Init

Prefab.Web/Workers/DataSeeder.cs

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+using Microsoft.EntityFrameworkCore;
+using Prefab.Web.Data;
+
+namespace Prefab.Web.Workers;
+
+/// <summary>
+/// Background service for seeding data. Collects seed tasks from a channel and executes them concurrently.
+/// </summary>
+public class DataSeeder(IServiceProvider serviceProvider, IConfiguration configuration, ILogger<DataSeeder> logger) : BackgroundService
+{
+    private readonly int _workerCount = configuration.GetValue("DataSeederWorkerCount", 4);
+    
+    private bool _databaseIsAvailable;
+    
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            if (_databaseIsAvailable)
+            {
+                var tasks = new List<Task>();
+
+                for (var i = 0; i < _workerCount; i++)
+                {
+                    tasks.Add(Task.Run(async () =>
+                    {
+                        await foreach (var seedTask in Prefab.Data.Seeder.Extensions.Channel.Reader.ReadAllAsync(stoppingToken))
+                        {
+                            try
+                            {
+                                await seedTask(serviceProvider, stoppingToken);
+                                logger.LogInformation("Seed task executed successfully.");
+                            }
+                            catch (Exception ex)
+                            {
+                                logger.LogError(ex, "Error executing seed task.");
+                                // Optionally, add retry logic here.
+                            }
+                        }
+                    }, stoppingToken));
+                }
+
+                await Task.WhenAll(tasks);
+            }
+            else
+            {
+                await WaitForDatabaseToAvailable(stoppingToken);
+            }
+        }
+    }
+    
+    private async Task WaitForDatabaseToAvailable(CancellationToken stoppingToken)
+    {
+        using var scope = serviceProvider.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<AppDb>();
+        var contextName = db.GetType().Name;
+        var loggerHasLoggedWaitingOnDatabaseMessage = false;
+        
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            try
+            {
+                if (await db.Database.CanConnectAsync(stoppingToken))
+                {
+                    if (loggerHasLoggedWaitingOnDatabaseMessage)
+                    {
+                        logger.LogInformation("Database connectivity confirmed for context {Context}.", contextName);
+                    }
+
+                    try
+                    {
+                        logger.LogInformation("Applying migrations for context {Context}...", contextName);
+                        await db.Database.MigrateAsync(stoppingToken);
+                        logger.LogInformation("Migrations applied for context {Context}.", contextName);
+                    }
+                    catch (Exception ex)
+                    {
+                        logger.LogError(ex, "Failed to apply migrations for context {Context}. Retrying shortly.", contextName);
+                        await Task.Delay(TimeSpan.FromSeconds(1), stoppingToken);
+                        continue;
+                    }
+                        
+                    _databaseIsAvailable = true;
+
+                    return;
+                }
+            }
+            catch (Exception ex)
+            {
+                logger.LogDebug(ex, "Database connectivity probe failed for context {Context}.", contextName);
+            }
+                
+            if (!loggerHasLoggedWaitingOnDatabaseMessage)
+            {
+                logger.LogInformation("Waiting for database availability before applying migrations for context {Context}...", contextName);
+                loggerHasLoggedWaitingOnDatabaseMessage = true;
+            }
+
+            await Task.Delay(TimeSpan.FromSeconds(1), stoppingToken);
+        }
+    }
+}