774); err != nil {
-			return model.NewAppError("moveFile", "api.file.move_file.rename.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-
-		if err := os.Rename(Cfg.FileSettings.Directory+oldPath, Cfg.FileSettings.Directory+newPath); err != nil {
-			return model.NewAppError("moveFile", "api.file.move_file.rename.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-	} else {
-		return model.NewAppError("moveFile", "api.file.move_file.configured.app_error", nil, "", http.StatusNotImplemented)
-	}
-
-	return nil
-}
-
-func WriteFile(f []byte, path string) *model.AppError {
-	if *Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_S3 {
-		endpoint := Cfg.FileSettings.AmazonS3Endpoint
-		accessKey := Cfg.FileSettings.AmazonS3AccessKeyId
-		secretKey := Cfg.FileSettings.AmazonS3SecretAccessKey
-		secure := *Cfg.FileSettings.AmazonS3SSL
-		signV2 := *Cfg.FileSettings.AmazonS3SignV2
-		region := Cfg.FileSettings.AmazonS3Region
-		encrypt := false
-		if *Cfg.FileSettings.AmazonS3SSE && IsLicensed() && *License().Features.Compliance {
-			encrypt = true
-		}
-
-		s3Clnt, err := s3New(endpoint, accessKey, secretKey, secure, signV2, region)
-		if err != nil {
-			return model.NewAppError("WriteFile", "api.file.write_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-
-		bucket := Cfg.FileSettings.AmazonS3Bucket
-		ext := filepath.Ext(path)
-		metaData := S3Metadata(encrypt, "binary/octet-stream")
-		if model.IsFileExtImage(ext) {
-			metaData = S3Metadata(encrypt, model.GetImageMimeType(ext))
-		}
-
-		_, err = s3Clnt.PutObjectWithMetadata(bucket, path, bytes.NewReader(f), metaData, nil)
-		if err != nil {
-			return model.NewAppError("WriteFile", "api.file.write_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-	} else if *Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_LOCAL {
-		if err := writeFileLocally(f, Cfg.FileSettings.Directory+path); err != nil {
-			return err
-		}
-	} else {
-		return model.NewAppError("WriteFile", "api.file.write_file.configured.app_error", nil, "", http.StatusNotImplemented)
-	}
-
-	return nil
-}
-
-func writeFileLocally(f []byte, path string) *model.AppError {
-	if err := os.MkdirAll(filepath.Dir(path), 0774); err != nil {
-		directory, _ := filepath.Abs(filepath.Dir(path))
-		return model.NewAppError("WriteFile", "api.file.write_file_locally.create_dir.app_error", nil, "directory="+directory+", err="+err.Error(), http.StatusInternalServerError)
-	}
-
-	if err := ioutil.WriteFile(path, f, 0644); err != nil {
-		return model.NewAppError("WriteFile", "api.file.write_file_locally.writing.app_error", nil, err.Error(), http.StatusInternalServerError)
-	}
-
-	return nil
-}
-
-func RemoveFile(path string) *model.AppError {
-	if *Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_S3 {
-		endpoint := Cfg.FileSettings.AmazonS3Endpoint
-		accessKey := Cfg.FileSettings.AmazonS3AccessKeyId
-		secretKey := Cfg.FileSettings.AmazonS3SecretAccessKey
-		secure := *Cfg.FileSettings.AmazonS3SSL
-		signV2 := *Cfg.FileSettings.AmazonS3SignV2
-		region := Cfg.FileSettings.AmazonS3Region
-
-		s3Clnt, err := s3New(endpoint, accessKey, secretKey, secure, signV2, region)
-		if err != nil {
-			return model.NewAppError("RemoveFile", "utils.file.remove_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-
-		bucket := Cfg.FileSettings.AmazonS3Bucket
-		if err := s3Clnt.RemoveObject(bucket, path); err != nil {
-			return model.NewAppError("RemoveFile", "utils.file.remove_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-	} else if *Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_LOCAL {
-		if err := os.Remove(Cfg.FileSettings.Directory + path); err != nil {
-			return model.NewAppError("RemoveFile", "utils.file.remove_file.local.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-	} else {
-		return model.NewAppError("RemoveFile", "utils.file.remove_file.configured.app_error", nil, "", http.StatusNotImplemented)
-	}
-
-	return nil
-}
-
-func getPathsFromObjectInfos(in <-chan s3.ObjectInfo) <-chan string {
-	out := make(chan string, 1)
-
-	go func() {
-		defer close(out)
-
-		for {
-			info, done := <-in
-
-			if !done {
-				break
-			}
-
-			out <- info.Key
-		}
-	}()
-
-	return out
-}
-
-// Returns a list of all the directories within the path directory provided.
-func ListDirectory(path string) (*[]string, *model.AppError) {
-	var paths []string
-
-	if *Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_S3 {
-		endpoint := Cfg.FileSettings.AmazonS3Endpoint
-		accessKey := Cfg.FileSettings.AmazonS3AccessKeyId
-		secretKey := Cfg.FileSettings.AmazonS3SecretAccessKey
-		secure := *Cfg.FileSettings.AmazonS3SSL
-		signV2 := *Cfg.FileSettings.AmazonS3SignV2
-		region := Cfg.FileSettings.AmazonS3Region
-
-		s3Clnt, err := s3New(endpoint, accessKey, secretKey, secure, signV2, region)
-		if err != nil {
-			return nil, model.NewAppError("ListDirectory", "utils.file.list_directory.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-
-		doneCh := make(chan struct{})
-
-		defer close(doneCh)
-
-		bucket := Cfg.FileSettings.AmazonS3Bucket
-		for object := range s3Clnt.ListObjects(bucket, path, false, doneCh) {
-			if object.Err != nil {
-				return nil, model.NewAppError("ListDirectory", "utils.file.list_directory.s3.app_error", nil, object.Err.Error(), http.StatusInternalServerError)
-			}
-			paths = append(paths, strings.Trim(object.Key, "/"))
-		}
-	} else if *Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_LOCAL {
-		if fileInfos, err := ioutil.ReadDir(Cfg.FileSettings.Directory + path); err != nil {
-			return nil, model.NewAppError("ListDirectory", "utils.file.list_directory.local.app_error", nil, err.Error(), http.StatusInternalServerError)
-		} else {
-			for _, fileInfo := range fileInfos {
-				if fileInfo.IsDir() {
-					paths = append(paths, filepath.Join(path, fileInfo.Name()))
-				}
-			}
-		}
-	} else {
-		return nil, model.NewAppError("ListDirectory", "utils.file.list_directory.configured.app_error", nil, "", http.StatusInternalServerError)
-	}
-
-	return &paths, nil
-}
-
-func RemoveDirectory(path string) *model.AppError {
-	if *Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_S3 {
-		endpoint := Cfg.FileSettings.AmazonS3Endpoint
-		accessKey := Cfg.FileSettings.AmazonS3AccessKeyId
-		secretKey := Cfg.FileSettings.AmazonS3SecretAccessKey
-		secure := *Cfg.FileSettings.AmazonS3SSL
-		signV2 := *Cfg.FileSettings.AmazonS3SignV2
-		region := Cfg.FileSettings.AmazonS3Region
-
-		s3Clnt, err := s3New(endpoint, accessKey, secretKey, secure, signV2, region)
-		if err != nil {
-			return model.NewAppError("RemoveDirectory", "utils.file.remove_directory.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-
-		doneCh := make(chan struct{})
-
-		bucket := Cfg.FileSettings.AmazonS3Bucket
-		for err := range s3Clnt.RemoveObjects(bucket, getPathsFromObjectInfos(s3Clnt.ListObjects(bucket, path, true, doneCh))) {
-			if err.Err != nil {
-				doneCh <- struct{}{}
-				return model.NewAppError("RemoveDirectory", "utils.file.remove_directory.s3.app_error", nil, err.Err.Error(), http.StatusInternalServerError)
-			}
-		}
-
-		close(doneCh)
-	} else if *Cfg.FileSettings.DriverName == model.IMAGE_DRIVER_LOCAL {
-		if err := os.RemoveAll(Cfg.FileSettings.Directory + path); err != nil {
-			return model.NewAppError("RemoveDirectory", "utils.file.remove_directory.local.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
-	} else {
-		return model.NewAppError("RemoveDirectory", "utils.file.remove_directory.configured.app_error", nil, "", http.StatusNotImplemented)
-	}
-
-	return nil
-}
-
-func S3Metadata(encrypt bool, contentType string) map[string][]string {
-	metaData := make(map[string][]string)
-	if contentType != "" {
-		metaData["Content-Type"] = []string{"contentType"}
-	}
-	if encrypt {
-		metaData["x-amz-server-side-encryption"] = []string{"AES256"}
-	}
-	return metaData
-}
-
-func CopyMetadata(encrypt bool) map[string]string {
-	metaData := make(map[string]string)
-	metaData["x-amz-server-side-encryption"] = "AES256"
-	return metaData
-}
-
 // CopyFile will copy a file from src path to dst path.
 // Overwrites any existing files at dst.
 // Permissions are copied from file at src to the new file at dst.
diff --git a/utils/file_backend.go b/utils/file_backend.go
new file mode 100644
index 000000000..3469a63fb
--- /dev/null
+++ b/utils/file_backend.go
@@ -0,0 +1,44 @@
+// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package utils
+
+import (
+	"net/http"
+
+	"github.com/mattermost/mattermost-server/model"
+)
+
+type FileBackend interface {
+	TestConnection() *model.AppError
+
+	ReadFile(path string) ([]byte, *model.AppError)
+	MoveFile(oldPath, newPath string) *model.AppError
+	WriteFile(f []byte, path string) *model.AppError
+	RemoveFile(path string) *model.AppError
+
+	ListDirectory(path string) (*[]string, *model.AppError)
+	RemoveDirectory(path string) *model.AppError
+}
+
+func NewFileBackend(settings *model.FileSettings) (FileBackend, *model.AppError) {
+	switch *settings.DriverName {
+	case model.IMAGE_DRIVER_S3:
+		return &S3FileBackend{
+			endpoint:  settings.AmazonS3Endpoint,
+			accessKey: settings.AmazonS3AccessKeyId,
+			secretKey: settings.AmazonS3SecretAccessKey,
+			secure:    settings.AmazonS3SSL == nil || *settings.AmazonS3SSL,
+			signV2:    settings.AmazonS3SignV2 != nil && *settings.AmazonS3SignV2,
+			region:    settings.AmazonS3Region,
+			bucket:    settings.AmazonS3Bucket,
+			encrypt:   settings.AmazonS3SSE != nil && *settings.AmazonS3SSE && IsLicensed() && *License().Features.Compliance,
+			trace:     settings.AmazonS3Trace != nil && *settings.AmazonS3Trace,
+		}, nil
+	case model.IMAGE_DRIVER_LOCAL:
+		return &LocalFileBackend{
+			directory: settings.Directory,
+		}, nil
+	}
+	return nil, model.NewAppError("NewFileBackend", "No file driver selected.", nil, "", http.StatusInternalServerError)
+}
diff --git a/utils/file_backend_local.go b/utils/file_backend_local.go
new file mode 100644
index 000000000..b5e67f8f0
--- /dev/null
+++ b/utils/file_backend_local.go
@@ -0,0 +1,98 @@
+// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package utils
+
+import (
+	"io/ioutil"
+	"net/http"
+	"os"
+	"path/filepath"
+
+	l4g "github.com/alecthomas/log4go"
+
+	"github.com/mattermost/mattermost-server/model"
+)
+
+const (
+	TEST_FILE_PATH = "/testfile"
+)
+
+type LocalFileBackend struct {
+	directory string
+}
+
+func (b *LocalFileBackend) TestConnection() *model.AppError {
+	f := []byte("testingwrite")
+	if err := writeFileLocally(f, filepath.Join(b.directory, TEST_FILE_PATH)); err != nil {
+		return model.NewAppError("TestFileConnection", "Don't have permissions to write to local path specified or other error.", nil, err.Error(), http.StatusInternalServerError)
+	}
+	os.Remove(filepath.Join(b.directory, TEST_FILE_PATH))
+	l4g.Info("Able to write files to local storage.")
+	return nil
+}
+
+func (b *LocalFileBackend) ReadFile(path string) ([]byte, *model.AppError) {
+	if f, err := ioutil.ReadFile(filepath.Join(b.directory, path)); err != nil {
+		return nil, model.NewAppError("ReadFile", "api.file.read_file.reading_local.app_error", nil, err.Error(), http.StatusInternalServerError)
+	} else {
+		return f, nil
+	}
+}
+
+func (b *LocalFileBackend) MoveFile(oldPath, newPath string) *model.AppError {
+	if err := os.MkdirAll(filepath.Dir(filepath.Join(b.directory, newPath)), 0774); err != nil {
+		return model.NewAppError("moveFile", "api.file.move_file.rename.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := os.Rename(filepath.Join(b.directory, oldPath), filepath.Join(b.directory, newPath)); err != nil {
+		return model.NewAppError("moveFile", "api.file.move_file.rename.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	return nil
+}
+
+func (b *LocalFileBackend) WriteFile(f []byte, path string) *model.AppError {
+	return writeFileLocally(f, filepath.Join(b.directory, path))
+}
+
+func writeFileLocally(f []byte, path string) *model.AppError {
+	if err := os.MkdirAll(filepath.Dir(path), 0774); err != nil {
+		directory, _ := filepath.Abs(filepath.Dir(path))
+		return model.NewAppError("WriteFile", "api.file.write_file_locally.create_dir.app_error", nil, "directory="+directory+", err="+err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := ioutil.WriteFile(path, f, 0644); err != nil {
+		return model.NewAppError("WriteFile", "api.file.write_file_locally.writing.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	return nil
+}
+
+func (b *LocalFileBackend) RemoveFile(path string) *model.AppError {
+	if err := os.Remove(filepath.Join(b.directory, path)); err != nil {
+		return model.NewAppError("RemoveFile", "utils.file.remove_file.local.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+	return nil
+}
+
+func (b *LocalFileBackend) ListDirectory(path string) (*[]string, *model.AppError) {
+	var paths []string
+	if fileInfos, err := ioutil.ReadDir(filepath.Join(b.directory, path)); err != nil {
+		return nil, model.NewAppError("ListDirectory", "utils.file.list_directory.local.app_error", nil, err.Error(), http.StatusInternalServerError)
+	} else {
+		for _, fileInfo := range fileInfos {
+			if fileInfo.IsDir() {
+				paths = append(paths, filepath.Join(path, fileInfo.Name()))
+			}
+		}
+	}
+	return &paths, nil
+}
+
+func (b *LocalFileBackend) RemoveDirectory(path string) *model.AppError {
+	if err := os.RemoveAll(filepath.Join(b.directory, path)); err != nil {
+		return model.NewAppError("RemoveDirectory", "utils.file.remove_directory.local.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+	return nil
+}
diff --git a/utils/file_backend_s3.go b/utils/file_backend_s3.go
new file mode 100644
index 000000000..ed88dc70c
--- /dev/null
+++ b/utils/file_backend_s3.go
@@ -0,0 +1,226 @@
+// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package utils
+
+import (
+	"bytes"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+
+	l4g "github.com/alecthomas/log4go"
+	s3 "github.com/minio/minio-go"
+	"github.com/minio/minio-go/pkg/credentials"
+
+	"github.com/mattermost/mattermost-server/model"
+)
+
+type S3FileBackend struct {
+	endpoint  string
+	accessKey string
+	secretKey string
+	secure    bool
+	signV2    bool
+	region    string
+	bucket    string
+	encrypt   bool
+	trace     bool
+}
+
+// Similar to s3.New() but allows initialization of signature v2 or signature v4 client.
+// If signV2 input is false, function always returns signature v4.
+//
+// Additionally this function also takes a user defined region, if set
+// disables automatic region lookup.
+func (b *S3FileBackend) s3New() (*s3.Client, error) {
+	var creds *credentials.Credentials
+	if b.signV2 {
+		creds = credentials.NewStatic(b.accessKey, b.secretKey, "", credentials.SignatureV2)
+	} else {
+		creds = credentials.NewStatic(b.accessKey, b.secretKey, "", credentials.SignatureV4)
+	}
+
+	s3Clnt, err := s3.NewWithCredentials(b.endpoint, creds, b.secure, b.region)
+	if err != nil {
+		return nil, err
+	}
+
+	if b.trace {
+		s3Clnt.TraceOn(os.Stdout)
+	}
+
+	return s3Clnt, nil
+}
+
+func (b *S3FileBackend) TestConnection() *model.AppError {
+	s3Clnt, err := b.s3New()
+	if err != nil {
+		return model.NewAppError("TestFileConnection", "Bad connection to S3 or minio.", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	exists, err := s3Clnt.BucketExists(b.bucket)
+	if err != nil {
+		return model.NewAppError("TestFileConnection", "Error checking if bucket exists.", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	if !exists {
+		l4g.Warn("Bucket specified does not exist. Attempting to create...")
+		err := s3Clnt.MakeBucket(b.bucket, b.region)
+		if err != nil {
+			l4g.Error("Unable to create bucket.")
+			return model.NewAppError("TestFileConnection", "Unable to create bucket", nil, err.Error(), http.StatusInternalServerError)
+		}
+	}
+	l4g.Info("Connection to S3 or minio is good. Bucket exists.")
+	return nil
+}
+
+func (b *S3FileBackend) ReadFile(path string) ([]byte, *model.AppError) {
+	s3Clnt, err := b.s3New()
+	if err != nil {
+		return nil, model.NewAppError("ReadFile", "api.file.read_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+	minioObject, err := s3Clnt.GetObject(b.bucket, path)
+	if err != nil {
+		return nil, model.NewAppError("ReadFile", "api.file.read_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+	defer minioObject.Close()
+	if f, err := ioutil.ReadAll(minioObject); err != nil {
+		return nil, model.NewAppError("ReadFile", "api.file.read_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
+	} else {
+		return f, nil
+	}
+}
+
+func (b *S3FileBackend) MoveFile(oldPath, newPath string) *model.AppError {
+	s3Clnt, err := b.s3New()
+	if err != nil {
+		return model.NewAppError("moveFile", "api.file.write_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	source := s3.NewSourceInfo(b.bucket, oldPath, nil)
+	destination, err := s3.NewDestinationInfo(b.bucket, newPath, nil, s3CopyMetadata(b.encrypt))
+	if err != nil {
+		return model.NewAppError("moveFile", "api.file.write_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+	if err = s3Clnt.CopyObject(destination, source); err != nil {
+		return model.NewAppError("moveFile", "api.file.move_file.delete_from_s3.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+	if err = s3Clnt.RemoveObject(b.bucket, oldPath); err != nil {
+		return model.NewAppError("moveFile", "api.file.move_file.delete_from_s3.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+	return nil
+}
+
+func (b *S3FileBackend) WriteFile(f []byte, path string) *model.AppError {
+	s3Clnt, err := b.s3New()
+	if err != nil {
+		return model.NewAppError("WriteFile", "api.file.write_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	ext := filepath.Ext(path)
+	metaData := s3Metadata(b.encrypt, "binary/octet-stream")
+	if model.IsFileExtImage(ext) {
+		metaData = s3Metadata(b.encrypt, model.GetImageMimeType(ext))
+	}
+
+	if _, err = s3Clnt.PutObjectWithMetadata(b.bucket, path, bytes.NewReader(f), metaData, nil); err != nil {
+		return model.NewAppError("WriteFile", "api.file.write_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	return nil
+}
+
+func (b *S3FileBackend) RemoveFile(path string) *model.AppError {
+	s3Clnt, err := b.s3New()
+	if err != nil {
+		return model.NewAppError("RemoveFile", "utils.file.remove_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := s3Clnt.RemoveObject(b.bucket, path); err != nil {
+		return model.NewAppError("RemoveFile", "utils.file.remove_file.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	return nil
+}
+
+func getPathsFromObjectInfos(in <-chan s3.ObjectInfo) <-chan string {
+	out := make(chan string, 1)
+
+	go func() {
+		defer close(out)
+
+		for {
+			info, done := <-in
+
+			if !done {
+				break
+			}
+
+			out <- info.Key
+		}
+	}()
+
+	return out
+}
+
+func (b *S3FileBackend) ListDirectory(path string) (*[]string, *model.AppError) {
+	var paths []string
+
+	s3Clnt, err := b.s3New()
+	if err != nil {
+		return nil, model.NewAppError("ListDirectory", "utils.file.list_directory.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	doneCh := make(chan struct{})
+
+	defer close(doneCh)
+
+	for object := range s3Clnt.ListObjects(b.bucket, path, false, doneCh) {
+		if object.Err != nil {
+			return nil, model.NewAppError("ListDirectory", "utils.file.list_directory.s3.app_error", nil, object.Err.Error(), http.StatusInternalServerError)
+		}
+		paths = append(paths, strings.Trim(object.Key, "/"))
+	}
+
+	return &paths, nil
+}
+
+func (b *S3FileBackend) RemoveDirectory(path string) *model.AppError {
+	s3Clnt, err := b.s3New()
+	if err != nil {
+		return model.NewAppError("RemoveDirectory", "utils.file.remove_directory.s3.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	doneCh := make(chan struct{})
+
+	for err := range s3Clnt.RemoveObjects(b.bucket, getPathsFromObjectInfos(s3Clnt.ListObjects(b.bucket, path, true, doneCh))) {
+		if err.Err != nil {
+			doneCh <- struct{}{}
+			return model.NewAppError("RemoveDirectory", "utils.file.remove_directory.s3.app_error", nil, err.Err.Error(), http.StatusInternalServerError)
+		}
+	}
+
+	close(doneCh)
+	return nil
+}
+
+func s3Metadata(encrypt bool, contentType string) map[string][]string {
+	metaData := make(map[string][]string)
+	if contentType != "" {
+		metaData["Content-Type"] = []string{"contentType"}
+	}
+	if encrypt {
+		metaData["x-amz-server-side-encryption"] = []string{"AES256"}
+	}
+	return metaData
+}
+
+func s3CopyMetadata(encrypt bool) map[string]string {
+	metaData := make(map[string]string)
+	metaData["x-amz-server-side-encryption"] = "AES256"
+	return metaData
+}
diff --git a/utils/file_backend_test.go b/utils/file_backend_test.go
new file mode 100644
index 000000000..0989f783c
--- /dev/null
+++ b/utils/file_backend_test.go
@@ -0,0 +1,164 @@
+// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package utils
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"github.com/stretchr/testify/suite"
+
+	"github.com/mattermost/mattermost-server/model"
+)
+
+type FileBackendTestSuite struct {
+	suite.Suite
+
+	settings model.FileSettings
+	backend  FileBackend
+}
+
+func TestLocalFileBackendTestSuite(t *testing.T) {
+	dir, err := ioutil.TempDir("", "")
+	require.NoError(t, err)
+	defer os.RemoveAll(dir)
+
+	suite.Run(t, &FileBackendTestSuite{
+		settings: model.FileSettings{
+			DriverName: model.NewString(model.IMAGE_DRIVER_LOCAL),
+			Directory:  dir,
+		},
+	})
+}
+
+func TestS3FileBackendTestSuite(t *testing.T) {
+	s3Host := os.Getenv("CI_HOST")
+	if s3Host == "" {
+		s3Host = "dockerhost"
+	}
+
+	s3Port := os.Getenv("CI_MINIO_PORT")
+	if s3Port == "" {
+		s3Port = "9001"
+	}
+
+	s3Endpoint := fmt.Sprintf("%s:%s", s3Host, s3Port)
+
+	suite.Run(t, &FileBackendTestSuite{
+		settings: model.FileSettings{
+			DriverName:              model.NewString(model.IMAGE_DRIVER_S3),
+			AmazonS3AccessKeyId:     "minioaccesskey",
+			AmazonS3SecretAccessKey: "miniosecretkey",
+			AmazonS3Bucket:          "mattermost-test",
+			AmazonS3Endpoint:        s3Endpoint,
+			AmazonS3SSL:             model.NewBool(false),
+		},
+	})
+}
+
+func (s *FileBackendTestSuite) SetupTest() {
+	TranslationsPreInit()
+
+	backend, err := NewFileBackend(&s.settings)
+	require.Nil(s.T(), err)
+	s.backend = backend
+}
+
+func (s *FileBackendTestSuite) TestConnection() {
+	s.Nil(s.backend.TestConnection())
+}
+
+func (s *FileBackendTestSuite) TestReadWriteFile() {
+	b := []byte("test")
+	path := "tests/" + model.NewId()
+
+	s.Nil(s.backend.WriteFile(b, path))
+	defer s.backend.RemoveFile(path)
+
+	read, err := s.backend.ReadFile(path)
+	s.Nil(err)
+
+	readString := string(read)
+	s.EqualValues(readString, "test")
+}
+
+func (s *FileBackendTestSuite) TestMoveFile() {
+	b := []byte("test")
+	path1 := "tests/" + model.NewId()
+	path2 := "tests/" + model.NewId()
+
+	s.Nil(s.backend.WriteFile(b, path1))
+	defer s.backend.RemoveFile(path1)
+
+	s.Nil(s.backend.MoveFile(path1, path2))
+	defer s.backend.RemoveFile(path2)
+
+	_, err := s.backend.ReadFile(path1)
+	s.Error(err)
+
+	_, err = s.backend.ReadFile(path2)
+	s.Nil(err)
+}
+
+func (s *FileBackendTestSuite) TestRemoveFile() {
+	b := []byte("test")
+	path := "tests/" + model.NewId()
+
+	s.Nil(s.backend.WriteFile(b, path))
+	s.Nil(s.backend.RemoveFile(path))
+
+	_, err := s.backend.ReadFile(path)
+	s.Error(err)
+
+	s.Nil(s.backend.WriteFile(b, "tests2/foo"))
+	s.Nil(s.backend.WriteFile(b, "tests2/bar"))
+	s.Nil(s.backend.WriteFile(b, "tests2/asdf"))
+	s.Nil(s.backend.RemoveDirectory("tests2"))
+}
+
+func (s *FileBackendTestSuite) TestListDirectory() {
+	b := []byte("test")
+	path1 := "19700101/" + model.NewId()
+	path2 := "19800101/" + model.NewId()
+
+	s.Nil(s.backend.WriteFile(b, path1))
+	defer s.backend.RemoveFile(path1)
+	s.Nil(s.backend.WriteFile(b, path2))
+	defer s.backend.RemoveFile(path2)
+
+	paths, err := s.backend.ListDirectory("")
+	s.Nil(err)
+
+	found1 := false
+	found2 := false
+	for _, path := range *paths {
+		if path == "19700101" {
+			found1 = true
+		} else if path == "19800101" {
+			found2 = true
+		}
+	}
+	s.True(found1)
+	s.True(found2)
+}
+
+func (s *FileBackendTestSuite) TestRemoveDirectory() {
+	b := []byte("test")
+
+	s.Nil(s.backend.WriteFile(b, "tests2/foo"))
+	s.Nil(s.backend.WriteFile(b, "tests2/bar"))
+	s.Nil(s.backend.WriteFile(b, "tests2/aaa"))
+
+	s.Nil(s.backend.RemoveDirectory("tests2"))
+
+	_, err := s.backend.ReadFile("tests2/foo")
+	s.Error(err)
+	_, err = s.backend.ReadFile("tests2/bar")
+	s.Error(err)
+	_, err = s.backend.ReadFile("tests2/asdf")
+	s.Error(err)
+}
diff --git a/utils/file_test.go b/utils/file_test.go
index 91e78f24e..6c7e3c462 100644
--- a/utils/file_test.go
+++ b/utils/file_test.go
@@ -4,7 +4,6 @@
 package utils
 
 import (
-	"fmt"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -12,179 +11,8 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"github.com/stretchr/testify/suite"
-
-	"github.com/mattermost/mattermost-server/model"
 )
 
-type FileTestSuite struct {
-	suite.Suite
-
-	testDriver string
-
-	// Config to be reset after tests.
-	driverName              string
-	amazonS3AccessKeyId     string
-	amazonS3SecretAccessKey string
-	amazonS3Bucket          string
-	amazonS3Endpoint        string
-	amazonS3SSL             bool
-}
-
-func TestFileLocalTestSuite(t *testing.T) {
-	testsuite := FileTestSuite{
-		testDriver: model.IMAGE_DRIVER_LOCAL,
-	}
-	suite.Run(t, &testsuite)
-}
-
-func TestFileMinioTestSuite(t *testing.T) {
-	testsuite := FileTestSuite{
-		testDriver: model.IMAGE_DRIVER_S3,
-	}
-	suite.Run(t, &testsuite)
-}
-
-func (s *FileTestSuite) SetupTest() {
-	TranslationsPreInit()
-	LoadGlobalConfig("config.json")
-	InitTranslations(Cfg.LocalizationSettings)
-
-	// Save state to restore after the test has run.
-	s.driverName = *Cfg.FileSettings.DriverName
-	s.amazonS3AccessKeyId = Cfg.FileSettings.AmazonS3AccessKeyId
-	s.amazonS3SecretAccessKey = Cfg.FileSettings.AmazonS3SecretAccessKey
-	s.amazonS3Bucket = Cfg.FileSettings.AmazonS3Bucket
-	s.amazonS3Endpoint = Cfg.FileSettings.AmazonS3Endpoint
-	s.amazonS3SSL = *Cfg.FileSettings.AmazonS3SSL
-
-	// Set up the state for the tests.
-	s3Host := os.Getenv("CI_HOST")
-	if s3Host == "" {
-		s3Host = "dockerhost"
-	}
-
-	s3Port := os.Getenv("CI_MINIO_PORT")
-	if s3Port == "" {
-		s3Port = "9001"
-	}
-
-	s3Endpoint := fmt.Sprintf("%s:%s", s3Host, s3Port)
-	if s.testDriver == model.IMAGE_DRIVER_LOCAL {
-		*Cfg.FileSettings.DriverName = model.IMAGE_DRIVER_LOCAL
-	} else if s.testDriver == model.IMAGE_DRIVER_S3 {
-		*Cfg.FileSettings.DriverName = model.IMAGE_DRIVER_S3
-		Cfg.FileSettings.AmazonS3AccessKeyId = "minioaccesskey"
-		Cfg.FileSettings.AmazonS3SecretAccessKey = "miniosecretkey"
-		Cfg.FileSettings.AmazonS3Bucket = "mattermost-test"
-		Cfg.FileSettings.AmazonS3Endpoint = s3Endpoint
-		*Cfg.FileSettings.AmazonS3SSL = false
-	} else {
-		s.T().Fatal("Invalid image driver set for test suite.")
-	}
-}
-
-func (s *FileTestSuite) TearDownTest() {
-	// Restore the test state.
-	*Cfg.FileSettings.DriverName = s.driverName
-	Cfg.FileSettings.AmazonS3AccessKeyId = s.amazonS3AccessKeyId
-	Cfg.FileSettings.AmazonS3SecretAccessKey = s.amazonS3SecretAccessKey
-	Cfg.FileSettings.AmazonS3Bucket = s.amazonS3Bucket
-	Cfg.FileSettings.AmazonS3Endpoint = s.amazonS3Endpoint
-	*Cfg.FileSettings.AmazonS3SSL = s.amazonS3SSL
-}
-
-func (s *FileTestSuite) TestReadWriteFile() {
-	b := []byte("test")
-	path := "tests/" + model.NewId()
-
-	s.Nil(WriteFile(b, path))
-	defer RemoveFile(path)
-
-	read, err := ReadFile(path)
-	s.Nil(err)
-
-	readString := string(read)
-	s.EqualValues(readString, "test")
-}
-
-func (s *FileTestSuite) TestMoveFile() {
-	b := []byte("test")
-	path1 := "tests/" + model.NewId()
-	path2 := "tests/" + model.NewId()
-
-	s.Nil(WriteFile(b, path1))
-	defer RemoveFile(path1)
-
-	s.Nil(MoveFile(path1, path2))
-	defer RemoveFile(path2)
-
-	_, err := ReadFile(path1)
-	s.Error(err)
-
-	_, err = ReadFile(path2)
-	s.Nil(err)
-}
-
-func (s *FileTestSuite) TestRemoveFile() {
-	b := []byte("test")
-	path := "tests/" + model.NewId()
-
-	s.Nil(WriteFile(b, path))
-	s.Nil(RemoveFile(path))
-
-	_, err := ReadFile(path)
-	s.Error(err)
-
-	s.Nil(WriteFile(b, "tests2/foo"))
-	s.Nil(WriteFile(b, "tests2/bar"))
-	s.Nil(WriteFile(b, "tests2/asdf"))
-	s.Nil(RemoveDirectory("tests2"))
-}
-
-func (s *FileTestSuite) TestListDirectory() {
-	b := []byte("test")
-	path1 := "19700101/" + model.NewId()
-	path2 := "19800101/" + model.NewId()
-
-	s.Nil(WriteFile(b, path1))
-	defer RemoveFile(path1)
-	s.Nil(WriteFile(b, path2))
-	defer RemoveFile(path2)
-
-	paths, err := ListDirectory("")
-	s.Nil(err)
-
-	found1 := false
-	found2 := false
-	for _, path := range *paths {
-		if path == "19700101" {
-			found1 = true
-		} else if path == "19800101" {
-			found2 = true
-		}
-	}
-	s.True(found1)
-	s.True(found2)
-}
-
-func (s *FileTestSuite) TestRemoveDirectory() {
-	b := []byte("test")
-
-	s.Nil(WriteFile(b, "tests2/foo"))
-	s.Nil(WriteFile(b, "tests2/bar"))
-	s.Nil(WriteFile(b, "tests2/aaa"))
-
-	s.Nil(RemoveDirectory("tests2"))
-
-	_, err := ReadFile("tests2/foo")
-	s.Error(err)
-	_, err = ReadFile("tests2/bar")
-	s.Error(err)
-	_, err = ReadFile("tests2/asdf")
-	s.Error(err)
-}
-
 func TestCopyDir(t *testing.T) {
 	srcDir, err := ioutil.TempDir("", "src")
 	require.NoError(t, err)