nebius.aio.token.token.Receiver

class documentation

class Receiver(ABC): (source)

Known subclasses: nebius.aio.token.exchangeable.Receiver, nebius.aio.token.federation_bearer.Receiver, nebius.aio.token.file.Receiver, nebius.aio.token.file_cache.async_renewable_bearer.AsynchronousRenewableFileCacheReceiver, nebius.aio.token.file_cache.file_bearer.PureFileCacheReceiver, nebius.aio.token.file_cache.renewable_bearer.RenewableFileCacheReceiver, nebius.aio.token.renewable.Receiver, nebius.aio.token.static.Receiver

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Abstract asynchronous token receiver interface.

Implementations fetch bearer tokens from an external source (for example an OAuth token endpoint or a local cache) and expose a small API that the request layer uses to obtain tokens for per-request authentication.

The receiver is responsible for fetching and refreshing the token for one request only, reflecting the authentication process, while the Bearer class supports multiple requests and provides per-request receivers on demand.

Method	`can_retry`	Decide whether a failed authentication attempt should be retried.
Async Method	`fetch`	Fetch a token and record it as the latest value.
Property	`latest`	Return the latest fetched token or `None`.
Async Method	`_fetch`	Low-level asynchronous fetch implementation.
Instance Variable	`_latest`	The most recently fetched token, or `None` if no token has been fetched yet. Implementations may update this to support inspection or caching by callers.

@abstractmethod
def can_retry(self, err: Exception, options: dict[str, str] | None = None) -> bool: (source) ¶

overridden in nebius.aio.token.exchangeable.Receiver, nebius.aio.token.federation_bearer.Receiver, nebius.aio.token.file.Receiver, nebius.aio.token.file_cache.async_renewable_bearer.AsynchronousRenewableFileCacheReceiver, nebius.aio.token.file_cache.file_bearer.PureFileCacheReceiver, nebius.aio.token.file_cache.renewable_bearer.RenewableFileCacheReceiver, nebius.aio.token.renewable.Receiver, nebius.aio.token.static.Receiver

Decide whether a failed authentication attempt should be retried.

Implementations inspect err (for example gRPC status codes or specific exception types) and optional options to decide whether a fresh call to fetch is likely to succeed (for example after refreshing credentials).

Default implementations should return False.

Parameters
err:`Exception`	The exception that triggered the retry decision.
options:`dict[str, str]` or `None`	Optional implementation-specific options.
Returns
`bool`	`True` when a retry is advisable, otherwise `False`.

async def fetch(self, timeout: float | None = None, options: dict[str, str] | None = None) -> Token: (source) ¶

Fetch a token and record it as the latest value.

This method calls the concrete _fetch implementation and stores the result on _latest before returning it.

Parameters
timeout:optional `float`	Optional timeout in seconds forwarded to the fetch.
options:optional `dict[str, str]`	Optional implementation-specific options.
Returns
`Token`	The fetched `Token`.

@property
latest: Token or None = (source) ¶

Return the latest fetched token or None.

@abstractmethod
async def _fetch(self, timeout: float | None = None, options: dict[str, str] | None = None) -> Token: (source) ¶

Low-level asynchronous fetch implementation.

Subclasses must implement this method to perform the actual token retrieval. This method is intentionally prefixed with an underscore to indicate it is the minimal primitive; callers should use fetch which records the result in _latest.

Parameters
timeout:optional `float`	Optional timeout in seconds for the fetch operation.
options:optional `dict[str, str]`	Optional implementation-specific options forwarded by the request layer.
Returns
`Token`	A freshly fetched `Token`.

_latest: Token | None = (source) ¶

overridden in nebius.aio.token.static.Receiver

The most recently fetched token, or None if no token has been fetched yet. Implementations may update this to support inspection or caching by callers.