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Added hosted services for monitoring instance lifetimes

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This commit is contained in:
Raymond den Haan 2024-02-09 14:07:04 +01:00
parent 9397fa1192
commit dd4c33c8cb
5 changed files with 192 additions and 0 deletions
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33
src/modules/Elsa.Hosting.Management/Elsa.Hosting.Management.csproj Normal file
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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<ImplicitUsings>enable</ImplicitUsings>
<Nullable>enable</Nullable>
<TargetFrameworks>net6.0;net7.0;net8.0</TargetFrameworks>
<LangVersion>latest</LangVersion>
<Copyright>2024</Copyright>
<PackageProjectUrl>https://github.com/elsa-workflows/elsa-core</PackageProjectUrl>
<PackageIcon>icon.png</PackageIcon>
<RepositoryUrl>https://github.com/elsa-workflows/elsa-core</RepositoryUrl>
</PropertyGroup>
<PropertyGroup>
<Description>
Provides hosting management functionality.
</Description>
<PackageTags>elsa module hosting</PackageTags>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.Extensions.Hosting.Abstractions" Version="8.0.0" />
</ItemGroup>
<ItemGroup>
<ProjectReference Include="..\Elsa.Workflows.Runtime\Elsa.Workflows.Runtime.csproj" />
</ItemGroup>
<ItemGroup>
<ProjectReference Include="..\Elsa.Workflows.Runtime\Elsa.Workflows.Runtime.csproj" />
</ItemGroup>
</Project>

81
src/modules/Elsa.Hosting.Management/HostedServices/InstanceHeartbeatMonitorService.cs Normal file
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using Elsa.Hosting.Management.Notifications;
using Elsa.Hosting.Management.Options;
using Elsa.Mediator.Contracts;
using Elsa.Workflows.Runtime.Contracts;
using Elsa.Workflows.Runtime.Models;
using Medallion.Threading;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Options;
namespace Elsa.Hosting.Management.HostedServices;
/// <summary>
/// Service to check the heartbeats of all running instances and determine whether instances have stopped working.
/// </summary>
public class InstanceHeartbeatMonitorService : IHostedService, IDisposable
{
private readonly IServiceProvider _serviceProvider;
private readonly HeartbeatSettings _heartbeatSettings;
private Timer? _timer;
/// <summary>
/// Creates a new instance of the <see cref="InstanceHeartbeatService"/>
/// </summary>
public InstanceHeartbeatMonitorService(IServiceProvider serviceProvider, IOptions<HeartbeatSettings> heartbeatSettings)
{
_serviceProvider = serviceProvider;
_heartbeatSettings = heartbeatSettings.Value;
}
public Task StartAsync(CancellationToken cancellationToken)
{
_timer = new Timer(MonitorHeartbeats, null, TimeSpan.Zero, _heartbeatSettings.InstanceHeartbeatRythm);
return Task.CompletedTask;
}
public Task StopAsync(CancellationToken cancellationToken)
{
_timer?.Change(Timeout.Infinite, Timeout.Infinite);
return Task.CompletedTask;
}
public void Dispose()
{
_timer?.Dispose();
}
private void MonitorHeartbeats(object? state)
{
_ = Task.Run(async () => await MonitorHeartbeatsAsync());
}
private async Task MonitorHeartbeatsAsync()
{
using var scope = _serviceProvider.CreateScope();
var lockProvider = scope.ServiceProvider.GetRequiredService<IDistributedLockProvider>();
var store = scope.ServiceProvider.GetRequiredService<IKeyValueStore>();
var notificationSender = scope.ServiceProvider.GetRequiredService<INotificationSender>();
var lockKey = "InstanceHeartbeatMonitorService";
await using var monitorLock = await lockProvider.TryAcquireLockAsync(lockKey, TimeSpan.Zero);
if (monitorLock == null)
return;
var filter = new KeyValueFilter { StartsWith = true, Key = "Heartbeat_" };
var heartbeats = await store.FindManyAsync(filter, default);
foreach (var heartbeat in heartbeats)
{
var lastHeartbeat = DateTime.Parse(heartbeat.SerializedValue);
if (DateTime.UtcNow - lastHeartbeat <= _heartbeatSettings.InstanceDeactivatedPeriod)
{
continue;
}
var instanceName = heartbeat.Key.Substring(InstanceHeartbeatService.HeartbeatKeyPrefix.Length);
await notificationSender.SendAsync(new InstanceDeactivated(instanceName));
}
}
}

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src/modules/Elsa.Hosting.Management/HostedServices/InstanceHeartbeatService.cs Normal file
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using Elsa.Hosting.Management.Options;
using Elsa.Workflows.Contracts;
using Elsa.Workflows.Runtime.Contracts;
using Elsa.Workflows.Runtime.Entities;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Options;
namespace Elsa.Hosting.Management.HostedServices;
/// <summary>
/// Service to write heartbeat messages per running instance.
/// </summary>
public class InstanceHeartbeatService : IHostedService, IDisposable
{
private readonly IServiceProvider _serviceProvider;
private readonly HeartbeatSettings _heartbeatSettings;
private Timer? _timer;
internal static string HeartbeatKeyPrefix = "Heartbeat_";
/// <summary>
/// Creates a new instance of the <see cref="InstanceHeartbeatService"/>
/// </summary>
public InstanceHeartbeatService(IServiceProvider serviceProvider, IOptions<HeartbeatSettings> heartbeatSettings)
{
_serviceProvider = serviceProvider;
_heartbeatSettings = heartbeatSettings.Value;
}
public Task StartAsync(CancellationToken cancellationToken)
{
_timer = new Timer(WriteHeartbeat, null, TimeSpan.Zero, _heartbeatSettings.InstanceHeartbeatRythm);
return Task.CompletedTask;
}
public Task StopAsync(CancellationToken cancellationToken)
{
_timer?.Change(Timeout.Infinite, Timeout.Infinite);
return Task.CompletedTask;
}
public void Dispose()
{
_timer?.Dispose();
}
private void WriteHeartbeat(object? state)
{
_ = Task.Run(async () => await WriteHeartbeatAsync());
}
private async Task WriteHeartbeatAsync()
{
using var scope = _serviceProvider.CreateScope();
var instanceNameRetriever = scope.ServiceProvider.GetRequiredService<IInstanceNameRetriever>();
var store = scope.ServiceProvider.GetRequiredService<IKeyValueStore>();
await store.SaveAsync(new SerializedKeyValuePair
{
Key = $"{HeartbeatKeyPrefix}{instanceNameRetriever.GetName()}",
SerializedValue = DateTime.UtcNow.ToString("o")
},
default);
}
}

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src/modules/Elsa.Hosting.Management/Notifications/InstanceDeactivated.cs Normal file
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using Elsa.Mediator.Contracts;
namespace Elsa.Hosting.Management.Notifications;
public record InstanceDeactivated(string InstanceName) : INotification;

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src/modules/Elsa.Hosting.Management/Options/HeartbeatSettings.cs Normal file
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namespace Elsa.Hosting.Management.Options;
public class HeartbeatSettings
{
public TimeSpan InstanceHeartbeatRythm { get; set; } = TimeSpan.FromMinutes(1);
public TimeSpan InstanceDeactivatedPeriod { get; set; } = TimeSpan.FromHours(1);
}