Reorganize file util functionality (#7848)

* reorganize file util functionality

* fix api test compilation

* fix rebase issue

1 files changed, 226 insertions, 0 deletions

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
+}