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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/barchart/aws-lambda-pdf-generator/llms.txt

Use this file to discover all available pages before exploring further.

All deployment configuration lives in a single file: packages/api/serverless.yml. This YAML file drives the Serverless framework and controls everything from Lambda memory allocation and timeouts, to environment variables, CORS headers, and the S3 bucket used for large HTTP responses. Edit this file before running yarn deploy:prod or yarn deploy:stage to tailor the stack to your environment.

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Lambda Function Settings

The stack defines two Lambda functions. The resource-intensive print function is tuned for Chromium workloads; the serviceRead function uses Serverless framework defaults.
Settingprint functionserviceRead function
Runtimenodejs20.xnodejs20.x
Memory2048 MBDefault (1024 MB)
Timeout30 secondsDefault (6 seconds)
CloudWatch log retention90 days90 days
The 30-second timeout on the print function mirrors the maximum integration timeout enforced by API Gateway. Increasing it beyond 30 seconds in serverless.yml will not extend the effective limit for synchronous HTTP requests.

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Environment Variables

The following environment variables are injected into every Lambda function at deploy time. They are defined under provider.environment in serverless.yml and can be overridden per function if needed.
VariableDefault valueDescription
NODE_ENVstage or prodSet to the Serverless stage name. Use this to branch application logic between environments.
S3_LARGE_HTTP_RESPONSE_REGIONus-east-1AWS region of the S3 bucket used to store oversized Lambda responses.
S3_LARGE_HTTP_RESPONSE_BUCKETbarchart-aws-lambda-responsesName of the S3 bucket used for large HTTP responses that exceed API Gateway’s 10 MB payload limit.

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CORS Configuration

CORS is enabled globally for all endpoints. The default policy allows requests from any origin and accepts the following headers:
  • Accept-Encoding
  • Content-Type
  • Content-Length
  • X-Amz-Date
  • Authorization
  • X-Api-Key
  • X-Amz-Security-Token
  • X-Amz-User-Agent
  • Access-Control-Allow-Origin
  • Access-Control-Allow-Headers
  • Access-Control-Allow-Methods
allowCredentials is set to false. To restrict the allowed origin to a specific domain, change the cors.origin value under custom in serverless.yml.

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Lambda Layer

The HeadlessChromium layer packages Chromium v122 and is built locally before every deployment by the predeploy script (make clean && make all). The Makefile clones the @sparticuz/chromium repository at tag v122.0.0, compiles it, and writes the output to layers/chromium-v122.zip.
PropertyValue
Layer nameserverless-headless-chromium-{stage}-v122
Compatible runtimesnodejs20.x
Artifact pathpackages/api/layers/chromium-v122.zip
Attached toprint function only
The serviceRead function does not attach this layer because it never invokes Chromium.

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Deployment Bucket

The Serverless framework uploads deployment artifacts (CloudFormation templates, zipped function code, and the Chromium layer) to an S3 bucket before applying the stack. The default bucket is barchart-serverless-deployments, configured under provider.deploymentBucket. Change this to a bucket you own before deploying to your own AWS account.
The S3 bucket specified in S3_LARGE_HTTP_RESPONSE_BUCKET (barchart-aws-lambda-responses by default) must already exist in the target region before deployment. The Serverless framework will not create this bucket automatically, and Lambda invocations that produce large responses will fail at runtime if the bucket is missing. Create the bucket manually in the AWS Console or via the AWS CLI before running yarn deploy:prod.

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serverless.yml Reference

The following snippet shows the full configuration section of packages/api/serverless.yml: 
service: serverless-pdf-generator

frameworkVersion: ">=3.38.0 <4.0.0"

custom:
  stage: ${opt:stage, 'stage'}

  s3:
    responseRegion: 'us-east-1'
    responseBucket: 'barchart-aws-lambda-responses'

  cors:
    origin: '*'
    headers:
      - Accept-Encoding
      - Content-Type
      - Content-Length
      - X-Amz-Date
      - Authorization
      - X-Api-Key
      - X-Amz-Security-Token
      - X-Amz-User-Agent
      - Access-Control-Allow-Origin
      - Access-Control-Allow-Headers
      - Access-Control-Allow-Methods
    allowCredentials: false

provider:
  name: aws
  runtime: nodejs20.x
  logRetentionInDays: 90
  deploymentBucket: barchart-serverless-deployments

  environment:
    NODE_ENV: ${self:custom.stage}
    S3_LARGE_HTTP_RESPONSE_REGION: ${self:custom.s3.responseRegion}
    S3_LARGE_HTTP_RESPONSE_BUCKET: ${self:custom.s3.responseBucket}

  iam:
    role:
      statements:
        - Effect: Allow
          Action:
            - s3:GetObject
            - s3:PutObject
          Resource: arn:aws:s3:::${self:custom.s3.responseBucket}/*

  apiGateway:
    shouldStartNameWithService: true

layers:
  HeadlessChromium:
    name: serverless-headless-chromium-${self:custom.stage}-v122
    description: Layer for puppeteer to launch headless Chromium v122
    compatibleRuntimes:
      - nodejs20.x
    package:
      artifact: layers/chromium-v122.zip

functions:
  print:
    handler: print/print.handler
    description: Generates a PDF from HTML (using Chromium v122)
    memorySize: 2048
    timeout: 30
    layers:
      - { Ref: HeadlessChromiumLambdaLayer }
    events:
      - http:
          path: /print
          method: POST
          cors: ${self:custom.cors}

  serviceRead:
    handler: service/version.handler
    description: Reads service metadata
    events:
      - http:
          method: GET
          path: service/version
          cors: ${self:custom.cors}

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