EmptyDir

Package: flyte.io

A sentinel :class:Dir representing ’no directory was produced'.

Use this as a return value when a task may or may not produce an output directory, e.g. flyte.run_python_script when the user did not request output_dir::

@env.task
async def maybe_produce_dir(...) -&gt; Output:
    if user_wants_dir:
        return Output(output_dir=await Dir.from_local(path))
    return Output(output_dir=EmptyDir())

On the receiving side, the value comes back as a plain Dir with :attr:Dir.is_empty set to True (the deserializer doesn’t preserve the EmptyDir subclass identity, but the sentinel path round-trips). Callers should branch on dir.is_empty rather than isinstance(dir, EmptyDir).

This exists because Optional[Dir] cannot round-trip through Flyte’s DataclassTransformer — mashumaro strips the Optional and calls Dir._deserialize(None) which fails. EmptyDir keeps the field type as plain Dir so the round-trip works.

Parameters

        
    
class EmptyDir(
    path: str,
    name: typing.Optional[str],
    format: str,
    hash: typing.Optional[str],
)

Create a new model by parsing and validating input data from keyword arguments.

Raises ValidationError if the input data cannot be validated to form a valid model.

self is explicitly positional-only to allow self as a field name.

Parameter	Type	Description
`path`	`str`
`name`	`typing.Optional[str]`
`format`	`str`
`hash`	`typing.Optional[str]`

Properties

Property	Type	Description
`is_empty`	`None`	True when this is a sentinel `Dir` produced by :class:`EmptyDir`/`Dir.empty()` — i.e. the task didn’t actually produce a directory. Use this to branch on whether the upstream task emitted real data without dealing with `Optional[Dir]` (which the type engine cannot round-trip correctly through `SerializableType`).
`lazy_uploader`	`None`

Methods

Method	Description
`download()`	Asynchronously download the entire directory to a local path.
`download_sync()`	Synchronously download the entire directory to a local path.
`empty()`	Return a sentinel `Dir` representing ’no directory was produced'.
`exists()`	Asynchronously check if the directory exists.
`exists_sync()`	Synchronously check if the directory exists.
`from_existing_remote()`	Create a Dir reference from an existing remote directory.
`from_local()`	Asynchronously create a new Dir by uploading a local directory to remote storage.
`from_local_sync()`	Synchronously create a new Dir by uploading a local directory to remote storage.
`get_file()`	Asynchronously get a specific file from the directory by name.
`get_file_sync()`	Synchronously get a specific file from the directory by name.
`list_files()`	Asynchronously get a list of all files in the directory (non-recursive).
`list_files_sync()`	Synchronously get a list of all files in the directory (non-recursive).
`model_post_init()`	This function is meant to behave like a BaseModel method to initialize private attributes.
`new_remote()`	Create a new Dir reference for a remote directory that will be written to.
`pre_init()`	Internal: Pydantic validator to set default name from path.
`schema_match()`	Internal: Check if incoming schema matches Dir schema.
`walk()`	Asynchronously walk through the directory and yield File objects.
`walk_sync()`	Synchronously walk through the directory and yield File objects.

download()

        
    
def download(
    local_path: Optional[Union[str, Path]],
) -> str

Asynchronously download the entire directory to a local path.

Use this when you need to download all files in a directory to your local filesystem for processing.

Example (Async):

        
    
@env.task
async def download_directory(d: Dir) -> str:
    local_dir = await d.download()
    # Process files in the local directory
    return local_dir

Example (Async - Download to specific path):

        
    
@env.task
async def download_to_path(d: Dir) -> str:
    local_dir = await d.download("/tmp/my_data/")
    return local_dir

Parameter	Type	Description
`local_path`	`Optional[Union[str, Path]]`	The local path to download the directory to. If None, a temporary directory will be used and a path will be generated.

Returns: The absolute path to the downloaded directory

download_sync()

        
    
def download_sync(
    local_path: Optional[Union[str, Path]],
) -> str

Synchronously download the entire directory to a local path.

Use this in non-async tasks when you need to download all files in a directory to your local filesystem.

Example (Sync):

        
    
@env.task
def download_directory_sync(d: Dir) -> str:
    local_dir = d.download_sync()
    # Process files in the local directory
    return local_dir

Example (Sync - Download to specific path):

        
    
@env.task
def download_to_path_sync(d: Dir) -> str:
    local_dir = d.download_sync("/tmp/my_data/")
    return local_dir

Parameter	Type	Description
`local_path`	`Optional[Union[str, Path]]`	The local path to download the directory to. If None, a temporary directory will be used and a path will be generated.

Returns: The absolute path to the downloaded directory

empty()

        
    
def empty()

Return a sentinel Dir representing ’no directory was produced'.

Use as the return value when a task may or may not produce an output directory; the caller can check :attr:Dir.is_empty to detect the sentinel. Round-trips cleanly through Flyte serialization (unlike Optional[Dir]).

exists()

        
    
def exists()

Asynchronously check if the directory exists.

Example (Async):

        
    
@env.task
async def check_directory(d: Dir) -> bool:
    if await d.exists():
        print("Directory exists!")
        return True
    return False

Returns

True if the directory exists, False otherwise

exists_sync()

        
    
def exists_sync()

Synchronously check if the directory exists.

Use this in non-async tasks or when you need synchronous directory existence checking.

Example (Sync):

        
    
@env.task
def check_directory_sync(d: Dir) -> bool:
    if d.exists_sync():
        print("Directory exists!")
        return True
    return False

Returns

True if the directory exists, False otherwise

from_existing_remote()

        
    
def from_existing_remote(
    remote_path: str,
    dir_cache_key: Optional[str],
) -> Dir[T]

Create a Dir reference from an existing remote directory.

Use this when you want to reference a directory that already exists in remote storage without uploading it.

        
    
@env.task
async def process_existing_directory() -> int:
    d = Dir.from_existing_remote("s3://my-bucket/data/")
    files = await d.list_files()
    return len(files)

Example (With cache key):

        
    
@env.task
async def process_with_cache_key() -> int:
    d = Dir.from_existing_remote("s3://my-bucket/data/", dir_cache_key="abc123")
    files = await d.list_files()
    return len(files)

Parameter	Type	Description
`remote_path`	`str`	The remote path to the existing directory
`dir_cache_key`	`Optional[str]`	Optional hash value to use for cache key computation. If not specified, the cache key will be computed based on the directory’s attributes.

Returns: A new Dir instance pointing to the existing remote directory

from_local()

        
    
def from_local(
    local_path: Union[str, Path],
    remote_destination: Optional[str],
    dir_cache_key: Optional[str],
    batch_size: Optional[int],
) -> Dir[T]

Asynchronously create a new Dir by uploading a local directory to remote storage.

Use this in async tasks when you have a local directory that needs to be uploaded to remote storage.

Example (Async):

        
    
@env.task
async def upload_local_directory() -> Dir:
    # Create a local directory with files
    os.makedirs("/tmp/data_dir", exist_ok=True)
    with open("/tmp/data_dir/file1.txt", "w") as f:
        f.write("data1")

    # Upload to remote storage
    remote_dir = await Dir.from_local("/tmp/data_dir/")
    return remote_dir

Example (Async - With specific destination):

        
    
@env.task
async def upload_to_specific_path() -> Dir:
    remote_dir = await Dir.from_local("/tmp/data_dir/", "s3://my-bucket/data/")
    return remote_dir

Example (Async - With cache key):

        
    
@env.task
async def upload_with_cache_key() -> Dir:
    remote_dir = await Dir.from_local("/tmp/data_dir/", dir_cache_key="my_cache_key_123")
    return remote_dir

Parameter	Type	Description
`local_path`	`Union[str, Path]`	Path to the local directory
`remote_destination`	`Optional[str]`	Optional remote path to store the directory. If None, a path will be automatically generated.
`dir_cache_key`	`Optional[str]`	Optional precomputed hash value to use for cache key computation when this Dir is used as an input to discoverable tasks. If not specified, the cache key will be based on directory attributes.
`batch_size`	`Optional[int]`	Optional concurrency limit for uploading files. If not specified, the default value is determined by the FLYTE_IO_BATCH_SIZE environment variable (default: 32).

Returns: A new Dir instance pointing to the uploaded directory

from_local_sync()

        
    
def from_local_sync(
    local_path: Union[str, Path],
    remote_destination: Optional[str],
    dir_cache_key: Optional[str],
) -> Dir[T]

Synchronously create a new Dir by uploading a local directory to remote storage.

Use this in non-async tasks when you have a local directory that needs to be uploaded to remote storage.

Example (Sync):

        
    
@env.task
def upload_local_directory_sync() -> Dir:
    # Create a local directory with files
    os.makedirs("/tmp/data_dir", exist_ok=True)
    with open("/tmp/data_dir/file1.txt", "w") as f:
        f.write("data1")

    # Upload to remote storage
    remote_dir = Dir.from_local_sync("/tmp/data_dir/")
    return remote_dir

Example (Sync - With specific destination):

        
    
@env.task
def upload_to_specific_path_sync() -> Dir:
    remote_dir = Dir.from_local_sync("/tmp/data_dir/", "s3://my-bucket/data/")
    return remote_dir

Example (Sync - With cache key):

        
    
@env.task
def upload_with_cache_key_sync() -> Dir:
    remote_dir = Dir.from_local_sync("/tmp/data_dir/", dir_cache_key="my_cache_key_123")
    return remote_dir

Parameter	Type	Description
`local_path`	`Union[str, Path]`	Path to the local directory
`remote_destination`	`Optional[str]`	Optional remote path to store the directory. If None, a path will be automatically generated.
`dir_cache_key`	`Optional[str]`	Optional precomputed hash value to use for cache key computation when this Dir is used as an input to discoverable tasks. If not specified, the cache key will be based on directory attributes.

Returns: A new Dir instance pointing to the uploaded directory

get_file()

        
    
def get_file(
    file_name: str,
) -> Optional[File[T]]

Asynchronously get a specific file from the directory by name.

Use this when you know the name of a specific file in the directory you want to access.

Example (Async):

        
    
@env.task
async def read_specific_file(d: Dir) -> str:
    file = await d.get_file("data.csv")
    if file:
        async with file.open("rb") as f:
            content = await f.read()
            return content.decode("utf-8")
    return "File not found"

Parameter	Type	Description
`file_name`	`str`	The name of the file to get

Returns: A File instance if the file exists, None otherwise

get_file_sync()

        
    
def get_file_sync(
    file_name: str,
) -> Optional[File[T]]

Synchronously get a specific file from the directory by name.

Use this in non-async tasks when you know the name of a specific file in the directory you want to access.

Example (Sync):

        
    
@env.task
def read_specific_file_sync(d: Dir) -> str:
    file = d.get_file_sync("data.csv")
    if file:
        with file.open_sync("rb") as f:
            content = f.read()
            return content.decode("utf-8")
    return "File not found"

Parameter	Type	Description
`file_name`	`str`	The name of the file to get

Returns: A File instance if the file exists, None otherwise

list_files()

        
    
def list_files()

Asynchronously get a list of all files in the directory (non-recursive).

Use this when you need a list of all files in the top-level directory at once.

Example (Async):

        
    
@env.task
async def count_files(d: Dir) -> int:
    files = await d.list_files()
    return len(files)

Example (Async - Process files):

        
    
@env.task
async def process_all_files(d: Dir) -> list[str]:
    files = await d.list_files()
    contents = []
    for file in files:
        async with file.open("rb") as f:
            content = await f.read()
            contents.append(content.decode("utf-8"))
    return contents

Returns

A list of File objects for files in the top-level directory

list_files_sync()

        
    
def list_files_sync()

Synchronously get a list of all files in the directory (non-recursive).

Use this in non-async tasks when you need a list of all files in the top-level directory at once.

Example (Sync):

        
    
@env.task
def count_files_sync(d: Dir) -> int:
    files = d.list_files_sync()
    return len(files)

Example (Sync - Process files):

        
    
@env.task
def process_all_files_sync(d: Dir) -> list[str]:
    files = d.list_files_sync()
    contents = []
    for file in files:
        with file.open_sync("rb") as f:
            content = f.read()
            contents.append(content.decode("utf-8"))
    return contents

Returns

A list of File objects for files in the top-level directory

model_post_init()

        
    
def model_post_init(
    context: Any,
)

This function is meant to behave like a BaseModel method to initialize private attributes.

It takes context as an argument since that’s what pydantic-core passes when calling it.

Parameter	Type	Description
`context`	`Any`	The context.

new_remote()

        
    
def new_remote(
    dir_name: Optional[str],
    hash: Optional[str],
) -> Dir[T]

Create a new Dir reference for a remote directory that will be written to.

Use this when you want to create a new directory and write files into it directly without creating a local directory first.

Parameter	Type	Description
`dir_name`	`Optional[str]`	Optional name for the remote directory. If not set, a generated name will be used.
`hash`	`Optional[str]`	Optional precomputed hash value to use for cache key computation when this Dir is used as an input to discoverable tasks.

Returns: A new Dir instance with a generated remote path.

pre_init()

        
    
def pre_init(
    data,
)

Internal: Pydantic validator to set default name from path. Not intended for direct use.

Parameter	Type	Description
`data`

schema_match()

        
    
def schema_match(
    incoming: dict,
)

Internal: Check if incoming schema matches Dir schema. Not intended for direct use.

Parameter	Type	Description
`incoming`	`dict`

walk()

        
    
def walk(
    recursive: bool,
    max_depth: Optional[int],
) -> AsyncIterator[File[T]]

Asynchronously walk through the directory and yield File objects.

Use this to iterate through all files in a directory. Each yielded File can be read directly without downloading.

Example (Async - Recursive):

        
    
@env.task
async def list_all_files(d: Dir) -> list[str]:
    file_names = []
    async for file in d.walk(recursive=True):
        file_names.append(file.name)
    return file_names

Example (Async - Non-recursive):

        
    
@env.task
async def list_top_level_files(d: Dir) -> list[str]:
    file_names = []
    async for file in d.walk(recursive=False):
        file_names.append(file.name)
    return file_names

Example (Async - With max depth):

        
    
@env.task
async def list_files_max_depth(d: Dir) -> list[str]:
    file_names = []
    async for file in d.walk(recursive=True, max_depth=2):
        file_names.append(file.name)
    return file_names

Yields: File objects for each file found in the directory

Parameter	Type	Description
`recursive`	`bool`	If True, recursively walk subdirectories. If False, only list files in the top-level directory.
`max_depth`	`Optional[int]`	Maximum depth for recursive walking. If None, walk through all subdirectories.

walk_sync()

        
    
def walk_sync(
    recursive: bool,
    file_pattern: str,
    max_depth: Optional[int],
) -> Iterator[File[T]]

Synchronously walk through the directory and yield File objects.

Use this in non-async tasks to iterate through all files in a directory.

Example (Sync - Recursive):

        
    
@env.task
def list_all_files_sync(d: Dir) -> list[str]:
    file_names = []
    for file in d.walk_sync(recursive=True):
        file_names.append(file.name)
    return file_names

Example (Sync - With file pattern):

        
    
@env.task
def list_text_files(d: Dir) -> list[str]:
    file_names = []
    for file in d.walk_sync(recursive=True, file_pattern="*.txt"):
        file_names.append(file.name)
    return file_names

Example (Sync - Non-recursive with max depth):

        
    
@env.task
def list_files_limited(d: Dir) -> list[str]:
    file_names = []
    for file in d.walk_sync(recursive=True, max_depth=2):
        file_names.append(file.name)
    return file_names

Yields: File objects for each file found in the directory

Parameter	Type	Description
`recursive`	`bool`	If True, recursively walk subdirectories. If False, only list files in the top-level directory.
`file_pattern`	`str`	Glob pattern to filter files (e.g., “.txt”, “.csv”). Default is “*” (all files).
`max_depth`	`Optional[int]`	Maximum depth for recursive walking. If None, walk through all subdirectories.