More carefully handle re-creation of global meter registry

metrics/api/src/main/java/io/helidon/metrics/api/MetricsConfigBlueprint.java

@@ -202,6 +202,7 @@ static List<Tag> createTags(String pairs) {
      *
      * @return metrics configuration
      */
+    @Option.Redundant
     Config config();
 
     /**

metrics/providers/micrometer/pom.xml

@@ -47,6 +47,10 @@
             <groupId>io.micrometer</groupId>
             <artifactId>micrometer-registry-prometheus</artifactId>
         </dependency>
+        <dependency>
+            <groupId>io.helidon.config</groupId>
+            <artifactId>helidon-config</artifactId>
+        </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>

metrics/providers/micrometer/src/main/java/io/helidon/metrics/providers/micrometer/MMeterRegistry.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023 Oracle and/or its affiliates.
+ * Copyright (c) 2023, 2024 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -217,6 +217,7 @@ static MMeterRegistry applyMetersProvidersToRegistry(MetricsFactory factory,
     public void close() {
         onAddListeners.clear();
         onRemoveListeners.clear();
+        List.copyOf(meters.values()).forEach(this::remove);
         meters.clear();
         buildersByPromMeterId.clear();
         scopeMembership.clear();
@@ -472,7 +473,7 @@ <HM extends MMeter<M>, M extends Meter, B, HB extends MMeter.Builder<B, M, HB, H
             if (builder == null) {
                 if (scope.isEmpty()) {
                     LOGGER.log(Level.DEBUG, "Processing meter creation with no scope from the meter or configuration: "
-                            + addedMeter);
+                            + addedMeter.getId());
                 }
                 id = neutralIdForAddedMeter;
                 mMeter = MMeter.create(id, addedMeter, scope);
@@ -506,7 +507,7 @@ void onMeterRemoved(Meter removedMeter) {
         try {
             MMeter<?> removedHelidonMeter = meters.remove(removedMeter);
             if (removedHelidonMeter == null) {
-                LOGGER.log(Level.WARNING, "No matching neutral meter for implementation meter " + removedMeter);
+                LOGGER.log(Level.WARNING, "No matching neutral meter for implementation meter " + removedMeter.getId());
             } else {
                 recordRemove(removedHelidonMeter);
             }
@@ -586,7 +587,7 @@ but we have no record of that meter being linked to one of ours. This is surpris
                 */
 
                 LOGGER.log(Level.WARNING,
-                           "Unexpected discovery of unknown previously-created meter; creating wrapper for " + meter);
+                           "Unexpected discovery of unknown previously-created meter; creating wrapper for " + meter.getId());
                 result = wrapMeter(id, meter, mBuilder.scope());
                 recordNewMeter(id, result, meter, effectiveScope);
             }

metrics/providers/micrometer/src/main/java/io/helidon/metrics/providers/micrometer/MicrometerMetricsFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023 Oracle and/or its affiliates.
+ * Copyright (c) 2023, 2024 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,7 +27,7 @@
 
 import io.helidon.common.HelidonServiceLoader;
 import io.helidon.common.LazyValue;
-import io.helidon.common.config.Config;
+import io.helidon.config.Config;
 import io.helidon.metrics.api.Clock;
 import io.helidon.metrics.api.Counter;
 import io.helidon.metrics.api.DistributionStatisticsConfig;
@@ -56,7 +56,6 @@
  */
 class MicrometerMetricsFactory implements MetricsFactory {
 
-    private final MetricsConfig metricsConfig;
     private final Collection<MetersProvider> metersProviders;
 
     private final Collection<MMeterRegistry> meterRegistries = new ConcurrentLinkedQueue<>();
@@ -74,14 +73,15 @@ class MicrometerMetricsFactory implements MetricsFactory {
                     .next());
 
     private MMeterRegistry globalMeterRegistry;
+    private MetricsConfig metricsConfig;
 
     private MicrometerMetricsFactory(MetricsConfig metricsConfig,
                                      Collection<MetersProvider> metersProviders) {
         this.metricsConfig = metricsConfig;
         this.metersProviders = metersProviders;
     }
 
-    static MicrometerMetricsFactory create(Config rootConfig,
+    static MicrometerMetricsFactory create(io.helidon.common.config.Config rootConfig,
                                            MetricsConfig metricsConfig,
                                            Collection<MetersProvider> metersProviders) {
 
@@ -114,7 +114,7 @@ public MMeterRegistry.Builder meterRegistryBuilder() {
 
     @Override
     public MeterRegistry createMeterRegistry(MetricsConfig metricsConfig) {
-        return save(MMeterRegistry.builder(Metrics.globalRegistry, this)
+        return save(metricsConfig, MMeterRegistry.builder(Metrics.globalRegistry, this)
                             .metricsConfig(metricsConfig)
                             .build());
     }
@@ -124,7 +124,7 @@ public MeterRegistry createMeterRegistry(MetricsConfig metricsConfig) {
     public MeterRegistry createMeterRegistry(MetricsConfig metricsConfig,
                                              Consumer<Meter> onAddListener,
                                              Consumer<Meter> onRemoveListener) {
-        return save(MMeterRegistry.builder(Metrics.globalRegistry,
+        return save(metricsConfig, MMeterRegistry.builder(Metrics.globalRegistry,
                                            this)
                             .metricsConfig(metricsConfig)
                             .onMeterAdded(onAddListener)
@@ -139,7 +139,7 @@ public MeterRegistry createMeterRegistry(Clock clock,
                                              Consumer<Meter> onAddListener,
                                              Consumer<Meter> onRemoveListener) {
 
-        return save(MMeterRegistry.builder(Metrics.globalRegistry,
+        return save(metricsConfig, MMeterRegistry.builder(Metrics.globalRegistry,
                                            this)
                             .metricsConfig(metricsConfig)
                             .clock(clock)
@@ -150,7 +150,7 @@ public MeterRegistry createMeterRegistry(Clock clock,
 
     @Override
     public MeterRegistry createMeterRegistry(Clock clock, MetricsConfig metricsConfig) {
-        return save(MMeterRegistry.builder(Metrics.globalRegistry, this)
+        return save(metricsConfig, MMeterRegistry.builder(Metrics.globalRegistry, this)
                             .clock(clock)
                             .metricsConfig(metricsConfig)
                             .build());
@@ -160,19 +160,26 @@ public MeterRegistry createMeterRegistry(Clock clock, MetricsConfig metricsConfi
     public MeterRegistry globalRegistry() {
         return globalMeterRegistry != null
                 ? globalMeterRegistry
-                : globalRegistry(MetricsConfig.create());
+                : globalRegistry(MetricsConfig.create(Config.global().get(MetricsConfig.METRICS_CONFIG_KEY)));
     }
 
     @Override
     public MeterRegistry globalRegistry(MetricsConfig metricsConfig) {
         lock.lock();
         try {
             if (globalMeterRegistry != null) {
+                if (metricsConfig.equals(this.metricsConfig)) {
+                    return globalMeterRegistry;
+                }
+                // Ideally this method will be invoked once with the proper MetricsConfig settings.
+                // But it's possible for it to be invoked more than once with different
+                // settings. In such a case we need to clear the old global registry and create a new one because
+                // the new settings might affect its behavior.
                 globalMeterRegistry.close();
                 meterRegistries.remove(globalMeterRegistry);
             }
             ensurePrometheusRegistry(Metrics.globalRegistry, metricsConfig);
-            globalMeterRegistry = save(MMeterRegistry.builder(Metrics.globalRegistry, this)
+            globalMeterRegistry = save(metricsConfig, MMeterRegistry.builder(Metrics.globalRegistry, this)
                                                .metricsConfig(metricsConfig)
                                                .build());
 
@@ -325,7 +332,8 @@ private <B extends Meter.Builder<B, M>, M extends Meter> MeterRegistry applyMete
         return registry;
     }
 
-    private MMeterRegistry save(MMeterRegistry meterRegistry) {
+    private MMeterRegistry save(MetricsConfig metricsConfig, MMeterRegistry meterRegistry) {
+        this.metricsConfig = metricsConfig;
         meterRegistries.add(meterRegistry);
         return meterRegistry;
     }

metrics/providers/micrometer/src/main/java/module-info.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023 Oracle and/or its affiliates.
+ * Copyright (c) 2023, 2024 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,8 +22,8 @@
     requires micrometer.core;
     requires static micrometer.registry.prometheus;
     requires io.helidon.common;
-    requires io.helidon.common.config;
     requires io.helidon.common.media.type;
+    requires io.helidon.config;
     requires simpleclient.common;
     requires simpleclient.tracer.common;
     requires simpleclient;