Fix running clean architecture template on Linux

[Copilot]

Fixes the issue where the Clean Architecture template web project cannot be run directly on Linux because it attempts to use LocalDB (SQL Server), which is not supported on non-Windows platforms.

Changes Made

1. InfrastructureServiceExtensions.cs: Modified to detect the operating system and skip the DefaultConnection (LocalDB) on non-Windows platforms, automatically falling back to SQLite. Added support for a USE_SQL_SERVER environment variable to force SQL Server mode when needed (e.g., for functional tests).

2. MiddlewareConfig.cs: Updated database migration logic to use EnsureCreated() for SQLite databases (development/local scenarios) and Migrate() for SQL Server (production scenarios).

3. appsettings.json: Updated comments to clarify the cross-platform behavior of connection strings.

4. CustomWebApplicationFactory.cs: Updated functional tests to set the USE_SQL_SERVER environment variable and configure the SQL Server connection from Testcontainers, ensuring tests work cross-platform.

Testing

• ✅ Web app runs successfully on Linux using SQLite
• ✅ All unit tests pass (12/12)
• ✅ All integration tests pass (3/3)
• ✅ All functional tests pass (3/3)

The template now works seamlessly on Linux, macOS, and Windows without any manual configuration changes.

Fixes #977

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Clean architecture template web project cannot be run directly on linux</issue_title>
<issue_description>

• .NET SDK Version: 10.0.100 [/usr/share/dotnet/sdk]
• Linux distribution: Arch Linux
• Uname -a output: Linux ARCHDESKTOP 6.17.7-arch1-1 ardalis/CleanArchitecture#1 SMP PREEMPT_DYNAMIC Sun, 02 Nov 2025 17:27:22 +0000 x86_64 GNU/Linux

Steps to Reproduce:

1. dotnet new install Ardalis.CleanArchitecture.Template
2. dotnet new clean-arch -o ArdalisCleanArchitecture
3. cd ArdalisCleanArchitecture
4. dotnet run --project src/ArdalisCleanArchitecture.Web/

Result:

Using launch settings from src/ArdalisCleanArchitecture.Web/Properties/launchSettings.json...
Building...
info: Program[0]
      Starting web host
info: Program[0]
      Options were configured
info: Program[0]
      Infrastructure services registered
info: Program[0]
      Registering Mediator SourceGen and Behaviors
info: Program[0]
      Mediator Source Generator and Email Sender services registered
info: FastEndpoints.StartupTimer[1]
      Registered 5 endpoints in 83 milliseconds.
[12:08:09 INF] Registered 5 endpoints in 83 milliseconds.
[12:08:09 INF] Registered 5 endpoints in 83 milliseconds.
info: Program[0]
      Applying database migrations...
[12:08:09 INF] Applying database migrations...
[12:08:09 INF] Applying database migrations...
fail: Program[0]
      An error occurred migrating the DB. LocalDB is not supported on this platform.
      System.PlatformNotSupportedException: LocalDB is not supported on this platform.
         at Microsoft.Data.SqlClient.ManagedSni.LocalDB.GetLocalDBConnectionString(String localDbInstance)
         at Microsoft.Data.SqlClient.ManagedSni.SniProxy.GetLocalDBDataSource(String fullServerName, Boolean& error)
         at Microsoft.Data.SqlClient.ManagedSni.SniProxy.CreateConnectionHandle(String fullServerName, TimeoutTimer timeout, Byte[]& instanceName, ResolvedServerSpn& resolvedSpn, String serverSPN, Boolean flushCache, Boolean async, Boolean parallel, Boolean isIntegratedSecurity, SqlConnectionIPAddressPreference ipPreference, String cachedFQDN, SQLDNSInfo& pendingDNSInfo, Boolean tlsFirst, String hostNameInCertificate, String serverCertificateFilename)
         at Microsoft.Data.SqlClient.ManagedSni.TdsParserStateObjectManaged.CreatePhysicalSNIHandle(String serverName, TimeoutTimer timeout, Byte[]& instanceName, ResolvedServerSpn& resolvedSpn, Boolean flushCache, Boolean async, Boolean parallel, SqlConnectionIPAddressPreference iPAddressPreference, String cachedFQDN, SQLDNSInfo& pendingDNSInfo, String serverSPN, Boolean isIntegratedSecurity, Boolean tlsFirst, String hostNameInCertificate, String serverCertificateFilename)
         at Microsoft.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, TimeoutTimer timeout, SqlConnectionString connectionOptions, Boolean withFailover)
         at Microsoft.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, TimeoutTimer timeout, Boolean withFailover)
         at Microsoft.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString connectionOptions, SqlCredential credential, TimeoutTimer timeout)
         at Microsoft.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance)
         at Microsoft.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, Boolean applyTransientFaultHandling, String accessToken, IDbConnectionPool pool, Func`3 accessTokenCallback)
         at Microsoft.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionPoolGroupProviderInfo poolGroupProviderInfo, IDbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions)
         at Microsoft.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(IDbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions)
         at Microsoft.Data.SqlClient.ConnectionPool.WaitHandleDbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
         at Microsoft.Data.SqlClient....

</details>

- Fixes ardalis/CleanArchitecture#977

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[ardalis]

@copilot resume work; git issues should be resolved.

[Copilot]

@copilot resume work; git issues should be resolved.

I've completed the fix for running the Clean Architecture template on Linux. The changes are in commit f112f95.

Summary of changes:

1. Modified infrastructure to skip LocalDB connection on non-Windows platforms, using SQLite instead
2. Updated database migration logic to use EnsureCreated() for SQLite and Migrate() for SQL Server
3. Updated functional tests to work cross-platform by forcing SQL Server mode via environment variable

Testing:

• ✅ Web app runs successfully on Linux using SQLite
• ✅ All unit tests pass (12/12)
• ✅ All integration tests pass (3/3)
• ✅ All functional tests pass (3/3)

The template now works seamlessly on Linux, macOS, and Windows without any manual configuration changes.