Exporter/OCAgent: Add OcAgentNodeUtils. (#1471)

* Exporter/OCAgent: Add OcAgentNodeUtils.

Add utilities for detecting and creating Node.
Equivalent to
https://github.com/census-ecosystem/opencensus-go-exporter-ocagent/blob/master/nodeinfo.go.

* Fix nullness checker.

* Use a local VERSION string in OC-Agent Exporter.

7 files changed, 314 insertions, 4 deletions

diff --git a/RELEASING.md b/RELEASING.md
index e4315cd2..649ac81f 100644
--- a/RELEASING.md
+++ b/RELEASING.md
@@ -65,6 +65,7 @@ token](https://help.github.com/articles/creating-a-personal-access-token-for-the
       examples/build.gradle
       examples/pom.xml
       api/src/main/java/io/opencensus/common/OpenCensusLibraryInformation.java
+      exporters/trace/ocagent/src/main/java/io/opencensus/exporter/trace/ocagent/OcAgentNodeUtils.java
       )
     $ git checkout -b v$MAJOR.$MINOR.x master
     $ git push upstream v$MAJOR.$MINOR.x
diff --git a/buildscripts/import-control.xml b/buildscripts/import-control.xml
index b4c7410b..002820d8 100644
--- a/buildscripts/import-control.xml
+++ b/buildscripts/import-control.xml
@@ -170,6 +170,7 @@ General guidelines on imports:
       </subpackage>
       <subpackage name="ocagent">
         <allow pkg="com.google.protobuf"/>
+        <allow pkg="io.opencensus.contrib.monitoredresource.util"/>
         <allow pkg="io.opencensus.contrib.opencensus.proto.util"/>
         <allow pkg="io.opencensus.exporter.trace.ocagent"/>
         <allow pkg="io.opencensus.proto"/>
diff --git a/exporters/trace/ocagent/build.gradle b/exporters/trace/ocagent/build.gradle
index 7214eb58..b9489864 100644
--- a/exporters/trace/ocagent/build.gradle
+++ b/exporters/trace/ocagent/build.gradle
@@ -15,5 +15,4 @@ dependencies {
     testCompile project(':opencensus-api')
 
     signature "org.codehaus.mojo.signature:java17:1.0@signature"
-    signature "net.sf.androidscents.signature:android-api-level-14:4.0_r4@signature"
 }
diff --git a/exporters/trace/ocagent/src/main/java/io/opencensus/exporter/trace/ocagent/OcAgentNodeUtils.java b/exporters/trace/ocagent/src/main/java/io/opencensus/exporter/trace/ocagent/OcAgentNodeUtils.java
new file mode 100644
index 00000000..65729803
--- /dev/null
+++ b/exporters/trace/ocagent/src/main/java/io/opencensus/exporter/trace/ocagent/OcAgentNodeUtils.java
@@ -0,0 +1,184 @@
+/*
+ * Copyright 2018, OpenCensus Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.opencensus.exporter.trace.ocagent;
+
+import com.google.common.annotations.VisibleForTesting;
+import io.opencensus.common.OpenCensusLibraryInformation;
+import io.opencensus.common.Timestamp;
+import io.opencensus.contrib.monitoredresource.util.MonitoredResource;
+import io.opencensus.contrib.monitoredresource.util.MonitoredResource.AwsEc2InstanceMonitoredResource;
+import io.opencensus.contrib.monitoredresource.util.MonitoredResource.GcpGceInstanceMonitoredResource;
+import io.opencensus.contrib.monitoredresource.util.MonitoredResource.GcpGkeContainerMonitoredResource;
+import io.opencensus.contrib.monitoredresource.util.MonitoredResourceUtils;
+import io.opencensus.proto.agent.common.v1.LibraryInfo;
+import io.opencensus.proto.agent.common.v1.LibraryInfo.Language;
+import io.opencensus.proto.agent.common.v1.Node;
+import io.opencensus.proto.agent.common.v1.ProcessIdentifier;
+import io.opencensus.proto.agent.common.v1.ServiceInfo;
+import java.lang.management.ManagementFactory;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.security.SecureRandom;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import javax.annotation.Nullable;
+
+/** Utilities for detecting and creating {@link Node}. */
+final class OcAgentNodeUtils {
+
+  // The current version of the OpenCensus OC-Agent Exporter.
+  @VisibleForTesting
+  static final String OC_AGENT_EXPORTER_VERSION = "0.17.0-SNAPSHOT"; // CURRENT_OPENCENSUS_VERSION
+
+  @VisibleForTesting static final String RESOURCE_TYPE_ATTRIBUTE_KEY = "OPENCENSUS_SOURCE_TYPE";
+  @VisibleForTesting static final String RESOURCE_LABEL_ATTRIBUTE_KEY = "OPENCENSUS_SOURCE_LABELS";
+
+  @Nullable
+  private static final MonitoredResource RESOURCE = MonitoredResourceUtils.getDefaultResource();
+
+  // Creates a Node with information from the OpenCensus library and environment variables.
+  static Node getNodeInfo(String serviceName) {
+    String jvmName = ManagementFactory.getRuntimeMXBean().getName();
+    Timestamp censusTimestamp = Timestamp.fromMillis(System.currentTimeMillis());
+    return Node.newBuilder()
+        .setIdentifier(getProcessIdentifier(jvmName, censusTimestamp))
+        .setLibraryInfo(getLibraryInfo(OpenCensusLibraryInformation.VERSION))
+        .setServiceInfo(getServiceInfo(serviceName))
+        .putAllAttributes(getAttributeMap(RESOURCE))
+        .build();
+  }
+
+  // Creates process identifier with the given JVM name and start time.
+  @VisibleForTesting
+  static ProcessIdentifier getProcessIdentifier(String jvmName, Timestamp censusTimestamp) {
+    String hostname;
+    int pid;
+    // jvmName should be something like '<pid>@<hostname>', at least in Oracle and OpenJdk JVMs
+    int delimiterIndex = jvmName.indexOf('@');
+    if (delimiterIndex < 1) {
+      // Not the expected format, generate a random number.
+      try {
+        hostname = InetAddress.getLocalHost().getHostName();
+      } catch (UnknownHostException e) {
+        hostname = "localhost";
+      }
+      // Generate a random number as the PID.
+      pid = new SecureRandom().nextInt();
+    } else {
+      hostname = jvmName.substring(delimiterIndex + 1, jvmName.length());
+      try {
+        pid = Integer.parseInt(jvmName.substring(0, delimiterIndex));
+      } catch (NumberFormatException e) {
+        // Generate a random number as the PID if format is unexpected.
+        pid = new SecureRandom().nextInt();
+      }
+    }
+
+    return ProcessIdentifier.newBuilder()
+        .setHostName(hostname)
+        .setPid(pid)
+        .setStartTimestamp(TraceProtoUtils.toTimestampProto(censusTimestamp))
+        .build();
+  }
+
+  // Creates library info with the given OpenCensus Java version.
+  @VisibleForTesting
+  static LibraryInfo getLibraryInfo(String currentOcJavaVersion) {
+    return LibraryInfo.newBuilder()
+        .setLanguage(Language.JAVA)
+        .setCoreLibraryVersion(currentOcJavaVersion)
+        .setExporterVersion(OC_AGENT_EXPORTER_VERSION)
+        .build();
+  }
+
+  // Creates service info with the given service name.
+  @VisibleForTesting
+  static ServiceInfo getServiceInfo(String serviceName) {
+    return ServiceInfo.newBuilder().setName(serviceName).build();
+  }
+
+  /*
+   * Creates an attribute map with the given MonitoredResource.
+   * If the given resource is not null, the attribute map contains exactly two entries:
+   *
+   * OPENCENSUS_SOURCE_TYPE:
+   *   A string that describes the type of the resource prefixed by a domain namespace,
+   *   e.g. “kubernetes.io/container”.
+   * OPENCENSUS_SOURCE_LABELS:
+   *   A comma-separated list of labels describing the source in more detail,
+   *   e.g. “key1=val1,key2=val2”. The allowed character set is appropriately constrained.
+   */
+  // TODO: update the resource attributes once we have an agreement on the resource specs:
+  // https://github.com/census-instrumentation/opencensus-specs/pull/162.
+  @VisibleForTesting
+  static Map<String, String> getAttributeMap(@Nullable MonitoredResource resource) {
+    if (resource == null) {
+      return Collections.emptyMap();
+    } else {
+      Map<String, String> resourceAttributes = new HashMap<String, String>();
+      resourceAttributes.put(RESOURCE_TYPE_ATTRIBUTE_KEY, resource.getResourceType().name());
+      resourceAttributes.put(RESOURCE_LABEL_ATTRIBUTE_KEY, getConcatenatedResourceLabels(resource));
+      return resourceAttributes;
+    }
+  }
+
+  // Encodes the attributes of MonitoredResource into a comma-separated list of labels.
+  // For example "aws_account=account1,instance_id=instance1,region=us-east-2".
+  private static String getConcatenatedResourceLabels(MonitoredResource resource) {
+    StringBuilder resourceLabels = new StringBuilder();
+    if (resource instanceof AwsEc2InstanceMonitoredResource) {
+      AwsEc2InstanceMonitoredResource awsEc2Resource = (AwsEc2InstanceMonitoredResource) resource;
+      putIntoBuilderIfHasValue(resourceLabels, "aws_account", awsEc2Resource.getAccount());
+      putIntoBuilderIfHasValue(resourceLabels, "instance_id", awsEc2Resource.getInstanceId());
+      putIntoBuilderIfHasValue(resourceLabels, "region", awsEc2Resource.getRegion());
+    } else if (resource instanceof GcpGceInstanceMonitoredResource) {
+      GcpGceInstanceMonitoredResource gceResource = (GcpGceInstanceMonitoredResource) resource;
+      putIntoBuilderIfHasValue(resourceLabels, "gcp_account", gceResource.getAccount());
+      putIntoBuilderIfHasValue(resourceLabels, "instance_id", gceResource.getInstanceId());
+      putIntoBuilderIfHasValue(resourceLabels, "zone", gceResource.getZone());
+    } else if (resource instanceof GcpGkeContainerMonitoredResource) {
+      GcpGkeContainerMonitoredResource gkeResource = (GcpGkeContainerMonitoredResource) resource;
+      putIntoBuilderIfHasValue(resourceLabels, "gcp_account", gkeResource.getAccount());
+      putIntoBuilderIfHasValue(resourceLabels, "instance_id", gkeResource.getInstanceId());
+      putIntoBuilderIfHasValue(resourceLabels, "location", gkeResource.getZone());
+      putIntoBuilderIfHasValue(resourceLabels, "namespace_name", gkeResource.getNamespaceId());
+      putIntoBuilderIfHasValue(resourceLabels, "cluster_name", gkeResource.getClusterName());
+      putIntoBuilderIfHasValue(resourceLabels, "container_name", gkeResource.getContainerName());
+      putIntoBuilderIfHasValue(resourceLabels, "pod_name", gkeResource.getPodId());
+    }
+    return resourceLabels.toString();
+  }
+
+  // If the given resourceValue is not empty, encodes resourceKey and resourceValue as
+  // "resourceKey:resourceValue" and puts it into the given StringBuilder. Otherwise skip the value.
+  private static void putIntoBuilderIfHasValue(
+      StringBuilder builder, String resourceKey, String resourceValue) {
+    if (resourceValue.isEmpty()) {
+      return;
+    }
+    if (!(builder.length() == 0)) {
+      // Appends the comma separator to the front, if the StringBuilder already has entries.
+      builder.append(',');
+    }
+    builder.append(resourceKey);
+    builder.append('=');
+    builder.append(resourceValue);
+  }
+
+  private OcAgentNodeUtils() {}
+}
diff --git a/exporters/trace/ocagent/src/main/java/io/opencensus/exporter/trace/ocagent/OcAgentTraceExporterHandler.java b/exporters/trace/ocagent/src/main/java/io/opencensus/exporter/trace/ocagent/OcAgentTraceExporterHandler.java
index 27e56c66..cb4b06aa 100644
--- a/exporters/trace/ocagent/src/main/java/io/opencensus/exporter/trace/ocagent/OcAgentTraceExporterHandler.java
+++ b/exporters/trace/ocagent/src/main/java/io/opencensus/exporter/trace/ocagent/OcAgentTraceExporterHandler.java
@@ -28,7 +28,7 @@ final class OcAgentTraceExporterHandler extends Handler {
   private static final String DEFAULT_SERVICE_NAME = "OpenCensus";
 
   // private final String endPoint;
-  // private final String serviceName;
+  // private final Node node;
   // private final boolean useInsecure;
 
   OcAgentTraceExporterHandler() {
@@ -38,7 +38,10 @@ final class OcAgentTraceExporterHandler extends Handler {
   OcAgentTraceExporterHandler(
       @Nullable String endPoint, @Nullable String serviceName, @Nullable Boolean useInsecure) {
     // this.endPoint = endPoint == null ? DEFAULT_END_POINT : endPoint;
-    // this.serviceName = serviceName == null ? DEFAULT_SERVICE_NAME : serviceName;
+    // if (serviceName == null) {
+    //   serviceName = DEFAULT_SERVICE_NAME;
+    // }
+    // this.node = OcAgentNodeUtils.getNodeInfo(serviceName);
     // this.useInsecure = useInsecure == null ? false : useInsecure;
   }
 
diff --git a/exporters/trace/ocagent/src/main/java/io/opencensus/exporter/trace/ocagent/TraceProtoUtils.java b/exporters/trace/ocagent/src/main/java/io/opencensus/exporter/trace/ocagent/TraceProtoUtils.java
index 26bae0ac..df11ef58 100644
--- a/exporters/trace/ocagent/src/main/java/io/opencensus/exporter/trace/ocagent/TraceProtoUtils.java
+++ b/exporters/trace/ocagent/src/main/java/io/opencensus/exporter/trace/ocagent/TraceProtoUtils.java
@@ -283,7 +283,7 @@ public final class TraceProtoUtils {
     return TruncatableString.newBuilder().setValue(string).setTruncatedByteCount(0).build();
   }
 
-  private static com.google.protobuf.Timestamp toTimestampProto(Timestamp timestamp) {
+  static com.google.protobuf.Timestamp toTimestampProto(Timestamp timestamp) {
     return com.google.protobuf.Timestamp.newBuilder()
         .setSeconds(timestamp.getSeconds())
         .setNanos(timestamp.getNanos())
diff --git a/exporters/trace/ocagent/src/test/java/io/opencensus/exporter/trace/ocagent/OcAgentNodeUtilsTest.java b/exporters/trace/ocagent/src/test/java/io/opencensus/exporter/trace/ocagent/OcAgentNodeUtilsTest.java
new file mode 100644
index 00000000..813066bc
--- /dev/null
+++ b/exporters/trace/ocagent/src/test/java/io/opencensus/exporter/trace/ocagent/OcAgentNodeUtilsTest.java
@@ -0,0 +1,122 @@
+/*
+ * Copyright 2018, OpenCensus Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.opencensus.exporter.trace.ocagent;
+
+import static com.google.common.truth.Truth.assertThat;
+import static io.opencensus.exporter.trace.ocagent.OcAgentNodeUtils.OC_AGENT_EXPORTER_VERSION;
+import static io.opencensus.exporter.trace.ocagent.OcAgentNodeUtils.RESOURCE_LABEL_ATTRIBUTE_KEY;
+import static io.opencensus.exporter.trace.ocagent.OcAgentNodeUtils.RESOURCE_TYPE_ATTRIBUTE_KEY;
+
+import io.opencensus.common.Timestamp;
+import io.opencensus.contrib.monitoredresource.util.MonitoredResource.AwsEc2InstanceMonitoredResource;
+import io.opencensus.contrib.monitoredresource.util.MonitoredResource.GcpGceInstanceMonitoredResource;
+import io.opencensus.contrib.monitoredresource.util.MonitoredResource.GcpGkeContainerMonitoredResource;
+import io.opencensus.proto.agent.common.v1.LibraryInfo;
+import io.opencensus.proto.agent.common.v1.LibraryInfo.Language;
+import io.opencensus.proto.agent.common.v1.ProcessIdentifier;
+import io.opencensus.proto.agent.common.v1.ServiceInfo;
+import java.util.Map;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Tests for {@link OcAgentNodeUtils}. */
+@RunWith(JUnit4.class)
+public class OcAgentNodeUtilsTest {
+
+  private static final AwsEc2InstanceMonitoredResource AWS_RESOURCE =
+      AwsEc2InstanceMonitoredResource.create("account1", "instance1", "us-east-2");
+  private static final GcpGceInstanceMonitoredResource GCE_RESOURCE =
+      GcpGceInstanceMonitoredResource.create("account2", "instance2", "us-west2");
+  private static final GcpGkeContainerMonitoredResource GKE_RESOURCE =
+      GcpGkeContainerMonitoredResource.create(
+          "account3", "cluster", "container", "", "instance3", "", "us-west4");
+
+  @Test
+  public void testConstants() {
+    assertThat(OC_AGENT_EXPORTER_VERSION).isEqualTo("0.17.0-SNAPSHOT");
+    assertThat(RESOURCE_TYPE_ATTRIBUTE_KEY).isEqualTo("OPENCENSUS_SOURCE_TYPE");
+    assertThat(RESOURCE_LABEL_ATTRIBUTE_KEY).isEqualTo("OPENCENSUS_SOURCE_LABELS");
+  }
+
+  @Test
+  public void getProcessIdentifier() {
+    String jvmName = "54321@my.org";
+    Timestamp timestamp = Timestamp.create(10, 20);
+    ProcessIdentifier processIdentifier = OcAgentNodeUtils.getProcessIdentifier(jvmName, timestamp);
+    assertThat(processIdentifier.getHostName()).isEqualTo("my.org");
+    assertThat(processIdentifier.getPid()).isEqualTo(54321);
+    assertThat(processIdentifier.getStartTimestamp())
+        .isEqualTo(com.google.protobuf.Timestamp.newBuilder().setSeconds(10).setNanos(20).build());
+  }
+
+  @Test
+  public void getLibraryInfo() {
+    String currentOcJavaVersion = "0.16.0";
+    LibraryInfo libraryInfo = OcAgentNodeUtils.getLibraryInfo(currentOcJavaVersion);
+    assertThat(libraryInfo.getLanguage()).isEqualTo(Language.JAVA);
+    assertThat(libraryInfo.getCoreLibraryVersion()).isEqualTo(currentOcJavaVersion);
+    assertThat(libraryInfo.getExporterVersion()).isEqualTo(OC_AGENT_EXPORTER_VERSION);
+  }
+
+  @Test
+  public void getServiceInfo() {
+    String serviceName = "my-service";
+    ServiceInfo serviceInfo = OcAgentNodeUtils.getServiceInfo(serviceName);
+    assertThat(serviceInfo.getName()).isEqualTo(serviceName);
+  }
+
+  @Test
+  public void getAttributeMap_Null() {
+    Map<String, String> attributeMap = OcAgentNodeUtils.getAttributeMap(null);
+    assertThat(attributeMap).isEmpty();
+  }
+
+  @Test
+  public void getAttributeMap_AwsEc2Resource() {
+    Map<String, String> attributeMap = OcAgentNodeUtils.getAttributeMap(AWS_RESOURCE);
+    assertThat(attributeMap)
+        .containsExactly(
+            RESOURCE_TYPE_ATTRIBUTE_KEY,
+            "AWS_EC2_INSTANCE",
+            RESOURCE_LABEL_ATTRIBUTE_KEY,
+            "aws_account=account1,instance_id=instance1,region=us-east-2");
+  }
+
+  @Test
+  public void getAttributeMap_GceResource() {
+    Map<String, String> attributeMap = OcAgentNodeUtils.getAttributeMap(GCE_RESOURCE);
+    assertThat(attributeMap)
+        .containsExactly(
+            RESOURCE_TYPE_ATTRIBUTE_KEY,
+            "GCP_GCE_INSTANCE",
+            RESOURCE_LABEL_ATTRIBUTE_KEY,
+            "gcp_account=account2,instance_id=instance2,zone=us-west2");
+  }
+
+  @Test
+  public void getAttributeMap_GkeResource() {
+    Map<String, String> attributeMap = OcAgentNodeUtils.getAttributeMap(GKE_RESOURCE);
+    assertThat(attributeMap)
+        .containsExactly(
+            RESOURCE_TYPE_ATTRIBUTE_KEY,
+            "GCP_GKE_CONTAINER",
+            RESOURCE_LABEL_ATTRIBUTE_KEY,
+            "gcp_account=account3,instance_id=instance3,location=us-west4,"
+                + "cluster_name=cluster,container_name=container");
+  }
+}