Add container.id to resource attributes (#129)

* Add container.id to resource attributes

Signed-off-by: Pavol Loffay <[email protected]>

* Add comments

Signed-off-by: Pavol Loffay <[email protected]>

* Adjust message

Signed-off-by: Pavol Loffay <[email protected]>

* fix

Signed-off-by: Pavol Loffay <[email protected]>

Author: pavolloffay

instrumentation/build.gradle.kts

@@ -34,6 +34,7 @@ dependencies{
     implementation(project(":instrumentation:spark-web-framework-2.3"))
     implementation(project(":instrumentation:grpc-1.5"))
     implementation(project(":instrumentation:okhttp:okhttp-3.0"))
+    implementation(project(":otel-extensions"))
 }
 
 tasks {

javaagent-core/src/main/resources/META-INF/services/io.opentelemetry.sdk.resources.ResourceProvider

@@ -0,0 +1,12 @@
+plugins {
+    `java-library`
+}
+
+dependencies {
+    implementation("org.slf4j:slf4j-api:1.7.30")
+    compileOnly("io.opentelemetry:opentelemetry-sdk:0.10.0")
+    implementation("com.google.auto.service:auto-service:1.0-rc7")
+    annotationProcessor("com.google.auto.service:auto-service:1.0-rc7")
+
+    testImplementation("io.opentelemetry:opentelemetry-sdk:0.10.0")
+}

otel-extensions/build.gradle.kts

@@ -0,0 +1,70 @@
+/*
+ * Copyright The Hypertrace 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 org.hypertrace.agent.otel.extensions;
+
+import java.io.BufferedReader;
+import java.io.FileNotFoundException;
+import java.io.FileReader;
+import java.io.IOException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class CgroupsReader {
+
+  private static final Logger log =
+      LoggerFactory.getLogger(HypertraceResourceProvider.class.getName());
+
+  private static final String DEFAULT_CGROUPS_PATH = "/proc/self/cgroup";
+  private static final int CONTAINER_ID_LENGTH = 64;
+
+  private final String cgroupsPath;
+
+  CgroupsReader() {
+    this.cgroupsPath = DEFAULT_CGROUPS_PATH;
+  }
+
+  CgroupsReader(String cgroupsPath) {
+    this.cgroupsPath = cgroupsPath;
+  }
+
+  /**
+   * Read container ID from cgroups file.
+   *
+   * @return docker container ID or empty string if not defined.
+   */
+  @SuppressWarnings("DefaultCharset")
+  public String readContainerId() {
+    try (BufferedReader br = new BufferedReader(new FileReader(cgroupsPath))) {
+      String line;
+      while ((line = br.readLine()) != null) {
+        if (line.length() > CONTAINER_ID_LENGTH) {
+          String id = line.substring(line.length() - CONTAINER_ID_LENGTH);
+          if (!id.contains("/")) {
+            return id;
+          }
+        }
+      }
+    } catch (FileNotFoundException ex) {
+      // do not pass exception to logger because it prints stacktrace, we don't want that in non
+      // container environments
+      log.warn("Failed to read container id, cgroups file does not exist: {}", ex.getMessage());
+    } catch (IOException ex) {
+      log.warn("Unable to read container id", ex);
+    }
+    return "";
+  }
+}

otel-extensions/src/main/java/org/hypertrace/agent/otel/extensions/CgroupsReader.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright The Hypertrace 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 org.hypertrace.agent.otel.extensions;
+
+import com.google.auto.service.AutoService;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.common.Attributes.Builder;
+import io.opentelemetry.sdk.resources.ResourceAttributes;
+import io.opentelemetry.sdk.resources.ResourceProvider;
+
+@AutoService(ResourceProvider.class)
+public class HypertraceResourceProvider extends ResourceProvider {
+
+  private final CgroupsReader cgroupsReader = new CgroupsReader();
+
+  @Override
+  protected Attributes getAttributes() {
+    Builder builder = Attributes.builder();
+    String containerId = this.cgroupsReader.readContainerId();
+    if (containerId != null && !containerId.isEmpty()) {
+      builder.put(ResourceAttributes.CONTAINER_ID.getKey(), containerId);
+    }
+    return builder.build();
+  }
+}

otel-extensions/src/main/java/org/hypertrace/agent/otel/extensions/HypertraceResourceProvider.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright The Hypertrace 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 org.hypertrace.agent.otel.extensions;
+
+import com.google.common.base.Charsets;
+import com.google.common.io.Files;
+import java.io.File;
+import java.io.IOException;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+public class DockerCgroupsReaderTest {
+
+  @Test
+  void testCgroupFileMissing() {
+    CgroupsReader cgroups = new CgroupsReader("doesnotexists");
+    Assertions.assertEquals("", cgroups.readContainerId());
+  }
+
+  @Test
+  void readContainerId(@TempDir File tempFolder) throws IOException {
+    File file = new File(tempFolder, "cgroup");
+    String expected = "987a1920640799b5bf5a39bd94e489e5159a88677d96ca822ce7c433ff350163";
+    String content = "dummy\n11:devices:/ecs/bbc36dd0-5ee0-4007-ba96-c590e0b278d2/" + expected;
+    Files.write(content.getBytes(Charsets.UTF_8), file);
+
+    CgroupsReader cgroupsReader = new CgroupsReader(file.getPath());
+    Assertions.assertEquals(expected, cgroupsReader.readContainerId());
+  }
+}

otel-extensions/src/main/resources/io.opentelemetry.sdk.resources.ResourceProvider

@@ -35,3 +35,4 @@ findProject(":instrumentation:grpc-1.5")?.name = "grpc-1.5"
 include("instrumentation:okhttp:okhttp-3.0")
 findProject(":instrumentation:okhttp:okhttp-3.0")?.name = "okhttp-3.0"
 include("filter-custom-opa")
+include("otel-extensions")

otel-extensions/src/test/java/org/hypertrace/agent/otel/extensions/DockerCgroupsReaderTest.java

@@ -113,6 +113,10 @@ public void get() throws IOException {
                 .map(attribute -> attribute.getValue().getStringValue())
                 .count()
             > 0);
+    // TODO test the container ID once we switch from Zipkin exporter
+    // Zipkin exporter does not add resource attributes to span
+    // https://github.com/open-telemetry/opentelemetry-java/issues/1970
+
     // OTEL BS smoke test app does not have an endpoint that uses content type what we capture
     // enable once we add smoke tests apps to our build.
     //    List<String> responseBodyAttributes =