| try: |
| from urllib.parse import urlparse, urlunparse |
| except ImportError: |
| raise ImportError( |
| "urllib cannot be found, urlparse from python2 is no longer supported." |
| ) |
| |
| import numbers |
| import os |
| import sys |
| from datetime import timedelta |
| from typing import Dict, Optional |
| |
| import torch._six as six |
| from torch.distributed import FileStore, PrefixStore, Store, TCPStore |
| |
| from .constants import default_pg_timeout |
| |
| |
| _rendezvous_handlers = {} |
| |
| |
| def register_rendezvous_handler(scheme, handler): |
| """Registers a new rendezvous handler. |
| |
| Before we can run collective algorithms, participating processes |
| need to find each other and exchange information to be able to |
| communicate. We call this process rendezvous. |
| |
| The outcome of the rendezvous process is a triplet containing a |
| shared key/value store, the rank of the process, and the total |
| number of participating processes. |
| |
| If none of the bundled rendezvous methods apply to your execution |
| environment you can opt to register your own rendezvous handler. |
| Pick a unique name and use the URL scheme to identify it when |
| calling the `rendezvous()` function. |
| |
| Args: |
| scheme (str): URL scheme to identify your rendezvous handler. |
| handler (function): Handler that is invoked when the |
| `rendezvous()` function is called with a URL that uses |
| the corresponding scheme. It must be a generator function |
| that yields the triplet. |
| """ |
| global _rendezvous_handlers |
| if scheme in _rendezvous_handlers: |
| raise RuntimeError( |
| "Rendezvous handler for {}:// already registered".format(scheme) |
| ) |
| _rendezvous_handlers[scheme] = handler |
| |
| |
| # Query will have format "rank=0&world_size=1" and is |
| # converted into {"rank": 0, "world_size": 1} |
| def _query_to_dict(query: str) -> Dict[str, str]: |
| return dict((pair[0], pair[1]) for pair in (pair.split("=") for pair in filter(None, query.split("&")))) |
| |
| |
| def _rendezvous_helper(url: str, rank: int, world_size_opt: Optional[int], **kwargs): |
| result = urlparse(url) |
| if world_size_opt is None: |
| world_size = -1 |
| if result.scheme == "env": |
| rank = int(os.environ.get("RANK", rank)) |
| # If the world_size env variable is not present then it is a dynamic group |
| world_size = int(os.environ.get("WORLD_SIZE", world_size)) |
| else: |
| world_size = world_size_opt |
| if rank != -1 or world_size != -1 or world_size_opt is None: |
| query_dict = _query_to_dict(result.query) |
| assert ( |
| "rank" not in query_dict and "world_size" not in query_dict |
| ), "The url: {url} has node-specific arguments(rank, world_size) already.".format( |
| url=url |
| ) |
| if rank != -1: |
| query_dict["rank"] = str(rank) |
| if world_size != -1 or world_size_opt is None: |
| query_dict["world_size"] = str(world_size) |
| result = result._replace( |
| query="{}".format( |
| "&".join(["{}={}".format(k, v) for k, v in query_dict.items()]) |
| ) |
| ) |
| url = urlunparse(result) |
| |
| if result.scheme not in _rendezvous_handlers: |
| raise RuntimeError("No rendezvous handler for {}://".format(result.scheme)) |
| return _rendezvous_handlers[result.scheme](url, **kwargs) |
| |
| |
| def rendezvous(url: str, rank: int = -1, world_size: int = -1, **kwargs): |
| if not isinstance(url, six.string_classes): |
| raise RuntimeError("`url` must be a string. {}: {}".format(type(url), url)) |
| |
| if not isinstance(rank, numbers.Integral): |
| raise RuntimeError("`rank` must be an integer. {}".format(rank)) |
| |
| if not isinstance(world_size, numbers.Integral): |
| raise RuntimeError("`world_size` must be an integer. {}".format(world_size)) |
| |
| return _rendezvous_helper(url, rank, world_size, **kwargs) |
| |
| |
| def _create_store_from_options(backend_options, rank): |
| store, _, _ = next(_rendezvous_helper(backend_options.init_method, rank, None)) |
| return store |
| |
| |
| def _rendezvous_error(msg): |
| return ValueError("Error initializing torch.distributed using " + msg) |
| |
| |
| def _file_rendezvous_handler(url: str, **kwargs): |
| def _error(msg): |
| return _rendezvous_error("file:// rendezvous: " + msg) |
| |
| result = urlparse(url) |
| path = result.path |
| if sys.platform == "win32": |
| import urllib.request |
| |
| full_path = result.netloc + result.path |
| path = urllib.request.url2pathname(full_path) |
| if path: |
| # Normalizing an empty string produces ".", which is not expected. |
| path = os.path.normpath(path) |
| |
| if not path: |
| raise _error("path missing") |
| query_dict = _query_to_dict(result.query) |
| if "rank" not in query_dict: |
| raise _error("rank parameter missing") |
| if "world_size" not in query_dict: |
| raise _error("world size parameter missing") |
| |
| rank = int(query_dict["rank"]) |
| world_size = int(query_dict["world_size"]) |
| store = FileStore(path, world_size) |
| yield (store, rank, world_size) |
| |
| # If this configuration is invalidated, there is nothing we can do about it |
| raise RuntimeError("Unable to perform rerendezvous using file:// method") |
| |
| |
| def _torchelastic_use_agent_store() -> bool: |
| return os.environ.get("TORCHELASTIC_USE_AGENT_STORE", None) == str(True) |
| |
| |
| def _create_c10d_store(hostname, port, rank, world_size, timeout) -> Store: |
| """ |
| Smartly creates a c10d Store object on ``rank`` based on whether |
| we need to re-use agent store. The TCPStore server is assumed to be hosted |
| on ``hostname:port``. |
| |
| If ``torchelastic_use_agent_store()`` is ``True``, then it is assumed that |
| the agent leader (node rank 0) hosts the TCPStore server (for which the |
| endpoint is specified by the given ``hostname:port``). Hence |
| ALL ranks will create and return a TCPStore client (e.g. ``start_daemon=False``). |
| |
| If ``torchelastic_use_agent_store()`` is ``False``, then rank 0 will host |
| the TCPStore (with multi-tenancy) and it is assumed that rank 0's hostname |
| and port are correctly passed via ``hostname`` and ``port``. All |
| non-zero ranks will create and return a TCPStore client. |
| """ |
| # check if port is uint16_t |
| if not 0 <= port < 2**16: |
| raise ValueError(f"port must have value from 0 to 65535 but was {port}.") |
| |
| if _torchelastic_use_agent_store(): |
| attempt = os.environ["TORCHELASTIC_RESTART_COUNT"] |
| tcp_store = TCPStore(hostname, port, world_size, False, timeout) |
| return PrefixStore(f"/worker/attempt_{attempt}", tcp_store) |
| else: |
| start_daemon = rank == 0 |
| return TCPStore( |
| hostname, port, world_size, start_daemon, timeout, multi_tenant=True |
| ) |
| |
| |
| def _tcp_rendezvous_handler( |
| url: str, timeout: timedelta = default_pg_timeout, **kwargs |
| ): |
| def _error(msg): |
| return _rendezvous_error("tcp:// rendezvous: " + msg) |
| |
| result = urlparse(url) |
| if not result.port: |
| raise _error("port number missing") |
| query_dict = _query_to_dict(result.query) |
| if "rank" not in query_dict: |
| raise _error("rank parameter missing") |
| if "world_size" not in query_dict: |
| raise _error("world size parameter missing") |
| |
| rank = int(query_dict["rank"]) |
| world_size = int(query_dict["world_size"]) |
| assert result.hostname is not None |
| |
| store = _create_c10d_store(result.hostname, result.port, rank, world_size, timeout) |
| |
| yield (store, rank, world_size) |
| |
| # If this configuration is invalidated, there is nothing we can do about it |
| raise RuntimeError("Unable to perform re-rendezvous using tcp:// method") |
| |
| |
| def _env_rendezvous_handler( |
| url: str, timeout: timedelta = default_pg_timeout, **kwargs |
| ): |
| def _error(msg): |
| return _rendezvous_error("env:// rendezvous: " + msg) |
| |
| def _env_error(var): |
| return _error("environment variable %s expected, but not set" % var) |
| |
| def _get_env_or_raise(env_var: str) -> str: |
| env_val = os.environ.get(env_var, None) |
| if not env_val: |
| raise _env_error(env_var) |
| else: |
| return env_val |
| |
| result = urlparse(url) |
| query_dict = _query_to_dict(result.query) |
| |
| rank: int |
| world_size: int |
| master_port: int |
| master_addr: str |
| |
| if "rank" in query_dict: |
| rank = int(query_dict["rank"]) |
| else: |
| rank = int(_get_env_or_raise("RANK")) |
| |
| if "world_size" in query_dict: |
| world_size = int(query_dict["world_size"]) |
| else: |
| world_size = int(_get_env_or_raise("WORLD_SIZE")) |
| |
| master_addr = _get_env_or_raise("MASTER_ADDR") |
| master_port = int(_get_env_or_raise("MASTER_PORT")) |
| |
| store = _create_c10d_store(master_addr, master_port, rank, world_size, timeout) |
| |
| yield (store, rank, world_size) |
| |
| # If this configuration is invalidated, there is nothing we can do about it |
| raise RuntimeError("Unable to perform re-rendezvous using env:// method") |
| |
| |
| register_rendezvous_handler("tcp", _tcp_rendezvous_handler) |
| register_rendezvous_handler("env", _env_rendezvous_handler) |
| register_rendezvous_handler("file", _file_rendezvous_handler) |