Enum FetcherError 

#[non_exhaustive]
pub enum FetcherError {
    ExhaustedRetries {
        attempts: u32,
        source: Error,
    },
    TooLarge {
        limit_bytes: usize,
        advertised_bytes: Option<u64>,
    },
    BodyRead(Error),
    Http(Error),
}

Errors from building a Fetcher or performing a request.

Variants are typed (rather than stringified) so callers can build retry policies: a timeout or connect failure is worth retrying, a body-size violation is not. Marked #[non_exhaustive] so future variants are not a breaking change — match with a wildcard arm.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

ExhaustedRetries

Every send attempt failed at the transport level (DNS, connect, TLS, timeout, …). source is the LAST attempt’s error; classify it with FetcherError::is_timeout / FetcherError::is_connect or inspect the reqwest::Error directly.

Fields

attempts: u32

Total attempts made (initial try + retries).

source: Error

The last attempt’s transport error.

TooLarge

The response body exceeded the configured size cap (FetcherConfig::max_body_bytes). Not retried — the same URL will exceed the cap again.

Fields

limit_bytes: usize

The configured cap.

advertised_bytes: Option<u64>

The server-advertised Content-Length, when the violation was detected up front; None when the cap was hit mid-stream.

BodyRead(Error)

A body chunk could not be read after the response headers arrived.

Http(Error)

The underlying reqwest client failed to build (e.g. TLS backend initialization).

Implementations

impl FetcherError

pub fn transport_error(&self) -> Option<&Error>

The underlying transport error, when this error wraps one. FetcherError::Http is excluded: it reports a client-BUILD failure (e.g. TLS backend init), not something that happened on the wire.

pub fn is_timeout(&self) -> bool

Whether the underlying failure was a timeout (worth retrying).

pub fn is_connect(&self) -> bool

Whether the underlying failure was a connection failure (DNS, refused, unreachable — often worth retrying or rotating a proxy).

Trait Implementations

impl Debug for FetcherError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for FetcherError

fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for FetcherError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl From<Error> for FetcherError

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<FetcherError> for SessionError

fn from(source: FetcherError) -> Self

Converts to this type from the input type.