feat(components): deprecate tracing MDC

Favoring instead the instrumentation provided into each specific tracing framework.

Closes CAMEL-21538

components/camel-observation/src/main/docs/observation.adoc

@@ -86,4 +86,6 @@ include::spring-boot:partial$starter.adoc[]
 
 == MDC Logging
 
-When MDC Logging is enabled for the active Camel context the Trace ID and Span ID will be added and removed from the MDC for each route, the keys are `trace_id` and `span_id`, respectively.
+You can add [Micrometer Observability Mapped Diagnostic Context tracing information](https://docs.micrometer.io/tracing/reference/index.html) (ie, `traceId` and `spanId`) adding some instrumentation bridge to your application. You may add the `io.micrometer:micrometer-tracing-bridge-otel` dependency and you will be able to get those MDC information automatically.
+
+NOTE: mind that MDC variables `traceId` and `spanId` are different from other tracing implementations (eg, `camel-opentelemetry`) which use `trace_id` and `span_id`.

components/camel-opentelemetry/src/main/docs/opentelemetry.adoc

@@ -158,4 +158,4 @@ Multiple `SpanExporters` can be used at the same time.
 
 == MDC Logging
 
-When MDC Logging is enabled for the active Camel context the Trace ID and Span ID will be added and removed from the MDC for each route, the keys are `trace_id` and `span_id`, respectively.
+You can add Mapped Diagnostic Context tracing information (ie, `trace_id` and `span_id`) adding the specific [Opentelemetry Logger MDC auto instrumentation](https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/main/docs/logger-mdc-instrumentation.md). The configuration depends on the logging framework you're using.

components/camel-tracing/src/main/docs/tracing.adoc

@@ -16,3 +16,6 @@ This module is not intended to be used by end users. Instead, you should use one
 * xref:opentelemetry.adoc[`camel-opentelemetry`]
 * xref:observation.adoc[`camel-observation`]
 
+== MDC logging
+
+Mapped Diagnostic Context logging *trace_id* and *span_id* are included when you're setting the MDC configuration `camel.main.use-mdc-logging = true`. However this is a **deprecated** feature that may disappear in future version of the project. The feature can be enabled using the specific tracing/telemetry framework SDK. See more detail on the tracing component documentation page you're using.

components/camel-tracing/src/main/java/org/apache/camel/tracing/ActiveSpanManager.java

@@ -27,7 +27,11 @@
  */
 public final class ActiveSpanManager {
 
+    @Deprecated
+    // Use specific MDC instrumentation provided by your tracing/telemetry SDK instead
     public static final String MDC_TRACE_ID = "trace_id";
+    @Deprecated
+    // Use specific MDC instrumentation provided by your tracing/telemetry SDK instead
     public static final String MDC_SPAN_ID = "span_id";
     private static final Logger LOG = LoggerFactory.getLogger(ActiveSpanManager.class);
 

components/camel-tracing/src/main/java/org/apache/camel/tracing/Tracer.java

@@ -173,6 +173,14 @@ protected void doInit() {
         initTracer();
         initContextPropagators();
         ServiceHelper.startService(eventNotifier);
+
+        if (Boolean.TRUE.equals(camelContext.isUseMDCLogging())) {
+            LOG.warn("Initialized tracing component to put trace_id and span_id into MDC. " +
+                     "This is a deprecated feature and may disappear in the future. " +
+                     "You should replace it with the specific MDC instrumentation provided by your tracing/telemetry SDK instead. "
+                     +
+                     "See the tracing component documentation to learn more about it.");
+        }
     }
 
     @Override

docs/user-manual/modules/ROOT/pages/camel-4x-upgrade-guide-4_10.adoc

@@ -21,10 +21,14 @@ The camel-jbang commands for `camel-k` has been removed.
 
 === camel-google-pubsub-lite
 
-The component `camel-google-pubsub-lite` has been deprecated following the deprecation of the corresponding service by Google Cloud Platform. 
+The component `camel-google-pubsub-lite` has been deprecated following the deprecation of the corresponding service by Google Cloud Platform.
 
 Google recommends migrating your Pub/Sub Lite service to either Google Cloud Managed Service for Apache Kafka or Google Cloud Pub/Sub. Depending on your choice, you should use `camel-kafka` or `camel-google-pubsub component`, respectively.
 
 == camel-spring-boot
 
 The `camel-k-starter` has been removed.
+
+=== camel-tracing
+
+We have deprecated the setting of MDC `trace_id` and `span_id` in favour of implementation specific feature. You need to check the specific tracing/telemetry component configuration to learn how to switch from the deprecated configuration to the new one. Most of the time you will need to remove the `camel.main.use-mdc-logging` Camel property (or set it to `false`) and add dependencies and configuration settings to enable the specific component instrumentation.

docs/user-manual/modules/ROOT/pages/camel-4x-upgrade-guide.adoc

@@ -19,4 +19,3 @@ You can find the upgrade guide for each release in the following pages:
 - xref:camel-4x-upgrade-guide-4_8.adoc[Upgrade guide 4.7 -> 4.8]
 - xref:camel-4x-upgrade-guide-4_9.adoc[Upgrade guide 4.8 -> 4.9]
 - xref:camel-4x-upgrade-guide-4_10.adoc[Upgrade guide 4.9 -> 4.10]
-