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SessionKeyGenerator

queue_runtime::sessions

Trait SessionKeyGenerator 

Source 
pub trait SessionKeyGenerator: Send + Sync {
    // Required method
    fn generate_key(
        &self,
        extractor: &dyn SessionKeyExtractor,
    ) -> Option<SessionId>;
}
Expand description

Strategy trait for generating session keys from messages.

Implementations define how messages are grouped for ordered processing. The generator extracts relevant metadata from messages and produces session keys that group related messages together.

§Design Principles

  • Domain-Agnostic: Works with any message structure via SessionKeyExtractor
  • Strategy Pattern: Different strategies provide different ordering semantics
  • Composable: Strategies can be combined or chained
  • Optional Ordering: Returning None allows concurrent processing

§Common Patterns

  • Entity-based: Group by entity ID (order-123, user-456)
  • Hierarchical: Group by parent/child relationships
  • Temporal: Group by time windows
  • Custom: Domain-specific grouping logic

§Example

use queue_runtime::sessions::{SessionKeyGenerator, SessionKeyExtractor};
use queue_runtime::message::SessionId;

struct ResourceIdStrategy;

impl SessionKeyGenerator for ResourceIdStrategy {
    fn generate_key(&self, extractor: &dyn SessionKeyExtractor) -> Option<SessionId> {
        extractor.get_metadata("resource_id")
            .and_then(|id| SessionId::new(format!("resource-{}", id)).ok())
    }
}

Required Methods§

Source

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

Generate a session key for the given message.

Returns None if the message should not be session-ordered, allowing it to be processed concurrently without ordering constraints.

§Arguments
  • extractor - Message implementing SessionKeyExtractor trait
§Returns

Optional session ID for grouping related messages

Implementors§