Struct FnError 

pub struct FnError {
    pub code: u32,
    pub message: String,
    pub retryable: bool,
}

Per-invocation error returned by a plugin’s work function.

FnError is what crosses the host↔plugin boundary on every call. The host wraps it into the user-facing error chain. WASM plugins return this shape over the WIT fn-error record.

Fields

code: u32

Plugin-defined error code. Reserved range 0..=0xFF for framework errors; plugins use 0x100..=u32::MAX.

message: String

Human-readable error message.

retryable: bool

Whether the caller should retry the operation (e.g., transient network failure).

Implementations

impl FnError

pub const CODE_UNKNOWN_FUNCTION: u32 = 0x01

Framework-reserved code for “unknown function name at dispatch site”.

pub const CODE_TYPE_COERCION: u32 = 0x02

Framework-reserved code for “type-coercion failure on input column”.

pub const CODE_UNEXPECTED_NULL: u32 = 0x03

Framework-reserved code for “null encountered where forbidden”.

pub const CODE_RESOURCE_LIMIT: u32 = 0x04

Framework-reserved code for “resource limit exceeded”.

pub const CODE_FORBIDDEN: u32 = 0x05

Framework-reserved code for “plugin attempted forbidden side effect”.

pub fn new(code: u32, message: impl Into<String>) -> Self

Build an FnError with the given code and message; not retryable.

pub fn retryable(code: u32, message: impl Into<String>) -> Self

Build a retryable FnError.

pub fn unknown_function(name: impl AsRef<str>) -> Self

Convenience constructor for “unknown function” errors.

Trait Implementations

impl Clone for FnError

fn clone(&self) -> FnError

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FnError

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

Formats the value using the given formatter.

impl Display for FnError

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

Formats the value using the given formatter.

impl Error for FnError

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.