Enum FailureStrategy 

pub enum FailureStrategy {
    Fatal,
    Skip,
    Retry,
}

Strategy for handling event processing failures.

When a projector’s apply() method returns an error, the on_error() callback determines how the projection runner should respond. This enum represents the available failure strategies.

Variants

• Fatal: Stop processing immediately and return the error
• Skip: Log the error and continue processing the next event
• Retry: Attempt to reprocess the event according to retry configuration

Example

fn on_error(
    &mut self,
    ctx: FailureContext<Self::Error>,
) -> FailureStrategy {
    match ctx.error {
        MyError::Transient(_) if ctx.retry_count < 3 => FailureStrategy::Retry,
        MyError::PoisonEvent(_) => FailureStrategy::Skip,
        _ => FailureStrategy::Fatal,
    }
}

Variants

Fatal

Stop processing immediately and return the error to the caller.

Use this when:

• The error is unrecoverable (e.g., database schema mismatch)
• The projector requires manual intervention
• Continuing would corrupt the read model

Skip

Skip this event and continue processing the next one.

Use this when:

• The event is malformed or invalid (poison event)
• Processing this event is not critical
• Continuing without this event is acceptable

Retry

Retry processing this event according to retry configuration.

Use this when:

• The error is likely transient (e.g., network timeout)
• Retrying might succeed
• The event is important and should not be skipped

Trait Implementations

impl Clone for FailureStrategy

fn clone(&self) -> FailureStrategy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FailureStrategy

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

Formats the value using the given formatter.

impl PartialEq for FailureStrategy

fn eq(&self, other: &FailureStrategy) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for FailureStrategy

impl Eq for FailureStrategy

impl StructuralPartialEq for FailureStrategy