feature: Add IdentityManager and create agentId based on PID and host…

…name (#26)

* Add IdentityManager and create agentId based on PID and hostname

* Fix review findings

* Fix remaining review findings

* Fix AgentInfoTest

inspectit-gepard-agent/src/main/java/rocks/inspectit/gepard/agent/internal/identity/IdentityManager.java

@@ -0,0 +1,58 @@
+/* (C) 2024 */
+package rocks.inspectit.gepard.agent.internal.identity;
+
+import java.lang.management.ManagementFactory;
+import java.lang.management.RuntimeMXBean;
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.Objects;
+import rocks.inspectit.gepard.agent.internal.identity.model.IdentityInfo;
+
+/** Responsible for generating the agentId. */
+public class IdentityManager {
+
+  private static IdentityManager instance;
+
+  private final IdentityInfo identityInfo;
+
+  private IdentityManager() {
+    RuntimeMXBean runtime = ManagementFactory.getRuntimeMXBean();
+    String vmId = runtime.getName();
+    this.identityInfo = new IdentityInfo(vmId, hash(vmId));
+  }
+
+  public static IdentityManager getInstance() {
+    if (Objects.isNull(instance)) instance = new IdentityManager();
+    return instance;
+  }
+
+  public IdentityInfo getIdentityInfo() {
+    return this.identityInfo;
+  }
+
+  /**
+   * Hashes the given input with SHA3-256.
+   *
+   * @param input the <code>String</code> to be hashed.
+   * @return the SHA3-256 hashed <code>String</code>
+   */
+  private static String hash(String input) {
+    MessageDigest messageDigest;
+    try {
+      messageDigest = MessageDigest.getInstance("SHA3-256");
+    } catch (NoSuchAlgorithmException e) {
+      throw new UnsupportedOperationException("SHA3-256 not supported", e);
+    }
+    byte[] bytes = messageDigest.digest(input.getBytes(StandardCharsets.UTF_8));
+    StringBuilder hexString = new StringBuilder(2 * bytes.length);
+    for (byte b : bytes) {
+      String hex = Integer.toHexString(0xff & b);
+      if (hex.length() == 1) {
+        hexString.append('0');
+      }
+      hexString.append(hex);
+    }
+    return hexString.toString();
+  }
+}

inspectit-gepard-agent/src/main/java/rocks/inspectit/gepard/agent/notification/model/AgentInfo.java → inspectit-gepard-agent/src/main/java/rocks/inspectit/gepard/agent/internal/identity/model/AgentInfo.java

@@ -1,5 +1,5 @@
 /* (C) 2024 */
-package rocks.inspectit.gepard.agent.notification.model;
+package rocks.inspectit.gepard.agent.internal.identity.model;
 
 import com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility;
 import com.fasterxml.jackson.annotation.PropertyAccessor;
@@ -11,6 +11,7 @@
 import java.lang.management.RuntimeMXBean;
 import java.util.Map;
 import java.util.Objects;
+import rocks.inspectit.gepard.agent.internal.identity.IdentityManager;
 import rocks.inspectit.gepard.agent.internal.properties.PropertiesResolver;
 
 /** Meta-information about the current agent */
@@ -31,18 +32,24 @@ public class AgentInfo {
 
   private final long startTime;
 
-  private final long pid;
+  private final String vmId;
+
+  private final String agentId;
 
   private final Map<String, String> attributes;
 
   private AgentInfo() {
+    IdentityManager identityManager = IdentityManager.getInstance();
+    IdentityInfo identityInfo = identityManager.getIdentityInfo();
+    RuntimeMXBean runtime = ManagementFactory.getRuntimeMXBean();
+
     this.serviceName = getServiceNameFromSdk();
     this.gepardVersion = "0.0.1";
     this.otelVersion = AgentVersion.VERSION;
     this.javaVersion = System.getProperty("java.version");
-    RuntimeMXBean runtime = ManagementFactory.getRuntimeMXBean();
     this.startTime = runtime.getStartTime();
-    this.pid = runtime.getPid();
+    this.vmId = identityInfo.vmId();
+    this.agentId = identityInfo.agentId();
     this.attributes = PropertiesResolver.getAttributes();
   }
 
@@ -67,15 +74,4 @@ private String getServiceNameFromSdk() {
         ? "inspectit-gepard-agent"
         : configuredServiceName;
   }
-
-  /**
-   * @return the service name of the agent.
-   */
-  public String getServiceName() {
-    return serviceName;
-  }
-
-  public long getPid() {
-    return pid;
-  }
 }

inspectit-gepard-agent/src/main/java/rocks/inspectit/gepard/agent/internal/identity/model/IdentityInfo.java

@@ -0,0 +1,21 @@
+/* (C) 2024 */
+package rocks.inspectit.gepard.agent.internal.identity.model;
+
+public final class IdentityInfo {
+
+  private final String vmId;
+  private final String agentId;
+
+  public IdentityInfo(String vmId, String agentId) {
+    this.vmId = vmId;
+    this.agentId = agentId;
+  }
+
+  public String vmId() {
+    return vmId;
+  }
+
+  public String agentId() {
+    return agentId;
+  }
+}

inspectit-gepard-agent/src/main/java/rocks/inspectit/gepard/agent/notification/http/NotificationFactory.java

@@ -7,7 +7,7 @@
 import org.apache.hc.client5.http.async.methods.SimpleHttpRequest;
 import org.apache.hc.client5.http.async.methods.SimpleRequestBuilder;
 import org.apache.hc.core5.http.ContentType;
-import rocks.inspectit.gepard.agent.notification.model.AgentInfo;
+import rocks.inspectit.gepard.agent.internal.identity.model.AgentInfo;
 
 /** This factory should create different HTTP requests for the configuration server */
 public class NotificationFactory {

inspectit-gepard-agent/src/test/java/rocks/inspectit/gepard/agent/internal/identity/IdentityManagerTest.java

@@ -0,0 +1,41 @@
+/* (C) 2024 */
+package rocks.inspectit.gepard.agent.internal.identity;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.lang.management.ManagementFactory;
+import java.lang.management.RuntimeMXBean;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.MockedStatic;
+import org.mockito.Mockito;
+import org.mockito.junit.jupiter.MockitoExtension;
+import rocks.inspectit.gepard.agent.internal.identity.model.IdentityInfo;
+
+@ExtendWith(MockitoExtension.class)
+class IdentityManagerTest {
+
+  @Test
+  void testCreateIdentityManagerSuccessfully() {
+    RuntimeMXBean mockRuntimeMXBean = mock(RuntimeMXBean.class);
+    when(mockRuntimeMXBean.getName()).thenReturn("12345@mockedHostName");
+
+    try (MockedStatic<ManagementFactory> managementFactoryMockedStatic =
+        Mockito.mockStatic(ManagementFactory.class)) {
+      managementFactoryMockedStatic
+          .when(ManagementFactory::getRuntimeMXBean)
+          .thenReturn(mockRuntimeMXBean);
+
+      IdentityManager identityManager = IdentityManager.getInstance();
+      IdentityInfo identityInfo = identityManager.getIdentityInfo();
+
+      assertNotNull(identityInfo);
+      assertEquals("12345@mockedHostName", identityInfo.vmId());
+      assertEquals(
+          "d29aca592fc2071bcef6577d649071d4d54a8ae6cd5c0be0e51f28af2867f207",
+          identityInfo.agentId());
+    }
+  }
+}

inspectit-gepard-agent/src/test/java/rocks/inspectit/gepard/agent/notification/model/AgentInfoTest.java → inspectit-gepard-agent/src/test/java/rocks/inspectit/gepard/agent/internal/identity/model/AgentInfoTest.java

@@ -1,5 +1,5 @@
 /* (C) 2024 */
-package rocks.inspectit.gepard.agent.notification.model;
+package rocks.inspectit.gepard.agent.internal.identity.model;
 
 import static org.junit.jupiter.api.Assertions.*;
 
@@ -23,7 +23,8 @@ void agentInformationContainsProperties() throws JsonProcessingException {
     assertTrue(info.contains("otelVersion"));
     assertTrue(info.contains("javaVersion"));
     assertTrue(info.contains("startTime"));
-    assertTrue(info.contains("pid"));
+    assertTrue(info.contains("vmId"));
+    assertTrue(info.contains("agentId"));
     assertTrue(info.contains("attributes"));
   }
 }

inspectit-gepard-agent/src/test/java/rocks/inspectit/gepard/agent/notification/http/NotificationFactoryTest.java

@@ -6,7 +6,7 @@
 import java.net.URISyntaxException;
 import org.apache.hc.client5.http.async.methods.SimpleHttpRequest;
 import org.junit.jupiter.api.Test;
-import rocks.inspectit.gepard.agent.notification.model.AgentInfo;
+import rocks.inspectit.gepard.agent.internal.identity.model.AgentInfo;
 
 class NotificationFactoryTest {