Source code for fsspec.asyn

import asyncio
import asyncio.events
import functools
import inspect
import io
import numbers
import os
import re
import threading
from contextlib import contextmanager
from glob import has_magic
from typing import TYPE_CHECKING, Iterable

from .callbacks import DEFAULT_CALLBACK
from .exceptions import FSTimeoutError
from .implementations.local import LocalFileSystem, make_path_posix, trailing_sep
from .spec import AbstractBufferedFile, AbstractFileSystem
from .utils import glob_translate, is_exception, other_paths

private = re.compile("_[^_]")
iothread = [None]  # dedicated fsspec IO thread
loop = [None]  # global event loop for any non-async instance
_lock = None  # global lock placeholder
get_running_loop = asyncio.get_running_loop


def get_lock():
    """Allocate or return a threading lock.

    The lock is allocated on first use to allow setting one lock per forked process.
    """
    global _lock
    if not _lock:
        _lock = threading.Lock()
    return _lock


def reset_lock():
    """Reset the global lock.

    This should be called only on the init of a forked process to reset the lock to
    None, enabling the new forked process to get a new lock.
    """
    global _lock

    iothread[0] = None
    loop[0] = None
    _lock = None


async def _runner(event, coro, result, timeout=None):
    timeout = timeout if timeout else None  # convert 0 or 0.0 to None
    if timeout is not None:
        coro = asyncio.wait_for(coro, timeout=timeout)
    try:
        result[0] = await coro
    except Exception as ex:
        result[0] = ex
    finally:
        event.set()


[docs]def sync(loop, func, *args, timeout=None, **kwargs): """ Make loop run coroutine until it returns. Runs in other thread Examples -------- >>> fsspec.asyn.sync(fsspec.asyn.get_loop(), func, *args, timeout=timeout, **kwargs) """ timeout = timeout if timeout else None # convert 0 or 0.0 to None # NB: if the loop is not running *yet*, it is OK to submit work # and we will wait for it if loop is None or loop.is_closed(): raise RuntimeError("Loop is not running") try: loop0 = asyncio.events.get_running_loop() if loop0 is loop: raise NotImplementedError("Calling sync() from within a running loop") except NotImplementedError: raise except RuntimeError: pass coro = func(*args, **kwargs) result = [None] event = threading.Event() asyncio.run_coroutine_threadsafe(_runner(event, coro, result, timeout), loop) while True: # this loops allows thread to get interrupted if event.wait(1): break if timeout is not None: timeout -= 1 if timeout < 0: raise FSTimeoutError return_result = result[0] if isinstance(return_result, asyncio.TimeoutError): # suppress asyncio.TimeoutError, raise FSTimeoutError raise FSTimeoutError from return_result elif isinstance(return_result, BaseException): raise return_result else: return return_result
[docs]def sync_wrapper(func, obj=None): """Given a function, make so can be called in blocking contexts Leave obj=None if defining within a class. Pass the instance if attaching as an attribute of the instance. """ @functools.wraps(func) def wrapper(*args, **kwargs): self = obj or args[0] return sync(self.loop, func, *args, **kwargs) return wrapper
@contextmanager def _selector_policy(): original_policy = asyncio.get_event_loop_policy() try: if os.name == "nt" and hasattr(asyncio, "WindowsSelectorEventLoopPolicy"): asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy()) yield finally: asyncio.set_event_loop_policy(original_policy)
[docs]def get_loop(): """Create or return the default fsspec IO loop The loop will be running on a separate thread. """ if loop[0] is None: with get_lock(): # repeat the check just in case the loop got filled between the # previous two calls from another thread if loop[0] is None: with _selector_policy(): loop[0] = asyncio.new_event_loop() th = threading.Thread(target=loop[0].run_forever, name="fsspecIO") th.daemon = True th.start() iothread[0] = th return loop[0]
if TYPE_CHECKING: import resource ResourceError = resource.error else: try: import resource except ImportError: resource = None ResourceError = OSError else: ResourceError = getattr(resource, "error", OSError) _DEFAULT_BATCH_SIZE = 128 _NOFILES_DEFAULT_BATCH_SIZE = 1280 def _get_batch_size(nofiles=False): from fsspec.config import conf if nofiles: if "nofiles_gather_batch_size" in conf: return conf["nofiles_gather_batch_size"] else: if "gather_batch_size" in conf: return conf["gather_batch_size"] if nofiles: return _NOFILES_DEFAULT_BATCH_SIZE if resource is None: return _DEFAULT_BATCH_SIZE try: soft_limit, _ = resource.getrlimit(resource.RLIMIT_NOFILE) except (ImportError, ValueError, ResourceError): return _DEFAULT_BATCH_SIZE if soft_limit == resource.RLIM_INFINITY: return -1 else: return soft_limit // 8 def running_async() -> bool: """Being executed by an event loop?""" try: asyncio.get_running_loop() return True except RuntimeError: return False async def _run_coros_in_chunks( coros, batch_size=None, callback=DEFAULT_CALLBACK, timeout=None, return_exceptions=False, nofiles=False, ): """Run the given coroutines in chunks. Parameters ---------- coros: list of coroutines to run batch_size: int or None Number of coroutines to submit/wait on simultaneously. If -1, then it will not be any throttling. If None, it will be inferred from _get_batch_size() callback: fsspec.callbacks.Callback instance Gets a relative_update when each coroutine completes timeout: number or None If given, each coroutine times out after this time. Note that, since there are multiple batches, the total run time of this function will in general be longer return_exceptions: bool Same meaning as in asyncio.gather nofiles: bool If inferring the batch_size, does this operation involve local files? If yes, you normally expect smaller batches. """ if batch_size is None: batch_size = _get_batch_size(nofiles=nofiles) if batch_size == -1: batch_size = len(coros) assert batch_size > 0 async def _run_coro(coro, i): try: return await asyncio.wait_for(coro, timeout=timeout), i except Exception as e: if not return_exceptions: raise return e, i finally: callback.relative_update(1) i = 0 n = len(coros) results = [None] * n pending = set() while pending or i < n: while len(pending) < batch_size and i < n: pending.add(asyncio.ensure_future(_run_coro(coros[i], i))) i += 1 if not pending: break done, pending = await asyncio.wait(pending, return_when=asyncio.FIRST_COMPLETED) while done: result, k = await done.pop() results[k] = result return results # these methods should be implemented as async by any async-able backend async_methods = [ "_ls", "_cat_file", "_get_file", "_put_file", "_rm_file", "_cp_file", "_pipe_file", "_expand_path", "_info", "_isfile", "_isdir", "_exists", "_walk", "_glob", "_find", "_du", "_size", "_mkdir", "_makedirs", ]
[docs]class AsyncFileSystem(AbstractFileSystem): """Async file operations, default implementations Passes bulk operations to asyncio.gather for concurrent operation. Implementations that have concurrent batch operations and/or async methods should inherit from this class instead of AbstractFileSystem. Docstrings are copied from the un-underscored method in AbstractFileSystem, if not given. """ # note that methods do not have docstring here; they will be copied # for _* methods and inferred for overridden methods. async_impl = True mirror_sync_methods = True disable_throttling = False def __init__(self, *args, asynchronous=False, loop=None, batch_size=None, **kwargs): self.asynchronous = asynchronous self._pid = os.getpid() if not asynchronous: self._loop = loop or get_loop() else: self._loop = None self.batch_size = batch_size super().__init__(*args, **kwargs) @property def loop(self): if self._pid != os.getpid(): raise RuntimeError("This class is not fork-safe") return self._loop async def _rm_file(self, path, **kwargs): raise NotImplementedError async def _rm(self, path, recursive=False, batch_size=None, **kwargs): # TODO: implement on_error batch_size = batch_size or self.batch_size path = await self._expand_path(path, recursive=recursive) return await _run_coros_in_chunks( [self._rm_file(p, **kwargs) for p in reversed(path)], batch_size=batch_size, nofiles=True, ) async def _cp_file(self, path1, path2, **kwargs): raise NotImplementedError async def _copy( self, path1, path2, recursive=False, on_error=None, maxdepth=None, batch_size=None, **kwargs, ): if on_error is None and recursive: on_error = "ignore" elif on_error is None: on_error = "raise" if isinstance(path1, list) and isinstance(path2, list): # No need to expand paths when both source and destination # are provided as lists paths1 = path1 paths2 = path2 else: source_is_str = isinstance(path1, str) paths1 = await self._expand_path( path1, maxdepth=maxdepth, recursive=recursive ) if source_is_str and (not recursive or maxdepth is not None): # Non-recursive glob does not copy directories paths1 = [ p for p in paths1 if not (trailing_sep(p) or await self._isdir(p)) ] if not paths1: return source_is_file = len(paths1) == 1 dest_is_dir = isinstance(path2, str) and ( trailing_sep(path2) or await self._isdir(path2) ) exists = source_is_str and ( (has_magic(path1) and source_is_file) or (not has_magic(path1) and dest_is_dir and not trailing_sep(path1)) ) paths2 = other_paths( paths1, path2, exists=exists, flatten=not source_is_str, ) batch_size = batch_size or self.batch_size coros = [self._cp_file(p1, p2, **kwargs) for p1, p2 in zip(paths1, paths2)] result = await _run_coros_in_chunks( coros, batch_size=batch_size, return_exceptions=True, nofiles=True ) for ex in filter(is_exception, result): if on_error == "ignore" and isinstance(ex, FileNotFoundError): continue raise ex async def _pipe_file(self, path, value, **kwargs): raise NotImplementedError async def _pipe(self, path, value=None, batch_size=None, **kwargs): if isinstance(path, str): path = {path: value} batch_size = batch_size or self.batch_size return await _run_coros_in_chunks( [self._pipe_file(k, v, **kwargs) for k, v in path.items()], batch_size=batch_size, nofiles=True, ) async def _process_limits(self, url, start, end): """Helper for "Range"-based _cat_file""" size = None suff = False if start is not None and start < 0: # if start is negative and end None, end is the "suffix length" if end is None: end = -start start = "" suff = True else: size = size or (await self._info(url))["size"] start = size + start elif start is None: start = 0 if not suff: if end is not None and end < 0: if start is not None: size = size or (await self._info(url))["size"] end = size + end elif end is None: end = "" if isinstance(end, numbers.Integral): end -= 1 # bytes range is inclusive return f"bytes={start}-{end}" async def _cat_file(self, path, start=None, end=None, **kwargs): raise NotImplementedError async def _cat( self, path, recursive=False, on_error="raise", batch_size=None, **kwargs ): paths = await self._expand_path(path, recursive=recursive) coros = [self._cat_file(path, **kwargs) for path in paths] batch_size = batch_size or self.batch_size out = await _run_coros_in_chunks( coros, batch_size=batch_size, nofiles=True, return_exceptions=True ) if on_error == "raise": ex = next(filter(is_exception, out), False) if ex: raise ex if ( len(paths) > 1 or isinstance(path, list) or paths[0] != self._strip_protocol(path) ): return { k: v for k, v in zip(paths, out) if on_error != "omit" or not is_exception(v) } else: return out[0] async def _cat_ranges( self, paths, starts, ends, max_gap=None, batch_size=None, on_error="return", **kwargs, ): """Get the contents of byte ranges from one or more files Parameters ---------- paths: list A list of of filepaths on this filesystems starts, ends: int or list Bytes limits of the read. If using a single int, the same value will be used to read all the specified files. """ # TODO: on_error if max_gap is not None: # use utils.merge_offset_ranges raise NotImplementedError if not isinstance(paths, list): raise TypeError if not isinstance(starts, Iterable): starts = [starts] * len(paths) if not isinstance(ends, Iterable): ends = [ends] * len(paths) if len(starts) != len(paths) or len(ends) != len(paths): raise ValueError coros = [ self._cat_file(p, start=s, end=e, **kwargs) for p, s, e in zip(paths, starts, ends) ] batch_size = batch_size or self.batch_size return await _run_coros_in_chunks( coros, batch_size=batch_size, nofiles=True, return_exceptions=True ) async def _put_file(self, lpath, rpath, **kwargs): raise NotImplementedError async def _put( self, lpath, rpath, recursive=False, callback=DEFAULT_CALLBACK, batch_size=None, maxdepth=None, **kwargs, ): """Copy file(s) from local. Copies a specific file or tree of files (if recursive=True). If rpath ends with a "/", it will be assumed to be a directory, and target files will go within. The put_file method will be called concurrently on a batch of files. The batch_size option can configure the amount of futures that can be executed at the same time. If it is -1, then all the files will be uploaded concurrently. The default can be set for this instance by passing "batch_size" in the constructor, or for all instances by setting the "gather_batch_size" key in ``fsspec.config.conf``, falling back to 1/8th of the system limit . """ if isinstance(lpath, list) and isinstance(rpath, list): # No need to expand paths when both source and destination # are provided as lists rpaths = rpath lpaths = lpath else: source_is_str = isinstance(lpath, str) if source_is_str: lpath = make_path_posix(lpath) fs = LocalFileSystem() lpaths = fs.expand_path(lpath, recursive=recursive, maxdepth=maxdepth) if source_is_str and (not recursive or maxdepth is not None): # Non-recursive glob does not copy directories lpaths = [p for p in lpaths if not (trailing_sep(p) or fs.isdir(p))] if not lpaths: return source_is_file = len(lpaths) == 1 dest_is_dir = isinstance(rpath, str) and ( trailing_sep(rpath) or await self._isdir(rpath) ) rpath = self._strip_protocol(rpath) exists = source_is_str and ( (has_magic(lpath) and source_is_file) or (not has_magic(lpath) and dest_is_dir and not trailing_sep(lpath)) ) rpaths = other_paths( lpaths, rpath, exists=exists, flatten=not source_is_str, ) is_dir = {l: os.path.isdir(l) for l in lpaths} rdirs = [r for l, r in zip(lpaths, rpaths) if is_dir[l]] file_pairs = [(l, r) for l, r in zip(lpaths, rpaths) if not is_dir[l]] await asyncio.gather(*[self._makedirs(d, exist_ok=True) for d in rdirs]) batch_size = batch_size or self.batch_size coros = [] callback.set_size(len(file_pairs)) for lfile, rfile in file_pairs: put_file = callback.branch_coro(self._put_file) coros.append(put_file(lfile, rfile, **kwargs)) return await _run_coros_in_chunks( coros, batch_size=batch_size, callback=callback ) async def _get_file(self, rpath, lpath, **kwargs): raise NotImplementedError async def _get( self, rpath, lpath, recursive=False, callback=DEFAULT_CALLBACK, maxdepth=None, **kwargs, ): """Copy file(s) to local. Copies a specific file or tree of files (if recursive=True). If lpath ends with a "/", it will be assumed to be a directory, and target files will go within. Can submit a list of paths, which may be glob-patterns and will be expanded. The get_file method will be called concurrently on a batch of files. The batch_size option can configure the amount of futures that can be executed at the same time. If it is -1, then all the files will be uploaded concurrently. The default can be set for this instance by passing "batch_size" in the constructor, or for all instances by setting the "gather_batch_size" key in ``fsspec.config.conf``, falling back to 1/8th of the system limit . """ if isinstance(lpath, list) and isinstance(rpath, list): # No need to expand paths when both source and destination # are provided as lists rpaths = rpath lpaths = lpath else: source_is_str = isinstance(rpath, str) # First check for rpath trailing slash as _strip_protocol removes it. source_not_trailing_sep = source_is_str and not trailing_sep(rpath) rpath = self._strip_protocol(rpath) rpaths = await self._expand_path( rpath, recursive=recursive, maxdepth=maxdepth ) if source_is_str and (not recursive or maxdepth is not None): # Non-recursive glob does not copy directories rpaths = [ p for p in rpaths if not (trailing_sep(p) or await self._isdir(p)) ] if not rpaths: return lpath = make_path_posix(lpath) source_is_file = len(rpaths) == 1 dest_is_dir = isinstance(lpath, str) and ( trailing_sep(lpath) or LocalFileSystem().isdir(lpath) ) exists = source_is_str and ( (has_magic(rpath) and source_is_file) or (not has_magic(rpath) and dest_is_dir and source_not_trailing_sep) ) lpaths = other_paths( rpaths, lpath, exists=exists, flatten=not source_is_str, ) [os.makedirs(os.path.dirname(lp), exist_ok=True) for lp in lpaths] batch_size = kwargs.pop("batch_size", self.batch_size) coros = [] callback.set_size(len(lpaths)) for lpath, rpath in zip(lpaths, rpaths): get_file = callback.branch_coro(self._get_file) coros.append(get_file(rpath, lpath, **kwargs)) return await _run_coros_in_chunks( coros, batch_size=batch_size, callback=callback ) async def _isfile(self, path): try: return (await self._info(path))["type"] == "file" except: # noqa: E722 return False async def _isdir(self, path): try: return (await self._info(path))["type"] == "directory" except OSError: return False async def _size(self, path): return (await self._info(path)).get("size", None) async def _sizes(self, paths, batch_size=None): batch_size = batch_size or self.batch_size return await _run_coros_in_chunks( [self._size(p) for p in paths], batch_size=batch_size ) async def _exists(self, path, **kwargs): try: await self._info(path, **kwargs) return True except FileNotFoundError: return False async def _info(self, path, **kwargs): raise NotImplementedError async def _ls(self, path, detail=True, **kwargs): raise NotImplementedError async def _walk(self, path, maxdepth=None, on_error="omit", **kwargs): if maxdepth is not None and maxdepth < 1: raise ValueError("maxdepth must be at least 1") path = self._strip_protocol(path) full_dirs = {} dirs = {} files = {} detail = kwargs.pop("detail", False) try: listing = await self._ls(path, detail=True, **kwargs) except (FileNotFoundError, OSError) as e: if on_error == "raise": raise elif callable(on_error): on_error(e) if detail: yield path, {}, {} else: yield path, [], [] return for info in listing: # each info name must be at least [path]/part , but here # we check also for names like [path]/part/ pathname = info["name"].rstrip("/") name = pathname.rsplit("/", 1)[-1] if info["type"] == "directory" and pathname != path: # do not include "self" path full_dirs[name] = pathname dirs[name] = info elif pathname == path: # file-like with same name as give path files[""] = info else: files[name] = info if detail: yield path, dirs, files else: yield path, list(dirs), list(files) if maxdepth is not None: maxdepth -= 1 if maxdepth < 1: return for d in dirs: async for _ in self._walk( full_dirs[d], maxdepth=maxdepth, detail=detail, **kwargs ): yield _ async def _glob(self, path, maxdepth=None, **kwargs): if maxdepth is not None and maxdepth < 1: raise ValueError("maxdepth must be at least 1") import re seps = (os.path.sep, os.path.altsep) if os.path.altsep else (os.path.sep,) ends_with_sep = path.endswith(seps) # _strip_protocol strips trailing slash path = self._strip_protocol(path) append_slash_to_dirname = ends_with_sep or path.endswith( tuple(sep + "**" for sep in seps) ) idx_star = path.find("*") if path.find("*") >= 0 else len(path) idx_qmark = path.find("?") if path.find("?") >= 0 else len(path) idx_brace = path.find("[") if path.find("[") >= 0 else len(path) min_idx = min(idx_star, idx_qmark, idx_brace) detail = kwargs.pop("detail", False) if not has_magic(path): if await self._exists(path, **kwargs): if not detail: return [path] else: return {path: await self._info(path, **kwargs)} else: if not detail: return [] # glob of non-existent returns empty else: return {} elif "/" in path[:min_idx]: min_idx = path[:min_idx].rindex("/") root = path[: min_idx + 1] depth = path[min_idx + 1 :].count("/") + 1 else: root = "" depth = path[min_idx + 1 :].count("/") + 1 if "**" in path: if maxdepth is not None: idx_double_stars = path.find("**") depth_double_stars = path[idx_double_stars:].count("/") + 1 depth = depth - depth_double_stars + maxdepth else: depth = None allpaths = await self._find( root, maxdepth=depth, withdirs=True, detail=True, **kwargs ) pattern = glob_translate(path + ("/" if ends_with_sep else "")) pattern = re.compile(pattern) out = { p: info for p, info in sorted(allpaths.items()) if pattern.match( ( p + "/" if append_slash_to_dirname and info["type"] == "directory" else p ) ) } if detail: return out else: return list(out) async def _du(self, path, total=True, maxdepth=None, **kwargs): sizes = {} # async for? for f in await self._find(path, maxdepth=maxdepth, **kwargs): info = await self._info(f) sizes[info["name"]] = info["size"] if total: return sum(sizes.values()) else: return sizes async def _find(self, path, maxdepth=None, withdirs=False, **kwargs): path = self._strip_protocol(path) out = {} detail = kwargs.pop("detail", False) # Add the root directory if withdirs is requested # This is needed for posix glob compliance if withdirs and path != "" and await self._isdir(path): out[path] = await self._info(path) # async for? async for _, dirs, files in self._walk(path, maxdepth, detail=True, **kwargs): if withdirs: files.update(dirs) out.update({info["name"]: info for name, info in files.items()}) if not out and (await self._isfile(path)): # walk works on directories, but find should also return [path] # when path happens to be a file out[path] = {} names = sorted(out) if not detail: return names else: return {name: out[name] for name in names} async def _expand_path(self, path, recursive=False, maxdepth=None): if maxdepth is not None and maxdepth < 1: raise ValueError("maxdepth must be at least 1") if isinstance(path, str): out = await self._expand_path([path], recursive, maxdepth) else: out = set() path = [self._strip_protocol(p) for p in path] for p in path: # can gather here if has_magic(p): bit = set(await self._glob(p, maxdepth=maxdepth)) out |= bit if recursive: # glob call above expanded one depth so if maxdepth is defined # then decrement it in expand_path call below. If it is zero # after decrementing then avoid expand_path call. if maxdepth is not None and maxdepth <= 1: continue out |= set( await self._expand_path( list(bit), recursive=recursive, maxdepth=maxdepth - 1 if maxdepth is not None else None, ) ) continue elif recursive: rec = set(await self._find(p, maxdepth=maxdepth, withdirs=True)) out |= rec if p not in out and (recursive is False or (await self._exists(p))): # should only check once, for the root out.add(p) if not out: raise FileNotFoundError(path) return sorted(out) async def _mkdir(self, path, create_parents=True, **kwargs): pass # not necessary to implement, may not have directories async def _makedirs(self, path, exist_ok=False): pass # not necessary to implement, may not have directories async def open_async(self, path, mode="rb", **kwargs): if "b" not in mode or kwargs.get("compression"): raise ValueError raise NotImplementedError
def mirror_sync_methods(obj): """Populate sync and async methods for obj For each method will create a sync version if the name refers to an async method (coroutine) and there is no override in the child class; will create an async method for the corresponding sync method if there is no implementation. Uses the methods specified in - async_methods: the set that an implementation is expected to provide - default_async_methods: that can be derived from their sync version in AbstractFileSystem - AsyncFileSystem: async-specific default coroutines """ from fsspec import AbstractFileSystem for method in async_methods + dir(AsyncFileSystem): if not method.startswith("_"): continue smethod = method[1:] if private.match(method): isco = inspect.iscoroutinefunction(getattr(obj, method, None)) unsync = getattr(getattr(obj, smethod, False), "__func__", None) is_default = unsync is getattr(AbstractFileSystem, smethod, "") if isco and is_default: mth = sync_wrapper(getattr(obj, method), obj=obj) setattr(obj, smethod, mth) if not mth.__doc__: mth.__doc__ = getattr( getattr(AbstractFileSystem, smethod, None), "__doc__", "" ) class FSSpecCoroutineCancel(Exception): pass def _dump_running_tasks( printout=True, cancel=True, exc=FSSpecCoroutineCancel, with_task=False ): import traceback tasks = [t for t in asyncio.tasks.all_tasks(loop[0]) if not t.done()] if printout: [task.print_stack() for task in tasks] out = [ { "locals": task._coro.cr_frame.f_locals, "file": task._coro.cr_frame.f_code.co_filename, "firstline": task._coro.cr_frame.f_code.co_firstlineno, "linelo": task._coro.cr_frame.f_lineno, "stack": traceback.format_stack(task._coro.cr_frame), "task": task if with_task else None, } for task in tasks ] if cancel: for t in tasks: cbs = t._callbacks t.cancel() asyncio.futures.Future.set_exception(t, exc) asyncio.futures.Future.cancel(t) [cb[0](t) for cb in cbs] # cancels any dependent concurrent.futures try: t._coro.throw(exc) # exits coro, unless explicitly handled except exc: pass return out class AbstractAsyncStreamedFile(AbstractBufferedFile): # no read buffering, and always auto-commit # TODO: readahead might still be useful here, but needs async version async def read(self, length=-1): """ Return data from cache, or fetch pieces as necessary Parameters ---------- length: int (-1) Number of bytes to read; if <0, all remaining bytes. """ length = -1 if length is None else int(length) if self.mode != "rb": raise ValueError("File not in read mode") if length < 0: length = self.size - self.loc if self.closed: raise ValueError("I/O operation on closed file.") if length == 0: # don't even bother calling fetch return b"" out = await self._fetch_range(self.loc, self.loc + length) self.loc += len(out) return out async def write(self, data): """ Write data to buffer. Buffer only sent on flush() or if buffer is greater than or equal to blocksize. Parameters ---------- data: bytes Set of bytes to be written. """ if self.mode not in {"wb", "ab"}: raise ValueError("File not in write mode") if self.closed: raise ValueError("I/O operation on closed file.") if self.forced: raise ValueError("This file has been force-flushed, can only close") out = self.buffer.write(data) self.loc += out if self.buffer.tell() >= self.blocksize: await self.flush() return out async def close(self): """Close file Finalizes writes, discards cache """ if getattr(self, "_unclosable", False): return if self.closed: return if self.mode == "rb": self.cache = None else: if not self.forced: await self.flush(force=True) if self.fs is not None: self.fs.invalidate_cache(self.path) self.fs.invalidate_cache(self.fs._parent(self.path)) self.closed = True async def flush(self, force=False): if self.closed: raise ValueError("Flush on closed file") if force and self.forced: raise ValueError("Force flush cannot be called more than once") if force: self.forced = True if self.mode not in {"wb", "ab"}: # no-op to flush on read-mode return if not force and self.buffer.tell() < self.blocksize: # Defer write on small block return if self.offset is None: # Initialize a multipart upload self.offset = 0 try: await self._initiate_upload() except: # noqa: E722 self.closed = True raise if await self._upload_chunk(final=force) is not False: self.offset += self.buffer.seek(0, 2) self.buffer = io.BytesIO() async def __aenter__(self): return self async def __aexit__(self, exc_type, exc_val, exc_tb): await self.close() async def _fetch_range(self, start, end): raise NotImplementedError async def _initiate_upload(self): pass async def _upload_chunk(self, final=False): raise NotImplementedError