Merge pull request #827 from DataDog/labbati/hostname

Detect hostname

CONTRIBUTING.md

@@ -20,8 +20,8 @@ Other source files (Groovy, Scala, etc) should ideally be formatted by Intellij
 Suggested plugins and settings:
 
 * Editor > Code Style > Java/Groovy > Imports
-  * Class count to use import with '*': `10` (some number sufficiently large that is unlikely to matter)
+  * Class count to use import with '*': `50` (some number sufficiently large that is unlikely to matter)
-  * Names count to use static import with '*': `10`
+  * Names count to use static import with '*': `50`
   * With java use the following import layout (groovy should still use the default) to ensure consistency with google-java-format:
     ![import layout](https://user-images.githubusercontent.com/734411/43430811-28442636-94ae-11e8-86f1-f270ddcba023.png)
 * [Google Java Format](https://plugins.jetbrains.com/plugin/8527-google-java-format)

dd-trace-api/src/main/java/datadog/trace/api/Config.java

@@ -1,5 +1,7 @@
 package datadog.trace.api;
 
+import java.net.InetAddress;
+import java.net.UnknownHostException;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
@@ -51,6 +53,7 @@ public class Config {
   public static final String TRACE_ANNOTATIONS = "trace.annotations";
   public static final String TRACE_METHODS = "trace.methods";
   public static final String TRACE_CLASSES_EXCLUDE = "trace.classes.exclude";
+  public static final String TRACE_REPORT_HOSTNAME = "trace.report-hostname";
   public static final String HEADER_TAGS = "trace.header.tags";
   public static final String HTTP_SERVER_ERROR_STATUSES = "http.server.error.statuses";
   public static final String HTTP_CLIENT_ERROR_STATUSES = "http.client.error.statuses";
@@ -105,11 +108,16 @@ public class Config {
 
   private static final String SPLIT_BY_SPACE_OR_COMMA_REGEX = "[,\\s]+";
 
+  private static final boolean DEFAULT_TRACE_REPORT_HOSTNAME = false;
+
   public enum PropagationStyle {
     DATADOG,
     B3
   }
 
+  /** A tag intended for internal use only, hence not added to the public api DDTags class. */
+  private static final String INTERNAL_HOST_NAME = "_dd.hostname";
+
   /**
    * this is a random UUID that gets generated on JVM start up and is attached to every root span
    * and every JMX metric that is sent out.
@@ -147,6 +155,8 @@ public class Config {
 
   @Getter private final boolean logsInjectionEnabled;
 
+  @Getter private final boolean reportHostName;
+
   // Read order: System Properties -> Env Variables, [-> default value]
   // Visible for testing
   Config() {
@@ -221,6 +231,9 @@ public class Config {
     logsInjectionEnabled =
         getBooleanSettingFromEnvironment(LOGS_INJECTION_ENABLED, DEFAULT_LOGS_INJECTION_ENABLED);
 
+    reportHostName =
+        getBooleanSettingFromEnvironment(TRACE_REPORT_HOSTNAME, DEFAULT_TRACE_REPORT_HOSTNAME);
+
     log.debug("New instance: {}", this);
   }
 
@@ -301,9 +314,24 @@ public class Config {
     logsInjectionEnabled =
         getBooleanSettingFromEnvironment(LOGS_INJECTION_ENABLED, DEFAULT_LOGS_INJECTION_ENABLED);
 
+    reportHostName =
+        getPropertyBooleanValue(properties, TRACE_REPORT_HOSTNAME, parent.reportHostName);
+
     log.debug("New instance: {}", this);
   }
 
+  /** @return A map of tags to be applied only to the local application root span. */
+  public Map<String, String> getLocalRootSpanTags() {
+    final Map<String, String> runtimeTags = getRuntimeTags();
+    final Map<String, String> result =
+        newHashMap(reportHostName ? (runtimeTags.size() + 1) : runtimeTags.size());
+    result.putAll(runtimeTags);
+    if (reportHostName) {
+      result.put(INTERNAL_HOST_NAME, getHostname());
+    }
+    return Collections.unmodifiableMap(result);
+  }
+
   public Map<String, String> getMergedSpanTags() {
     // DO not include runtimeId into span tags: we only want that added to the root span
     final Map<String, String> result = newHashMap(globalTags.size() + spanTags.size());
@@ -336,7 +364,7 @@ public class Config {
    *
    * @return A map of tag-name -> tag-value
    */
-  public Map<String, String> getRuntimeTags() {
+  private Map<String, String> getRuntimeTags() {
     final Map<String, String> result = newHashMap(2);
     result.put(RUNTIME_ID_TAG, runtimeId);
     result.put(LANGUAGE_TAG_KEY, LANGUAGE_TAG_VALUE);
@@ -636,6 +664,20 @@ public class Config {
     return Collections.unmodifiableSet(result);
   }
 
+  /**
+   * Returns the detected hostname. This operation is time consuming so if the usage changes and
+   * this method will be called several times then we should implement some sort of caching.
+   */
+  private String getHostname() {
+    try {
+      return InetAddress.getLocalHost().getHostName();
+    } catch (UnknownHostException e) {
+      // If we are not able to detect the hostname we do not throw an exception.
+    }
+
+    return null;
+  }
+
   // This has to be placed after all other static fields to give them a chance to initialize
   private static final Config INSTANCE = new Config();
 

dd-trace-api/src/main/java/datadog/trace/api/interceptor/MutableSpan.java

@@ -50,5 +50,16 @@ public interface MutableSpan {
 
   MutableSpan setError(boolean value);
 
+  /** @deprecated Use {@link #getLocalRootSpan()} instead. */
+  @Deprecated
   MutableSpan getRootSpan();
+
+  /**
+   * Returns the root span for current the trace fragment. In the context of distributed tracing
+   * this method returns the root span only for the fragment generated by the currently traced
+   * application.
+   *
+   * @return The root span for the current trace fragment.
+   */
+  MutableSpan getLocalRootSpan();
 }

dd-trace-api/src/test/groovy/datadog/trace/api/ConfigTest.groovy

@@ -35,6 +35,7 @@ import static datadog.trace.api.Config.SERVICE_MAPPING
 import static datadog.trace.api.Config.SERVICE_NAME
 import static datadog.trace.api.Config.SPAN_TAGS
 import static datadog.trace.api.Config.TRACE_AGENT_PORT
+import static datadog.trace.api.Config.TRACE_REPORT_HOSTNAME
 import static datadog.trace.api.Config.TRACE_ENABLED
 import static datadog.trace.api.Config.TRACE_RESOLVER_ENABLED
 import static datadog.trace.api.Config.WRITER_TYPE
@@ -56,6 +57,7 @@ class ConfigTest extends Specification {
   private static final DD_JMXFETCH_METRICS_CONFIGS_ENV = "DD_JMXFETCH_METRICS_CONFIGS"
   private static final DD_TRACE_AGENT_PORT_ENV = "DD_TRACE_AGENT_PORT"
   private static final DD_AGENT_PORT_LEGACY_ENV = "DD_AGENT_PORT"
+  private static final DD_TRACE_REPORT_HOSTNAME = "DD_TRACE_REPORT_HOSTNAME"
 
   def "verify defaults"() {
     when:
@@ -78,6 +80,7 @@ class ConfigTest extends Specification {
     config.httpClientErrorStatuses == (400..499).toSet()
     config.httpClientSplitByDomain == false
     config.partialFlushMinSpans == 1000
+    config.reportHostName == false
     config.runtimeContextFieldInjection == true
     config.propagationStylesToExtract.toList() == [Config.PropagationStyle.DATADOG]
     config.propagationStylesToInject.toList() == [Config.PropagationStyle.DATADOG]
@@ -118,6 +121,7 @@ class ConfigTest extends Specification {
     prop.setProperty(HTTP_CLIENT_ERROR_STATUSES, "111")
     prop.setProperty(HTTP_CLIENT_HOST_SPLIT_BY_DOMAIN, "true")
     prop.setProperty(PARTIAL_FLUSH_MIN_SPANS, "15")
+    prop.setProperty(TRACE_REPORT_HOSTNAME, "true")
     prop.setProperty(RUNTIME_CONTEXT_FIELD_INJECTION, "false")
     prop.setProperty(PROPAGATION_STYLE_EXTRACT, "Datadog, B3")
     prop.setProperty(PROPAGATION_STYLE_INJECT, "B3, Datadog")
@@ -148,6 +152,7 @@ class ConfigTest extends Specification {
     config.httpClientErrorStatuses == (111..111).toSet()
     config.httpClientSplitByDomain == true
     config.partialFlushMinSpans == 15
+    config.reportHostName == true
     config.runtimeContextFieldInjection == false
     config.propagationStylesToExtract.toList() == [Config.PropagationStyle.DATADOG, Config.PropagationStyle.B3]
     config.propagationStylesToInject.toList() == [Config.PropagationStyle.B3, Config.PropagationStyle.DATADOG]
@@ -179,6 +184,7 @@ class ConfigTest extends Specification {
     System.setProperty(PREFIX + HTTP_CLIENT_ERROR_STATUSES, "111")
     System.setProperty(PREFIX + HTTP_CLIENT_HOST_SPLIT_BY_DOMAIN, "true")
     System.setProperty(PREFIX + PARTIAL_FLUSH_MIN_SPANS, "25")
+    System.setProperty(PREFIX + TRACE_REPORT_HOSTNAME, "true")
     System.setProperty(PREFIX + RUNTIME_CONTEXT_FIELD_INJECTION, "false")
     System.setProperty(PREFIX + PROPAGATION_STYLE_EXTRACT, "Datadog, B3")
     System.setProperty(PREFIX + PROPAGATION_STYLE_INJECT, "B3, Datadog")
@@ -209,6 +215,7 @@ class ConfigTest extends Specification {
     config.httpClientErrorStatuses == (111..111).toSet()
     config.httpClientSplitByDomain == true
     config.partialFlushMinSpans == 25
+    config.reportHostName == true
     config.runtimeContextFieldInjection == false
     config.propagationStylesToExtract.toList() == [Config.PropagationStyle.DATADOG, Config.PropagationStyle.B3]
     config.propagationStylesToInject.toList() == [Config.PropagationStyle.B3, Config.PropagationStyle.DATADOG]
@@ -228,6 +235,7 @@ class ConfigTest extends Specification {
     environmentVariables.set(DD_PROPAGATION_STYLE_EXTRACT, "B3 Datadog")
     environmentVariables.set(DD_PROPAGATION_STYLE_INJECT, "Datadog B3")
     environmentVariables.set(DD_JMXFETCH_METRICS_CONFIGS_ENV, "some/file")
+    environmentVariables.set(DD_TRACE_REPORT_HOSTNAME, "true")
 
     when:
     def config = new Config()
@@ -239,6 +247,7 @@ class ConfigTest extends Specification {
     config.propagationStylesToExtract.toList() == [Config.PropagationStyle.B3, Config.PropagationStyle.DATADOG]
     config.propagationStylesToInject.toList() == [Config.PropagationStyle.DATADOG, Config.PropagationStyle.B3]
     config.jmxFetchMetricsConfigs == ["some/file"]
+    config.reportHostName == true
   }
 
   def "sys props override env vars"() {
@@ -649,4 +658,27 @@ class ConfigTest extends Specification {
     listString | list
     ""         | []
   }
+
+  def "verify hostname not added to root span tags by default"() {
+    setup:
+    Properties properties = new Properties()
+
+    when:
+    def config = Config.get(properties)
+
+    then:
+    !config.localRootSpanTags.containsKey('_dd.hostname')
+  }
+
+  def "verify configuration to add hostname to root span tags"() {
+    setup:
+    Properties properties = new Properties()
+    properties.setProperty(TRACE_REPORT_HOSTNAME, 'true')
+
+    when:
+    def config = Config.get(properties)
+
+    then:
+    config.localRootSpanTags.get('_dd.hostname') == InetAddress.localHost.hostName
+  }
 }

dd-trace-ot/src/main/java/datadog/opentracing/DDSpan.java

@@ -110,8 +110,16 @@ public class DDSpan implements Span, MutableSpan {
     finishAndAddToTrace(TimeUnit.MICROSECONDS.toNanos(stoptimeMicros - startTimeMicro));
   }
 
+  @Override
+  public DDSpan setError(final boolean error) {
+    context.setErrorFlag(true);
+    return this;
+  }
+
   /**
-   * Check if the span is the root parent. It means that the traceId is the same as the spanId
+   * Check if the span is the root parent. It means that the traceId is the same as the spanId. In
+   * the context of distributed tracing this will return true if an only if this is the application
+   * initializing the trace.
    *
    * @return true if root, false otherwise
    */
@@ -121,13 +129,15 @@ public class DDSpan implements Span, MutableSpan {
   }
 
   @Override
-  public DDSpan setError(final boolean error) {
+  @Deprecated
-    context.setErrorFlag(true);
+  @JsonIgnore
-    return this;
+  public MutableSpan getRootSpan() {
+    return getLocalRootSpan();
   }
 
   @Override
-  public MutableSpan getRootSpan() {
+  @JsonIgnore
+  public MutableSpan getLocalRootSpan() {
     return context().getTrace().getRootSpan();
   }
 

dd-trace-ot/src/main/java/datadog/opentracing/DDTracer.java

@@ -56,8 +56,8 @@ public class DDTracer implements io.opentracing.Tracer, Closeable, datadog.trace
   /** Scope manager is in charge of managing the scopes from which spans are created */
   final ContextualScopeManager scopeManager = new ContextualScopeManager();
 
-  /** Tags required to link apm traces to runtime metrics */
+  /** A set of tags that are added only to the application's root span */
-  final Map<String, String> runtimeTags;
+  private final Map<String, String> localRootSpanTags;
   /** A set of tags that are added to every span */
   private final Map<String, String> defaultSpanTags;
   /** A configured mapping of service names to update with new values */
@@ -107,7 +107,7 @@ public class DDTracer implements io.opentracing.Tracer, Closeable, datadog.trace
 
   // This constructor is already used in the wild, so we have to keep it inside this API for now.
   public DDTracer(final String serviceName, final Writer writer, final Sampler sampler) {
-    this(serviceName, writer, sampler, Config.get().getRuntimeTags());
+    this(serviceName, writer, sampler, Config.get().getLocalRootSpanTags());
   }
 
   private DDTracer(final String serviceName, final Config config) {
@@ -115,7 +115,7 @@ public class DDTracer implements io.opentracing.Tracer, Closeable, datadog.trace
         serviceName,
         Writer.Builder.forConfig(config),
         Sampler.Builder.forConfig(config),
-        config.getRuntimeTags(),
+        config.getLocalRootSpanTags(),
         config.getMergedSpanTags(),
         config.getServiceMapping(),
         config.getHeaderTags(),
@@ -149,7 +149,7 @@ public class DDTracer implements io.opentracing.Tracer, Closeable, datadog.trace
         config.getServiceName(),
         writer,
         Sampler.Builder.forConfig(config),
-        config.getRuntimeTags(),
+        config.getLocalRootSpanTags(),
         config.getMergedSpanTags(),
         config.getServiceMapping(),
         config.getHeaderTags(),
@@ -165,6 +165,7 @@ public class DDTracer implements io.opentracing.Tracer, Closeable, datadog.trace
       final Writer writer,
       final Sampler sampler,
       final String runtimeId,
+      final Map<String, String> localRootSpanTags,
       final Map<String, String> defaultSpanTags,
       final Map<String, String> serviceNameMappings,
       final Map<String, String> taggedHeaders) {
@@ -172,7 +173,7 @@ public class DDTracer implements io.opentracing.Tracer, Closeable, datadog.trace
         serviceName,
         writer,
         sampler,
-        customRuntimeTags(runtimeId),
+        customRuntimeTags(runtimeId, localRootSpanTags),
         defaultSpanTags,
         serviceNameMappings,
         taggedHeaders,
@@ -187,7 +188,7 @@ public class DDTracer implements io.opentracing.Tracer, Closeable, datadog.trace
       final String serviceName,
       final Writer writer,
       final Sampler sampler,
-      final Map<String, String> runtimeTags,
+      final Map<String, String> localRootSpanTags,
       final Map<String, String> defaultSpanTags,
       final Map<String, String> serviceNameMappings,
       final Map<String, String> taggedHeaders) {
@@ -195,7 +196,7 @@ public class DDTracer implements io.opentracing.Tracer, Closeable, datadog.trace
         serviceName,
         writer,
         sampler,
-        runtimeTags,
+        localRootSpanTags,
         defaultSpanTags,
         serviceNameMappings,
         taggedHeaders,
@@ -206,12 +207,12 @@ public class DDTracer implements io.opentracing.Tracer, Closeable, datadog.trace
       final String serviceName,
       final Writer writer,
       final Sampler sampler,
-      final Map<String, String> runtimeTags,
+      final Map<String, String> localRootSpanTags,
       final Map<String, String> defaultSpanTags,
       final Map<String, String> serviceNameMappings,
       final Map<String, String> taggedHeaders,
       final int partialFlushMinSpans) {
-    assert runtimeTags != null;
+    assert localRootSpanTags != null;
     assert defaultSpanTags != null;
     assert serviceNameMappings != null;
     assert taggedHeaders != null;
@@ -220,8 +221,8 @@ public class DDTracer implements io.opentracing.Tracer, Closeable, datadog.trace
     this.writer = writer;
     this.writer.start();
     this.sampler = sampler;
+    this.localRootSpanTags = localRootSpanTags;
     this.defaultSpanTags = defaultSpanTags;
-    this.runtimeTags = runtimeTags;
     this.serviceNameMappings = serviceNameMappings;
     this.partialFlushMinSpans = partialFlushMinSpans;
 
@@ -439,9 +440,9 @@ public class DDTracer implements io.opentracing.Tracer, Closeable, datadog.trace
   }
 
   @Deprecated
-  private static Map<String, String> customRuntimeTags(final String runtimeId) {
+  private static Map<String, String> customRuntimeTags(
-    final Map<String, String> runtimeTags = new HashMap<>();
+      final String runtimeId, Map<String, String> applicationRootSpanTags) {
-    runtimeTags.putAll(Config.get().getRuntimeTags());
+    final Map<String, String> runtimeTags = new HashMap<>(applicationRootSpanTags);
     runtimeTags.put(Config.RUNTIME_ID_TAG, runtimeId);
     return Collections.unmodifiableMap(runtimeTags);
   }
@@ -623,7 +624,9 @@ public class DDTracer implements io.opentracing.Tracer, Closeable, datadog.trace
         }
       }
 
-      // Propagate internal trace
+      // Propagate internal trace.
+      // Note: if we are not in the context of distributed tracing and we are starting the first
+      // root span, parentContext will be null at this point.
       if (parentContext instanceof DDSpanContext) {
         final DDSpanContext ddsc = (DDSpanContext) parentContext;
         traceId = ddsc.getTraceId();
@@ -660,10 +663,7 @@ public class DDTracer implements io.opentracing.Tracer, Closeable, datadog.trace
           origin = null;
         }
 
-        // add runtime tags to the root span
+        tags.putAll(localRootSpanTags);
-        for (final Map.Entry<String, String> runtimeTag : runtimeTags.entrySet()) {
-          tags.put(runtimeTag.getKey(), runtimeTag.getValue());
-        }
 
         parentTrace = new PendingTrace(DDTracer.this, traceId, serviceNameMappings);
       }

dd-trace-ot/src/test/groovy/datadog/opentracing/DDSpanTest.groovy

@@ -5,6 +5,7 @@ import datadog.opentracing.propagation.TagContext
 import datadog.trace.api.sampling.PrioritySampling
 import datadog.trace.common.sampling.RateByServiceSampler
 import datadog.trace.common.writer.ListWriter
+import io.opentracing.SpanContext
 import spock.lang.Shared
 import spock.lang.Specification
 
@@ -207,18 +208,45 @@ class DDSpanTest extends Specification {
     new ExtractedContext("1", "2", 0, "some-origin", [:], [:]) | _
   }
 
-  def "getRootSpan returns the root span"() {
+  def "isRootSpan() in and not in the context of distributed tracing"() {
     setup:
-    def root = tracer.buildSpan("root").start()
+    def root = tracer.buildSpan("root").asChildOf((SpanContext)extractedContext).start()
     def child = tracer.buildSpan("child").asChildOf(root).start()
 
     expect:
-    root.getRootSpan() == root
+    root.isRootSpan() == isTraceRootSpan
-    child.getRootSpan() == root
+    !child.isRootSpan()
 
     cleanup:
     child.finish()
     root.finish()
+
+    where:
+    extractedContext | isTraceRootSpan
+    null | true
+    new ExtractedContext("123", "456", 1, "789", [:], [:]) | false
+  }
+
+  def "getApplicationRootSpan() in and not in the context of distributed tracing"() {
+    setup:
+    def root = tracer.buildSpan("root").asChildOf((SpanContext)extractedContext).start()
+    def child = tracer.buildSpan("child").asChildOf(root).start()
+
+    expect:
+    root.localRootSpan == root
+    child.localRootSpan == root
+    // Checking for backward compatibility method names
+    root.rootSpan == root
+    child.rootSpan == root
+
+    cleanup:
+    child.finish()
+    root.finish()
+
+    where:
+    extractedContext | isTraceRootSpan
+    null | true
+    new ExtractedContext("123", "456", 1, "789", [:], [:]) | false
   }
 
   def "setting forced tracing via tag"() {

dd-trace-ot/src/test/groovy/datadog/opentracing/decorators/SpanDecoratorTest.groovy

@@ -49,6 +49,7 @@ class SpanDecoratorTest extends Specification {
       new AllSampler(),
       "some-runtime-id",
       emptyMap(),
+      emptyMap(),
       mapping,
       emptyMap()
     )
@@ -80,6 +81,7 @@ class SpanDecoratorTest extends Specification {
       new AllSampler(),
       "some-runtime-id",
       emptyMap(),
+      emptyMap(),
       mapping,
       emptyMap()
     )
@@ -126,6 +128,7 @@ class SpanDecoratorTest extends Specification {
       new AllSampler(),
       "some-runtime-id",
       emptyMap(),
+      emptyMap(),
       mapping,
       emptyMap()
     )

dd-trace-ot/src/test/groovy/datadog/trace/DDTracerTest.groovy

@@ -31,7 +31,7 @@ class DDTracerTest extends Specification {
     // assert that a trace agent isn't running locally as that messes up the test.
     try {
       (new Socket("localhost", 8126)).close()
-      throw new IllegalStateException("Trace Agent unexpectedly running locally.")
+      throw new IllegalStateException("An agent is already running locally on port 8126. Please stop it if you want to run tests locally.")
     } catch (final ConnectException ioe) {
       // trace agent is not running locally.
     }
@@ -126,8 +126,8 @@ class DDTracerTest extends Specification {
     tracer.serviceName == DEFAULT_SERVICE_NAME
     tracer.sampler == sampler
     tracer.writer == writer
-    tracer.runtimeTags[Config.RUNTIME_ID_TAG].size() > 0 // not null or empty
+    tracer.localRootSpanTags[Config.RUNTIME_ID_TAG].size() > 0 // not null or empty
-    tracer.runtimeTags[Config.LANGUAGE_TAG_KEY] == Config.LANGUAGE_TAG_VALUE
+    tracer.localRootSpanTags[Config.LANGUAGE_TAG_KEY] == Config.LANGUAGE_TAG_VALUE
   }
 
   def "Shares TraceCount with DDApi with #key = #value"() {
@@ -144,4 +144,19 @@ class DDTracerTest extends Specification {
     PRIORITY_SAMPLING | "true"
     PRIORITY_SAMPLING | "false"
   }
+
+  def "root tags are applied only to root spans"() {
+    setup:
+    def tracer = new DDTracer('my_service', new ListWriter(), new AllSampler(), '', ['only_root': 'value'], [:], [:], [:])
+    def root = tracer.buildSpan('my_root').start()
+    def child = tracer.buildSpan('my_child').asChildOf(root).start()
+
+    expect:
+    root.context().tags.containsKey('only_root')
+    !child.context().tags.containsKey('only_root')
+
+    cleanup:
+    child.finish()
+    root.finish()
+  }
 }