Handle error when SSH agent is not accessible (in Docker)

[OlivierBouchoms]

The container fails to connect to the SSH auth sock. An empty response body is returned. This happens when running the Docker Compose application in Linux.

If this happens, the API should handle the exception gracefully and return an error with code SshAgentNotAccessible. The frontend should display this error, so the user can properly troubleshoot.

Error log:

fail: Microsoft.AspNetCore.Server.Kestrel[13]
      Connection id "0HNIE2TGKU63Q", Request id "0HNIE2TGKU63Q:00000002": An unhandled exception was thrown by the application.
      System.Net.Sockets.SocketException (111): Connection refused /run/user/1000/keyring/ssh
         at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)
         at System.Net.Sockets.Socket.Connect(EndPoint remoteEP)
         at SshNet.Agent.SshAgentSocketStream..ctor(String socketPath, TimeSpan timeout)
         at SshNet.Agent.SshAgent.Send(IAgentMessage message)
         at SshNet.Agent.SshAgent.RequestIdentities()
         at SqliteRemoteApi.Factory.SshClientFactory.CreateSshClient(SshHost host) in /app/Factory/SshClientFactory.cs:line 25
         at SqliteRemoteApi.Manager.SqLiteDatabaseManager.Connect(String hostName, String dbPath) in /app/Manager/SqLiteDatabaseManager.cs:line 265
         at SqliteRemoteApi.Manager.SqLiteDatabaseManager.Connect(DatabaseConnectInput input) in /app/Manager/SqLiteDatabaseManager.cs:line 35
         at SqliteRemoteApi.Controllers.ServerController.Connect(ServerConnectRequestDto dto) in /app/Controllers/ServerController.cs:line 18
         at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.TaskOfIActionResultExecutor.Execute(ActionContext actionContext, IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Awaited|12_0(ControllerActionInvoker invoker, ValueTask`1 actionResultValueTask)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeNextActionFilterAsync>g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeInnerFilterAsync>g__Awaited|13_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|20_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)
         at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|7_0(Endpoint endpoint, Task requestTask, ILogger logger)
         at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)
         at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
         at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
         at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
         at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.ProcessRequests[TContext](IHttpApplication`1 application)

[OlivierBouchoms]

Check if this can be resolved by starting the SSH agent on the host machine. If this resolves the issue, this information should be displayed in the user interface as well.

[OlivierBouchoms]

Started the SSH agent and rebuilt the container

➜  sqlite-remote git:(main) ✗ eval $(ssh-agent -s)
Agent pid 10213
➜  sqlite-remote git:(main) ✗ docker compose up -d --force-recreate --build
 ⠿ Container sqliteremote-frontend-1  Started                              1.7s
 ⠿ Container sqliteremote-api-1       St...                                1.7s

Still results in a connection refused error

[OlivierBouchoms]

Let's try to reproduce using a fresh Ubuntu installation later

[OlivierBouchoms]

Tested using fresh Ubuntu 22.04 and Ubuntu 24.04 VMs and it works fine on these setups.