Treat EventLevel.Verbose as debug log level

When using SDK diagnostics, the lowest supported log level for
OTEL_LOG_LEVEL is 'debug'. To align with this, we emit verbose
logs captured by the EventListener under debug.

This change also updates the logger messages to not use trace level
and prefer debug in those cases. This make diagnostics and support
easier as we only need to instruct the customer to use the levels as
supported upstream.

src/Elastic.OpenTelemetry.Core/Diagnostics/LoggerMessages.cs

@@ -12,10 +12,11 @@ namespace Elastic.OpenTelemetry.Diagnostics;
 
 internal static partial class LoggerMessages
 {
-	// NOTE:
-	// The IDs and EventNames should ideally not change to ensure constistency in log querying.
+	// NOTES:
+	// - The IDs and EventNames should ideally not change to ensure constistency in log querying.
+	// - Avoid using LogLevel.Trace as this level doesn't align well with the upstream diagnostic levels.
 
-	[LoggerMessage(EventId = 1, EventName = "BootstrapInvoked", Level = LogLevel.Trace, Message = "Bootstrap has been invoked {InvocationCount} times.")]
+	[LoggerMessage(EventId = 1, EventName = "BootstrapInvoked", Level = LogLevel.Debug, Message = "Bootstrap has been invoked {InvocationCount} times.")]
 	public static partial void LogBootstrapInvoked(this ILogger logger, int invocationCount);
 
 	[LoggerMessage(EventId = 2, EventName = "ComponentsCreated", Level = LogLevel.Debug, Message = "Elastic OpenTelemetry components created. {newline}{StackTrace}")]
@@ -31,10 +32,10 @@ internal static partial class LoggerMessages
 	[LoggerMessage(EventId = 5, EventName = "ServiceCollectionComponentsReused", Level = LogLevel.Debug, Message = "Reusing existing components on IServiceCollection.")]
 	public static partial void LogServiceCollectionComponentsReused(this ILogger logger);
 
-	[LoggerMessage(EventId = 6, EventName = "NoExistingComponents", Level = LogLevel.Trace, Message = "No existing components have been found for the {BuilderName} (instance:{BuilderInstanceId}).")]
+	[LoggerMessage(EventId = 6, EventName = "NoExistingComponents", Level = LogLevel.Debug, Message = "No existing components have been found for the {BuilderName} (instance:{BuilderInstanceId}).")]
 	public static partial void LogNoExistingComponents(this ILogger logger, string builderName, string builderInstanceId);
 
-	[LoggerMessage(EventId = 7, EventName = "StoringBuilderState", Level = LogLevel.Trace, Message = "Storing state for the current {BuilderName} (instance:{BuilderInstanceId}).")]
+	[LoggerMessage(EventId = 7, EventName = "StoringBuilderState", Level = LogLevel.Debug, Message = "Storing state for the current {BuilderName} (instance:{BuilderInstanceId}).")]
 	public static partial void LogStoringBuilderState(this ILogger logger, string builderName, string builderInstanceId);
 
 	[LoggerMessage(EventId = 8, EventName = "MultipleWithElasticDefaultsCalls", Level = LogLevel.Warning, Message = "The `WithElasticDefaults` method has been called {CallCount} " +
@@ -45,7 +46,7 @@ internal static partial class LoggerMessages
 		"times across all TracerProviderBuilder instances. This method is generally expected to be invoked on a single builder instance. Consider reviewing its usage.")]
 	public static partial void LogMultipleAddElasticProcessorsCallsWarning(this ILogger logger, int callCount);
 
-	[LoggerMessage(EventId = 10, EventName = "AddingResourceAttribute", Level = LogLevel.Trace, Message = "Adding resource attribute '{AttributeName}' with value '{AttributeValue}' to " +
+	[LoggerMessage(EventId = 10, EventName = "AddingResourceAttribute", Level = LogLevel.Debug, Message = "Adding resource attribute '{AttributeName}' with value '{AttributeValue}' to " +
 		"the ResourceBuilder (instance:{BuilderInstanceId}).")]
 	public static partial void LogAddingResourceAttribute(this ILogger logger, string attributeName, string attributeValue, string builderInstanceId);
 
@@ -79,7 +80,7 @@ internal static partial class LoggerMessages
 
 
 
-	[LoggerMessage(EventId = 30, EventName = "LocatedInstrumentationAssembly", Level = LogLevel.Trace, Message = "Located {AssemblyFilename} in {Path}.")]
+	[LoggerMessage(EventId = 30, EventName = "LocatedInstrumentationAssembly", Level = LogLevel.Debug, Message = "Located {AssemblyFilename} in {Path}.")]
 	public static partial void LogLocatedInstrumentationAssembly(this ILogger logger, string assemblyFilename, string path);
 
 	[LoggerMessage(EventId = 31, EventName = "AddedInstrumentation", Level = LogLevel.Debug, Message = "Added contrib instrumentation '{InstrumentationName}' " +
@@ -109,7 +110,7 @@ internal static partial class LoggerMessages
 		"perform instrumentation assembly scanning.")]
 	public static partial void LogBaseDirectoryWarning(this ILogger logger);
 
-	[LoggerMessage(EventId = 38, EventName = "SkippingAssemblyScanning", Level = LogLevel.Trace, Message = "Skipping instrumentation assembly scanning on " +
+	[LoggerMessage(EventId = 38, EventName = "SkippingAssemblyScanning", Level = LogLevel.Debug, Message = "Skipping instrumentation assembly scanning on " +
 		"{ProviderBuilderType} (instance:{BuilderInstanceId}) because it is disabled in configuration.")]
 	public static partial void LogSkippingAssemblyScanning(this ILogger logger, string providerBuilderType, string builderInstanceId);
 
@@ -133,10 +134,10 @@ internal static partial class LoggerMessages
 
 
 
-	[LoggerMessage(EventId = 50, EventName = "FoundTag", Level = LogLevel.Trace, Message = "{ProcessorName} found '{AttributeName}' attribute with value '{AttributeValue}' on the span.")]
+	[LoggerMessage(EventId = 50, EventName = "FoundTag", Level = LogLevel.Debug, Message = "{ProcessorName} found '{AttributeName}' attribute with value '{AttributeValue}' on the span.")]
 	internal static partial void LogFoundTag(this ILogger logger, string processorName, string attributeName, object attributeValue);
 
-	[LoggerMessage(EventId = 51, EventName = "SetTag", Level = LogLevel.Trace, Message = "{ProcessorName} set '{AttributeName}' attribute with value '{AttributeValue}' on the span.")]
+	[LoggerMessage(EventId = 51, EventName = "SetTag", Level = LogLevel.Debug, Message = "{ProcessorName} set '{AttributeName}' attribute with value '{AttributeValue}' on the span.")]
 	internal static partial void LogSetTag(this ILogger logger, string processorName, string attributeName, object attributeValue);
 
 

src/Elastic.OpenTelemetry.Core/Diagnostics/LoggingEventListener.cs

@@ -94,7 +94,7 @@ static LogLevel GetLogLevel(EventWrittenEventArgs eventData) =>
 				EventLevel.Error => LogLevel.Error,
 				EventLevel.Warning => LogLevel.Warning,
 				EventLevel.Informational => LogLevel.Information,
-				EventLevel.Verbose => LogLevel.Trace,
+				EventLevel.Verbose => LogLevel.Debug,
 				EventLevel.LogAlways => LogLevel.Information,
 				_ => LogLevel.None
 			};