New pattern - Lambda SnapStart with Amazon Bedrock (CDK)

lambda-snapstart-bedrock-cdk/.gitignore

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+*.js
+!src/*.js
+*.d.ts
+node_modules
+cdk.out
+package-lock.json

lambda-snapstart-bedrock-cdk/.npmignore

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+*.ts
+!*.d.ts
+cdk.out

lambda-snapstart-bedrock-cdk/README.md

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+# Lambda SnapStart with Amazon Bedrock
+
+This pattern deploys a Python Lambda function with **SnapStart** enabled that invokes Amazon Bedrock (Claude Sonnet) for text generation, using AWS CDK.
+
+Learn more about this pattern at Serverless Land Patterns: https://serverlessland.com/patterns/lambda-snapstart-bedrock-cdk
+
+Important: this application uses various AWS services and there are costs associated with these services after the Free Tier usage - please see the [AWS Pricing page](https://aws.amazon.com/pricing/) for details. You are responsible for any AWS costs incurred. No warranty is implied in this example.
+
+## Requirements
+
+- [Create an AWS account](https://portal.aws.amazon.com/gp/aws/developer/registration/index.html) if you do not already have one and log in. The IAM user that you use must have sufficient permissions to make necessary AWS service calls and manage AWS resources.
+- [AWS CLI](https://docs.aws.amazon.com/cli/latest/userguide/install-cliv2.html) installed and configured
+- [AWS CDK](https://docs.aws.amazon.com/cdk/latest/guide/cli.html) installed
+- [Node.js](https://nodejs.org/) 18.x or later
+- [Amazon Bedrock model access](https://docs.aws.amazon.com/bedrock/latest/userguide/model-access.html) enabled for Anthropic Claude Sonnet in your AWS account
+
+## How it works
+
+Lambda SnapStart reduces cold start latency by up to 10x by pre-initializing the execution environment and caching a snapshot of the initialized state. When a new execution environment is needed, Lambda restores from the cached snapshot instead of running full initialization.
+
+**Key points:**
+- SnapStart is enabled via `snapStart: lambda.SnapStartConf.ON_PUBLISHED_VERSIONS` in CDK
+- SnapStart only applies to **published versions**, not `$LATEST` — the pattern creates a version and alias automatically
+- Supported runtimes: Java 11/17/21, Python 3.12/3.13, .NET 8
+- The Bedrock client is initialized at module level (outside the handler) so it gets captured in the SnapStart snapshot
+
+```
+┌──────────────────────┐         ┌──────────────────────┐
+│                      │         │                      │
+│  Lambda (SnapStart)  │────────▶│   Amazon Bedrock     │
+│  Python 3.13         │         │   Claude Sonnet      │
+│                      │◀────────│                      │
+└──────────────────────┘         └──────────────────────┘
+```
+
+## Deployment
+
+1. Install dependencies:
+   ```bash
+   cd lambda-snapstart-bedrock-cdk
+   npm install
+   ```
+
+2. Deploy the stack:
+   ```bash
+   cdk deploy
+   ```
+
+## Testing
+
+Invoke the function via the **alias** (SnapStart only applies to published versions):
+
+```bash
+aws lambda invoke \
+  --function-name snapstart-bedrock-cdk:live \
+  --payload '{"prompt": "Explain Lambda SnapStart in one paragraph"}' \
+  --cli-binary-format raw-in-base64-out \
+  output.json
+
+cat output.json | python3 -m json.tool
+```
+
+To compare cold start times, invoke `$LATEST` (no SnapStart) vs the alias (with SnapStart):
+
+```bash
+# Without SnapStart ($LATEST)
+aws lambda invoke --function-name snapstart-bedrock-cdk \
+  --payload '{"prompt": "Hello"}' --cli-binary-format raw-in-base64-out /dev/null
+
+# With SnapStart (alias)
+aws lambda invoke --function-name snapstart-bedrock-cdk:live \
+  --payload '{"prompt": "Hello"}' --cli-binary-format raw-in-base64-out /dev/null
+```
+
+Check the `Init Duration` in CloudWatch Logs — SnapStart-optimized invocations show `Restore Duration` instead, which is significantly lower.
+
+## Cleanup
+
+```bash
+cdk destroy
+```
+
+---
+
+Copyright 2025 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+
+SPDX-License-Identifier: MIT-0

lambda-snapstart-bedrock-cdk/bin/app.ts

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+#!/usr/bin/env node
+import "source-map-support/register";
+import * as cdk from "aws-cdk-lib";
+import { LambdaSnapstartBedrockStack } from "../lib/lambda-snapstart-bedrock-stack";
+
+const app = new cdk.App();
+new LambdaSnapstartBedrockStack(app, "LambdaSnapstartBedrockStack");

lambda-snapstart-bedrock-cdk/cdk.context.json

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+{
+  "acknowledged-issue-numbers": [
+    33623,
+    34635,
+    34892
+  ]
+}

lambda-snapstart-bedrock-cdk/cdk.json

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+{
+  "app": "npx ts-node bin/app.ts"
+}

lambda-snapstart-bedrock-cdk/example-pattern.json

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+{
+  "title": "Lambda SnapStart with Amazon Bedrock",
+  "description": "Invoke Amazon Bedrock from a Lambda function with SnapStart enabled for dramatically reduced cold start latency, deployed with AWS CDK.",
+  "language": "Python",
+  "level": "200",
+  "framework": "CDK",
+  "introBox": {
+    "headline": "How it works",
+    "text": [
+      "This pattern deploys a Python Lambda function with SnapStart enabled that invokes Amazon Bedrock (Claude Sonnet) for text generation.",
+      "Lambda SnapStart reduces cold start latency by up to 10x by pre-initializing the execution environment and caching a snapshot of the initialized state.",
+      "When a new execution environment is needed, Lambda restores from the cached snapshot instead of running full initialization, providing near-instant cold starts.",
+      "A published version and alias are created to activate SnapStart optimization — SnapStart only applies to published versions, not $LATEST."
+    ]
+  },
+  "gitHub": {
+    "template": {
+      "repoURL": "https://github.com/aws-samples/serverless-patterns/tree/main/lambda-snapstart-bedrock-cdk",
+      "templateURL": "serverless-patterns/lambda-snapstart-bedrock-cdk",
+      "projectFolder": "lambda-snapstart-bedrock-cdk",
+      "templateFile": "lib/lambda-snapstart-bedrock-stack.ts"
+    }
+  },
+  "resources": {
+    "bullets": [
+      { "text": "Lambda SnapStart documentation", "link": "https://docs.aws.amazon.com/lambda/latest/dg/snapstart.html" },
+      { "text": "Lambda SnapStart for Python and .NET", "link": "https://aws.amazon.com/blogs/aws/reduce-cold-starts-for-your-lambda-functions-with-snapstart-for-python-and-net/" },
+      { "text": "Amazon Bedrock documentation", "link": "https://docs.aws.amazon.com/bedrock/latest/userguide/" }
+    ]
+  },
+  "deploy": {
+    "text": ["cdk deploy"]
+  },
+  "testing": {
+    "text": ["See the README for testing instructions."]
+  },
+  "cleanup": {
+    "text": ["cdk destroy"]
+  },
+  "authors": [
+    {
+      "name": "Nithin Chandran R",
+      "bio": "Technical Account Manager at AWS",
+      "linkedin": "nithin-chandran-r"
+    }
+  ],
+  "patternArch": {
+    "icon1": { "x": 20, "y": 50, "service": "lambda", "label": "Lambda (SnapStart)" },
+    "icon2": { "x": 80, "y": 50, "service": "bedrock", "label": "Amazon Bedrock" },
+    "line1": { "from": "icon1", "to": "icon2" }
+  }
+}

lambda-snapstart-bedrock-cdk/lib/lambda-snapstart-bedrock-stack.ts

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+import * as cdk from "aws-cdk-lib";
+import * as lambda from "aws-cdk-lib/aws-lambda";
+import * as iam from "aws-cdk-lib/aws-iam";
+import * as logs from "aws-cdk-lib/aws-logs";
+import { Construct } from "constructs";
+
+export class LambdaSnapstartBedrockStack extends cdk.Stack {
+  constructor(scope: Construct, id: string, props?: cdk.StackProps) {
+    super(scope, id, props);
+
+    const modelId = new cdk.CfnParameter(this, "BedrockModelId", {
+      type: "String",
+      default: "us.anthropic.claude-sonnet-4-20250514-v1:0",
+      description: "Bedrock inference profile model ID",
+    });
+
+    const functionName = "snapstart-bedrock-cdk";
+
+    const logGroup = new logs.LogGroup(this, "LogGroup", {
+      logGroupName: `/aws/lambda/${functionName}`,
+      retention: logs.RetentionDays.TWO_WEEKS,
+      removalPolicy: cdk.RemovalPolicy.DESTROY,
+    });
+
+    const fn = new lambda.Function(this, "BedrockFn", {
+      runtime: lambda.Runtime.PYTHON_3_13,
+      handler: "index.handler",
+      code: lambda.Code.fromAsset("src"),
+      timeout: cdk.Duration.seconds(30),
+      memorySize: 512,
+      functionName,
+      description: "Bedrock invocation with SnapStart for reduced cold starts",
+      loggingFormat: lambda.LoggingFormat.JSON,
+      logGroup,
+      snapStart: lambda.SnapStartConf.ON_PUBLISHED_VERSIONS,
+      environment: { MODEL_ID: modelId.valueAsString },
+    });
+
+    fn.addToRolePolicy(
+      new iam.PolicyStatement({
+        actions: ["bedrock:InvokeModel"],
+        resources: [
+          `arn:aws:bedrock:${this.region}:${this.account}:inference-profile/${modelId.valueAsString}`,
+          "arn:aws:bedrock:*::foundation-model/*",
+        ],
+      })
+    );
+
+    // Publish a version to activate SnapStart
+    const version = fn.currentVersion;
+
+    // Alias pointing to the SnapStart-optimized version
+    const alias = new lambda.Alias(this, "LiveAlias", {
+      aliasName: "live",
+      version,
+    });
+
+    new cdk.CfnOutput(this, "FunctionName", { value: fn.functionName });
+    new cdk.CfnOutput(this, "FunctionArn", { value: fn.functionArn });
+    new cdk.CfnOutput(this, "AliasArn", { value: alias.functionArn });
+    new cdk.CfnOutput(this, "LogGroupName", { value: logGroup.logGroupName });
+  }
+}

lambda-snapstart-bedrock-cdk/package.json

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+{
+  "name": "lambda-snapstart-bedrock-cdk",
+  "version": "1.0.0",
+  "bin": { "app": "bin/app.ts" },
+  "scripts": { "build": "tsc", "cdk": "cdk" },
+  "dependencies": {
+    "aws-cdk-lib": "2.236.0",
+    "constructs": "10.4.2"
+  },
+  "devDependencies": {
+    "@types/node": "^22.0.0",
+    "ts-node": "^10.9.0",
+    "typescript": "~5.7.0"
+  }
+}

lambda-snapstart-bedrock-cdk/src/index.py

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+import json
+import os
+import boto3
+
+bedrock = boto3.client("bedrock-runtime")
+MODEL_ID = os.environ["MODEL_ID"]
+
+
+def handler(event, context):
+    prompt = event.get("prompt", "What are the benefits of Lambda SnapStart?")
+
+    response = bedrock.invoke_model(
+        modelId=MODEL_ID,
+        contentType="application/json",
+        accept="application/json",
+        body=json.dumps({
+            "anthropic_version": "bedrock-2023-05-31",
+            "max_tokens": 1024,
+            "messages": [{"role": "user", "content": prompt}],
+        }),
+    )
+
+    body = json.loads(response["body"].read())
+
+    return {
+        "statusCode": 200,
+        "body": json.dumps({
+            "prompt": prompt,
+            "response": body["content"][0]["text"],
+            "model": MODEL_ID,
+            "usage": body["usage"],
+        }),
+    }

lambda-snapstart-bedrock-cdk/tsconfig.json

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+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "module": "commonjs",
+    "lib": ["es2020"],
+    "declaration": true,
+    "strict": true,
+    "noImplicitAny": true,
+    "strictNullChecks": true,
+    "noImplicitThis": true,
+    "alwaysStrict": true,
+    "noUnusedLocals": false,
+    "noUnusedParameters": false,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": false,
+    "inlineSourceMap": true,
+    "inlineSources": true,
+    "experimentalDecorators": true,
+    "strictPropertyInitialization": false
+  },
+  "exclude": ["cdk.out"]
+}