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July 26, 2024 04:08
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cloudformation template to demo AWS lambda with SSE
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| AWSTemplateFormatVersion: '2010-09-09' | |
| Description: 'CloudFormation template for SSE with Lambda Function URL' | |
| Resources: | |
| LambdaExecutionRole: | |
| Type: AWS::IAM::Role | |
| Properties: | |
| AssumeRolePolicyDocument: | |
| Version: '2012-10-17' | |
| Statement: | |
| - Effect: Allow | |
| Principal: | |
| Service: lambda.amazonaws.com | |
| Action: sts:AssumeRole | |
| Policies: | |
| - PolicyName: LambdaExecutionPolicy | |
| PolicyDocument: | |
| Version: '2012-10-17' | |
| Statement: | |
| - Effect: Allow | |
| Action: | |
| - logs:CreateLogGroup | |
| - logs:CreateLogStream | |
| - logs:PutLogEvents | |
| Resource: arn:aws:logs:*:*:* | |
| SSELambdaFunction: | |
| Type: AWS::Lambda::Function | |
| Properties: | |
| FunctionName: SSETestFunction | |
| Handler: index.handler | |
| Role: !GetAtt LambdaExecutionRole.Arn | |
| Code: | |
| ZipFile: | | |
| exports.handler = awslambda.streamifyResponse(async (event, responseStream, context) => { | |
| console.log('Event:', JSON.stringify(event, null, 2)); | |
| console.log('Headers:', JSON.stringify(event.headers, null, 2)); | |
| const headers = { | |
| 'Access-Control-Allow-Origin': 'http://localhost:3000', | |
| 'Access-Control-Allow-Methods': 'GET, OPTIONS', | |
| 'Access-Control-Allow-Headers': 'Accept, Accept-Language, Content-Type, Origin, Referer, User-Agent', | |
| 'Access-Control-Max-Age': '86400', | |
| 'Vary': 'Origin' | |
| }; | |
| if (event.requestContext.http.method === 'OPTIONS') { | |
| // Handle CORS preflight request | |
| const response = { | |
| statusCode: 204, | |
| headers: headers, | |
| body: '' | |
| }; | |
| responseStream.write(JSON.stringify(response)); | |
| responseStream.end(); | |
| return; | |
| } | |
| const httpResponseMetadata = { | |
| statusCode: 200, | |
| headers: { | |
| ...headers, | |
| 'Content-Type': 'text/event-stream', | |
| 'Cache-Control': 'no-cache', | |
| 'Connection': 'keep-alive' | |
| } | |
| }; | |
| responseStream = awslambda.HttpResponseStream.from(responseStream, httpResponseMetadata); | |
| const generateEvents = async function* () { | |
| for (let i = 0; i < 5; i++) { | |
| yield `event: message\ndata: ${JSON.stringify({message: `Event ${i}`})}\n\n`; | |
| await new Promise(resolve => setTimeout(resolve, 1000)); | |
| } | |
| }; | |
| try { | |
| for await (const chunk of generateEvents()) { | |
| responseStream.write(chunk); | |
| } | |
| } catch (error) { | |
| console.error('Error:', error); | |
| responseStream.write('event: error\ndata: Internal Server Error\n\n'); | |
| } finally { | |
| responseStream.end(); | |
| } | |
| }); | |
| Runtime: nodejs20.x | |
| Timeout: 60 | |
| SSELambdaFunctionUrl: | |
| Type: AWS::Lambda::Url | |
| Properties: | |
| AuthType: NONE | |
| TargetFunctionArn: !Ref SSELambdaFunction | |
| InvokeMode: RESPONSE_STREAM | |
| SSELambdaPermission: | |
| Type: AWS::Lambda::Permission | |
| Properties: | |
| FunctionName: !Ref SSELambdaFunction | |
| Action: lambda:InvokeFunctionUrl | |
| Principal: "*" | |
| FunctionUrlAuthType: NONE | |
| Outputs: | |
| LambdaFunctionUrl: | |
| Description: "Lambda Function URL for SSE testing" | |
| Value: !GetAtt SSELambdaFunctionUrl.FunctionUrl |
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| <!DOCTYPE html> | |
| <html> | |
| <body> | |
| <h1>SSE Test</h1> | |
| <div id="events"></div> | |
| <script> | |
| const eventsDiv = document.getElementById('events'); | |
| const eventSource = new EventSource('https://REPLACEME.lambda-url.us-east-1.on.aws/'); | |
| eventSource.onmessage = function(event) { | |
| const p = document.createElement('p'); | |
| p.textContent = event.data; | |
| eventsDiv.appendChild(p); | |
| }; | |
| eventSource.onerror = function(error) { | |
| console.error('EventSource failed:', error); | |
| eventSource.close(); | |
| }; | |
| </script> | |
| </body> | |
| </html> |
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