OpenAI: Fix model property being overwritten by default value

Fixes gh-671

Signed-off-by: Thomas Vitale <ThomasVitale@users.noreply.github.com>

Author: ThomasVitale

models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiImageOptions.java

@@ -19,7 +19,6 @@
 import com.fasterxml.jackson.annotation.JsonProperty;
 
 import org.springframework.ai.image.ImageOptions;
-import org.springframework.ai.openai.api.OpenAiImageApi;
 
 import java.util.Objects;
 
@@ -44,7 +43,7 @@ public class OpenAiImageOptions implements ImageOptions {
 	 * The model to use for image generation.
 	 */
 	@JsonProperty("model")
-	private String model = OpenAiImageApi.DEFAULT_IMAGE_MODEL;
+	private String model;
 
 	/**
 	 * The width of the generated images. Must be one of 256, 512, or 1024 for dall-e-2.

spring-ai-spring-boot-autoconfigure/src/main/java/org/springframework/ai/autoconfigure/openai/OpenAiImageProperties.java

@@ -16,6 +16,7 @@
 package org.springframework.ai.autoconfigure.openai;
 
 import org.springframework.ai.openai.OpenAiImageOptions;
+import org.springframework.ai.openai.api.OpenAiImageApi;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.boot.context.properties.NestedConfigurationProperty;
 
@@ -30,6 +31,8 @@ public class OpenAiImageProperties extends OpenAiParentProperties {
 
 	public static final String CONFIG_PREFIX = "spring.ai.openai.image";
 
+	public static final String DEFAULT_IMAGE_MODEL = OpenAiImageApi.ImageModel.DALL_E_3.getValue();
+
 	/**
 	 * Enable OpenAI Image client.
 	 */
@@ -39,7 +42,7 @@ public class OpenAiImageProperties extends OpenAiParentProperties {
 	 * Options for OpenAI Image API.
 	 */
 	@NestedConfigurationProperty
-	private OpenAiImageOptions options = OpenAiImageOptions.builder().build();
+	private OpenAiImageOptions options = OpenAiImageOptions.builder().withModel(DEFAULT_IMAGE_MODEL).build();
 
 	public OpenAiImageOptions getOptions() {
 		return options;

spring-ai-spring-boot-autoconfigure/src/test/java/org/springframework/ai/autoconfigure/openai/OpenAiAutoConfigurationIT.java

@@ -144,4 +144,19 @@ void generateImage() {
 		});
 	}
 
+	@Test
+	void generateImageWithModel() {
+		// The 256x256 size is supported by dall-e-2, but not by dall-e-3.
+		contextRunner
+			.withPropertyValues("spring.ai.openai.image.options.model=dall-e-2",
+					"spring.ai.openai.image.options.size=256x256")
+			.run(context -> {
+				OpenAiImageClient client = context.getBean(OpenAiImageClient.class);
+				ImageResponse imageResponse = client.call(new ImagePrompt("forest"));
+				assertThat(imageResponse.getResults()).hasSize(1);
+				assertThat(imageResponse.getResult().getOutput().getUrl()).isNotEmpty();
+				logger.info("Generated image: " + imageResponse.getResult().getOutput().getUrl());
+			});
+	}
+
 }