Merge pull request #27 from wolfeidau/feat_add_write_file

feat(write_file): added write file extension for simple put object

README.md

@@ -22,6 +22,7 @@ The `s3File` implements the following interfaces:
 In addition to this the `S3FS` also implements the following interfaces:
 
 - `RemoveFS`, which provides a `Remove(name string) error` method.
+- `WriteFileFS` which provides a `WriteFile(name string, data []byte, perm fs.FileMode) error` method.
 
 This enables libraries such as [apache arrow](https://arrow.apache.org/) to read parts of a parquet file from S3, without downloading the entire file.
 # Usage 

integration/s3fs_test.go

@@ -289,3 +289,28 @@ func TestRemove(t *testing.T) {
 		assert.Error(err)
 	})
 }
+
+func TestWriteFile(t *testing.T) {
+
+	t.Run("should write and read file", func(t *testing.T) {
+		assert := require.New(t)
+
+		s3fs := s3iofs.NewWithClient(testBucketName, client)
+
+		err := s3fs.WriteFile("test_write_read.txt", oneKilobyte, 0644)
+		assert.NoError(err)
+
+		data, err := fs.ReadFile(s3fs, "test_write_read.txt")
+		assert.NoError(err)
+		assert.Equal(oneKilobyte, data)
+	})
+
+	t.Run("invalid name should error", func(t *testing.T) {
+		assert := require.New(t)
+
+		s3fs := s3iofs.NewWithClient(testBucketName, client)
+
+		err := s3fs.WriteFile("", []byte{}, 0644)
+		assert.Error(err)
+	})
+}

s3.go

@@ -12,4 +12,5 @@ type S3API interface {
 	ListObjectsV2(ctx context.Context, params *s3.ListObjectsV2Input, optFns ...func(*s3.Options)) (*s3.ListObjectsV2Output, error)
 	HeadObject(ctx context.Context, params *s3.HeadObjectInput, optFns ...func(*s3.Options)) (*s3.HeadObjectOutput, error)
 	DeleteObject(ctx context.Context, params *s3.DeleteObjectInput, optFns ...func(*s3.Options)) (*s3.DeleteObjectOutput, error)
+	PutObject(ctx context.Context, params *s3.PutObjectInput, optFns ...func(*s3.Options)) (*s3.PutObjectOutput, error)
 }

s3file_test.go

@@ -42,6 +42,11 @@ func (m *mockS3Client) DeleteObject(ctx context.Context, params *s3.DeleteObject
 	return args.Get(0).(*s3.DeleteObjectOutput), args.Error(1)
 }
 
+func (m *mockS3Client) PutObject(ctx context.Context, params *s3.PutObjectInput, optFns ...func(*s3.Options)) (*s3.PutObjectOutput, error) {
+	args := m.Called(ctx, params, optFns)
+	return args.Get(0).(*s3.PutObjectOutput), args.Error(1)
+}
+
 func TestReadFile(t *testing.T) {
 	type args struct {
 		bucket string

s3iofs.go

@@ -1,6 +1,7 @@
 package s3iofs
 
 import (
+	"bytes"
 	"errors"
 	"io/fs"
 	"os"
@@ -17,6 +18,7 @@ var (
 	_ fs.StatFS    = (*S3FS)(nil)
 	_ fs.ReadDirFS = (*S3FS)(nil)
 	_ RemoveFS     = (*S3FS)(nil)
+	_ WriteFileFS  = (*S3FS)(nil)
 )
 
 // RemoveFS extend the fs.FS interface to add the Remove method.
@@ -25,6 +27,12 @@ type RemoveFS interface {
 	Remove(name string) error
 }
 
+// WriteFileFS extend the fs.FS interface to add the WriteFile method.
+type WriteFileFS interface {
+	fs.FS
+	WriteFile(name string, data []byte, perm os.FileMode) error
+}
+
 // S3FS is a filesystem implementation using S3.
 type S3FS struct {
 	bucket   string
@@ -162,6 +170,9 @@ func (s3fs *S3FS) ReadDir(name string) ([]fs.DirEntry, error) {
 	return entries, nil
 }
 
+// Remove removes the named file or directory.
+//
+// Note if the file doesn't exist in the s3 bucket, Remove returns nil.
 func (s3fs *S3FS) Remove(name string) error {
 	if name == "." {
 		return &fs.PathError{Op: "remove", Path: name, Err: fs.ErrInvalid}
@@ -181,6 +192,32 @@ func (s3fs *S3FS) Remove(name string) error {
 	return nil
 }
 
+// WriteFile writes the data to the named file in s3.
+//
+// Note:
+//   - If the file exists, WriteFile overwrites it.
+//   - The provided mode is unused by this implementation.
+func (s3fs *S3FS) WriteFile(name string, data []byte, perm os.FileMode) error {
+	if name == "." {
+		return &fs.PathError{Op: "write", Path: name, Err: fs.ErrInvalid}
+	}
+	if name == "" {
+		return &fs.PathError{Op: "write", Path: name, Err: fs.ErrInvalid}
+	}
+
+	_, err := s3fs.s3client.PutObject(context.TODO(), &s3.PutObjectInput{
+		Bucket: aws.String(s3fs.bucket),
+		Key:    aws.String(name),
+		Body:   bytes.NewReader(data),
+	})
+
+	if err != nil {
+		return &fs.PathError{Op: "write", Path: name, Err: err}
+	}
+
+	return nil
+}
+
 func (s3fs *S3FS) stat(name string) (fs.FileInfo, error) {
 	if name == "." {
 		return &s3File{