Remove QUERY_TEXT_MAX_LENGTH from Observation.Context

The query text max length configuration constant was stored in every Observation.Context and extracted back in the MicrometerSpan constructor. This value never changes between observations and is not output as any signal. Pass it directly via constructor parameter instead.

Author: nhachicha

driver-core/src/main/com/mongodb/internal/observability/micrometer/MicrometerTracer.java

@@ -54,22 +54,13 @@ public class MicrometerTracer implements Tracer {
     private final ObservationRegistry observationRegistry;
     private final boolean allowCommandPayload;
     private final int textMaxLength;
-    private static final String QUERY_TEXT_LENGTH_CONTEXT_KEY = "QUERY_TEXT_MAX_LENGTH";
 
     /**
      * Constructs a new {@link MicrometerTracer} instance.
      *
      * @param observationRegistry The Micrometer {@link ObservationRegistry} to delegate tracing operations to.
-     */
-    public MicrometerTracer(final ObservationRegistry observationRegistry) {
-        this(observationRegistry, false, 0);
-    }
-
-    /**
-     * Constructs a new {@link MicrometerTracer} instance with an option to allow command payloads.
-     *
-     * @param observationRegistry The Micrometer {@link ObservationRegistry} to delegate tracing operations to.
      * @param allowCommandPayload Whether to allow command payloads in the trace context.
+     * @param textMaxLength       The maximum length for query text truncation.
      */
     public MicrometerTracer(final ObservationRegistry observationRegistry, final boolean allowCommandPayload, final int textMaxLength) {
         this.allowCommandPayload = allowCommandPayload;
@@ -91,7 +82,7 @@ public Span nextSpan(final MongodbObservation observationType, final String name
             }
         }
 
-        return new MicrometerSpan(observation.start(), namespace);
+        return new MicrometerSpan(observation.start(), namespace, textMaxLength);
     }
 
     @Override
@@ -105,11 +96,9 @@ public boolean includeCommandPayload() {
     }
 
     private Observation getObservation(final MongodbObservation observationType, final String name) {
-        Observation observation = observationType.observation(observationRegistry,
+        return observationType.observation(observationRegistry,
                         () -> new SenderContext<>((carrier, key, value) -> {}, Kind.CLIENT))
                 .contextualName(name);
-        observation.getContext().put(QUERY_TEXT_LENGTH_CONTEXT_KEY, textMaxLength);
-        return observation;
     }
     /**
      * Represents a Micrometer-based trace context.
@@ -139,16 +128,14 @@ private static class MicrometerSpan implements Span {
         /**
          * Constructs a new {@link MicrometerSpan} instance with an associated Observation and MongoDB namespace.
          *
-         * @param observation The Micrometer {@link Observation}, or null if none exists.
-         * @param namespace   The MongoDB namespace associated with the span.
+         * @param observation     The Micrometer {@link Observation}, or null if none exists.
+         * @param namespace       The MongoDB namespace associated with the span.
+         * @param queryTextLength The maximum length for query text truncation.
          */
-        MicrometerSpan(final Observation observation, @Nullable final MongoNamespace namespace) {
+        MicrometerSpan(final Observation observation, @Nullable final MongoNamespace namespace, final int queryTextLength) {
             this.namespace = namespace;
             this.observation = observation;
-            this.queryTextLength = ofNullable(observation.getContext().get(QUERY_TEXT_LENGTH_CONTEXT_KEY))
-                    .filter(Integer.class::isInstance)
-                    .map(Integer.class::cast)
-                    .orElse(Integer.MAX_VALUE);
+            this.queryTextLength = queryTextLength;
         }
 
         @Override