Struct Context 

pub struct Context { /* private fields */ }

Builder describing how to convert an external error into AppError.

The context captures the target AppCode, AppErrorKind, optional metadata fields and redaction policy. It is primarily consumed by ResultExt when promoting Result<T, E> values into AppError.

Examples

use std::io::{Error as IoError, ErrorKind};

use masterror::{AppErrorKind, Context, ResultExt, field};

fn failing_io() -> Result<(), IoError> {
    Err(IoError::from(ErrorKind::Other))
}

let err = failing_io()
    .ctx(|| {
        Context::new(AppErrorKind::Service)
            .with(field::str("operation", "sync"))
            .redact(true)
            .track_caller()
    })
    .unwrap_err();

assert_eq!(err.kind, AppErrorKind::Service);
assert!(err.metadata().get("operation").is_some());

Implementations

impl Context

pub fn new(category: AppErrorKind) -> Self

Create a new Context targeting the provided AppErrorKind.

The initial AppCode defaults to the canonical mapping for the supplied kind. Use Context::code to override it.

pub fn code(self, code: AppCode) -> Self

Override the public AppCode.

Examples

use masterror::{AppCode, AppErrorKind, Context};

let ctx = Context::new(AppErrorKind::Service).code(AppCode::Internal);

pub fn category(self, category: AppErrorKind) -> Self

Update the AppErrorKind.

When the code has not been overridden explicitly, it is kept in sync with the new kind.

Examples

use masterror::{AppErrorKind, Context};

let ctx = Context::new(AppErrorKind::BadRequest).category(AppErrorKind::Service);

pub fn with(self, field: Field) -> Self

Attach a metadata Field.

Examples

use masterror::{AppErrorKind, Context, field};

let ctx = Context::new(AppErrorKind::Service)
    .with(field::str("operation", "sync"))
    .with(field::u64("retry_count", 3));

pub fn redact_field(self, name: &'static str, redaction: FieldRedaction) -> Self

Override the redaction policy for a metadata field.

Examples

use masterror::{AppErrorKind, Context, FieldRedaction, field};

let ctx = Context::new(AppErrorKind::Service)
    .with(field::str("password", "secret"))
    .redact_field("password", FieldRedaction::Redact);

pub fn redact_field_mut( &mut self, name: &'static str, redaction: FieldRedaction, ) -> &mut Self

Override the redaction policy for a metadata field in place.

pub fn redact(self, redact: bool) -> Self

Toggle message redaction policy.

Examples

use masterror::{AppErrorKind, Context};

let ctx = Context::new(AppErrorKind::Service).redact(true);

pub fn track_caller(self) -> Self

Capture caller location and store it as metadata.

Trait Implementations

impl Clone for Context

fn clone(&self) -> Context

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Context

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

Formats the value using the given formatter.