feat(remove): added support for removing files via an extension

To enable removal of files, and support the work going on in https://github.com/apache/iceberg-go I have added a new extension to s3iofs which supports the remove file operation.

README.md

@@ -6,7 +6,7 @@ This package provides an S3 implementation for [Go1.16 filesystem interface](htt
 
 This package provides an S3 implementation for the Go1.16 filesystem interface using the [AWS SDK for Go v2](https://github.com/aws/aws-sdk-go-v2).
 
-The `S3FS` is currently read-only, and implements the following interfaces:
+The `S3FS` implements the following interfaces:
 
 - `fs.FS`
 - `fs.StatFS`
@@ -19,6 +19,10 @@ The `s3File` implements the following interfaces:
 - `io.ReaderAt`
 - `io.Seeker`
 
+In addition to this the `S3FS` also implements the following interfaces:
+
+- `RemoveFS`, which provides a `Remove(name string) 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

@@ -237,3 +237,19 @@ func TestReadBigEOF(t *testing.T) {
 	assert.ErrorIs(err, io.ErrUnexpectedEOF)
 	assert.Equal(oneMegabyte, n)
 }
+
+func TestRemove(t *testing.T) {
+	assert := require.New(t)
+
+	_, err := client.PutObject(context.Background(), &s3.PutObjectInput{
+		Bucket: aws.String(testBucketName),
+		Key:    aws.String("test_remove.txt"),
+		Body:   bytes.NewReader(generateData(oneMegabyte)),
+	})
+	assert.NoError(err)
+
+	s3fs := s3iofs.NewWithClient(testBucketName, client)
+
+	err = s3fs.Remove("test_remove.txt")
+	assert.NoError(err)
+}

s3.go

@@ -11,4 +11,5 @@ type S3API interface {
 	GetObject(ctx context.Context, params *s3.GetObjectInput, optFns ...func(*s3.Options)) (*s3.GetObjectOutput, error)
 	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)
 }

s3file_test.go

@@ -37,6 +37,11 @@ func (m *mockS3Client) ListObjectsV2(ctx context.Context, params *s3.ListObjects
 	return args.Get(0).(*s3.ListObjectsV2Output), args.Error(1)
 }
 
+func (m *mockS3Client) DeleteObject(ctx context.Context, params *s3.DeleteObjectInput, optFns ...func(*s3.Options)) (*s3.DeleteObjectOutput, error) {
+	args := m.Called(ctx, params, optFns)
+	return args.Get(0).(*s3.DeleteObjectOutput), args.Error(1)
+}
+
 func TestReadFile(t *testing.T) {
 	type args struct {
 		bucket string

s3iofs.go

@@ -16,8 +16,15 @@ var (
 	_ fs.FS        = (*S3FS)(nil)
 	_ fs.StatFS    = (*S3FS)(nil)
 	_ fs.ReadDirFS = (*S3FS)(nil)
+	_ RemoveFS     = (*S3FS)(nil)
 )
 
+// RemoveFS extend the fs.FS interface to add the Remove method.
+type RemoveFS interface {
+	fs.FS
+	Remove(name string) error
+}
+
 // S3FS is a filesystem implementation using S3.
 type S3FS struct {
 	bucket   string
@@ -155,6 +162,31 @@ func (s3fs *S3FS) ReadDir(name string) ([]fs.DirEntry, error) {
 	return entries, nil
 }
 
+func (s3fs *S3FS) Remove(name string) error {
+	if name == "." {
+		return &fs.PathError{Op: "remove", Path: name, Err: fs.ErrInvalid}
+	}
+	if name == "" {
+		return &fs.PathError{Op: "remove", Path: name, Err: fs.ErrInvalid}
+	}
+
+	_, err := s3fs.s3client.DeleteObject(context.TODO(), &s3.DeleteObjectInput{
+		Bucket: aws.String(s3fs.bucket),
+		Key:    aws.String(name),
+	})
+	if err != nil {
+		var nfe *types.NotFound
+		if errors.As(err, &nfe) {
+			// deleting a file which doesn't exist is not an error
+			return nil
+		}
+
+		return &fs.PathError{Op: "remove", Path: name, Err: err}
+	}
+
+	return nil
+}
+
 func (s3fs *S3FS) stat(name string) (fs.FileInfo, error) {
 	if name == "." {
 		return &s3File{