36 lines
2.1 KiB
C#
36 lines
2.1 KiB
C#
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using CShells.Lifecycle;
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using Elsa.Workflows.Runtime.Services;
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using Microsoft.Extensions.Hosting;
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using Microsoft.Extensions.Logging;
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namespace Elsa.Workflows.Runtime.Lifecycle;
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/// <summary>
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/// CShells <see cref="IDrainHandler"/> that bridges per-shell drain into the workflow runtime's
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/// <see cref="IDrainOrchestrator"/>. The shell platform invokes this when a shell enters
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/// <see cref="ShellLifecycleState.Draining"/> (e.g., on shell reload or host shutdown). The drain handler's
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/// <see cref="CancellationToken"/> is signalled when the CShells drain deadline elapses, so the orchestrator's
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/// own deadline-bounded protocol nests cleanly inside the per-shell deadline policy.
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/// </summary>
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/// <remarks>
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/// <para>
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/// Registered as transient via <c>IShellFeature.ConfigureServices</c>; CShells resolves all
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/// <see cref="IDrainHandler"/> implementations from the shell's <see cref="IServiceProvider"/> at draining time
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/// and invokes them in parallel. This gives FR-027 ("a shell moving into its deactivation phase drains that
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/// shell's runtime, scoped so sibling shells are unaffected") a first-class, per-shell mechanism — replacing
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/// the earlier R3 design that relied on <c>IHostApplicationLifetime.ApplicationStopping</c>.
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/// </para>
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/// <para>
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/// In CShells-hosted deployments this is the sole drain trigger: host stop reaches the runtime via CShells's
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/// shell-drain pipeline (<c>CShellsStartupHostedService.StopAsync</c>), not via a host-level
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/// <see cref="IHostedService"/>. The host-stop <c>DrainOrchestratorHostedService</c> registration only lives on
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/// the IModule <c>Features/WorkflowRuntimeFeature</c> path, where there is no shell platform.
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/// </para>
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/// </remarks>
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public sealed class ElsaShellDrainHandler(IDrainOrchestrator orchestrator, ILogger<ElsaShellDrainHandler> logger) : IDrainHandler
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{
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/// <inheritdoc />
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public Task DrainAsync(IDrainExtensionHandle extensionHandle, CancellationToken cancellationToken) =>
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DrainTriggerExecutor.RunAsync(orchestrator, DrainTrigger.ShellDeactivation, logger, "Shell drain", cancellationToken);
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}
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