From c5e7479ee458278088ceb9a58b50b5bb5ed28489 Mon Sep 17 00:00:00 2001
From: Joseph Doherty <dohejw01@gmail.com>
Date: Sun, 24 May 2026 07:10:32 -0400
Subject: [PATCH] Dashboard: admin-only Close session / Kill worker

Add IDashboardSessionAdminService (Admin-role gate, friendly errors,
audit logging) wrapping a new ISessionManager.KillWorkerAsync that
skips graceful shutdown and cleans up registry/metrics. Sessions,
Workers, and SessionDetails pages render Close / Kill buttons only
when CanManage; the service re-checks the role on every call so
forged clicks return Unauthenticated.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 .../Components/Pages/SessionDetailsPage.razor |  79 ++++++-
 .../Components/Pages/SessionsPage.razor       |  83 +++++++
 .../Components/Pages/WorkersPage.razor        |  67 ++++++
 .../DashboardServiceCollectionExtensions.cs   |   1 +
 .../Dashboard/DashboardSessionAdminResult.cs  |  16 ++
 .../Dashboard/DashboardSessionAdminService.cs | 136 +++++++++++
 .../IDashboardSessionAdminService.cs          |  18 ++
 .../Sessions/ISessionManager.cs               |  13 +
 .../Sessions/SessionManager.cs                |  50 ++++
 .../DashboardSessionAdminServiceTests.cs      | 223 ++++++++++++++++++
 .../Gateway/Grpc/EventStreamServiceTests.cs   |   9 +
 .../MxAccessGatewayServiceConstraintTests.cs  |   6 +
 .../Grpc/MxAccessGatewayServiceTests.cs       |   9 +
 .../Gateway/Sessions/SessionManagerTests.cs   |  32 +++
 ...atewayGrpcAuthorizationInterceptorTests.cs |   9 +
 15 files changed, 750 insertions(+), 1 deletion(-)
 create mode 100644 src/ZB.MOM.WW.MxGateway.Server/Dashboard/DashboardSessionAdminResult.cs
 create mode 100644 src/ZB.MOM.WW.MxGateway.Server/Dashboard/DashboardSessionAdminService.cs
 create mode 100644 src/ZB.MOM.WW.MxGateway.Server/Dashboard/IDashboardSessionAdminService.cs
 create mode 100644 src/ZB.MOM.WW.MxGateway.Tests/Gateway/Dashboard/DashboardSessionAdminServiceTests.cs

diff --git a/src/ZB.MOM.WW.MxGateway.Server/Dashboard/Components/Pages/SessionDetailsPage.razor b/src/ZB.MOM.WW.MxGateway.Server/Dashboard/Components/Pages/SessionDetailsPage.razor
index 4a0814d..1c5616e 100644
--- a/src/ZB.MOM.WW.MxGateway.Server/Dashboard/Components/Pages/SessionDetailsPage.razor
+++ b/src/ZB.MOM.WW.MxGateway.Server/Dashboard/Components/Pages/SessionDetailsPage.razor
@@ -4,6 +4,8 @@
 @using Microsoft.AspNetCore.SignalR.Client
 @using ZB.MOM.WW.MxGateway.Contracts.Proto
 @using ZB.MOM.WW.MxGateway.Server.Dashboard.Hubs
+@inject AuthenticationStateProvider AuthenticationStateProvider
+@inject IDashboardSessionAdminService SessionAdminService
 
 <PageTitle>Dashboard Session</PageTitle>
 
@@ -25,9 +27,33 @@ else
             <h1>Session Details</h1>
             <div class="text-secondary"><code>@CurrentSession.SessionId</code></div>
         </div>
-        <StatusBadge Text="@CurrentSession.State.ToString()" />
+        <div class="d-flex align-items-center gap-2">
+            <StatusBadge Text="@CurrentSession.State.ToString()" />
+            @if (CanManage)
+            {
+                <div class="btn-group btn-group-sm" role="group" aria-label="Session admin actions">
+                    <button type="button" class="btn btn-outline-warning"
+                            disabled="@IsBusy"
+                            @onclick="CloseSessionAsync">
+                        Close session
+                    </button>
+                    <button type="button" class="btn btn-outline-danger"
+                            disabled="@IsBusy"
+                            @onclick="KillWorkerAsync">
+                        Kill worker
+                    </button>
+                </div>
+            }
+        </div>
     </div>
 
+    @if (CanManage && !string.IsNullOrWhiteSpace(ResultMessage))
+    {
+        <div class="alert @(LastOperationSucceeded ? "alert-success" : "alert-danger")" role="alert">
+            @ResultMessage
+        </div>
+    }
+
     <section class="dashboard-section">
         <div class="section-heading">
             <h2>Session</h2>
@@ -124,6 +150,23 @@ else
     private string? _subscribedSessionId;
     private readonly LinkedList<MxEvent> _recentEvents = new();
 
+    private bool CanManage { get; set; }
+
+    private bool IsBusy { get; set; }
+
+    private string? ResultMessage { get; set; }
+
+    private bool LastOperationSucceeded { get; set; }
+
+    protected override async Task OnInitializedAsync()
+    {
+        await base.OnInitializedAsync().ConfigureAwait(false);
+
+        AuthenticationState authenticationState = await AuthenticationStateProvider.GetAuthenticationStateAsync()
+            .ConfigureAwait(false);
+        CanManage = SessionAdminService.CanManage(authenticationState.User);
+    }
+
     protected override async Task OnParametersSetAsync()
     {
         if (!string.Equals(_subscribedSessionId, SessionId, StringComparison.Ordinal))
@@ -133,6 +176,40 @@ else
         }
     }
 
+    private Task CloseSessionAsync()
+    {
+        return RunAdminActionAsync(user => SessionAdminService.CloseSessionAsync(user, SessionId, CancellationToken.None));
+    }
+
+    private Task KillWorkerAsync()
+    {
+        return RunAdminActionAsync(user => SessionAdminService.KillWorkerAsync(user, SessionId, CancellationToken.None));
+    }
+
+    private async Task RunAdminActionAsync(
+        Func<System.Security.Claims.ClaimsPrincipal, Task<DashboardSessionAdminResult>> action)
+    {
+        if (IsBusy)
+        {
+            return;
+        }
+
+        IsBusy = true;
+        try
+        {
+            AuthenticationState authenticationState = await AuthenticationStateProvider.GetAuthenticationStateAsync()
+                .ConfigureAwait(false);
+            CanManage = SessionAdminService.CanManage(authenticationState.User);
+            DashboardSessionAdminResult result = await action(authenticationState.User).ConfigureAwait(false);
+            ResultMessage = result.Message;
+            LastOperationSucceeded = result.Succeeded;
+        }
+        finally
+        {
+            IsBusy = false;
+        }
+    }
+
     private async Task AttachEventsHubAsync()
     {
         if (string.IsNullOrWhiteSpace(SessionId))
diff --git a/src/ZB.MOM.WW.MxGateway.Server/Dashboard/Components/Pages/SessionsPage.razor b/src/ZB.MOM.WW.MxGateway.Server/Dashboard/Components/Pages/SessionsPage.razor
index e8df4dc..c4d801c 100644
--- a/src/ZB.MOM.WW.MxGateway.Server/Dashboard/Components/Pages/SessionsPage.razor
+++ b/src/ZB.MOM.WW.MxGateway.Server/Dashboard/Components/Pages/SessionsPage.razor
@@ -1,5 +1,7 @@
 @page "/sessions"
 @inherits DashboardPageBase
+@inject AuthenticationStateProvider AuthenticationStateProvider
+@inject IDashboardSessionAdminService SessionAdminService
 
 <PageTitle>Dashboard Sessions</PageTitle>
 
@@ -16,6 +18,13 @@ else
         </div>
     </div>
 
+    @if (CanManage && !string.IsNullOrWhiteSpace(ResultMessage))
+    {
+        <div class="alert @(LastOperationSucceeded ? "alert-success" : "alert-danger")" role="alert">
+            @ResultMessage
+        </div>
+    }
+
     <section class="dashboard-section">
         @if (Snapshot.Sessions.Count == 0)
         {
@@ -37,6 +46,10 @@ else
                             <th scope="col">Activity</th>
                             <th scope="col">Heartbeat</th>
                             <th scope="col">Fault</th>
+                            @if (CanManage)
+                            {
+                                <th scope="col">Actions</th>
+                            }
                         </tr>
                     </thead>
                     <tbody>
@@ -59,6 +72,23 @@ else
                                 <td>@DashboardDisplay.DateTime(session.LastClientActivityAt)</td>
                                 <td>@DashboardDisplay.DateTime(session.LastWorkerHeartbeatAt)</td>
                                 <td>@DashboardDisplay.Text(session.LastFault)</td>
+                                @if (CanManage)
+                                {
+                                    <td>
+                                        <div class="btn-group btn-group-sm" role="group" aria-label="Session actions">
+                                            <button type="button" class="btn btn-outline-warning"
+                                                    disabled="@IsBusy"
+                                                    @onclick="() => CloseSessionAsync(session.SessionId)">
+                                                Close
+                                            </button>
+                                            <button type="button" class="btn btn-outline-danger"
+                                                    disabled="@IsBusy"
+                                                    @onclick="() => KillWorkerAsync(session.SessionId)">
+                                                Kill
+                                            </button>
+                                        </div>
+                                    </td>
+                                }
                             </tr>
                         }
                     </tbody>
@@ -67,3 +97,56 @@ else
         }
     </section>
 }
+
+@code {
+    private bool CanManage { get; set; }
+
+    private bool IsBusy { get; set; }
+
+    private string? ResultMessage { get; set; }
+
+    private bool LastOperationSucceeded { get; set; }
+
+    protected override async Task OnInitializedAsync()
+    {
+        await base.OnInitializedAsync().ConfigureAwait(false);
+
+        AuthenticationState authenticationState = await AuthenticationStateProvider.GetAuthenticationStateAsync()
+            .ConfigureAwait(false);
+        CanManage = SessionAdminService.CanManage(authenticationState.User);
+    }
+
+    private Task CloseSessionAsync(string sessionId)
+    {
+        return RunActionAsync(user => SessionAdminService.CloseSessionAsync(user, sessionId, CancellationToken.None));
+    }
+
+    private Task KillWorkerAsync(string sessionId)
+    {
+        return RunActionAsync(user => SessionAdminService.KillWorkerAsync(user, sessionId, CancellationToken.None));
+    }
+
+    private async Task RunActionAsync(
+        Func<System.Security.Claims.ClaimsPrincipal, Task<DashboardSessionAdminResult>> action)
+    {
+        if (IsBusy)
+        {
+            return;
+        }
+
+        IsBusy = true;
+        try
+        {
+            AuthenticationState authenticationState = await AuthenticationStateProvider.GetAuthenticationStateAsync()
+                .ConfigureAwait(false);
+            CanManage = SessionAdminService.CanManage(authenticationState.User);
+            DashboardSessionAdminResult result = await action(authenticationState.User).ConfigureAwait(false);
+            ResultMessage = result.Message;
+            LastOperationSucceeded = result.Succeeded;
+        }
+        finally
+        {
+            IsBusy = false;
+        }
+    }
+}
diff --git a/src/ZB.MOM.WW.MxGateway.Server/Dashboard/Components/Pages/WorkersPage.razor b/src/ZB.MOM.WW.MxGateway.Server/Dashboard/Components/Pages/WorkersPage.razor
index 4811852..5fd3edb 100644
--- a/src/ZB.MOM.WW.MxGateway.Server/Dashboard/Components/Pages/WorkersPage.razor
+++ b/src/ZB.MOM.WW.MxGateway.Server/Dashboard/Components/Pages/WorkersPage.razor
@@ -1,5 +1,7 @@
 @page "/workers"
 @inherits DashboardPageBase
+@inject AuthenticationStateProvider AuthenticationStateProvider
+@inject IDashboardSessionAdminService SessionAdminService
 
 <PageTitle>Dashboard Workers</PageTitle>
 
@@ -16,6 +18,13 @@ else
         </div>
     </div>
 
+    @if (CanManage && !string.IsNullOrWhiteSpace(ResultMessage))
+    {
+        <div class="alert @(LastOperationSucceeded ? "alert-success" : "alert-danger")" role="alert">
+            @ResultMessage
+        </div>
+    }
+
     <section class="dashboard-section">
         @if (Snapshot.Workers.Count == 0)
         {
@@ -32,6 +41,10 @@ else
                             <th scope="col">Session</th>
                             <th scope="col">Heartbeat</th>
                             <th scope="col">Fault</th>
+                            @if (CanManage)
+                            {
+                                <th scope="col">Actions</th>
+                            }
                         </tr>
                     </thead>
                     <tbody>
@@ -43,6 +56,16 @@ else
                                 <td><NavLink href="@($"sessions/{Uri.EscapeDataString(worker.SessionId)}")"><code>@worker.SessionId</code></NavLink></td>
                                 <td>@DashboardDisplay.DateTime(worker.LastHeartbeatAt)</td>
                                 <td>@DashboardDisplay.Text(worker.LastFault)</td>
+                                @if (CanManage)
+                                {
+                                    <td>
+                                        <button type="button" class="btn btn-sm btn-outline-danger"
+                                                disabled="@IsBusy"
+                                                @onclick="() => KillWorkerAsync(worker.SessionId)">
+                                            Kill
+                                        </button>
+                                    </td>
+                                }
                             </tr>
                         }
                     </tbody>
@@ -51,3 +74,47 @@ else
         }
     </section>
 }
+
+@code {
+    private bool CanManage { get; set; }
+
+    private bool IsBusy { get; set; }
+
+    private string? ResultMessage { get; set; }
+
+    private bool LastOperationSucceeded { get; set; }
+
+    protected override async Task OnInitializedAsync()
+    {
+        await base.OnInitializedAsync().ConfigureAwait(false);
+
+        AuthenticationState authenticationState = await AuthenticationStateProvider.GetAuthenticationStateAsync()
+            .ConfigureAwait(false);
+        CanManage = SessionAdminService.CanManage(authenticationState.User);
+    }
+
+    private async Task KillWorkerAsync(string sessionId)
+    {
+        if (IsBusy)
+        {
+            return;
+        }
+
+        IsBusy = true;
+        try
+        {
+            AuthenticationState authenticationState = await AuthenticationStateProvider.GetAuthenticationStateAsync()
+                .ConfigureAwait(false);
+            CanManage = SessionAdminService.CanManage(authenticationState.User);
+            DashboardSessionAdminResult result = await SessionAdminService
+                .KillWorkerAsync(authenticationState.User, sessionId, CancellationToken.None)
+                .ConfigureAwait(false);
+            ResultMessage = result.Message;
+            LastOperationSucceeded = result.Succeeded;
+        }
+        finally
+        {
+            IsBusy = false;
+        }
+    }
+}
diff --git a/src/ZB.MOM.WW.MxGateway.Server/Dashboard/DashboardServiceCollectionExtensions.cs b/src/ZB.MOM.WW.MxGateway.Server/Dashboard/DashboardServiceCollectionExtensions.cs
index 1382c11..7380b97 100644
--- a/src/ZB.MOM.WW.MxGateway.Server/Dashboard/DashboardServiceCollectionExtensions.cs
+++ b/src/ZB.MOM.WW.MxGateway.Server/Dashboard/DashboardServiceCollectionExtensions.cs
@@ -20,6 +20,7 @@ public static class DashboardServiceCollectionExtensions
         services.AddSingleton<IDashboardAuthenticator, DashboardAuthenticator>();
         services.AddSingleton<DashboardApiKeyAuthorization>();
         services.AddSingleton<IDashboardApiKeyManagementService, DashboardApiKeyManagementService>();
+        services.AddSingleton<IDashboardSessionAdminService, DashboardSessionAdminService>();
         services.AddSingleton<HubTokenService>();
         services.AddScoped<Hubs.DashboardHubConnectionFactory>();
         services.AddSingleton<Hubs.IDashboardEventBroadcaster, Hubs.DashboardEventBroadcaster>();
diff --git a/src/ZB.MOM.WW.MxGateway.Server/Dashboard/DashboardSessionAdminResult.cs b/src/ZB.MOM.WW.MxGateway.Server/Dashboard/DashboardSessionAdminResult.cs
new file mode 100644
index 0000000..ed7f05a
--- /dev/null
+++ b/src/ZB.MOM.WW.MxGateway.Server/Dashboard/DashboardSessionAdminResult.cs
@@ -0,0 +1,16 @@
+namespace ZB.MOM.WW.MxGateway.Server.Dashboard;
+
+public sealed record DashboardSessionAdminResult(
+    bool Succeeded,
+    string Message)
+{
+    public static DashboardSessionAdminResult Success(string message)
+    {
+        return new DashboardSessionAdminResult(true, message);
+    }
+
+    public static DashboardSessionAdminResult Fail(string message)
+    {
+        return new DashboardSessionAdminResult(false, message);
+    }
+}
diff --git a/src/ZB.MOM.WW.MxGateway.Server/Dashboard/DashboardSessionAdminService.cs b/src/ZB.MOM.WW.MxGateway.Server/Dashboard/DashboardSessionAdminService.cs
new file mode 100644
index 0000000..7fc6c80
--- /dev/null
+++ b/src/ZB.MOM.WW.MxGateway.Server/Dashboard/DashboardSessionAdminService.cs
@@ -0,0 +1,136 @@
+using System.Security.Claims;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Abstractions;
+using ZB.MOM.WW.MxGateway.Server.Sessions;
+
+namespace ZB.MOM.WW.MxGateway.Server.Dashboard;
+
+public sealed class DashboardSessionAdminService(
+    ISessionManager sessionManager,
+    IHttpContextAccessor httpContextAccessor,
+    ILogger<DashboardSessionAdminService>? logger = null) : IDashboardSessionAdminService
+{
+    private const string UnauthorizedMessage = "Sign in as an Admin to close sessions or kill workers.";
+    private const string KillReason = "dashboard-admin-kill";
+
+    private readonly ILogger<DashboardSessionAdminService> _logger =
+        logger ?? NullLogger<DashboardSessionAdminService>.Instance;
+
+    public bool CanManage(ClaimsPrincipal user)
+    {
+        ArgumentNullException.ThrowIfNull(user);
+
+        return user.Identity?.IsAuthenticated == true
+            && user.IsInRole(DashboardRoles.Admin);
+    }
+
+    public async Task<DashboardSessionAdminResult> CloseSessionAsync(
+        ClaimsPrincipal user,
+        string sessionId,
+        CancellationToken cancellationToken)
+    {
+        if (!CanManage(user))
+        {
+            return DashboardSessionAdminResult.Fail(UnauthorizedMessage);
+        }
+
+        if (string.IsNullOrWhiteSpace(sessionId))
+        {
+            return DashboardSessionAdminResult.Fail("Session id is required.");
+        }
+
+        string actor = ResolveActor(user);
+        try
+        {
+            SessionCloseResult result = await sessionManager
+                .CloseSessionAsync(sessionId, cancellationToken)
+                .ConfigureAwait(false);
+
+            _logger.LogInformation(
+                "Dashboard admin {Actor} closed session {SessionId} from {RemoteAddress}; alreadyClosed={AlreadyClosed}.",
+                actor,
+                sessionId,
+                ResolveRemoteAddress(),
+                result.AlreadyClosed);
+
+            return DashboardSessionAdminResult.Success(
+                result.AlreadyClosed
+                    ? $"Session {sessionId} was already closed."
+                    : $"Session {sessionId} closed.");
+        }
+        catch (SessionManagerException exception) when (exception.ErrorCode == SessionManagerErrorCode.SessionNotFound)
+        {
+            return DashboardSessionAdminResult.Fail($"Session {sessionId} was not found.");
+        }
+        catch (SessionManagerException exception)
+        {
+            _logger.LogWarning(
+                exception,
+                "Dashboard admin {Actor} close failed for session {SessionId}.",
+                actor,
+                sessionId);
+            return DashboardSessionAdminResult.Fail(
+                $"Close failed: {exception.Message}");
+        }
+    }
+
+    public async Task<DashboardSessionAdminResult> KillWorkerAsync(
+        ClaimsPrincipal user,
+        string sessionId,
+        CancellationToken cancellationToken)
+    {
+        if (!CanManage(user))
+        {
+            return DashboardSessionAdminResult.Fail(UnauthorizedMessage);
+        }
+
+        if (string.IsNullOrWhiteSpace(sessionId))
+        {
+            return DashboardSessionAdminResult.Fail("Session id is required.");
+        }
+
+        string actor = ResolveActor(user);
+        try
+        {
+            SessionCloseResult result = await sessionManager
+                .KillWorkerAsync(sessionId, KillReason, cancellationToken)
+                .ConfigureAwait(false);
+
+            _logger.LogInformation(
+                "Dashboard admin {Actor} killed worker for session {SessionId} from {RemoteAddress}; alreadyClosed={AlreadyClosed}.",
+                actor,
+                sessionId,
+                ResolveRemoteAddress(),
+                result.AlreadyClosed);
+
+            return DashboardSessionAdminResult.Success(
+                result.AlreadyClosed
+                    ? $"Session {sessionId} was already closed."
+                    : $"Worker for session {sessionId} killed.");
+        }
+        catch (SessionManagerException exception) when (exception.ErrorCode == SessionManagerErrorCode.SessionNotFound)
+        {
+            return DashboardSessionAdminResult.Fail($"Session {sessionId} was not found.");
+        }
+        catch (SessionManagerException exception)
+        {
+            _logger.LogWarning(
+                exception,
+                "Dashboard admin {Actor} kill failed for session {SessionId}.",
+                actor,
+                sessionId);
+            return DashboardSessionAdminResult.Fail(
+                $"Kill failed: {exception.Message}");
+        }
+    }
+
+    private static string ResolveActor(ClaimsPrincipal user)
+    {
+        return user.Identity?.Name ?? "<unknown>";
+    }
+
+    private string? ResolveRemoteAddress()
+    {
+        return httpContextAccessor.HttpContext?.Connection.RemoteIpAddress?.ToString();
+    }
+}
diff --git a/src/ZB.MOM.WW.MxGateway.Server/Dashboard/IDashboardSessionAdminService.cs b/src/ZB.MOM.WW.MxGateway.Server/Dashboard/IDashboardSessionAdminService.cs
new file mode 100644
index 0000000..d313609
--- /dev/null
+++ b/src/ZB.MOM.WW.MxGateway.Server/Dashboard/IDashboardSessionAdminService.cs
@@ -0,0 +1,18 @@
+using System.Security.Claims;
+
+namespace ZB.MOM.WW.MxGateway.Server.Dashboard;
+
+public interface IDashboardSessionAdminService
+{
+    bool CanManage(ClaimsPrincipal user);
+
+    Task<DashboardSessionAdminResult> CloseSessionAsync(
+        ClaimsPrincipal user,
+        string sessionId,
+        CancellationToken cancellationToken);
+
+    Task<DashboardSessionAdminResult> KillWorkerAsync(
+        ClaimsPrincipal user,
+        string sessionId,
+        CancellationToken cancellationToken);
+}
diff --git a/src/ZB.MOM.WW.MxGateway.Server/Sessions/ISessionManager.cs b/src/ZB.MOM.WW.MxGateway.Server/Sessions/ISessionManager.cs
index 0c137ee..2d84f26 100644
--- a/src/ZB.MOM.WW.MxGateway.Server/Sessions/ISessionManager.cs
+++ b/src/ZB.MOM.WW.MxGateway.Server/Sessions/ISessionManager.cs
@@ -49,6 +49,19 @@ public interface ISessionManager
         string sessionId,
         CancellationToken cancellationToken);
 
+    /// <summary>
+    /// Forcefully terminates a session's worker without attempting graceful shutdown,
+    /// transitions the session to Closed, and removes it from the registry.
+    /// </summary>
+    /// <param name="sessionId">Identifier of the session whose worker to kill.</param>
+    /// <param name="reason">Reason for killing the worker (recorded in logs/audit).</param>
+    /// <param name="cancellationToken">Token to cancel the asynchronous operation.</param>
+    /// <returns>The result of closing the session.</returns>
+    Task<SessionCloseResult> KillWorkerAsync(
+        string sessionId,
+        string reason,
+        CancellationToken cancellationToken);
+
     /// <summary>Closes all sessions with expired leases at the specified time.</summary>
     /// <param name="now">The current time to evaluate expiration against.</param>
     /// <param name="cancellationToken">Token to cancel the asynchronous operation.</param>
diff --git a/src/ZB.MOM.WW.MxGateway.Server/Sessions/SessionManager.cs b/src/ZB.MOM.WW.MxGateway.Server/Sessions/SessionManager.cs
index a648762..68807f2 100644
--- a/src/ZB.MOM.WW.MxGateway.Server/Sessions/SessionManager.cs
+++ b/src/ZB.MOM.WW.MxGateway.Server/Sessions/SessionManager.cs
@@ -203,6 +203,56 @@ public sealed class SessionManager : ISessionManager
         return result;
     }
 
+    /// <summary>
+    /// Forcefully terminates a session's worker without attempting graceful shutdown.
+    /// Mirrors the registry/metrics cleanup that <see cref="CloseSessionCoreAsync"/>
+    /// performs after a successful close, but skips the <c>WorkerClient.ShutdownAsync</c>
+    /// step that <see cref="GatewaySession.CloseAsync"/> would otherwise attempt.
+    /// </summary>
+    /// <param name="sessionId">Session identifier.</param>
+    /// <param name="reason">Reason recorded for the kill.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>Session close result.</returns>
+    public async Task<SessionCloseResult> KillWorkerAsync(
+        string sessionId,
+        string reason,
+        CancellationToken cancellationToken)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(reason);
+        cancellationToken.ThrowIfCancellationRequested();
+
+        GatewaySession session = GetRequiredSession(sessionId);
+        bool wasClosed = session.State == SessionState.Closed;
+
+        try
+        {
+            session.KillWorker(reason);
+        }
+        catch (Exception exception)
+        {
+            session.MarkFaulted(exception.Message);
+            _metrics.Fault(SessionManagerErrorCode.CloseFailed.ToString());
+            await RemoveSessionAsync(session).ConfigureAwait(false);
+            throw new SessionManagerException(
+                SessionManagerErrorCode.CloseFailed,
+                $"Failed to kill worker for session {sessionId}.",
+                exception);
+        }
+
+        if (!wasClosed)
+        {
+            _metrics.SessionClosed();
+        }
+
+        await RemoveSessionAsync(session).ConfigureAwait(false);
+        _logger.LogInformation(
+            "Worker for session {SessionId} killed; reason={Reason}.",
+            sessionId,
+            reason);
+
+        return new SessionCloseResult(sessionId, SessionState.Closed, AlreadyClosed: wasClosed);
+    }
+
     /// <summary>
     /// Closes all sessions with expired leases asynchronously.
     /// </summary>
diff --git a/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Dashboard/DashboardSessionAdminServiceTests.cs b/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Dashboard/DashboardSessionAdminServiceTests.cs
new file mode 100644
index 0000000..74dc162
--- /dev/null
+++ b/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Dashboard/DashboardSessionAdminServiceTests.cs
@@ -0,0 +1,223 @@
+using System.Diagnostics.CodeAnalysis;
+using System.Security.Claims;
+using Microsoft.AspNetCore.Http;
+using ZB.MOM.WW.MxGateway.Contracts.Proto;
+using ZB.MOM.WW.MxGateway.Server.Dashboard;
+using ZB.MOM.WW.MxGateway.Server.Sessions;
+
+namespace ZB.MOM.WW.MxGateway.Tests.Gateway.Dashboard;
+
+public sealed class DashboardSessionAdminServiceTests
+{
+    [Fact]
+    public async Task CloseSessionAsync_ViewerCannotManage()
+    {
+        FakeSessionManager sessionManager = new();
+        DashboardSessionAdminService service = CreateService(sessionManager);
+
+        DashboardSessionAdminResult result = await service.CloseSessionAsync(
+            CreateUser(DashboardRoles.Viewer),
+            "session-1",
+            CancellationToken.None);
+
+        Assert.False(result.Succeeded);
+        Assert.Equal(0, sessionManager.CloseCount);
+    }
+
+    [Fact]
+    public async Task CloseSessionAsync_AdminClosesSession()
+    {
+        FakeSessionManager sessionManager = new();
+        DashboardSessionAdminService service = CreateService(sessionManager);
+
+        DashboardSessionAdminResult result = await service.CloseSessionAsync(
+            CreateUser(DashboardRoles.Admin),
+            "session-1",
+            CancellationToken.None);
+
+        Assert.True(result.Succeeded);
+        Assert.Equal(1, sessionManager.CloseCount);
+        Assert.Equal("session-1", sessionManager.LastClosedSessionId);
+    }
+
+    [Fact]
+    public async Task CloseSessionAsync_WhenSessionMissing_ReportsFriendlyError()
+    {
+        FakeSessionManager sessionManager = new()
+        {
+            CloseThrowsNotFound = true,
+        };
+        DashboardSessionAdminService service = CreateService(sessionManager);
+
+        DashboardSessionAdminResult result = await service.CloseSessionAsync(
+            CreateUser(DashboardRoles.Admin),
+            "session-missing",
+            CancellationToken.None);
+
+        Assert.False(result.Succeeded);
+        Assert.Contains("not found", result.Message, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public async Task KillWorkerAsync_ViewerCannotManage()
+    {
+        FakeSessionManager sessionManager = new();
+        DashboardSessionAdminService service = CreateService(sessionManager);
+
+        DashboardSessionAdminResult result = await service.KillWorkerAsync(
+            CreateUser(DashboardRoles.Viewer),
+            "session-1",
+            CancellationToken.None);
+
+        Assert.False(result.Succeeded);
+        Assert.Equal(0, sessionManager.KillCount);
+    }
+
+    [Fact]
+    public async Task KillWorkerAsync_AdminKillsWorker()
+    {
+        FakeSessionManager sessionManager = new();
+        DashboardSessionAdminService service = CreateService(sessionManager);
+
+        DashboardSessionAdminResult result = await service.KillWorkerAsync(
+            CreateUser(DashboardRoles.Admin),
+            "session-1",
+            CancellationToken.None);
+
+        Assert.True(result.Succeeded);
+        Assert.Equal(1, sessionManager.KillCount);
+        Assert.Equal("session-1", sessionManager.LastKilledSessionId);
+        Assert.False(string.IsNullOrWhiteSpace(sessionManager.LastKillReason));
+    }
+
+    [Fact]
+    public async Task KillWorkerAsync_BlankSessionId_ReturnsFailure()
+    {
+        FakeSessionManager sessionManager = new();
+        DashboardSessionAdminService service = CreateService(sessionManager);
+
+        DashboardSessionAdminResult result = await service.KillWorkerAsync(
+            CreateUser(DashboardRoles.Admin),
+            "   ",
+            CancellationToken.None);
+
+        Assert.False(result.Succeeded);
+        Assert.Equal(0, sessionManager.KillCount);
+    }
+
+    [Fact]
+    public void CanManage_RejectsUnauthenticatedAndViewer()
+    {
+        DashboardSessionAdminService service = CreateService(new FakeSessionManager());
+
+        Assert.False(service.CanManage(new ClaimsPrincipal(new ClaimsIdentity())));
+        Assert.False(service.CanManage(CreateUser(DashboardRoles.Viewer)));
+        Assert.True(service.CanManage(CreateUser(DashboardRoles.Admin)));
+    }
+
+    private static DashboardSessionAdminService CreateService(ISessionManager sessionManager)
+    {
+        DefaultHttpContext httpContext = new();
+        httpContext.Connection.RemoteIpAddress = System.Net.IPAddress.Loopback;
+
+        return new DashboardSessionAdminService(
+            sessionManager,
+            new HttpContextAccessor { HttpContext = httpContext });
+    }
+
+    private static ClaimsPrincipal CreateUser(string role)
+    {
+        ClaimsIdentity identity = new(
+            [new Claim(ClaimTypes.Name, "tester"), new Claim(ClaimTypes.Role, role)],
+            DashboardAuthenticationDefaults.AuthenticationScheme,
+            ClaimTypes.Name,
+            ClaimTypes.Role);
+
+        return new ClaimsPrincipal(identity);
+    }
+
+    private sealed class FakeSessionManager : ISessionManager
+    {
+        public int CloseCount { get; private set; }
+
+        public int KillCount { get; private set; }
+
+        public string? LastClosedSessionId { get; private set; }
+
+        public string? LastKilledSessionId { get; private set; }
+
+        public string? LastKillReason { get; private set; }
+
+        public bool CloseThrowsNotFound { get; init; }
+
+        public Task<GatewaySession> OpenSessionAsync(
+            SessionOpenRequest request,
+            string? clientIdentity,
+            CancellationToken cancellationToken)
+        {
+            throw new NotSupportedException();
+        }
+
+        public bool TryGetSession(
+            string sessionId,
+            [MaybeNullWhen(false)] out GatewaySession session)
+        {
+            session = null;
+            return false;
+        }
+
+        public Task<WorkerCommandReply> InvokeAsync(
+            string sessionId,
+            WorkerCommand command,
+            CancellationToken cancellationToken)
+        {
+            throw new NotSupportedException();
+        }
+
+        public IAsyncEnumerable<WorkerEvent> ReadEventsAsync(
+            string sessionId,
+            CancellationToken cancellationToken)
+        {
+            throw new NotSupportedException();
+        }
+
+        public Task<SessionCloseResult> CloseSessionAsync(
+            string sessionId,
+            CancellationToken cancellationToken)
+        {
+            CloseCount++;
+            LastClosedSessionId = sessionId;
+            if (CloseThrowsNotFound)
+            {
+                throw new SessionManagerException(
+                    SessionManagerErrorCode.SessionNotFound,
+                    $"Session {sessionId} was not found.");
+            }
+
+            return Task.FromResult(new SessionCloseResult(sessionId, SessionState.Closed, AlreadyClosed: false));
+        }
+
+        public Task<SessionCloseResult> KillWorkerAsync(
+            string sessionId,
+            string reason,
+            CancellationToken cancellationToken)
+        {
+            KillCount++;
+            LastKilledSessionId = sessionId;
+            LastKillReason = reason;
+            return Task.FromResult(new SessionCloseResult(sessionId, SessionState.Closed, AlreadyClosed: false));
+        }
+
+        public Task<int> CloseExpiredLeasesAsync(
+            DateTimeOffset now,
+            CancellationToken cancellationToken)
+        {
+            return Task.FromResult(0);
+        }
+
+        public Task ShutdownAsync(CancellationToken cancellationToken)
+        {
+            return Task.CompletedTask;
+        }
+    }
+}
diff --git a/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Grpc/EventStreamServiceTests.cs b/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Grpc/EventStreamServiceTests.cs
index fc11e9c..990195a 100644
--- a/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Grpc/EventStreamServiceTests.cs
+++ b/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Grpc/EventStreamServiceTests.cs
@@ -505,6 +505,15 @@ public sealed class EventStreamServiceTests
             return Task.FromResult(new SessionCloseResult(sessionId, SessionState.Closed, AlreadyClosed: false));
         }
 
+        /// <inheritdoc />
+        public Task<SessionCloseResult> KillWorkerAsync(
+            string sessionId,
+            string reason,
+            CancellationToken cancellationToken)
+        {
+            return Task.FromResult(new SessionCloseResult(sessionId, SessionState.Closed, AlreadyClosed: false));
+        }
+
         /// <inheritdoc />
         public Task<int> CloseExpiredLeasesAsync(
             DateTimeOffset now,
diff --git a/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Grpc/MxAccessGatewayServiceConstraintTests.cs b/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Grpc/MxAccessGatewayServiceConstraintTests.cs
index 6b84b4d..9e99dd3 100644
--- a/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Grpc/MxAccessGatewayServiceConstraintTests.cs
+++ b/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Grpc/MxAccessGatewayServiceConstraintTests.cs
@@ -898,6 +898,12 @@ public sealed class MxAccessGatewayServiceConstraintTests
             CancellationToken cancellationToken) =>
             Task.FromResult(new SessionCloseResult(sessionId, SessionState.Closed, AlreadyClosed: false));
 
+        public Task<SessionCloseResult> KillWorkerAsync(
+            string sessionId,
+            string reason,
+            CancellationToken cancellationToken) =>
+            Task.FromResult(new SessionCloseResult(sessionId, SessionState.Closed, AlreadyClosed: false));
+
         public Task<int> CloseExpiredLeasesAsync(
             DateTimeOffset now,
             CancellationToken cancellationToken) => Task.FromResult(0);
diff --git a/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Grpc/MxAccessGatewayServiceTests.cs b/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Grpc/MxAccessGatewayServiceTests.cs
index 3aec895..3b4bcd5 100644
--- a/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Grpc/MxAccessGatewayServiceTests.cs
+++ b/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Grpc/MxAccessGatewayServiceTests.cs
@@ -539,6 +539,15 @@ public sealed class MxAccessGatewayServiceTests
             return Task.FromResult(new SessionCloseResult(sessionId, SessionState.Closed, AlreadyClosed: false));
         }
 
+        /// <inheritdoc />
+        public Task<SessionCloseResult> KillWorkerAsync(
+            string sessionId,
+            string reason,
+            CancellationToken cancellationToken)
+        {
+            return Task.FromResult(new SessionCloseResult(sessionId, SessionState.Closed, AlreadyClosed: false));
+        }
+
         /// <inheritdoc />
         public Task<int> CloseExpiredLeasesAsync(
             DateTimeOffset now,
diff --git a/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Sessions/SessionManagerTests.cs b/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Sessions/SessionManagerTests.cs
index 5c64db7..7fea357 100644
--- a/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Sessions/SessionManagerTests.cs
+++ b/src/ZB.MOM.WW.MxGateway.Tests/Gateway/Sessions/SessionManagerTests.cs
@@ -463,6 +463,38 @@ public sealed class SessionManagerTests
         Assert.Equal(0, metrics.GetSnapshot().OpenSessions);
     }
 
+    /// <summary>Verifies that killing a worker removes the session from the registry without calling shutdown.</summary>
+    [Fact]
+    public async Task KillWorkerAsync_KillsWorkerAndRemovesSession()
+    {
+        FakeWorkerClient workerClient = new();
+        using GatewayMetrics metrics = new();
+        SessionManager manager = CreateManager(new FakeSessionWorkerClientFactory(workerClient), metrics: metrics);
+        GatewaySession session = await manager.OpenSessionAsync(CreateOpenRequest(), "client-1", CancellationToken.None);
+
+        SessionCloseResult result = await manager.KillWorkerAsync(session.SessionId, "test-kill", CancellationToken.None);
+
+        Assert.False(result.AlreadyClosed);
+        Assert.Equal(SessionState.Closed, result.FinalState);
+        Assert.Equal(1, workerClient.KillCount);
+        Assert.Equal(0, workerClient.ShutdownCount);
+        Assert.False(manager.TryGetSession(session.SessionId, out _));
+        Assert.Equal(1, metrics.GetSnapshot().SessionsClosed);
+        Assert.Equal(0, metrics.GetSnapshot().OpenSessions);
+    }
+
+    /// <summary>Verifies that killing the worker for an unknown session raises SessionNotFound.</summary>
+    [Fact]
+    public async Task KillWorkerAsync_WhenSessionMissing_ThrowsSessionNotFound()
+    {
+        SessionManager manager = CreateManager(new FakeSessionWorkerClientFactory(new FakeWorkerClient()));
+
+        SessionManagerException exception = await Assert.ThrowsAsync<SessionManagerException>(
+            async () => await manager.KillWorkerAsync("session-missing", "test-kill", CancellationToken.None));
+
+        Assert.Equal(SessionManagerErrorCode.SessionNotFound, exception.ErrorCode);
+    }
+
     /// <summary>Verifies that when worker creation fails, the session is removed from the registry.</summary>
     [Fact]
     public async Task OpenSessionAsync_WhenWorkerCreationFails_RemovesSessionFromRegistry()
diff --git a/src/ZB.MOM.WW.MxGateway.Tests/Security/Authorization/GatewayGrpcAuthorizationInterceptorTests.cs b/src/ZB.MOM.WW.MxGateway.Tests/Security/Authorization/GatewayGrpcAuthorizationInterceptorTests.cs
index e7cc3c5..c171b3a 100644
--- a/src/ZB.MOM.WW.MxGateway.Tests/Security/Authorization/GatewayGrpcAuthorizationInterceptorTests.cs
+++ b/src/ZB.MOM.WW.MxGateway.Tests/Security/Authorization/GatewayGrpcAuthorizationInterceptorTests.cs
@@ -458,6 +458,15 @@ public sealed class GatewayGrpcAuthorizationInterceptorTests
             return Task.FromResult(new SessionCloseResult(sessionId, SessionState.Closed, AlreadyClosed: false));
         }
 
+        /// <inheritdoc />
+        public Task<SessionCloseResult> KillWorkerAsync(
+            string sessionId,
+            string reason,
+            CancellationToken cancellationToken)
+        {
+            return Task.FromResult(new SessionCloseResult(sessionId, SessionState.Closed, AlreadyClosed: false));
+        }
+
         /// <inheritdoc />
         public Task<int> CloseExpiredLeasesAsync(
             DateTimeOffset now,