feat: Add custom session id functionality to vertex ai session service

google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/genai/Sessions.java

@@ -96,6 +96,13 @@ ObjectNode createAgentEngineSessionConfigToVertex(JsonNode fromObject, ObjectNod
           Common.getValueByPath(fromObject, new String[] {"labels"}));
     }
 
+    if (Common.getValueByPath(fromObject, new String[] {"sessionId"}) != null) {
+      Common.setValueByPath(
+          parentObject,
+          new String[] {"_query", "sessionId"},
+          Common.getValueByPath(fromObject, new String[] {"sessionId"}));
+    }
+
     return toObject;
   }
 
@@ -259,6 +266,13 @@ ObjectNode updateAgentEngineSessionConfigToVertex(JsonNode fromObject, ObjectNod
           Common.getValueByPath(fromObject, new String[] {"labels"}));
     }
 
+    if (Common.getValueByPath(fromObject, new String[] {"sessionId"}) != null) {
+      Common.setValueByPath(
+          parentObject,
+          new String[] {"_query", "sessionId"},
+          Common.getValueByPath(fromObject, new String[] {"sessionId"}));
+    }
+
     if (Common.getValueByPath(fromObject, new String[] {"updateMask"}) != null) {
       Common.setValueByPath(
           parentObject,

google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/genai/types/CreateAgentEngineSessionConfig.java

@@ -74,6 +74,15 @@ public abstract class CreateAgentEngineSessionConfig extends JsonSerializable {
   @JsonProperty("labels")
   public abstract Optional<Map<String, String>> labels();
 
+  /**
+   * Optional. The user defined ID to use for session, which will become the final component of the
+   * session resource name. If not provided, Vertex AI will generate a value for this ID. This value
+   * may be up to 63 characters, and valid characters are `[a-z0-9-]`. The first character must be a
+   * letter, and the last character must be a letter or number.
+   */
+  @JsonProperty("sessionId")
+  public abstract Optional<String> sessionId();
+
   /** Instantiates a builder for CreateAgentEngineSessionConfig. */
   @ExcludeFromGeneratedCoverageReport
   public static Builder builder() {
@@ -226,6 +235,27 @@ public Builder clearLabels() {
       return labels(Optional.empty());
     }
 
+    /**
+     * Setter for sessionId.
+     *
+     * <p>sessionId: Optional. The user defined ID to use for session, which will become the final
+     * component of the session resource name. If not provided, Vertex AI will generate a value for
+     * this ID. This value may be up to 63 characters, and valid characters are `[a-z0-9-]`. The
+     * first character must be a letter, and the last character must be a letter or number.
+     */
+    @JsonProperty("sessionId")
+    public abstract Builder sessionId(String sessionId);
+
+    @ExcludeFromGeneratedCoverageReport
+    abstract Builder sessionId(Optional<String> sessionId);
+
+    /** Clears the value of sessionId field. */
+    @ExcludeFromGeneratedCoverageReport
+    @CanIgnoreReturnValue
+    public Builder clearSessionId() {
+      return sessionId(Optional.empty());
+    }
+
     public abstract CreateAgentEngineSessionConfig build();
   }
 

google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/genai/types/UpdateAgentEngineSessionConfig.java

@@ -74,6 +74,15 @@ public abstract class UpdateAgentEngineSessionConfig extends JsonSerializable {
   @JsonProperty("labels")
   public abstract Optional<Map<String, String>> labels();
 
+  /**
+   * Optional. The user defined ID to use for session, which will become the final component of the
+   * session resource name. If not provided, Vertex AI will generate a value for this ID. This value
+   * may be up to 63 characters, and valid characters are `[a-z0-9-]`. The first character must be a
+   * letter, and the last character must be a letter or number.
+   */
+  @JsonProperty("sessionId")
+  public abstract Optional<String> sessionId();
+
   /**
    * The update mask to apply. For the `FieldMask` definition, see
    * https://protobuf.dev/reference/protobuf/google.protobuf/#field-mask.
@@ -237,6 +246,27 @@ public Builder clearLabels() {
       return labels(Optional.empty());
     }
 
+    /**
+     * Setter for sessionId.
+     *
+     * <p>sessionId: Optional. The user defined ID to use for session, which will become the final
+     * component of the session resource name. If not provided, Vertex AI will generate a value for
+     * this ID. This value may be up to 63 characters, and valid characters are `[a-z0-9-]`. The
+     * first character must be a letter, and the last character must be a letter or number.
+     */
+    @JsonProperty("sessionId")
+    public abstract Builder sessionId(String sessionId);
+
+    @ExcludeFromGeneratedCoverageReport
+    abstract Builder sessionId(Optional<String> sessionId);
+
+    /** Clears the value of sessionId field. */
+    @ExcludeFromGeneratedCoverageReport
+    @CanIgnoreReturnValue
+    public Builder clearSessionId() {
+      return sessionId(Optional.empty());
+    }
+
     /**
      * Setter for updateMask.
      *