Enum Error 

#[non_exhaustive]
pub enum Error {
    Io(Error),
    Json(Error),
    Utf8(Utf8Error),
    Decode {
        key: String,
        message: String,
    },
    Encode {
        key: String,
        message: String,
    },
    MissingKey {
        wanted: Vec<String>,
        available: Vec<String>,
    },
    DuplicateKey {
        key: String,
        sample_key: String,
    },
    Security(String),
    Subprocess(String),
    Format(String),
    Unsupported(String),
    Value(String),
    Empty(String),
    Context {
        context: String,
        source: Box<Error>,
    },
}

The error type used throughout the webdataset crates.

Errors carry enough context to be reported usefully by the pluggable Handler implementations: the URL of the shard and the key of the sample are attached as they travel up the pipeline.

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.

Io(Error)

Available on crate feature std only.

An underlying I/O failure.

Json(Error)

Available on crate feature json only.

A JSON value could not be parsed or serialized.

Utf8(Utf8Error)

Bytes that were expected to be UTF-8 were not.

Decode

A sample field could not be decoded.

Fields

key: String

The field (file extension) that failed to decode.

message: String

A human readable description of the failure.

Encode

A sample field could not be encoded for writing.

Fields

key: String

The field that failed to encode.

message: String

A human readable description of the failure.

MissingKey

A required key was not present in a sample.

Fields

wanted: Vec<String>

The key(s) that were looked up.

available: Vec<String>

The keys the sample actually had.

DuplicateKey

The same key occurred twice while grouping files into a sample.

Fields

key: String

The duplicated field name.

sample_key: String

The key of the sample being assembled.

Security(String)

An operation was refused because secure mode is enabled.

Subprocess(String)

A subprocess used to open a URL failed.

Format(String)

Malformed input data (bad archive, bad header, bad brace expression).

Unsupported(String)

The requested functionality is not available in this build.

Value(String)

A value had the right shape but the wrong contents.

Empty(String)

A pipeline stage that was declared non-empty produced no data.

Context

An error with additional context attached.

Fields

context: String

What was being attempted.

source: Box<Error>

The underlying error.

Implementations

impl Error

pub fn format(message: impl Display) -> Self

Build an Error::Format from anything printable.

pub fn value(message: impl Display) -> Self

Build an Error::Value from anything printable.

pub fn unsupported(message: impl Display) -> Self

Build an Error::Unsupported from anything printable.

pub fn decode(key: impl Into<String>, message: impl Display) -> Self

Build an Error::Decode for the given field.

pub fn encode(key: impl Into<String>, message: impl Display) -> Self

Build an Error::Encode for the given field.

pub fn context(self, context: impl Display) -> Self

Attach context to an error, mirroring the way the Python implementation appends the offending URL to exn.args.

Trait Implementations

impl Debug for Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Error for Error

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 Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Utf8Error> for Error

fn from(source: Utf8Error) -> Self

Converts to this type from the input type.