Struct FallbackStrategy 

pub struct FallbackStrategy { /* private fields */ }

Strategy that tries multiple generators in order, using the first success.

This implements a fallback chain: try the primary strategy first, and if it returns None, try the next strategy, and so on. Useful for providing fine-grained ordering when possible, with coarser fallbacks.

Example

use queue_runtime::sessions::{FallbackStrategy, SingleFieldStrategy, CompositeKeyStrategy};

// Try specific entity ID first, fall back to tenant-level ordering
let primary = SingleFieldStrategy::new("entity_id", Some("entity"));
let fallback = SingleFieldStrategy::new("tenant_id", Some("tenant"));

let strategy = FallbackStrategy::new(vec![
    Box::new(primary),
    Box::new(fallback),
]);

Implementations

impl FallbackStrategy

pub fn new(strategies: Vec<Box<dyn SessionKeyGenerator>>) -> Self

Create a new fallback strategy with ordered generators.

Arguments

• strategies - Ordered list of generators to try

Example

use queue_runtime::sessions::{FallbackStrategy, SingleFieldStrategy, NoOrderingStrategy};

let strategy = FallbackStrategy::new(vec![
    Box::new(SingleFieldStrategy::new("user_id", Some("user"))),
    Box::new(NoOrderingStrategy), // Ultimate fallback: no ordering
]);

Trait Implementations

impl SessionKeyGenerator for FallbackStrategy

fn generate_key(&self, extractor: &dyn SessionKeyExtractor) -> Option<SessionId>

Generate a session key for the given message.