OpenAI: Add support for streamin token usage.

- OpenAiApi: add StreamingOptions class and ChatCompletionRequest#streamingOptions field.
 - add OpenAiChatOption#withStreamingUsage(boolean) to set/unset the StreamingOptions.
 - add a boolean (get/set)StreamUsage() to OpenAiChatOptions that internally set the SstreamOptions.
   Later allows the "spring.ai.openai.chat.options.stream-usage" property.
 - update the OpenAI property documentation.

Co-authored-by: Christian Tzolov <ctzolov@vmware.com>

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

@@ -222,7 +222,12 @@ public class OpenAiChatModel extends
 							return generation;
 						}).toList();
 
-						return new ChatResponse(generations);
+						if (chatCompletion.usage() != null) {
+							return new ChatResponse(generations, OpenAiChatResponseMetadata.from(chatCompletion));
+						}
+						else {
+							return new ChatResponse(generations);
+						}
 					}
 					catch (Exception e) {
 						logger.error("Error processing chat completion", e);
@@ -245,7 +250,7 @@ public class OpenAiChatModel extends
 			.toList();
 
 		return new OpenAiApi.ChatCompletion(chunk.id(), choices, chunk.created(), chunk.model(),
-				chunk.systemFingerprint(), "chat.completion", null);
+				chunk.systemFingerprint(), "chat.completion", chunk.usage());
 	}
 
 	/**
@@ -306,6 +311,12 @@ public class OpenAiChatModel extends
 					request, ChatCompletionRequest.class);
 		}
 
+		// Remove `streamOptions` from the request if it is not a streaming request
+		if (request.streamOptions() != null && !stream) {
+			logger.warn("Removing streamOptions from the request as it is not a streaming request!");
+			request = request.withStreamOptions(null);
+		}
+
 		return request;
 	}
 

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

@@ -27,6 +27,7 @@ import org.springframework.ai.model.function.FunctionCallback;
 import org.springframework.ai.model.function.FunctionCallingOptions;
 import org.springframework.ai.openai.api.OpenAiApi;
 import org.springframework.ai.openai.api.OpenAiApi.ChatCompletionRequest.ResponseFormat;
+import org.springframework.ai.openai.api.OpenAiApi.ChatCompletionRequest.StreamOptions;
 import org.springframework.ai.openai.api.OpenAiApi.ChatCompletionRequest.ToolChoiceBuilder;
 import org.springframework.ai.openai.api.OpenAiApi.FunctionTool;
 import org.springframework.boot.context.properties.NestedConfigurationProperty;
@@ -39,6 +40,7 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 
 /**
  * @author Christian Tzolov
+ * @author Mariusz Bernacki
  * @since 0.8.0
  */
 @JsonInclude(Include.NON_NULL)
@@ -93,6 +95,10 @@ public class OpenAiChatOptions implements FunctionCallingOptions, ChatOptions {
 	 * "json_object" } enables JSON mode, which guarantees the message the model generates is valid JSON.
 	 */
 	private @JsonProperty("response_format") ResponseFormat responseFormat;
+	/**
+	 * Options for streaming response. Included in the API only if streaming-mode completion is requested.
+	 */
+	private @JsonProperty("stream_options") StreamOptions streamOptions;
 	/**
 	 * This feature is in Beta. If specified, our system will make a best effort to sample
 	 * deterministically, such that repeated requests with the same seed and parameters should return the same result.
@@ -226,6 +232,13 @@ public class OpenAiChatOptions implements FunctionCallingOptions, ChatOptions {
 			return this;
 		}
 
+		public Builder withStreamUsage(boolean enableStreamUsage) {
+			if (enableStreamUsage) {
+				this.options.streamOptions = (enableStreamUsage) ? StreamOptions.INCLUDE_USAGE : null;
+			}
+			return this;
+		}
+
 		public Builder withSeed(Integer seed) {
 			this.options.seed = seed;
 			return this;
@@ -284,6 +297,14 @@ public class OpenAiChatOptions implements FunctionCallingOptions, ChatOptions {
 
 	}
 
+	public Boolean getStreamUsage() {
+		return this.streamOptions != null;
+	}
+
+	public void setStreamUsage(Boolean enableStreamUsage) {
+		this.streamOptions = (enableStreamUsage) ? StreamOptions.INCLUDE_USAGE : null;
+	}
+
 	public String getModel() {
 		return this.model;
 	}
@@ -356,6 +377,14 @@ public class OpenAiChatOptions implements FunctionCallingOptions, ChatOptions {
 		this.responseFormat = responseFormat;
 	}
 
+	public StreamOptions getStreamOptions() {
+		return streamOptions;
+	}
+
+	public void setStreamOptions(StreamOptions streamOptions) {
+		this.streamOptions = streamOptions;
+	}
+
 	public Integer getSeed() {
 		return this.seed;
 	}
@@ -446,6 +475,7 @@ public class OpenAiChatOptions implements FunctionCallingOptions, ChatOptions {
 		result = prime * result + ((n == null) ? 0 : n.hashCode());
 		result = prime * result + ((presencePenalty == null) ? 0 : presencePenalty.hashCode());
 		result = prime * result + ((responseFormat == null) ? 0 : responseFormat.hashCode());
+		result = prime * result + ((streamOptions == null) ? 0 : streamOptions.hashCode());
 		result = prime * result + ((seed == null) ? 0 : seed.hashCode());
 		result = prime * result + ((stop == null) ? 0 : stop.hashCode());
 		result = prime * result + ((temperature == null) ? 0 : temperature.hashCode());
@@ -519,6 +549,12 @@ public class OpenAiChatOptions implements FunctionCallingOptions, ChatOptions {
 		}
 		else if (!this.responseFormat.equals(other.responseFormat))
 			return false;
+		if (this.streamOptions == null) {
+			if (other.streamOptions != null)
+				return false;
+		}
+		else if (!this.streamOptions.equals(other.streamOptions))
+			return false;
 		if (this.seed == null) {
 			if (other.seed != null)
 				return false;
@@ -586,6 +622,7 @@ public class OpenAiChatOptions implements FunctionCallingOptions, ChatOptions {
 			.withN(fromOptions.getN())
 			.withPresencePenalty(fromOptions.getPresencePenalty())
 			.withResponseFormat(fromOptions.getResponseFormat())
+			.withStreamUsage(fromOptions.getStreamUsage())
 			.withSeed(fromOptions.getSeed())
 			.withStop(fromOptions.getStop())
 			.withTemperature(fromOptions.getTemperature())

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

@@ -47,6 +47,7 @@ import org.springframework.web.reactive.function.client.WebClient;
  *
  * @author Christian Tzolov
  * @author Michael Lavelle
+ * @author Mariusz Bernacki
  */
 public class OpenAiApi {
 
@@ -314,6 +315,7 @@ public class OpenAiApi {
 	 * @param stop Up to 4 sequences where the API will stop generating further tokens.
 	 * @param stream If set, partial message deltas will be sent.Tokens will be sent as data-only server-sent events as
 	 * they become available, with the stream terminated by a data: [DONE] message.
+	 * @param streamOptions Options for streaming response. Only set this when you set.
 	 * @param temperature What sampling temperature to use, between 0 and 1. Higher values like 0.8 will make the output
 	 * more random, while lower values like 0.2 will make it more focused and deterministic. We generally recommend
 	 * altering this or top_p but not both.
@@ -345,6 +347,7 @@ public class OpenAiApi {
 			@JsonProperty("seed") Integer seed,
 			@JsonProperty("stop") List<String> stop,
 			@JsonProperty("stream") Boolean stream,
+			@JsonProperty("stream_options") StreamOptions streamOptions,
 			@JsonProperty("temperature") Float temperature,
 			@JsonProperty("top_p") Float topP,
 			@JsonProperty("tools") List<FunctionTool> tools,
@@ -360,7 +363,7 @@ public class OpenAiApi {
 		 */
 		public ChatCompletionRequest(List<ChatCompletionMessage> messages, String model, Float temperature) {
 			this(messages, model, null, null, null, null, null, null, null,
-					null, null, null, false, temperature, null,
+					null, null, null, false, null, temperature, null,
 					null, null, null);
 		}
 
@@ -375,7 +378,7 @@ public class OpenAiApi {
 		 */
 		public ChatCompletionRequest(List<ChatCompletionMessage> messages, String model, Float temperature, boolean stream) {
 			this(messages, model, null, null, null, null, null, null, null,
-					null, null, null, stream, temperature, null,
+					null, null, null, stream, null, temperature, null,
 					null, null, null);
 		}
 
@@ -391,7 +394,7 @@ public class OpenAiApi {
 		public ChatCompletionRequest(List<ChatCompletionMessage> messages, String model,
 				List<FunctionTool> tools, Object toolChoice) {
 			this(messages, model, null, null, null, null, null, null, null,
-					null, null, null, false, 0.8f, null,
+					null, null, null, false, null, 0.8f, null,
 					tools, toolChoice, null);
 		}
 
@@ -404,10 +407,22 @@ public class OpenAiApi {
 		 */
 		public ChatCompletionRequest(List<ChatCompletionMessage> messages, Boolean stream) {
 			this(messages, null, null, null, null, null, null, null, null,
-					null, null, null, stream, null, null,
+					null, null, null, stream, null, null, null,
 					null, null, null);
 		}
 
+		/**
+		 * Sets the {@link StreamOptions} for this request.
+		 *
+		 * @param streamOptions The new stream options to use.
+		 * @return A new {@link ChatCompletionRequest} with the specified stream options.
+		 */
+		public ChatCompletionRequest withStreamOptions(StreamOptions streamOptions) {
+			return new ChatCompletionRequest(messages, model, frequencyPenalty, logitBias, logprobs, topLogprobs, maxTokens, n, presencePenalty,
+					responseFormat, seed, stop, stream, streamOptions, temperature, topP,
+					tools, toolChoice, user);
+		}
+
 		/**
 		 * Helper factory that creates a tool_choice of type 'none', 'auto' or selected function by name.
 		 */
@@ -437,6 +452,20 @@ public class OpenAiApi {
 		public record ResponseFormat(
 				@JsonProperty("type") String type) {
 		}
+
+		/**
+		 * @param includeUsage If set, an additional chunk will be streamed 
+		 * before the data: [DONE] message. The usage field on this chunk 
+		 * shows the token usage statistics for the entire request, and 
+		 * the choices field will always be an empty array. All other chunks
+		 * will also include a usage field, but with a null value.
+		 */
+		@JsonInclude(Include.NON_NULL)
+		public record StreamOptions(
+				@JsonProperty("include_usage") Boolean includeUsage) {
+
+			public static StreamOptions INCLUDE_USAGE = new StreamOptions(true);
+		}
 	}
 
 	/**
@@ -742,7 +771,8 @@ public class OpenAiApi {
 			@JsonProperty("created") Long created,
 			@JsonProperty("model") String model,
 			@JsonProperty("system_fingerprint") String systemFingerprint,
-			@JsonProperty("object") String object) {
+			@JsonProperty("object") String object,
+			@JsonProperty("usage") Usage usage) {
 
 		/**
 		 * Chat completion choice.
@@ -825,7 +855,7 @@ public class OpenAiApi {
 				// Flux<Flux<ChatCompletionChunk>> -> Flux<Mono<ChatCompletionChunk>>
 				.concatMapIterable(window -> {
 					Mono<ChatCompletionChunk> monoChunk = window.reduce(
-							new ChatCompletionChunk(null, null, null, null, null, null),
+							new ChatCompletionChunk(null, null, null, null, null, null, null),
 							(previous, current) -> this.chunkMerger.merge(previous, current));
 					return List.of(monoChunk);
 				})

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

@@ -28,6 +28,7 @@ import org.springframework.ai.openai.api.OpenAiApi.ChatCompletionChunk.ChunkChoi
 import org.springframework.ai.openai.api.OpenAiApi.ChatCompletionMessage.ChatCompletionFunction;
 import org.springframework.ai.openai.api.OpenAiApi.ChatCompletionMessage.Role;
 import org.springframework.ai.openai.api.OpenAiApi.ChatCompletionMessage.ToolCall;
+import org.springframework.ai.openai.api.OpenAiApi.Usage;
 import org.springframework.util.CollectionUtils;
 
 /**
@@ -58,13 +59,14 @@ public class OpenAiStreamFunctionCallingHelper {
 		String systemFingerprint = (current.systemFingerprint() != null ? current.systemFingerprint()
 				: previous.systemFingerprint());
 		String object = (current.object() != null ? current.object() : previous.object());
+		Usage usage = (current.usage() != null ? current.usage() : previous.usage());
 
 		ChunkChoice previousChoice0 = (CollectionUtils.isEmpty(previous.choices()) ? null : previous.choices().get(0));
 		ChunkChoice currentChoice0 = (CollectionUtils.isEmpty(current.choices()) ? null : current.choices().get(0));
 
 		ChunkChoice choice = merge(previousChoice0, currentChoice0);
 		List<ChunkChoice> chunkChoices = choice == null ? List.of() : List.of(choice);
-		return new ChatCompletionChunk(id, chunkChoices, created, model, systemFingerprint, object);
+		return new ChatCompletionChunk(id, chunkChoices, created, model, systemFingerprint, object, usage);
 	}
 
 	private ChunkChoice merge(ChunkChoice previous, ChunkChoice current) {

models/spring-ai-openai/src/test/java/org/springframework/ai/openai/chat/MessageTypeContentTests.java

@@ -61,7 +61,7 @@ public class MessageTypeContentTests {
 	ArgumentCaptor<ChatCompletionRequest> promptCaptor;
 
 	Flux<ChatCompletionChunk> fluxResponse = Flux
-		.generate(() -> new ChatCompletionChunk("id", List.of(), 0l, "model", "fp", "object"), (state, sink) -> {
+		.generate(() -> new ChatCompletionChunk("id", List.of(), 0l, "model", "fp", "object", null), (state, sink) -> {
 			sink.next(state);
 			sink.complete();
 			return state;

models/spring-ai-openai/src/test/java/org/springframework/ai/openai/chat/OpenAiChatModelIT.java

@@ -15,6 +15,8 @@
  */
 package org.springframework.ai.openai.chat;
 
+import static org.assertj.core.api.Assertions.assertThat;
+
 import java.io.IOException;
 import java.net.URL;
 import java.util.ArrayList;
@@ -29,14 +31,12 @@ import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import reactor.core.publisher.Flux;
-
-import org.springframework.ai.chat.model.ChatResponse;
-import org.springframework.ai.chat.model.Generation;
 import org.springframework.ai.chat.messages.AssistantMessage;
 import org.springframework.ai.chat.messages.Media;
 import org.springframework.ai.chat.messages.Message;
 import org.springframework.ai.chat.messages.UserMessage;
+import org.springframework.ai.chat.model.ChatResponse;
+import org.springframework.ai.chat.model.Generation;
 import org.springframework.ai.chat.prompt.Prompt;
 import org.springframework.ai.chat.prompt.PromptTemplate;
 import org.springframework.ai.chat.prompt.SystemPromptTemplate;
@@ -56,7 +56,7 @@ import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.Resource;
 import org.springframework.util.MimeTypeUtils;
 
-import static org.assertj.core.api.Assertions.assertThat;
+import reactor.core.publisher.Flux;
 
 @SpringBootTest(classes = OpenAiTestConfiguration.class)
 @EnabledIfEnvironmentVariable(named = "OPENAI_API_KEY", matches = ".+")
@@ -103,6 +103,24 @@ class OpenAiChatModelIT extends AbstractIT {
 
 	}
 
+	@Test
+	void streamingWithTokenUsage() {
+		var promptOptions = OpenAiChatOptions.builder().withStreamUsage(true).withSeed(1).build();
+
+		var prompt = new Prompt("List two colors of the Polish flag. Be brief.", promptOptions);
+		var streamingTokenUsage = this.chatModel.stream(prompt).blockLast().getMetadata().getUsage();
+		var referenceTokenUsage = this.chatModel.call(prompt).getMetadata().getUsage();
+
+		assertThat(streamingTokenUsage.getPromptTokens()).isGreaterThan(0);
+		assertThat(streamingTokenUsage.getGenerationTokens()).isGreaterThan(0);
+		assertThat(streamingTokenUsage.getTotalTokens()).isGreaterThan(0);
+
+		assertThat(streamingTokenUsage.getPromptTokens()).isEqualTo(referenceTokenUsage.getPromptTokens());
+		assertThat(streamingTokenUsage.getGenerationTokens()).isEqualTo(referenceTokenUsage.getGenerationTokens());
+		assertThat(streamingTokenUsage.getTotalTokens()).isEqualTo(referenceTokenUsage.getTotalTokens());
+
+	}
+
 	@Test
 	void listOutputConverter() {
 		DefaultConversionService conversionService = new DefaultConversionService();

models/spring-ai-openai/src/test/java/org/springframework/ai/openai/chat/OpenAiRetryTests.java

@@ -167,7 +167,7 @@ public class OpenAiRetryTests {
 		var choice = new ChatCompletionChunk.ChunkChoice(ChatCompletionFinishReason.STOP, 0,
 				new ChatCompletionMessage("Response", Role.ASSISTANT), null);
 		ChatCompletionChunk expectedChatCompletion = new ChatCompletionChunk("id", List.of(choice), 666l, "model", null,
-				null);
+				null, null);
 
 		when(openAiApi.chatCompletionStream(isA(ChatCompletionRequest.class)))
 			.thenThrow(new TransientAiException("Transient Error 1"))

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/chat/openai-chat.adoc

@@ -105,6 +105,7 @@ The prefix `spring.ai.openai.chat` is the property prefix that lets you configur
 | spring.ai.openai.chat.options.toolChoice | Controls which (if any) function is called by the model. none means the model will not call a function and instead generates a message. auto means the model can pick between generating a message or calling a function. Specifying a particular function via {"type: "function", "function": {"name": "my_function"}} forces the model to call that function. none is the default when no functions are present. auto is the default if functions are present. | -
 | spring.ai.openai.chat.options.user | A unique identifier representing your end-user, which can help OpenAI to monitor and detect abuse. | -
 | spring.ai.openai.chat.options.functions | List of functions, identified by their names, to enable for function calling in a single prompt requests. Functions with those names must exist in the functionCallbacks registry. | -
+| spring.ai.openai.chat.options.stream-usage | (For streaming only) Set to add an additional chunk with token usage statistics for the entire request. The `choices` field for this chuk is an empty array and all other chunks will also include a usage field, but with a null value. | false
 |====
 
 NOTE: You can override the common `spring.ai.openai.base-url` and `spring.ai.openai.api-key` for the `ChatModel` and `EmbeddingModel` implementations.

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

@@ -26,6 +26,7 @@ import org.apache.commons.logging.LogFactory;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.condition.EnabledIfEnvironmentVariable;
 import org.springframework.ai.chat.messages.UserMessage;
+import org.springframework.ai.chat.metadata.Usage;
 import org.springframework.ai.chat.model.ChatResponse;
 import org.springframework.ai.chat.prompt.Prompt;
 import org.springframework.ai.embedding.EmbeddingResponse;
@@ -113,6 +114,28 @@ public class OpenAiAutoConfigurationIT {
 		});
 	}
 
+	@Test
+	void streamingWithTokenUsage() {
+		contextRunner.withPropertyValues("spring.ai.openai.chat.options.stream-usage=true").run(context -> {
+			OpenAiChatModel chatModel = context.getBean(OpenAiChatModel.class);
+
+			Flux<ChatResponse> responseFlux = chatModel.stream(new Prompt(new UserMessage("Hello")));
+
+			Usage[] streamingTokenUsage = new Usage[1];
+			String response = responseFlux.collectList().block().stream().map(chatResponse -> {
+				streamingTokenUsage[0] = chatResponse.getMetadata().getUsage();
+				return (chatResponse.getResult() != null) ? chatResponse.getResult().getOutput().getContent() : "";
+			}).collect(Collectors.joining());
+
+			assertThat(streamingTokenUsage[0].getPromptTokens()).isGreaterThan(0);
+			assertThat(streamingTokenUsage[0].getGenerationTokens()).isGreaterThan(0);
+			assertThat(streamingTokenUsage[0].getTotalTokens()).isGreaterThan(0);
+
+			assertThat(response).isNotEmpty();
+			logger.info("Response: " + response);
+		});
+	}
+
 	@Test
 	void embedding() {
 		contextRunner.run(context -> {