Replace Hangfire with custom CRON job runner

.gitignore

@@ -368,4 +368,8 @@ FodyWeavers.xsd
 *.code-workspace
 
 # Postgress data
-postgres-data/
+postgres-data/
+
+# VS Code
+.vscode
+

HonzaBotner.sln

@@ -9,6 +9,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 	ProjectSection(SolutionItems) = preProject
 		Directory.Build.props = Directory.Build.props
 		CONTRIBUTING.md = CONTRIBUTING.md
+		Packages.props = Packages.props
 	EndProjectSection
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "HonzaBotner", "src\HonzaBotner\HonzaBotner.csproj", "{04BEA8DF-6FDB-465A-BF6C-D28BADBD572F}"
@@ -23,6 +24,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "HonzaBotner.Database", "src
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "HonzaBotner.Services.Test", "src\HonzaBotner.Services.Test\HonzaBotner.Services.Test.csproj", "{AB6030AC-D422-4A52-A980-08D3836E4437}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "HonzaBotner.Scheduler", "src\HonzaBotner.Scheduler\HonzaBotner.Scheduler.csproj", "{3C66CBA5-C1F4-4B3E-8D23-94B15652A452}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -57,6 +60,10 @@ Global
 		{AB6030AC-D422-4A52-A980-08D3836E4437}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{AB6030AC-D422-4A52-A980-08D3836E4437}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{AB6030AC-D422-4A52-A980-08D3836E4437}.Release|Any CPU.Build.0 = Release|Any CPU
+		{3C66CBA5-C1F4-4B3E-8D23-94B15652A452}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{3C66CBA5-C1F4-4B3E-8D23-94B15652A452}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{3C66CBA5-C1F4-4B3E-8D23-94B15652A452}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{3C66CBA5-C1F4-4B3E-8D23-94B15652A452}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

Packages.props

@@ -1,6 +1,7 @@
 <Project>
     <ItemGroup>
         <PackageReference Update="Chronic.Core" Version="0.4.0" />
+        <PackageReference Update="Cronos" Version="0.7.1" />
         <PackageReference Update="DSharpPlus" Version="4.1.0" />
         <PackageReference Update="DSharpPlus.CommandsNext" Version="4.1.0" />
         <PackageReference Update="DSharpPlus.Interactivity" Version="4.1.0" />
@@ -26,5 +27,6 @@
         <PackageReference Update="coverlet.collector" Version="3.1.0" />
         <PackageReference Update="xunit" Version="2.4.1" />
         <PackageReference Update="xunit.runner.visualstudio" Version="2.4.3" />
+        <PackageReference Update="Shouldly" Version="4.0.3" />
     </ItemGroup>
-</Project>
+</Project>

src/HonzaBotner.Database/CountedEmoji.cs

@@ -6,6 +6,6 @@ public class CountedEmoji
     {
         public ulong Id { get; set; }
         public ulong Times { get; set; }
-        public DateTime FirstUsedAt { get; set; } = DateTime.Now;
+        public DateTime FirstUsedAt { get; set; } = DateTime.UtcNow;
     }
 }

src/HonzaBotner.Discord.Services/Commands/ReminderCommands.cs

@@ -51,7 +51,7 @@ public async Task Create(
             string? content
         )
         {
-            DateTime now = DateTime.Now;
+            DateTime now = DateTime.UtcNow;
             DateTime? datetime = ParseDateTime(rawDatetime);
 
             if (content == null)
@@ -89,7 +89,7 @@ await context.RespondErrorAsync(
                 context.User.Id,
                 message.Id,
                 message.ChannelId,
-                datetime.Value, // This is safe, as the nullability is validated above
+                datetime.Value.ToUniversalTime(), // This is safe, as the nullability is validated above
                 content
             );
 

src/HonzaBotner.Discord.Services/Extensions/CommandContextExtensions.cs

@@ -14,7 +14,7 @@ public static async Task RespondErrorAsync(this CommandContext context, string t
                 .WithTitle(title.RemoveDiscordMentions(context.Guild))
                 .WithDescription(content?.RemoveDiscordMentions(context.Guild) ?? "No additional content provided")
                 .WithColor(DiscordColor.Red)
-                .WithTimestamp(DateTime.Now)
+                .WithTimestamp(DateTime.UtcNow)
                 .Build();
 
             await context.RespondAsync(embed);

src/HonzaBotner.Discord.Services/HonzaBotner.Discord.Services.csproj

@@ -3,12 +3,12 @@
   <ItemGroup>
     <ProjectReference Include="..\HonzaBotner.Database\HonzaBotner.Database.csproj" />
     <ProjectReference Include="..\HonzaBotner.Discord\HonzaBotner.Discord.csproj" />
+    <ProjectReference Include="..\HonzaBotner.Scheduler\HonzaBotner.Scheduler.csproj" />
     <ProjectReference Include="..\HonzaBotner.Services.Contract\HonzaBotner.Services.Contract.csproj" />
   </ItemGroup>
 
   <ItemGroup>
     <PackageReference Include="Chronic.Core" />
-    <PackageReference Include="Hangfire.Core" />
   </ItemGroup>
-  
+
 </Project>

src/HonzaBotner.Discord.Services/Jobs/TriggerRemindersJobProvider.cs

@@ -1,18 +1,20 @@
 using System;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using DSharpPlus.Entities;
-using Hangfire;
 using HonzaBotner.Discord.Managers;
 using HonzaBotner.Discord.Services.Options;
+using HonzaBotner.Scheduler.Contract;
 using HonzaBotner.Services.Contract;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 using HonzaBotner.Services.Contract.Dto;
 
 namespace HonzaBotner.Discord.Services.Jobs
 {
-    public class TriggerRemindersJobProvider : IRecurringJobProvider
+    [Cron("*/5 * * * * *")]
+    public class TriggerRemindersJobProvider : IJob
     {
         private readonly IRemindersService _remindersService;
 
@@ -39,13 +41,11 @@ IReminderManager reminderManager
             _reminderManager = reminderManager;
         }
 
-        public const string Key = "reminders-trigger";
+        public string Name { get; } = "reminders-trigger";
 
-        public static string CronExpression => Cron.Minutely();
-
-        public async Task Run()
+        public async Task ExecuteAsync(CancellationToken cancellationToken)
         {
-            var now = DateTime.Now; // Fix one point in time.
+            var now = DateTime.UtcNow; // Fix one point in time.
             var reminders = await _remindersService.GetRemindersToExecuteAsync(now);
             await _remindersService.DeleteExecutedRemindersAsync(now);
 

src/HonzaBotner.Discord/Extensions/DiscordExtensions.cs

@@ -20,7 +20,7 @@ await channel.SendMessageAsync(
                     .WithColor(DiscordColor.Red)
                     .AddField("Message:", exception.Message, true)
                     .AddField("Stack Trace:", Truncate(exception.StackTrace ?? "No stack trace", 500))
-                    .WithTimestamp(DateTime.Now)
+                    .WithTimestamp(DateTime.UtcNow)
                     .WithDescription(
                         "Please react to this message to indicate that it is already logged in isssue or solved"
                     )

src/HonzaBotner.Scheduler/Contract/CronAttribute.cs

@@ -0,0 +1,15 @@
+using System;
+
+namespace HonzaBotner.Scheduler.Contract
+{
+    [AttributeUsage(AttributeTargets.Class)]
+    public class CronAttribute : Attribute
+    {
+        public string Expression { get; }
+
+        public CronAttribute(string expression)
+        {
+            Expression = expression;
+        }
+    }
+}

src/HonzaBotner.Scheduler/Contract/ICronJob.cs

@@ -0,0 +1,8 @@
+namespace HonzaBotner.Scheduler.Contract
+{
+    public interface ICronJob : IJob
+    {
+        string CronExpression { get; }
+
+    }
+}

src/HonzaBotner.Scheduler/Contract/IJob.cs

@@ -0,0 +1,12 @@
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace HonzaBotner.Scheduler.Contract
+{
+    public interface IJob
+    {
+        string Name { get; }
+
+        Task ExecuteAsync(CancellationToken cancellationToken = default);
+    }
+}

src/HonzaBotner.Scheduler/CronJobWrapper.cs

@@ -0,0 +1,39 @@
+using System;
+using Cronos;
+using HonzaBotner.Scheduler.Contract;
+
+namespace HonzaBotner.Scheduler
+{
+    internal class CronJobWrapper
+    {
+        private const string CetId = "Central Europe Standard Time";
+        private readonly TimeZoneInfo _centralEuropeTimezone =
+            TimeZoneInfo.FindSystemTimeZoneById(CetId);
+
+        public CronJobWrapper(ICronJob job, string cronExpression, DateTime nextRunTime)
+        {
+            Job = job;
+            Expression = CronExpression.Parse(cronExpression, CronFormat.IncludeSeconds);
+            NextRunTime = nextRunTime;
+        }
+
+        public ICronJob Job { get; }
+        private CronExpression Expression { get; }
+
+        public DateTime NextRunTime { get; private set; }
+        public DateTime LastRunTime { get; private set; }
+
+
+        public void Next()
+        {
+            LastRunTime = NextRunTime;
+            NextRunTime = Expression.GetNextOccurrence(NextRunTime, _centralEuropeTimezone) ?? NextRunTime;
+        }
+
+        public bool ShouldRun(DateTime currentTime)
+        {
+            return NextRunTime < currentTime && LastRunTime != NextRunTime;
+        }
+    }
+}
+

src/HonzaBotner.Scheduler/HonzaBotner.Scheduler.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <ItemGroup>
+      <PackageReference Include="Cronos" />
+      <PackageReference Include="Microsoft.Extensions.Hosting.Abstractions" />
+      <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" />
+    </ItemGroup>
+
+</Project>

src/HonzaBotner.Scheduler/InvalidConfigurationException.cs

@@ -0,0 +1,14 @@
+using System;
+
+namespace HonzaBotner.Scheduler
+{
+    public class InvalidConfigurationException : Exception
+    {
+        public Type Type { get; }
+
+        public InvalidConfigurationException(string message, Type type) : base(message)
+        {
+            Type = type;
+        }
+    }
+}

src/HonzaBotner.Scheduler/SchedulerHostedService.cs

@@ -0,0 +1,68 @@
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using HonzaBotner.Scheduler.Contract;
+
+namespace HonzaBotner.Scheduler
+{
+    public class SchedulerHostedService : BackgroundService
+    {
+        private readonly int _delay;
+        private readonly ILogger<SchedulerHostedService> _logger;
+        private readonly IList<CronJobWrapper> _cronJobs;
+
+        public SchedulerHostedService(int delay, IEnumerable<ICronJob> cronJobs, ILogger<SchedulerHostedService> logger)
+        {
+            DateTime now = DateTime.UtcNow;
+
+            _delay = delay;
+            _logger = logger;
+            _cronJobs = cronJobs
+                .Select(j => new CronJobWrapper(j, j.CronExpression, now))
+                .ToList();
+        }
+
+        protected override async Task ExecuteAsync(CancellationToken cancellationToken)
+        {
+            while (!cancellationToken.IsCancellationRequested)
+            {
+                DateTime currentTime = DateTime.UtcNow;
+
+               _logger.LogInformation("Scheduler running at: {Time}", currentTime.ToLocalTime());
+               await RunOnceAsync(currentTime, cancellationToken);
+
+               await Task.Delay(_delay, cancellationToken);
+            }
+        }
+
+        private async Task RunOnceAsync(DateTime currentTime, CancellationToken cancellationToken)
+        {
+            TaskFactory taskFactory = new(TaskScheduler.Current);
+
+            IList<CronJobWrapper> jobsToRun = _cronJobs.Where(job => job.ShouldRun(currentTime)).ToList();
+
+            foreach (CronJobWrapper cronJob in jobsToRun)
+            {
+                cronJob.Next();
+
+                await taskFactory.StartNew(async () =>
+                {
+                    try
+                    {
+                        _logger.LogInformation("Starting job {JobType}", cronJob.Job.Name);
+                        await cronJob.Job.ExecuteAsync(cancellationToken);
+                    }
+                    catch (Exception e)
+                    {
+                        _logger.LogError(e,"Job {JobType} failed", cronJob.Job.Name);
+                        // NOTE: Exception is not propagated, since we dont want crash scheduler.
+                    }
+                }, cancellationToken);
+            }
+        }
+    }
+}

src/HonzaBotner.Scheduler/ScopedSchedulerJobWrapper.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using HonzaBotner.Scheduler.Contract;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+
+namespace HonzaBotner.Scheduler
+{
+    internal class ScopedSchedulerJobProvider<TJob> : ICronJob where TJob : class, IJob
+    {
+        private readonly IServiceProvider _serviceProvider;
+        private readonly ILogger<ScopedSchedulerJobProvider<TJob>> _logger;
+        public string Name { get; } = typeof(TJob).Name;
+        public string CronExpression { get; }
+
+        public ScopedSchedulerJobProvider(string cronExpression, IServiceProvider serviceProvider,
+            ILogger<ScopedSchedulerJobProvider<TJob>> logger)
+        {
+            _serviceProvider = serviceProvider;
+            _logger = logger;
+
+            CronExpression = cronExpression;
+        }
+
+        public async Task ExecuteAsync(CancellationToken cancellationToken = default)
+        {
+            _logger.LogDebug("Creating scope for {JobName}", Name);
+            await using AsyncServiceScope scope = _serviceProvider.CreateAsyncScope();
+
+            IJob cronJob = scope.ServiceProvider.GetRequiredService<TJob>();
+
+            await cronJob.ExecuteAsync(cancellationToken);
+        }
+    }
+}