optimize first run (#2516)

* do not accept ui requests until database is ready

* add empty database to greatly speed up initial startup

* remove middleware

CHANGELOG.md

@@ -11,6 +11,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   - Add `get_directory_name` and `get_filename_without_extension` functions for path processing
 - Add `Block Playout Troubleshooting` tool to help investigate block playout history
 - Add sequential schedule file and scripted schedule file names to playouts table
+- Add empty (but already up-to-date) sqlite3 database to greatly speed up initial startup for fresh installs
 
 ### Fixed
 - Fix NVIDIA startup errors on arm64

ErsatzTV/ErsatzTV.csproj

@@ -101,6 +101,7 @@
         <EmbeddedResource Include="Resources\Templates\_song.sbntxt" />
         <EmbeddedResource Include="Resources\sequential-schedule-import.schema.json" />
         <EmbeddedResource Include="Resources\sequential-schedule.schema.json" />
+        <EmbeddedResource Include="Resources\empty.sqlite3" />
     </ItemGroup>
 
     <ItemGroup>

ErsatzTV/Services/RunOnce/DatabaseMigratorService.cs

@@ -1,4 +1,5 @@
-using Dapper;
+using System.Reflection;
+using Dapper;
 using ErsatzTV.Core;
 using ErsatzTV.Infrastructure.Data;
 using Microsoft.Data.Sqlite;
@@ -26,11 +27,24 @@ public class DatabaseMigratorService : BackgroundService
     {
         await Task.Yield();
 
-        _logger.LogInformation("Applying database migrations");
-
         using IServiceScope scope = _serviceScopeFactory.CreateScope();
         await using TvContext dbContext = scope.ServiceProvider.GetRequiredService<TvContext>();
 
+        // extract empty database to speed up initial startup
+        if (TvContext.IsSqlite && !File.Exists(FileSystemLayout.DatabasePath))
+        {
+            _logger.LogInformation("Extracting empty database to {DatabasePath}", FileSystemLayout.DatabasePath);
+            await using Stream resource = typeof(ResourceExtractorService).GetTypeInfo().Assembly
+                .GetManifestResourceStream("ErsatzTV.Resources.empty.sqlite3");
+            if (resource != null)
+            {
+                await using FileStream fs = File.Create(FileSystemLayout.DatabasePath);
+                await resource.CopyToAsync(fs, stoppingToken);
+            }
+        }
+
+        _logger.LogInformation("Applying database migrations");
+
         if (TvContext.IsSqlite)
         {
             int count = await dbContext.Connection.ExecuteScalarAsync<int>(