Add IdentityManager and create agentId based on PID and hostname

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

@@ -0,0 +1,76 @@
+/* (C) 2024 */
+package rocks.inspectit.gepard.agent.internal.identity;
+
+import java.lang.management.ManagementFactory;
+import java.lang.management.RuntimeMXBean;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import rocks.inspectit.gepard.agent.internal.identity.model.IdentityInfo;
+
+public class IdentityManager {
+
+  private static final Logger log = LoggerFactory.getLogger(IdentityManager.class);
+
+  private final IdentityInfo identityInfo;
+
+  private IdentityManager() {
+    RuntimeMXBean runtime = ManagementFactory.getRuntimeMXBean();
+    long pid = runtime.getPid();
+    String localHostName = getLocalHostname();
+    this.identityInfo = new IdentityInfo(pid, localHostName, hash(pid + localHostName));
+  }
+
+  public static IdentityManager getInstance() {
+    return new IdentityManager();
+  }
+
+  public IdentityInfo getIdentityInfo() {
+    return this.identityInfo;
+  }
+
+  /**
+   * Determines the current hostname.
+   *
+   * @return the hostname or if the operation is not allowed by the security check, the textual
+   *     representation of the IP address. The default value is "0.0.0.0".
+   */
+  private String getLocalHostname() {
+    String localHostName = "0.0.0.0";
+    try {
+      localHostName = InetAddress.getLocalHost().getHostName();
+    } catch (UnknownHostException e) {
+      log.info("Could not determine hostname", e);
+    }
+    return localHostName;
+  }
+
+  /**
+   * 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/internal/identity/model/IdentityInfo.java

@@ -0,0 +1,4 @@
+/* (C) 2024 */
+package rocks.inspectit.gepard.agent.internal.identity.model;
+
+public record IdentityInfo(long pid, String hostname, String agentId) {}

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

@@ -11,6 +11,8 @@
 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.identity.model.IdentityInfo;
 import rocks.inspectit.gepard.agent.internal.properties.PropertiesResolver;
 
 /** Meta-information about the current agent */
@@ -33,16 +35,25 @@ public class AgentInfo {
 
   private final long pid;
 
+  private final String hostname;
+
+  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.pid = identityInfo.pid();
+    this.hostname = identityInfo.hostname();
+    this.agentId = identityInfo.agentId();
     this.attributes = PropertiesResolver.getAttributes();
   }
 
@@ -67,15 +78,4 @@ 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/test/java/rocks/inspectit/gepard/agent/internal/identity/IdentityManagerTest.java

@@ -0,0 +1,64 @@
+/* (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 java.net.InetAddress;
+import java.net.UnknownHostException;
+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() {
+    InetAddress mockInetAddress = mock(InetAddress.class);
+    when(mockInetAddress.getHostName()).thenReturn("mockedHostName");
+
+    RuntimeMXBean mockRuntimeMXBean = mock(RuntimeMXBean.class);
+    when(mockRuntimeMXBean.getPid()).thenReturn(12345L);
+
+    try (MockedStatic<InetAddress> mockedStatic = Mockito.mockStatic(InetAddress.class);
+        MockedStatic<ManagementFactory> managementFactoryMockedStatic =
+            Mockito.mockStatic(ManagementFactory.class)) {
+      mockedStatic.when(InetAddress::getLocalHost).thenReturn(mockInetAddress);
+      managementFactoryMockedStatic
+          .when(ManagementFactory::getRuntimeMXBean)
+          .thenReturn(mockRuntimeMXBean);
+
+      IdentityManager identityManager = IdentityManager.getInstance();
+      IdentityInfo identityInfo = identityManager.getIdentityInfo();
+
+      assertNotNull(identityInfo);
+      assertEquals("mockedHostName", identityInfo.hostname());
+      assertEquals(12345L, identityInfo.pid());
+      assertEquals(
+          "ef138ea8d422d1df09c3f94b675a99bb475cdae966d067f58a0887ab54ab35e0",
+          identityInfo.agentId());
+    }
+  }
+
+  @Test
+  void testCreateIdentityManagerWithUnknownHostException() {
+    try (MockedStatic<InetAddress> mockedStatic = Mockito.mockStatic(InetAddress.class)) {
+      mockedStatic
+          .when(InetAddress::getLocalHost)
+          .thenThrow(new UnknownHostException("Mocked Exception"));
+
+      IdentityManager identityManager = IdentityManager.getInstance();
+      IdentityInfo identityInfo = identityManager.getIdentityInfo();
+
+      assertNotNull(identityInfo);
+      assertEquals("0.0.0.0", identityInfo.hostname());
+    }
+  }
+}

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

@@ -24,6 +24,8 @@ void agentInformationContainsProperties() throws JsonProcessingException {
     assertTrue(info.contains("javaVersion"));
     assertTrue(info.contains("startTime"));
     assertTrue(info.contains("pid"));
+    assertTrue(info.contains("hostname"));
+    assertTrue(info.contains("agentId"));
     assertTrue(info.contains("attributes"));
   }
 }