Add agent identifier generation

inspectit-gepard-agent/src/main/java/rocks/inspectit/gepard/agent/InspectitAgentExtension.java

@@ -16,6 +16,7 @@
 import rocks.inspectit.gepard.agent.instrumentation.state.InstrumentationState;
 import rocks.inspectit.gepard.agent.instrumentation.state.configuration.InspectitConfigurationHolder;
 import rocks.inspectit.gepard.agent.instrumentation.state.configuration.resolver.ConfigurationResolver;
+import rocks.inspectit.gepard.agent.internal.identity.IdentityManager;
 import rocks.inspectit.gepard.agent.internal.otel.OpenTelemetryAccessor;
 import rocks.inspectit.gepard.agent.notification.NotificationManager;
 import rocks.inspectit.gepard.agent.transformation.TransformationManager;
@@ -68,6 +69,10 @@ public AgentBuilder extend(AgentBuilder agentBuilder, ConfigProperties config) {
     instrumentationManager.startClassDiscovery();
     instrumentationManager.startBatchInstrumentation(instrumentationState);
 
+    // Set agentId based on generation type
+    IdentityManager identityManager = IdentityManager.getInstance();
+    identityManager.setIdentity();
+
     // Start loading the inspectIT configuration
     ConfigurationManager configurationManager = ConfigurationManager.create();
     configurationManager.loadConfiguration();

inspectit-gepard-agent/src/main/java/rocks/inspectit/gepard/agent/configuration/ConfigurationManager.java

@@ -10,6 +10,7 @@
 import rocks.inspectit.gepard.agent.configuration.persistence.file.ConfigurationFileReader;
 import rocks.inspectit.gepard.agent.configuration.persistence.file.ConfigurationFileWriter;
 import rocks.inspectit.gepard.agent.internal.file.FileAccessor;
+import rocks.inspectit.gepard.agent.internal.identity.IdentityManager;
 import rocks.inspectit.gepard.agent.internal.properties.PropertiesResolver;
 import rocks.inspectit.gepard.agent.internal.schedule.InspectitScheduler;
 
@@ -46,7 +47,9 @@ public void loadConfiguration() {
    */
   private void startHttpPolling(String serverUrl, ConfigurationPersistence persistence) {
     InspectitScheduler scheduler = InspectitScheduler.getInstance();
-    HttpConfigurationPoller poller = new HttpConfigurationPoller(serverUrl, persistence);
+    IdentityManager identityManager = IdentityManager.getInstance();
+    HttpConfigurationPoller poller =
+        new HttpConfigurationPoller(serverUrl, identityManager.getAgentId(), persistence);
     Duration pollingInterval = PropertiesResolver.getPollingInterval();
     scheduler.startRunnable(poller, pollingInterval);
   }

inspectit-gepard-agent/src/main/java/rocks/inspectit/gepard/agent/configuration/http/HttpConfigurationFactory.java

@@ -21,10 +21,10 @@ private HttpConfigurationFactory() {}
    * @return the HTTP post request, containing agent information
    * @throws URISyntaxException invalid uri
    */
-  public static SimpleHttpRequest createConfigurationRequest(String baseUrl)
+  public static SimpleHttpRequest createConfigurationRequest(String baseUrl, String agentId)
       throws URISyntaxException {
     URI uri = new URIBuilder(baseUrl + "/agent-configuration").build();
 
-    return SimpleRequestBuilder.get(uri).build();
+    return SimpleRequestBuilder.get(uri).addParameter("id", agentId).build();
   }
 }

inspectit-gepard-agent/src/main/java/rocks/inspectit/gepard/agent/configuration/http/HttpConfigurationPoller.java

@@ -16,13 +16,17 @@ public class HttpConfigurationPoller implements NamedRunnable {
 
   private final String serverUrl;
 
+  private final String agentId;
+
   private final ConfigurationPersistence persistence;
 
   /** Flag to mark first polling attempt */
   private boolean isFirstAttempt = true;
 
-  public HttpConfigurationPoller(String serverUrl, ConfigurationPersistence persistence) {
+  public HttpConfigurationPoller(
+      String serverUrl, String agentId, ConfigurationPersistence persistence) {
     this.serverUrl = serverUrl;
+    this.agentId = agentId;
     this.persistence = persistence;
   }
 
@@ -63,7 +67,7 @@ boolean pollConfiguration() {
   private SimpleHttpRequest createConfigurationRequest() {
     SimpleHttpRequest request = null;
     try {
-      request = HttpConfigurationFactory.createConfigurationRequest(serverUrl);
+      request = HttpConfigurationFactory.createConfigurationRequest(serverUrl, agentId);
     } catch (URISyntaxException e) {
       log.error("Error building HTTP URI for configuration polling", e);
     }

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

@@ -0,0 +1,68 @@
+/* (C) 2024 */
+package rocks.inspectit.gepard.agent.internal.identity;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.Objects;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import rocks.inspectit.gepard.agent.internal.identity.type.IdGenerationType;
+import rocks.inspectit.gepard.agent.internal.properties.PropertiesResolver;
+
+public class IdentityManager {
+  private static final Logger log = LoggerFactory.getLogger(IdentityManager.class);
+
+  private String agentId;
+
+  private static IdentityManager instance;
+
+  private IdentityManager() {}
+
+  public static IdentityManager getInstance() {
+    if (Objects.isNull(instance)) instance = new IdentityManager();
+    return instance;
+  }
+
+  public String getAgentId() {
+    return agentId;
+  }
+
+  public void setIdentity() {
+    IdGenerationType idGenerationType = PropertiesResolver.getIdGenerationType();
+    try {
+      switch (idGenerationType) {
+        case FQDN -> agentId = hash(InetAddress.getLocalHost().getCanonicalHostName());
+        case IP_ADDRESS -> agentId = hash(InetAddress.getLocalHost().getHostAddress());
+        case SERVICE_PROCESS_NAME ->
+            ProcessHandle.current()
+                .info()
+                .commandLine()
+                .ifPresent(commandLine -> agentId = commandLine.trim());
+      }
+    } catch (UnknownHostException e) {
+      log.info("Could not determine hostname", e);
+    }
+  }
+
+  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/type/IdGenerationType.java

@@ -0,0 +1,8 @@
+/* (C) 2024 */
+package rocks.inspectit.gepard.agent.internal.identity.type;
+
+public enum IdGenerationType {
+  IP_ADDRESS,
+  FQDN,
+  SERVICE_PROCESS_NAME
+}

inspectit-gepard-agent/src/main/java/rocks/inspectit/gepard/agent/internal/properties/PropertiesResolver.java

@@ -10,6 +10,7 @@
 import java.util.stream.Collectors;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import rocks.inspectit.gepard.agent.internal.identity.type.IdGenerationType;
 
 /**
  * This resolver provides configurable properties or their default values. Currently, it is possible
@@ -37,6 +38,12 @@ public class PropertiesResolver {
       "inspectit.config.http.attributes.";
   public static final String ATTRIBUTES_ENV_PROPERTY_PREFIX = "INSPECTIT_CONFIG_HTTP_ATTRIBUTES_";
 
+  public static final String ID_GENERATION_TYPE_SYSTEM_PROPERTY =
+      "inspectit.config.id-generation-type";
+
+  public static final String ID_GENERATION_TYPE_ENV_PROPERTY =
+      "INSPECTIT_CONFIG_ID_GENERATION_TYPE";
+
   private static final Logger log = LoggerFactory.getLogger(PropertiesResolver.class);
 
   private PropertiesResolver() {}
@@ -167,4 +174,36 @@ private static Map<String, String> getAttributesFromSystemProperties() {
                     entry.getKey().toString().substring(ATTRIBUTES_SYSTEM_PROPERTY_PREFIX.length()),
                 entry -> entry.getValue().toString()));
   }
+
+  /**
+   * TODO
+   *
+   * @return
+   */
+  public static IdGenerationType getIdGenerationType() {
+    String idGenerationTypeSystemProperty = System.getProperty(ID_GENERATION_TYPE_SYSTEM_PROPERTY);
+    if (Objects.nonNull(idGenerationTypeSystemProperty))
+      return convertToIdGenerationType(idGenerationTypeSystemProperty);
+
+    String idGenerationTypeEnvProperty = System.getenv(ID_GENERATION_TYPE_ENV_PROPERTY);
+    return convertToIdGenerationType(idGenerationTypeEnvProperty);
+  }
+
+  /**
+   * TODO
+   *
+   * @param idGenerationType
+   * @return
+   */
+  private static IdGenerationType convertToIdGenerationType(String idGenerationType) {
+    IdGenerationType idGeneration = IdGenerationType.FQDN;
+    if (Objects.nonNull(idGenerationType)) {
+      try {
+        idGeneration = IdGenerationType.valueOf(idGenerationType);
+      } catch (IllegalArgumentException e) {
+        log.info("Unknown id-generation type: {}. Using fallback: FQDN", idGenerationType);
+      }
+    }
+    return idGeneration;
+  }
 }