Files
scadaproj/ZB.MOM.WW.Telemetry/src/ZB.MOM.WW.Telemetry.Serilog/ZbSerilogExtensions.cs
T
Joseph Doherty f569d537d1 fix(telemetry.serilog): don't set process-global Log.Logger in AddZbSerilog (multi-host safe)
Remove the Stage-1 bootstrap-logger line (Log.Logger = new LoggerConfiguration()
.WriteTo.Console().CreateBootstrapLogger()) from AddZbSerilog. A shared library must
not mutate process-global state: when multiple hosts are built in one process (integration
tests, Aspire multi-host, parallel test runs) the second call throws "The logger is
already frozen".

AddSerilog is now called with preserveStaticLogger: true so Serilog.Extensions.Hosting
leaves the static Log.Logger entirely untouched. The DI-registered application logger is
the only artifact AddZbSerilog produces.

Apps that want a pre-Build() bootstrap logger should set Log.Logger themselves in
Program.cs before calling AddZbSerilog — that decision belongs to the application.

Three new regression tests in MultiHostTests verify: two hosts build in the same process
without throwing; Log.Logger is not mutated; each host gets its own independent DI ILogger.

Docs (SPEC.md §5 and shared-contract ZB.MOM.WW.Telemetry.md) updated: the "two-stage
bootstrap" framing is replaced with the correct description — library registers only the
DI application logger; optional Stage-1 bootstrap is the app's responsibility.
2026-06-01 08:13:35 -04:00

85 lines
3.9 KiB
C#

using Microsoft.Extensions.Hosting;
using Serilog;
using Serilog.Events;
using ZB.MOM.WW.Telemetry;
namespace ZB.MOM.WW.Telemetry.Serilog;
/// <summary>
/// Extension point for configuring the shared Serilog application logger 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>
/// This method intentionally does <strong>not</strong> set the process-global
/// <see cref="Log.Logger"/> (via <c>CreateBootstrapLogger</c> or otherwise). Mutating
/// process-global state in a shared library causes "logger is already frozen" exceptions
/// when multiple hosts are built in the same process (integration tests, multi-host apps).
/// </para>
/// <para>
/// Apps that need a pre-<c>Build()</c> bootstrap logger to capture early startup exceptions
/// should set <see cref="Log.Logger"/> themselves in <c>Program.cs</c> before calling
/// <c>AddZbSerilog</c>:
/// <code>
/// Log.Logger = new LoggerConfiguration().WriteTo.Console().CreateBootstrapLogger();
/// // ... then build the host ...
/// builder.AddZbSerilog(o => { ... });
/// </code>
/// This keeps global-state mutation firmly in the application, not the library.
/// </para>
/// </summary>
public static class ZbSerilogExtensions
{
/// <summary>
/// Registers the Serilog application logger in DI. Wires 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"/>).
///
/// <para>
/// This method does <strong>not</strong> set the process-global <see cref="Log.Logger"/>.
/// <c>preserveStaticLogger: true</c> is passed to <c>AddSerilog</c> so the static logger
/// is left entirely untouched — safe to call multiple times in the same process (integration
/// tests, multi-host scenarios) without hitting "logger is already frozen".
/// </para>
/// <para>
/// If early-startup bootstrap logging is required (before <c>Build()</c>), set
/// <c>Log.Logger = new LoggerConfiguration().WriteTo.Console().CreateBootstrapLogger();</c>
/// in <c>Program.cs</c> before calling this method. That decision belongs to the
/// application, not the shared library.
/// </para>
/// </summary>
/// <param name="builder">The host application builder.</param>
/// <param name="configure">Populates the <see cref="ZbTelemetryOptions"/>.</param>
public static IHostApplicationBuilder AddZbSerilog(
this IHostApplicationBuilder builder,
Action<ZbTelemetryOptions> configure)
{
ArgumentNullException.ThrowIfNull(builder);
ArgumentNullException.ThrowIfNull(configure);
var options = new ZbTelemetryOptions();
configure(options);
// Register the application logger in DI only. preserveStaticLogger: true ensures
// AddSerilog does NOT freeze or replace Log.Logger — critical for multi-host
// processes (integration tests etc.) where AddZbSerilog may be called more than once.
builder.Services.AddSerilog(
(serviceProvider, loggerConfiguration) =>
{
loggerConfiguration
.MinimumLevel.Is(LogEventLevel.Information)
.ReadFrom.Configuration(builder.Configuration);
ZbSerilogConfig.Apply(loggerConfiguration, options, serviceProvider);
},
preserveStaticLogger: true);
return builder;
}
}