refactor(telemetry.serilog): review fixes (thread-safe redactor, bootstrap logger, minlevel ordering, test coverage)

ZB.MOM.WW.Telemetry/src/ZB.MOM.WW.Telemetry.Serilog/ZbSerilogExtensions.cs

@@ -1,5 +1,3 @@
-using Microsoft.Extensions.Configuration;
-using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Serilog;
 using Serilog.Events;
@@ -8,22 +6,46 @@ using ZB.MOM.WW.Telemetry;
 namespace ZB.MOM.WW.Telemetry.Serilog;
 
 /// <summary>
-/// Extension point for configuring the shared Serilog bootstrap on an
+/// Extension point for configuring the shared Serilog two-stage bootstrap on an
 /// <see cref="IHostApplicationBuilder"/>. Wires config-driven sinks
 /// (<c>ReadFrom.Configuration</c>), an explicit minimum level (<c>Serilog:MinimumLevel</c>,
 /// default <see cref="LogEventLevel.Information"/>), and the shared enricher/redaction/OTel-export
 /// set via <see cref="ZbSerilogConfig"/>. Does NOT configure OTel metrics/traces — call
 /// <c>AddZbTelemetry</c> in the core package for that.
+///
+/// <para>
+/// Stage 1 (bootstrap): sets <see cref="Log.Logger"/> to a console-only logger before
+/// <c>Build()</c> is called, capturing any startup exceptions that occur before the DI
+/// container is ready.
+/// </para>
+/// <para>
+/// Stage 2 (application): wires the full Serilog pipeline via
+/// <see cref="SerilogHostBuilderExtensions.UseSerilog(IHostBuilder,Action{HostBuilderContext,IServiceProvider,LoggerConfiguration},bool,bool)"/>
+/// once the host builds, replacing the bootstrap logger with the configuration-driven one.
+/// </para>
 /// </summary>
 public static class ZbSerilogExtensions
 {
     /// <summary>
-    /// Registers Serilog on the host with the shared ZB.MOM.WW configuration: sinks read from
-    /// <see cref="IConfiguration"/> (<c>ReadFrom.Configuration</c>), an explicit minimum level
-    /// (<c>Serilog:MinimumLevel</c>, default <see cref="LogEventLevel.Information"/>), and the
-    /// identity enrichers (<c>SiteId</c>/<c>NodeRole</c> from <paramref name="configure"/>,
-    /// <c>NodeHostname</c> = <see cref="System.Environment.MachineName"/>). The
-    /// <paramref name="configure"/> delegate receives the same <see cref="ZbTelemetryOptions"/>
+    /// Registers Serilog on the host with a two-stage bootstrap:
+    /// <list type="number">
+    /// <item>
+    ///   <description>
+    ///   Stage 1 — immediately sets <see cref="Log.Logger"/> to a console-only bootstrap logger
+    ///   so that startup exceptions before <c>Build()</c> are captured.
+    ///   </description>
+    /// </item>
+    /// <item>
+    ///   <description>
+    ///   Stage 2 — registers the full pipeline via <c>AddSerilog</c>: configuration-driven sinks
+    ///   (<c>ReadFrom.Configuration</c>), a code default of <see cref="LogEventLevel.Information"/>
+    ///   that config can override via <c>Serilog:MinimumLevel</c> or namespace overrides, plus
+    ///   the identity enrichers (<c>SiteId</c>/<c>NodeRole</c> from <paramref name="configure"/>,
+    ///   <c>NodeHostname</c> = <see cref="System.Environment.MachineName"/>).
+    ///   </description>
+    /// </item>
+    /// </list>
+    /// The <paramref name="configure"/> delegate receives the same <see cref="ZbTelemetryOptions"/>
     /// used by <c>AddZbTelemetry</c> — typically share one options-population lambda across both.
     /// </summary>
     /// <param name="builder">The host application builder.</param>
@@ -38,32 +60,21 @@ public static class ZbSerilogExtensions
         var options = new ZbTelemetryOptions();
         configure(options);
 
-        var minimumLevel = ReadMinimumLevel(builder.Configuration);
+        // Stage 1: bootstrap logger captures startup exceptions before Build().
+        Log.Logger = new LoggerConfiguration()
+            .WriteTo.Console()
+            .CreateBootstrapLogger();
 
+        // Stage 2: full application logger — code default first, then config overrides.
         builder.Services.AddSerilog((serviceProvider, loggerConfiguration) =>
         {
             loggerConfiguration
-                .ReadFrom.Configuration(builder.Configuration)
-                .MinimumLevel.Is(minimumLevel);
+                .MinimumLevel.Is(LogEventLevel.Information)
+                .ReadFrom.Configuration(builder.Configuration);
 
             ZbSerilogConfig.Apply(loggerConfiguration, options, serviceProvider);
         });
 
         return builder;
     }
-
-    /// <summary>
-    /// Reads <c>Serilog:MinimumLevel</c> (or the nested <c>Serilog:MinimumLevel:Default</c>) from
-    /// configuration, falling back to <see cref="LogEventLevel.Information"/> for missing or
-    /// unparseable values.
-    /// </summary>
-    private static LogEventLevel ReadMinimumLevel(IConfiguration configuration)
-    {
-        var raw = configuration["Serilog:MinimumLevel"]
-            ?? configuration["Serilog:MinimumLevel:Default"];
-
-        return Enum.TryParse<LogEventLevel>(raw, ignoreCase: true, out var parsed)
-            ? parsed
-            : LogEventLevel.Information;
-    }
 }