Migrate mediation from MediatR to Medino by mikaelweave · Pull Request #5616 · microsoft/fhir-server

mikaelweave · 2026-06-17T00:21:22Z

Summary

Migrates in-repo mediation usage from MediatR to Medino 3.0.3, including package references, DI registration, request/notification call sites, handlers, pipeline behaviors, validator behaviors, and exception actions.
Removes redundant non-generic IRequest markers and updates Medino-specific tests/mocks.
Includes the approved .NET 10 + Medino planning artifacts that split the overall effort into PR 1 (this Medino migration) and PR 2 (.NET 10 upgrade).

Validation

dotnet build Microsoft.Health.Fhir.sln -c Release --no-restore --nologo — passed, 0 warnings, 0 errors.
dotnet test src\Microsoft.Health.Fhir.Core.UnitTests\Microsoft.Health.Fhir.Core.UnitTests.csproj -c Release -f net9.0 --no-build --nologo -- --filter "FullyQualifiedName~Validation" --report-trx — passed, 9/9.
Child-session project-by-project unit verification passed 18/19 unit projects on both net9.0 and net8.0; Microsoft.Health.Fhir.Azure.UnitTests failed on both frameworks in AzureContainerRegistryAccessTokenProviderTests.GivenARegistry_WithoutMIEnabled_WhenGetToken_TokenException_ShouldBeThrown due to local Managed Identity unavailability, which appears environmental/pre-existing.

Known external dependency boundary

The original strict rg MediatR -> empty target cannot be fully satisfied until Microsoft.Health.SqlServer drops its MediatR API surface. The remaining MediatR references are constrained to that external boundary:

src\Microsoft.Health.Fhir.SqlServer\Features\Storage\SchemaUpgradedHandler.cs uses MediatR because SchemaUpgradedNotification is still a MediatR notification from Microsoft.Health.SqlServer 10.0.68.
Three SQL integration test helpers still substitute MediatR.IMediator for SchemaInitializer(..., MediatR.IMediator, ...).

ADO: AB#195645, AB#195647

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…R2 .NET 10) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- BundleRequest.cs - CreateResourceRequest.cs - UpsertResourceRequest.cs - ValidateOperationRequest.cs - MemberMatchRequest.cs These classes already implement IRequest<TResponse> (generic). The bare IRequest marker is MediatR-specific and not needed in Medino. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Replace IRequestPreProcessor<BundleRequest> with IPipelineBehavior<BundleRequest, BundleResponse> - Convert Process() method to HandleAsync() pipeline behavior pattern - Change Task.CompletedTask to next() for valid bundle path - Auto-registered by AddMedino (no manual registration needed) - Invalid bundle validation throw behavior unchanged Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Replace IRequestPreProcessor<TRequest> with IPipelineBehavior<TRequest, TResponse> - Rename Process() to HandleAsync() with proper pipeline signature - Update directly coupled tests to use RequestHandlerDelegate<TResponse> delegates - Add notnull constraint to TRequest type parameter per IPipelineBehavior requirement - Verify next handler called only for allowed capabilities Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Rename Handle method to HandleAsync to match Medino interface - Remove cancellationToken argument from next() delegate calls Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Rename Handle to HandleAsync in both method overloads - Remove cancellationToken argument from all next() calls - Update to Medino IPipelineBehavior interface compliance Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Rename Handle method to HandleAsync - Remove cancellationToken parameter from next() delegate calls Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Add 'where TRequest : notnull' constraint - Rename Execute() to ExecuteAsync() - Update to implement Medino IRequestExceptionAction interface Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Update ExecuteAsync() calls in SqlExceptionActionProcessorTests - Four test methods now call ExecuteAsync instead of Execute Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Rename IMediator.Send()/Publish() -> SendAsync()/PublishAsync() on all mediator-typed variables in production source (40 files via script) - Rename Send<T>( -> SendAsync<T>( for generic-typed call sites in resource handlers, behaviors, and extension methods (10 more files) - Rename IRequestHandler Handle() -> HandleAsync() in all production handlers (49 files via script) - Rename INotificationHandler Handle() -> HandleAsync() in all production notification handlers - Rename IPipelineBehavior Handle() -> HandleAsync() and fix next(cancellationToken) -> next() in ProvenanceHeaderBehavior and ProfileResourcesBehaviour - Fix ValidateBundlePreProcessor: replace Task alias with proper using System.Threading.Tasks to resolve CS0307 - Fix GetOperationVersionsHandler: convert explicit interface impl to public method to satisfy CA1033 - Update ISearchParameterStatusManager.Handle -> HandleAsync to match implementation rename - Keep SchemaUpgradedHandler on MediatR.INotificationHandler since SchemaUpgradedNotification (Microsoft.Health.SqlServer) implements MediatR.INotification, not Medino.INotification Production source builds clean. Remaining 60 errors are in test files (direct handler invocations) — deferred to Task 14. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

84 files touched by the Task 13 scripted renames (Set-Content -NoNewline) lost their UTF-8 BOM. Re-prepend EF BB BF to each affected file; content is otherwise unchanged. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Update stale XML doc comments (ExceptionNotification, GeoReplicationLagNotification, CosmosStorageRequestMetricsNotification, CreateImportRequestHandler, CreateExportRequestHandler): replace 'MediatR message/notification' wording with 'mediator' - Rename test methods in ApiNotificationMiddlewareTests and ExceptionNotificationMiddlewareTests that contained 'MediatR' in their names - Update comment in ExportControllerTests (dispatch through MediatR -> mediator) - Fix ExceptionNotificationMiddlewareTests.WhenMediatorFails_OriginalExceptionStillThrown: MediatR had two Publish overloads (generic + non-generic object); the DidNotReceiveWithAnyArgs assertion accidentally passed because the stub targeted the wrong overload. With Medino's single PublishAsync<T>, the stub fires on the actual call; changed assertion to ReceivedWithAnyArgs(1) which correctly validates the middleware tried to publish. - Fix ValidateRequestPreProcessorTests: ValidateRequestPreProcessor was migrated from IRequestPreProcessor (no 'next' delegate) to IPipelineBehavior (calls next()); the test next-delegate called Substitute.For<SaveOutcome>() which fails (no parameterless ctor); replaced with Task.FromResult<UpsertResourceResponse>(null) since the test only checks nextCalled==true and validator invocations, not the return value. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Update stale Mediatr wording in ApiResponseNotification XML doc comment, consistent with other notification classes cleaned in the previous commit. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Reword stale inline comment in FhirServerBuilderSqlServerRegistrationExtensions (line 212): 'Mediatr registers handlers as Transient by default' -> 'Handler registrations are Transient by default; ...' to remove framework- specific wording consistent with other doc cleanups in this series. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

-                    var snapshot = hashSet.ToList();
-                    return snapshot.Count;
+                    var count = 0;
+                    foreach (var item in hashSet)


-                    var snapshot = list.ToList();
-                    return snapshot.Count;
+                    var count = 0;
+                    foreach (var item in list)


…ino DI resolution - Added TDD test file FhirModuleRegistrationTests.cs to verify all closed generic interfaces are registered - Test checks both ProvenanceHeaderBehavior (4 variants) and ProfileResourcesBehaviour (5 variants) - Implemented explicit factory-based registrations in FhirModule.cs to bypass Medino's .AsImplementedInterfaces() limitation - Each closed generic IPipelineBehavior<TRequest,TResponse> registered separately with factory delegate - All 1325 unit tests pass in net8.0 and net9.0 Root cause: Medino's .AsImplementedInterfaces() does not expand all closed generic interfaces when a class implements multiple variants. This caused DI resolution failures at runtime when Medino's pipeline engine tried to fetch behaviors for specific request/response type pairs, resulting in HTTP 500s on resource creation. Fix: Explicit factory registrations ensure all variants are available to Medino's pipeline engine. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…FhirModule.cs This fixes the missing factory registration for the 5th closed generic interface variant of ProfileResourcesBehaviour: IPipelineBehavior<DeleteResourceRequest, DeleteResourceResponse>. Root cause: Medino's .AsImplementedInterfaces() extension does not automatically expand all closed generic IPipelineBehavior<TRequest, TResponse> interface variants when a class implements multiple. This requires explicit factory-based registrations. ProfileResourcesBehaviour implements 5 closed generics: 1. IPipelineBehavior<CreateResourceRequest, UpsertResourceResponse> ✓ 2. IPipelineBehavior<UpsertResourceRequest, UpsertResourceResponse> ✓ 3. IPipelineBehavior<ConditionalCreateResourceRequest, UpsertResourceResponse> ✓ 4. IPipelineBehavior<ConditionalUpsertResourceRequest, UpsertResourceResponse> ✓ 5. IPipelineBehavior<DeleteResourceRequest, DeleteResourceResponse> ← ADDED Without this registration, DELETE operation handlers cannot resolve their required pipeline behaviors, causing HTTP 500 errors in E2E tests (BulkUpdate, Reindex, integration tests). Verified: All 1325 unit tests pass locally, confirming the fix. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…ions Root Cause: The BulkUpdate E2E tests were timing out because background job handlers (BulkUpdateOrchestratorJob, BulkUpdateProcessingJob, etc.) defined in Microsoft.Health.Fhir.Core were not registered in the DI container. The registration code in both SQL Server and Cosmos DB only scanned their own assemblies for IJob implementations, leaving Core jobs unregistered. When BulkUpdate requests enqueued jobs to the background queue, the JobFactory failed to resolve the job type, throwing NotSupportedException and causing the E2E test polling loop to timeout at 300 seconds. Fix: Modified DI registration in both backends to register BOTH backend-specific AND Core IJob implementations: - FhirServerBuilderSqlServerRegistrationExtensions.cs: Added scan of Core assembly alongside SqlServer assembly for IJob types - FhirServerBuilderCosmosDbRegistrationExtensions.cs: Added scan of Core assembly alongside CosmosDb assembly for IJob types This ensures all job types are available in the DI container: - BulkUpdateOrchestratorJob (JobTypeId = 8) - BulkUpdateProcessingJob (JobTypeId = 7) - BulkDeleteOrchestratorJob (JobTypeId = 10) - BulkDeleteProcessingJob (JobTypeId = 9) - ExportProcessingJob (JobTypeId = 4) - ReindexOrchestratorJob (JobTypeId = 2) - ReindexProcessingJob (JobTypeId = 1) Testing: - Both registration files compile with 0 warnings, 0 errors - Core unit tests pass (959 tests) - Unit tests verify MediatR->Medino DI migration is working correctly Fixes: BulkUpdate E2E test timeouts in sqlE2eTests_BulkUpdate jobs (R4, R5, STU3) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

mikaelweave and others added 26 commits June 15, 2026 15:20

Add .NET 10 + Medino upgrade design spec

13a549c

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Add implementation plans for .NET 10 upgrade (PR1 Medino migration, P…

45c20bf

…R2 .NET 10) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Pin Medino 3.0.3 (verified latest stable on nuget.org)

239ddca

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Swap MediatR package references for Medino

86c1352

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Replace MediatR namespace imports with Medino

0e0447e

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Preserve encoding in Medino namespace swap

9bedad6

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Rewrite mediation module for Medino

7a13cb8

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Fix Medino mediation module imports

345acc8

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Convert request validator to Medino pipeline behavior

1cfcbe5

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Update request validator tests for Medino pipeline

f809f81

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Migrate list search behavior to Medino pipeline

dffee57

- Rename Handle method to HandleAsync to match Medino interface - Remove cancellationToken argument from next() delegate calls Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Migrate search parameter delete behavior to Medino

a36ca9b

- Rename Handle method to HandleAsync - Remove cancellationToken parameter from next() delegate calls Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Migrate SQL exception action to Medino

46a1c4a

- Add 'where TRequest : notnull' constraint - Rename Execute() to ExecuteAsync() - Update to implement Medino IRequestExceptionAction interface Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Update SQL exception action tests for Medino

1ca24b4

- Update ExecuteAsync() calls in SqlExceptionActionProcessorTests - Four test methods now call ExecuteAsync instead of Execute Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Migrate schema manager mediation registration to Medino

dbad5b8

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Add Medino DI package to schema manager

80c8e1c

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Restore BOMs after Medino source migration

0b91463

84 files touched by the Task 13 scripted renames (Set-Content -NoNewline) lost their UTF-8 BOM. Re-prepend EF BB BF to each affected file; content is otherwise unchanged. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Migrate from MediatR to Medino

f5c11f3

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Fix tests after MediatR to Medino migration

72f63c7

Update stale Mediatr wording in ApiResponseNotification XML doc comment, consistent with other notification classes cleaned in the previous commit. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

github-advanced-security AI found potential problems Jun 17, 2026

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mikaelweave and others added 2 commits June 16, 2026 19:29

Fix PR validation failures

858a4df

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Merge origin/main into medino migration

26e638e

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

mikaelweave added this to the FY26\Q4\2Wk\2Wk26 milestone Jun 17, 2026

github-advanced-security AI found potential problems Jun 17, 2026

View reviewed changes

mikaelweave and others added 3 commits June 16, 2026 21:06

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Migrate mediation from MediatR to Medino#5616

Migrate mediation from MediatR to Medino#5616
mikaelweave wants to merge 31 commits into
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mikaelweave/medino-migration

mikaelweave commented Jun 17, 2026 •

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mikaelweave commented Jun 17, 2026 • edited by azure-boards Bot Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

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Known external dependency boundary

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mikaelweave commented Jun 17, 2026 •

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