Introduce API for metrics collection that does not depend on agent-core

apm-agent-core/pom.xml

@@ -149,11 +149,6 @@
             <version>${version.jetty-server}</version>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>com.dslplatform</groupId>
-            <artifactId>dsl-json</artifactId>
-            <version>1.9.3</version>
-        </dependency>
         <!--Used to test old class file versions-->
         <dependency>
             <groupId>commons-math</groupId>

apm-agent-core/src/main/java/co/elastic/apm/agent/bci/InstrumentationStatsLifecycleListener.java

@@ -19,10 +19,10 @@
 package co.elastic.apm.agent.bci;
 
 import co.elastic.apm.agent.bci.bytebuddy.MatcherTimer;
-import co.elastic.apm.agent.context.AbstractLifecycleListener;
-import co.elastic.apm.agent.impl.ElasticApmTracer;
+import co.elastic.apm.agent.tracer.AbstractLifecycleListener;
 import co.elastic.apm.agent.sdk.logging.Logger;
 import co.elastic.apm.agent.sdk.logging.LoggerFactory;
+import co.elastic.apm.agent.tracer.Tracer;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -31,7 +31,7 @@ public class InstrumentationStatsLifecycleListener extends AbstractLifecycleList
     private static final Logger logger = LoggerFactory.getLogger(InstrumentationStatsLifecycleListener.class);
 
     @Override
-    public void init(ElasticApmTracer tracer) {
+    public void init(Tracer tracer) {
         InstrumentationStats instrumentationStats = ElasticApmAgent.getInstrumentationStats();
         instrumentationStats.reset();
         instrumentationStats.setMeasureMatching(logger.isDebugEnabled());

apm-agent-core/src/main/java/co/elastic/apm/agent/collections/WeakMapCleaner.java

@@ -18,8 +18,8 @@
  */
 package co.elastic.apm.agent.collections;
 
-import co.elastic.apm.agent.context.AbstractLifecycleListener;
-import co.elastic.apm.agent.impl.ElasticApmTracer;
+import co.elastic.apm.agent.tracer.AbstractLifecycleListener;
+import co.elastic.apm.agent.tracer.Tracer;
 import co.elastic.apm.agent.util.ExecutorUtils;
 import co.elastic.apm.agent.sdk.logging.Logger;
 import co.elastic.apm.agent.sdk.logging.LoggerFactory;
@@ -41,7 +41,7 @@ public WeakMapCleaner() {
     }
 
     @Override
-    public void start(ElasticApmTracer tracer) {
+    public void start(Tracer tracer) {
         scheduler.scheduleWithFixedDelay(this, 1, 1, TimeUnit.SECONDS);
     }
 

apm-agent-core/src/main/java/co/elastic/apm/agent/configuration/ApmServerConfigurationSource.java

@@ -18,12 +18,13 @@
  */
 package co.elastic.apm.agent.configuration;
 
-import co.elastic.apm.agent.context.LifecycleListener;
+import co.elastic.apm.agent.tracer.LifecycleListener;
 import co.elastic.apm.agent.impl.ElasticApmTracer;
 import co.elastic.apm.agent.report.ApmServerClient;
 import co.elastic.apm.agent.report.serialize.DslJsonSerializer;
 import co.elastic.apm.agent.sdk.logging.Logger;
 import co.elastic.apm.agent.sdk.logging.LoggerFactory;
+import co.elastic.apm.agent.tracer.Tracer;
 import co.elastic.apm.agent.util.ExecutorUtils;
 import com.dslplatform.json.DslJson;
 import com.dslplatform.json.JsonReader;
@@ -111,17 +112,17 @@ public void reload() {
     }
 
     @Override
-    public void init(ElasticApmTracer tracer) throws Exception {
+    public void init(Tracer tracer) throws Exception {
         // noop
     }
 
     @Override
-    public void start(final ElasticApmTracer tracer) {
+    public void start(final Tracer tracer) {
         threadPool = ExecutorUtils.createSingleThreadDaemonPool("remote-config-poller", 1);
         threadPool.execute(new Runnable() {
             @Override
             public void run() {
-                pollConfig(tracer.getConfigurationRegistry());
+                pollConfig(tracer.require(ElasticApmTracer.class).getConfigurationRegistry());
             }
         });
     }

apm-agent-core/src/main/java/co/elastic/apm/agent/configuration/StartupInfo.java

@@ -18,8 +18,9 @@
  */
 package co.elastic.apm.agent.configuration;
 
+import co.elastic.apm.agent.tracer.Tracer;
 import co.elastic.apm.agent.tracer.configuration.TimeDuration;
-import co.elastic.apm.agent.context.AbstractLifecycleListener;
+import co.elastic.apm.agent.tracer.AbstractLifecycleListener;
 import co.elastic.apm.agent.impl.ElasticApmTracer;
 import co.elastic.apm.agent.impl.stacktrace.StacktraceConfiguration;
 import co.elastic.apm.agent.util.VersionUtils;
@@ -56,8 +57,8 @@ private static String getJvmAndOsVersionString() {
     }
 
     @Override
-    public void init(ElasticApmTracer tracer) {
-        ConfigurationRegistry configurationRegistry = tracer.getConfigurationRegistry();
+    public void init(Tracer tracer) {
+        ConfigurationRegistry configurationRegistry = tracer.require(ElasticApmTracer.class).getConfigurationRegistry();
         logConfiguration(configurationRegistry, logger);
     }
 

apm-agent-core/src/main/java/co/elastic/apm/agent/context/ClosableLifecycleListenerAdapter.java

@@ -18,17 +18,18 @@
  */
 package co.elastic.apm.agent.context;
 
-import java.io.Closeable;
+import co.elastic.apm.agent.tracer.AbstractLifecycleListener;
+import co.elastic.apm.agent.tracer.LifecycleListener;
 
 public class ClosableLifecycleListenerAdapter extends AbstractLifecycleListener {
 
-    private final Closeable closeable;
+    private final AutoCloseable closeable;
 
-    public static LifecycleListener of(Closeable closeable) {
+    public static LifecycleListener of(AutoCloseable closeable) {
         return new ClosableLifecycleListenerAdapter(closeable);
     }
 
-    private ClosableLifecycleListenerAdapter(Closeable closeable) {
+    private ClosableLifecycleListenerAdapter(AutoCloseable closeable) {
         this.closeable = closeable;
     }
 

apm-agent-core/src/main/java/co/elastic/apm/agent/impl/ElasticApmTracer.java

@@ -35,11 +35,13 @@
 import co.elastic.apm.agent.impl.metadata.NameAndIdField;
 import co.elastic.apm.agent.impl.metadata.ServiceFactory;
 import co.elastic.apm.agent.sdk.internal.util.LoggerUtils;
+import co.elastic.apm.agent.tracer.metrics.DoubleSupplier;
+import co.elastic.apm.agent.tracer.metrics.Labels;
 import co.elastic.apm.agent.tracer.service.Service;
 import co.elastic.apm.agent.tracer.service.ServiceInfo;
 import co.elastic.apm.agent.configuration.SpanConfiguration;
 import co.elastic.apm.agent.context.ClosableLifecycleListenerAdapter;
-import co.elastic.apm.agent.context.LifecycleListener;
+import co.elastic.apm.agent.tracer.LifecycleListener;
 import co.elastic.apm.agent.impl.baggage.Baggage;
 import co.elastic.apm.agent.impl.baggage.W3CBaggagePropagation;
 import co.elastic.apm.agent.impl.error.ErrorCapture;
@@ -71,12 +73,12 @@
 import co.elastic.apm.agent.tracer.reference.ReferenceCountedMap;
 import co.elastic.apm.agent.util.DependencyInjectingServiceLoader;
 import co.elastic.apm.agent.util.ExecutorUtils;
+import com.dslplatform.json.JsonWriter;
 import org.stagemonitor.configuration.ConfigurationOption;
 import org.stagemonitor.configuration.ConfigurationOptionProvider;
 import org.stagemonitor.configuration.ConfigurationRegistry;
 
 import javax.annotation.Nullable;
-import java.io.Closeable;
 import java.io.File;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -954,7 +956,8 @@ public ScheduledThreadPoolExecutor getSharedSingleThreadedPool() {
         return sharedPool;
     }
 
-    public void addShutdownHook(Closeable closeable) {
+    @Override
+    public void addShutdownHook(AutoCloseable closeable) {
         lifecycleListeners.add(ClosableLifecycleListenerAdapter.of(closeable));
     }
 
@@ -1044,4 +1047,30 @@ public void completeMetaData(String name, String version, String id, String regi
             region
         ));
     }
+
+    @Override
+    public void removeGauge(String name, Labels.Immutable labels) {
+        metricRegistry.removeGauge(name, labels);
+    }
+
+    @Override
+    public void addGauge(String name, Labels.Immutable labels, DoubleSupplier supplier) {
+        metricRegistry.add(name, labels, supplier);
+    }
+
+    @Override
+    public void submit(Runnable job) {
+        sharedPool.submit(job);
+    }
+
+    @Override
+    public void schedule(Runnable job, long interval, TimeUnit timeUnit) {
+        sharedPool.scheduleAtFixedRate(job, 0, interval, timeUnit);
+    }
+
+    @Override
+    public void reportMetric(JsonWriter metrics) {
+        reporter.reportMetrics(metrics);
+    }
+
 }

apm-agent-core/src/main/java/co/elastic/apm/agent/impl/ElasticApmTracerBuilder.java

@@ -26,7 +26,7 @@
 import co.elastic.apm.agent.configuration.source.ConfigSources;
 import co.elastic.apm.agent.configuration.source.SystemPropertyConfigurationSource;
 import co.elastic.apm.agent.context.ClosableLifecycleListenerAdapter;
-import co.elastic.apm.agent.context.LifecycleListener;
+import co.elastic.apm.agent.tracer.LifecycleListener;
 import co.elastic.apm.agent.impl.metadata.MetaData;
 import co.elastic.apm.agent.impl.metadata.MetaDataFuture;
 import co.elastic.apm.agent.impl.stacktrace.StacktraceConfiguration;

apm-agent-core/src/main/java/co/elastic/apm/agent/impl/circuitbreaker/CircuitBreaker.java

@@ -18,8 +18,9 @@
  */
 package co.elastic.apm.agent.impl.circuitbreaker;
 
-import co.elastic.apm.agent.context.AbstractLifecycleListener;
+import co.elastic.apm.agent.tracer.AbstractLifecycleListener;
 import co.elastic.apm.agent.impl.ElasticApmTracer;
+import co.elastic.apm.agent.tracer.Tracer;
 import co.elastic.apm.agent.util.ExecutorUtils;
 import co.elastic.apm.agent.sdk.logging.Logger;
 import co.elastic.apm.agent.sdk.logging.LoggerFactory;
@@ -50,7 +51,7 @@ public CircuitBreaker(ElasticApmTracer tracer) {
     }
 
     @Override
-    public void start(ElasticApmTracer tracer) {
+    public void start(Tracer tracer) {
         // failsafe loading of stress monitors in isolation
         loadGCStressMonitor(tracer);
         loadSystemCpuStressMonitor(tracer);
@@ -63,15 +64,15 @@ public void run() {
         });
     }
 
-    private void loadGCStressMonitor(ElasticApmTracer tracer) {
+    private void loadGCStressMonitor(Tracer tracer) {
         try {
             stressMonitors.add(new GCStressMonitor(tracer));
         } catch (Throwable throwable) {
             logger.error("Failed to load the GC stress monitor. Circuit breaker will not be triggered based on GC events.", throwable);
         }
     }
 
-    private void loadSystemCpuStressMonitor(ElasticApmTracer tracer) {
+    private void loadSystemCpuStressMonitor(Tracer tracer) {
         try {
             stressMonitors.add(new SystemCpuStressMonitor(tracer));
         } catch (Throwable throwable) {

apm-agent-core/src/main/java/co/elastic/apm/agent/impl/circuitbreaker/GCStressMonitor.java

@@ -21,6 +21,7 @@
 import co.elastic.apm.agent.impl.ElasticApmTracer;
 import co.elastic.apm.agent.sdk.logging.Logger;
 import co.elastic.apm.agent.sdk.logging.LoggerFactory;
+import co.elastic.apm.agent.tracer.Tracer;
 
 import java.lang.management.ManagementFactory;
 import java.lang.management.MemoryPoolMXBean;
@@ -35,7 +36,7 @@ class GCStressMonitor extends StressMonitor {
     private final List<MemoryPoolMXBean> heapMBeans = new ArrayList<>();
     private final StringBuilder latestStressDetectionInfo = new StringBuilder("No stress has been detected so far.");
 
-    GCStressMonitor(ElasticApmTracer tracer) {
+    GCStressMonitor(Tracer tracer) {
         super(tracer);
         discoverMBeans();
     }

apm-agent-core/src/main/java/co/elastic/apm/agent/impl/circuitbreaker/StressMonitor.java

@@ -18,13 +18,13 @@
  */
 package co.elastic.apm.agent.impl.circuitbreaker;
 
-import co.elastic.apm.agent.impl.ElasticApmTracer;
+import co.elastic.apm.agent.tracer.Tracer;
 
 abstract class StressMonitor {
 
     protected final CircuitBreakerConfiguration circuitBreakerConfiguration;
 
-    public StressMonitor(ElasticApmTracer tracer) {
+    public StressMonitor(Tracer tracer) {
         circuitBreakerConfiguration = tracer.getConfig(CircuitBreakerConfiguration.class);
     }
 

apm-agent-core/src/main/java/co/elastic/apm/agent/impl/circuitbreaker/SystemCpuStressMonitor.java

@@ -18,7 +18,7 @@
  */
 package co.elastic.apm.agent.impl.circuitbreaker;
 
-import co.elastic.apm.agent.impl.ElasticApmTracer;
+import co.elastic.apm.agent.tracer.Tracer;
 import co.elastic.apm.agent.util.JmxUtils;
 import co.elastic.apm.agent.sdk.logging.Logger;
 import co.elastic.apm.agent.sdk.logging.LoggerFactory;
@@ -45,7 +45,7 @@ public class SystemCpuStressMonitor extends StressMonitor {
     @Nullable
     private final Method systemCpuUsageMethod;
 
-    SystemCpuStressMonitor(ElasticApmTracer tracer) {
+    SystemCpuStressMonitor(Tracer tracer) {
         super(tracer);
         operatingSystemBean = ManagementFactory.getOperatingSystemMXBean();
         systemCpuUsageMethod = JmxUtils.getOperatingSystemMBeanMethod(operatingSystemBean, "getSystemCpuLoad");

apm-agent-core/src/main/java/co/elastic/apm/agent/impl/transaction/Transaction.java

@@ -27,7 +27,7 @@
 import co.elastic.apm.agent.impl.context.Response;
 import co.elastic.apm.agent.impl.context.TransactionContext;
 import co.elastic.apm.agent.impl.sampling.Sampler;
-import co.elastic.apm.agent.metrics.Labels;
+import co.elastic.apm.agent.tracer.metrics.Labels;
 import co.elastic.apm.agent.metrics.MetricRegistry;
 import co.elastic.apm.agent.metrics.Timer;
 import co.elastic.apm.agent.tracer.Outcome;

apm-agent-core/src/main/java/co/elastic/apm/agent/logging/ApmServerLogAppender.java

@@ -18,10 +18,11 @@
  */
 package co.elastic.apm.agent.logging;
 
-import co.elastic.apm.agent.context.AbstractLifecycleListener;
-import co.elastic.apm.agent.context.LifecycleListener;
+import co.elastic.apm.agent.tracer.AbstractLifecycleListener;
+import co.elastic.apm.agent.tracer.LifecycleListener;
 import co.elastic.apm.agent.impl.ElasticApmTracer;
 import co.elastic.apm.agent.report.Reporter;
+import co.elastic.apm.agent.tracer.Tracer;
 import co.elastic.logging.log4j2.EcsLayout;
 import org.apache.logging.log4j.core.Appender;
 import org.apache.logging.log4j.core.Core;
@@ -103,8 +104,8 @@ public void append(LogEvent event) {
     public LifecycleListener getInitListener() {
         return new AbstractLifecycleListener() {
             @Override
-            public void init(ElasticApmTracer tracer) throws Exception {
-                initStreaming(tracer.getConfig(LoggingConfiguration.class), tracer.getReporter());
+            public void init(Tracer tracer) throws Exception {
+                initStreaming(tracer.getConfig(LoggingConfiguration.class), tracer.require(ElasticApmTracer.class).getReporter());
             }
         };
     }

apm-agent-core/src/main/java/co/elastic/apm/agent/metrics/MetricCollector.java

@@ -18,6 +18,8 @@
  */
 package co.elastic.apm.agent.metrics;
 
+import co.elastic.apm.agent.tracer.metrics.Labels;
+
 public interface MetricCollector {
 
     void addMetricValue(String metric, Labels labels, double value);

apm-agent-core/src/main/java/co/elastic/apm/agent/metrics/MetricRegistry.java

@@ -23,6 +23,8 @@
 import co.elastic.apm.agent.report.ReporterConfiguration;
 import co.elastic.apm.agent.sdk.logging.Logger;
 import co.elastic.apm.agent.sdk.logging.LoggerFactory;
+import co.elastic.apm.agent.tracer.metrics.DoubleSupplier;
+import co.elastic.apm.agent.tracer.metrics.Labels;
 import org.HdrHistogram.WriterReaderPhaser;
 
 import javax.annotation.Nonnull;

apm-agent-core/src/main/java/co/elastic/apm/agent/metrics/MetricSet.java

@@ -18,6 +18,8 @@
  */
 package co.elastic.apm.agent.metrics;
 
+import co.elastic.apm.agent.tracer.metrics.DoubleSupplier;
+import co.elastic.apm.agent.tracer.metrics.Labels;
 import co.elastic.apm.agent.tracer.pooling.Recyclable;
 
 import javax.annotation.Nullable;

apm-agent-core/src/main/java/co/elastic/apm/agent/metrics/builtin/AgentOverheadMetrics.java

@@ -19,9 +19,10 @@
 package co.elastic.apm.agent.metrics.builtin;
 
 import co.elastic.apm.agent.configuration.MetricsConfiguration;
-import co.elastic.apm.agent.context.AbstractLifecycleListener;
+import co.elastic.apm.agent.tracer.AbstractLifecycleListener;
 import co.elastic.apm.agent.impl.ElasticApmTracer;
-import co.elastic.apm.agent.metrics.Labels;
+import co.elastic.apm.agent.tracer.Tracer;
+import co.elastic.apm.agent.tracer.metrics.Labels;
 import co.elastic.apm.agent.metrics.MetricCollector;
 import co.elastic.apm.agent.metrics.MetricRegistry;
 import co.elastic.apm.agent.metrics.MetricsProvider;
@@ -113,8 +114,8 @@ public AgentOverheadMetrics() {
     }
 
     @Override
-    public void start(ElasticApmTracer tracer) throws Exception {
-        MetricRegistry metricRegistry = tracer.getMetricRegistry();
+    public void start(Tracer tracer) throws Exception {
+        MetricRegistry metricRegistry = tracer.require(ElasticApmTracer.class).getMetricRegistry();
         MetricsConfiguration config = tracer.getConfig(MetricsConfiguration.class);
         bindTo(metricRegistry, config);
     }

apm-agent-core/src/main/java/co/elastic/apm/agent/metrics/builtin/AgentReporterMetrics.java

@@ -19,7 +19,7 @@
 package co.elastic.apm.agent.metrics.builtin;
 
 import co.elastic.apm.agent.configuration.MetricsConfiguration;
-import co.elastic.apm.agent.metrics.Labels;
+import co.elastic.apm.agent.tracer.metrics.Labels;
 import co.elastic.apm.agent.metrics.MetricCollector;
 import co.elastic.apm.agent.metrics.MetricRegistry;
 import co.elastic.apm.agent.metrics.MetricsProvider;