Pluggable Mediation Strategies

• ID: runtime.mediation-strategies
• Name: Pluggable mediation strategies
• Maturity: GA
• Summary: Defines strategy contracts and default single-main-handler task and stream strategies.

What It Does

Strategies implementing IMessageMediationStrategy<TMessage,TResult> control pre, main, post, and error handler execution. Runtime ships single-main-handler strategies for Task, Task<T>, and IAsyncEnumerable<T>.

Public Surface

Packages

• LiteBus.Messaging
• LiteBus.Messaging.Abstractions

Requires

• runtime.handler-descriptors
• runtime.message-registry

Invariants

• Direct main handlers are preferred over indirect handlers.
• Zero or multiple main handlers fail with explicit exceptions.
• Recoverable exceptions invoke error handlers.

Non-Goals

• Built-in parallel multi-main-handler strategies.

Observability

No dedicated strategy telemetry.

Test Coverage

Covered Use Cases

MediationCorrectnessTests.Send_Command_ShouldRetainAmbientScopeUntilHandlerContinuationCompletes

• Test kind: Unit
• Expected outcome: strategy preserves ambient execution semantics

PostHandlerResultOverrideTests.Send_CommandWithMultiplePostHandlers_LastWriteWins

• Test kind: Unit
• Expected outcome: post-handler override semantics are respected

MediationScopeRetentionTests.Mediate_stream_result_retains_dispatch_scope_until_enumeration_completes

• Test kind: Unit
• Expected outcome: stream strategy retains scope through enumeration

Untested Use Cases

Out-of-Scope Use Cases

• Parallel fan-out strategy implementation in core runtime package.