There are more AWS SDK examples available in the [AWS Doc SDK Examples](https://github.com/awsdocs/aws-doc-sdk-examples) GitHub repo.
# Invoke Anthropic Claude models on Amazon Bedrock using the Invoke Model API with a response stream
The following code examples show how to send a text message to Anthropic Claude models, using the Invoke Model API, and print the response stream.
------
#### [ .NET ]
**SDK for .NET**
There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/dotnetv3/Bedrock-runtime#code-examples).
Use the Invoke Model API to send a text message and process the response stream in real-time.
```
// Use the native inference API to send a text message to Anthropic Claude
// and print the response stream.
using System;
using System.IO;
using System.Text.Json;
using System.Text.Json.Nodes;
using Amazon;
using Amazon.BedrockRuntime;
using Amazon.BedrockRuntime.Model;
// Create a Bedrock Runtime client in the AWS Region you want to use.
var client = new AmazonBedrockRuntimeClient(RegionEndpoint.USEast1);
// Set the model ID, e.g., Claude 3 Haiku.
var modelId = "anthropic.claude-3-haiku-20240307-v1:0";
// Define the user message.
var userMessage = "Describe the purpose of a 'hello world' program in one line.";
//Format the request payload using the model's native structure.
var nativeRequest = JsonSerializer.Serialize(new
{
anthropic_version = "bedrock-2023-05-31",
max_tokens = 512,
temperature = 0.5,
messages = new[]
{
new { role = "user", content = userMessage }
}
});
// Create a request with the model ID, the user message, and an inference configuration.
var request = new InvokeModelWithResponseStreamRequest()
{
ModelId = modelId,
Body = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(nativeRequest)),
ContentType = "application/json"
};
try
{
// Send the request to the Bedrock Runtime and wait for the response.
var streamingResponse = await client.InvokeModelWithResponseStreamAsync(request);
// Extract and print the streamed response text in real-time.
foreach (var item in streamingResponse.Body)
{
var chunk = JsonSerializer.Deserialize((item as PayloadPart).Bytes);
var text = chunk["delta"]?["text"] ?? "";
Console.Write(text);
}
}
catch (AmazonBedrockRuntimeException e)
{
Console.WriteLine($"ERROR: Can't invoke '{modelId}'. Reason: {e.Message}");
throw;
}
```
+ For API details, see [InvokeModelWithResponseStream](https://docs.aws.amazon.com/goto/DotNetSDKV3/bedrock-runtime-2023-09-30/InvokeModelWithResponseStream) in *AWS SDK for .NET API Reference*.
------
#### [ Go ]
**SDK for Go V2**
There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/bedrock-runtime#code-examples).
Use the Invoke Model API to send a text message and process the response stream in real-time.
```
import (
"bytes"
"context"
"encoding/json"
"fmt"
"log"
"strings"
"github.com/aws/aws-sdk-go-v2/aws"
"github.com/aws/aws-sdk-go-v2/service/bedrockruntime"
"github.com/aws/aws-sdk-go-v2/service/bedrockruntime/types"
)
// InvokeModelWithResponseStreamWrapper encapsulates Amazon Bedrock actions used in the examples.
// It contains a Bedrock Runtime client that is used to invoke foundation models.
type InvokeModelWithResponseStreamWrapper struct {
BedrockRuntimeClient *bedrockruntime.Client
}
// Each model provider defines their own individual request and response formats.
// For the format, ranges, and default values for the different models, refer to:
// https://docs.aws.amazon.com/bedrock/latest/userguide/model-parameters.html
type Request struct {
Prompt string `json:"prompt"`
MaxTokensToSample int `json:"max_tokens_to_sample"`
Temperature float64 `json:"temperature,omitempty"`
}
type Response struct {
Completion string `json:"completion"`
}
// Invokes Anthropic Claude on Amazon Bedrock to run an inference and asynchronously
// process the response stream.
func (wrapper InvokeModelWithResponseStreamWrapper) InvokeModelWithResponseStream(ctx context.Context, prompt string) (string, error) {
modelId := "anthropic.claude-v2"
// Anthropic Claude requires you to enclose the prompt as follows:
prefix := "Human: "
postfix := "\n\nAssistant:"
prompt = prefix + prompt + postfix
request := ClaudeRequest{
Prompt: prompt,
MaxTokensToSample: 200,
Temperature: 0.5,
StopSequences: []string{"\n\nHuman:"},
}
body, err := json.Marshal(request)
if err != nil {
log.Panicln("Couldn't marshal the request: ", err)
}
output, err := wrapper.BedrockRuntimeClient.InvokeModelWithResponseStream(ctx, &bedrockruntime.InvokeModelWithResponseStreamInput{
Body: body,
ModelId: aws.String(modelId),
ContentType: aws.String("application/json"),
})
if err != nil {
errMsg := err.Error()
if strings.Contains(errMsg, "no such host") {
log.Printf("The Bedrock service is not available in the selected region. Please double-check the service availability for your region at https://aws.amazon.com/about-aws/global-infrastructure/regional-product-services/.\n")
} else if strings.Contains(errMsg, "Could not resolve the foundation model") {
log.Printf("Could not resolve the foundation model from model identifier: \"%v\". Please verify that the requested model exists and is accessible within the specified region.\n", modelId)
} else {
log.Printf("Couldn't invoke Anthropic Claude. Here's why: %v\n", err)
}
}
resp, err := processStreamingOutput(ctx, output, func(ctx context.Context, part []byte) error {
fmt.Print(string(part))
return nil
})
if err != nil {
log.Fatal("streaming output processing error: ", err)
}
return resp.Completion, nil
}
type StreamingOutputHandler func(ctx context.Context, part []byte) error
func processStreamingOutput(ctx context.Context, output *bedrockruntime.InvokeModelWithResponseStreamOutput, handler StreamingOutputHandler) (Response, error) {
var combinedResult string
resp := Response{}
for event := range output.GetStream().Events() {
switch v := event.(type) {
case *types.ResponseStreamMemberChunk:
//fmt.Println("payload", string(v.Value.Bytes))
var resp Response
err := json.NewDecoder(bytes.NewReader(v.Value.Bytes)).Decode(&resp)
if err != nil {
return resp, err
}
err = handler(ctx, []byte(resp.Completion))
if err != nil {
return resp, err
}
combinedResult += resp.Completion
case *types.UnknownUnionMember:
fmt.Println("unknown tag:", v.Tag)
default:
fmt.Println("union is nil or unknown type")
}
}
resp.Completion = combinedResult
return resp, nil
}
```
+ For API details, see [InvokeModelWithResponseStream](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/bedrockruntime#Client.InvokeModelWithResponseStream) in *AWS SDK for Go API Reference*.
------
#### [ Java ]
**SDK for Java 2.x**
There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/bedrock-runtime#code-examples).
Use the Invoke Model API to send a text message and process the response stream in real-time.
```
// Use the native inference API to send a text message to Anthropic Claude
// and print the response stream.
import org.json.JSONObject;
import org.json.JSONPointer;
import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;
import software.amazon.awssdk.core.SdkBytes;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.bedrockruntime.BedrockRuntimeAsyncClient;
import software.amazon.awssdk.services.bedrockruntime.model.InvokeModelWithResponseStreamRequest;
import software.amazon.awssdk.services.bedrockruntime.model.InvokeModelWithResponseStreamResponseHandler;
import java.util.Objects;
import java.util.concurrent.ExecutionException;
import static software.amazon.awssdk.services.bedrockruntime.model.InvokeModelWithResponseStreamResponseHandler.Visitor;
public class InvokeModelWithResponseStream {
public static String invokeModelWithResponseStream() {
// Create a Bedrock Runtime client in the AWS Region you want to use.
// Replace the DefaultCredentialsProvider with your preferred credentials provider.
var client = BedrockRuntimeAsyncClient.builder()
.credentialsProvider(DefaultCredentialsProvider.create())
.region(Region.US_EAST_1)
.build();
// Set the model ID, e.g., Claude 3 Haiku.
var modelId = "anthropic.claude-3-haiku-20240307-v1:0";
// The InvokeModelWithResponseStream API uses the model's native payload.
// Learn more about the available inference parameters and response fields at:
// https://docs.aws.amazon.com/bedrock/latest/userguide/model-parameters-anthropic-claude-messages.html
var nativeRequestTemplate = """
{
"anthropic_version": "bedrock-2023-05-31",
"max_tokens": 512,
"temperature": 0.5,
"messages": [{
"role": "user",
"content": "{{prompt}}"
}]
}""";
// Define the prompt for the model.
var prompt = "Describe the purpose of a 'hello world' program in one line.";
// Embed the prompt in the model's native request payload.
String nativeRequest = nativeRequestTemplate.replace("{{prompt}}", prompt);
// Create a request with the model ID and the model's native request payload.
var request = InvokeModelWithResponseStreamRequest.builder()
.body(SdkBytes.fromUtf8String(nativeRequest))
.modelId(modelId)
.build();
// Prepare a buffer to accumulate the generated response text.
var completeResponseTextBuffer = new StringBuilder();
// Prepare a handler to extract, accumulate, and print the response text in real-time.
var responseStreamHandler = InvokeModelWithResponseStreamResponseHandler.builder()
.subscriber(Visitor.builder().onChunk(chunk -> {
var response = new JSONObject(chunk.bytes().asUtf8String());
// Extract and print the text from the content blocks.
if (Objects.equals(response.getString("type"), "content_block_delta")) {
var text = new JSONPointer("/delta/text").queryFrom(response);
System.out.print(text);
// Append the text to the response text buffer.
completeResponseTextBuffer.append(text);
}
}).build()).build();
try {
// Send the request and wait for the handler to process the response.
client.invokeModelWithResponseStream(request, responseStreamHandler).get();
// Return the complete response text.
return completeResponseTextBuffer.toString();
} catch (ExecutionException | InterruptedException e) {
System.err.printf("Can't invoke '%s': %s", modelId, e.getCause().getMessage());
throw new RuntimeException(e);
}
}
public static void main(String[] args) throws ExecutionException, InterruptedException {
invokeModelWithResponseStream();
}
}
```
+ For API details, see [InvokeModelWithResponseStream](https://docs.aws.amazon.com/goto/SdkForJavaV2/bedrock-runtime-2023-09-30/InvokeModelWithResponseStream) in *AWS SDK for Java 2.x API Reference*.
------
#### [ JavaScript ]
**SDK for JavaScript (v3)**
There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/bedrock-runtime#code-examples).
Use the Invoke Model API to send a text message and process the response stream in real-time.
```
import { fileURLToPath } from "node:url";
import { FoundationModels } from "../../config/foundation_models.js";
import {
BedrockRuntimeClient,
InvokeModelCommand,
InvokeModelWithResponseStreamCommand,
} from "@aws-sdk/client-bedrock-runtime";
/**
* @typedef {Object} ResponseContent
* @property {string} text
*
* @typedef {Object} MessagesResponseBody
* @property {ResponseContent[]} content
*
* @typedef {Object} Delta
* @property {string} text
*
* @typedef {Object} Message
* @property {string} role
*
* @typedef {Object} Chunk
* @property {string} type
* @property {Delta} delta
* @property {Message} message
*/
/**
* Invokes Anthropic Claude 3 using the Messages API.
*
* To learn more about the Anthropic Messages API, go to:
* https://docs.aws.amazon.com/bedrock/latest/userguide/model-parameters-anthropic-claude-messages.html
*
* @param {string} prompt - The input text prompt for the model to complete.
* @param {string} [modelId] - The ID of the model to use. Defaults to "anthropic.claude-3-haiku-20240307-v1:0".
*/
export const invokeModel = async (
prompt,
modelId = "anthropic.claude-3-haiku-20240307-v1:0",
) => {
// Create a new Bedrock Runtime client instance.
const client = new BedrockRuntimeClient({ region: "us-east-1" });
// Prepare the payload for the model.
const payload = {
anthropic_version: "bedrock-2023-05-31",
max_tokens: 1000,
messages: [
{
role: "user",
content: [{ type: "text", text: prompt }],
},
],
};
// Invoke Claude with the payload and wait for the response.
const command = new InvokeModelCommand({
contentType: "application/json",
body: JSON.stringify(payload),
modelId,
});
const apiResponse = await client.send(command);
// Decode and return the response(s)
const decodedResponseBody = new TextDecoder().decode(apiResponse.body);
/** @type {MessagesResponseBody} */
const responseBody = JSON.parse(decodedResponseBody);
return responseBody.content[0].text;
};
/**
* Invokes Anthropic Claude 3 and processes the response stream.
*
* To learn more about the Anthropic Messages API, go to:
* https://docs.aws.amazon.com/bedrock/latest/userguide/model-parameters-anthropic-claude-messages.html
*
* @param {string} prompt - The input text prompt for the model to complete.
* @param {string} [modelId] - The ID of the model to use. Defaults to "anthropic.claude-3-haiku-20240307-v1:0".
*/
export const invokeModelWithResponseStream = async (
prompt,
modelId = "anthropic.claude-3-haiku-20240307-v1:0",
) => {
// Create a new Bedrock Runtime client instance.
const client = new BedrockRuntimeClient({ region: "us-east-1" });
// Prepare the payload for the model.
const payload = {
anthropic_version: "bedrock-2023-05-31",
max_tokens: 1000,
messages: [
{
role: "user",
content: [{ type: "text", text: prompt }],
},
],
};
// Invoke Claude with the payload and wait for the API to respond.
const command = new InvokeModelWithResponseStreamCommand({
contentType: "application/json",
body: JSON.stringify(payload),
modelId,
});
const apiResponse = await client.send(command);
let completeMessage = "";
// Decode and process the response stream
for await (const item of apiResponse.body) {
/** @type Chunk */
const chunk = JSON.parse(new TextDecoder().decode(item.chunk.bytes));
const chunk_type = chunk.type;
if (chunk_type === "content_block_delta") {
const text = chunk.delta.text;
completeMessage = completeMessage + text;
process.stdout.write(text);
}
}
// Return the final response
return completeMessage;
};
// Invoke the function if this file was run directly.
if (process.argv[1] === fileURLToPath(import.meta.url)) {
const prompt = 'Write a paragraph starting with: "Once upon a time..."';
const modelId = FoundationModels.CLAUDE_3_HAIKU.modelId;
console.log(`Prompt: ${prompt}`);
console.log(`Model ID: ${modelId}`);
try {
console.log("-".repeat(53));
const response = await invokeModel(prompt, modelId);
console.log(`\n${"-".repeat(53)}`);
console.log("Final structured response:");
console.log(response);
} catch (err) {
console.log(`\n${err}`);
}
}
```
+ For API details, see [InvokeModelWithResponseStream](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/bedrock-runtime/command/InvokeModelWithResponseStreamCommand) in *AWS SDK for JavaScript API Reference*.
------
#### [ Python ]
**SDK for Python (Boto3)**
There's more on GitHub. Find the complete example and learn how to set up and run in the [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/python/example_code/bedrock-runtime#code-examples).
Use the Invoke Model API to send a text message and process the response stream in real-time.
```
# Use the native inference API to send a text message to Anthropic Claude
# and print the response stream.
import boto3
import json
# Create a Bedrock Runtime client in the AWS Region of your choice.
client = boto3.client("bedrock-runtime", region_name="us-east-1")
# Set the model ID, e.g., Claude 3 Haiku.
model_id = "anthropic.claude-3-haiku-20240307-v1:0"
# Define the prompt for the model.
prompt = "Describe the purpose of a 'hello world' program in one line."
# Format the request payload using the model's native structure.
native_request = {
"anthropic_version": "bedrock-2023-05-31",
"max_tokens": 512,
"temperature": 0.5,
"messages": [
{
"role": "user",
"content": [{"type": "text", "text": prompt}],
}
],
}
# Convert the native request to JSON.
request = json.dumps(native_request)
# Invoke the model with the request.
streaming_response = client.invoke_model_with_response_stream(
modelId=model_id, body=request
)
# Extract and print the response text in real-time.
for event in streaming_response["body"]:
chunk = json.loads(event["chunk"]["bytes"])
if chunk["type"] == "content_block_delta":
print(chunk["delta"].get("text", ""), end="")
```
+ For API details, see [InvokeModelWithResponseStream](https://docs.aws.amazon.com/goto/boto3/bedrock-runtime-2023-09-30/InvokeModelWithResponseStream) in *AWS SDK for Python (Boto3) API Reference*.
------