AWS Lambda PHP Integration

Patterns for deploying PHP and Symfony applications on AWS Lambda using the Bref framework.

Overview

Two approaches available:

• Bref Framework - Standard PHP on Lambda with Symfony support, built-in routing, cold start < 2s
• Raw PHP - Minimal overhead, maximum control, cold start < 500ms

Both support API Gateway integration with production-ready configurations.

When to Use

• Creating new Lambda functions in PHP
• Migrating existing Symfony applications to Lambda
• Optimizing cold start performance
• Configuring API Gateway or SQS/SNS event triggers
• Setting up deployment pipelines for PHP Lambda

Instructions

1. Choose Your Approach

2. Project Structure

Symfony with Bref Structure

my-symfony-lambda/
├── composer.json
├── serverless.yml
├── public/
│   └── index.php         # Lambda entry point
├── src/
│   └── Kernel.php        # Symfony Kernel
├── config/
│   ├── bundles.php
│   ├── routes.yaml
│   └── services.yaml
└── templates/

Raw PHP Structure

my-lambda-function/
├── public/
│   └── index.php         # Handler entry point
├── composer.json
├── serverless.yml
└── src/
    └── Services/

3. Implementation

Symfony with Bref:

// public/index.php
use Bref\Symfony\Bref;
use App\Kernel;
use Symfony\Component\HttpFoundation\Request;

require __DIR__.'/../vendor/autoload.php';

$kernel = new Kernel($_SERVER['APP_ENV'] ?? 'dev', $_SERVER['APP_DEBUG'] ?? true);
$kernel->boot();

$bref = new Bref($kernel);
return $bref->run($event, $context);

Raw PHP Handler:

// public/index.php
use function Bref\Lambda\main;

main(function ($event) {
    $path = $event['path'] ?? '/';
    $method = $event['httpMethod'] ?? 'GET';

    return [
        'statusCode' => 200,
        'body' => json_encode(['message' => 'Hello from PHP Lambda!'])
    ];
});

4. Cold Start Optimization

1. Lazy loading - Defer heavy services until needed
2. Disable unused Symfony features - Turn off validation, annotations
3. Optimize composer autoload - Use classmap for production
4. Use Bref optimized runtime - Leverage PHP 8.x optimizations

5. Connection Management

// Cache AWS clients at function level
use Aws\DynamoDb\DynamoDbClient;

class DatabaseService
{
    private static ?DynamoDbClient $client = null;

    public static function getClient(): DynamoDbClient
    {
        if (self::$client === null) {
            self::$client = new DynamoDbClient([
                'region' => getenv('AWS_REGION'),
                'version' => 'latest'
            ]);
        }
        return self::$client;
    }
}

Best Practices

Memory and Timeout

• Memory: Start with 512MB for Symfony, 256MB for raw PHP
• Timeout: Symfony 10-30s for cold start buffer, Raw PHP 3-10s typically sufficient

Dependencies

{
    "require": {
        "php": "^8.2",
        "bref/bref": "^2.0",
        "symfony/framework-bundle": "^6.0"
    },
    "config": {
        "optimize-autoloader": true,
        "preferred-install": "dist"
    }
}

Error Handling

try {
    $result = processRequest($event);
    return [
        'statusCode' => 200,
        'body' => json_encode($result)
    ];
} catch (ValidationException $e) {
    return [
        'statusCode' => 400,
        'body' => json_encode(['error' => $e->getMessage()])
    ];
} catch (Exception $e) {
    error_log($e->getMessage());
    return [
        'statusCode' => 500,
        'body' => json_encode(['error' => 'Internal error'])
    ];
}

Logging

error_log(json_encode([
    'level' => 'info',
    'message' => 'Request processed',
    'request_id' => $context->getAwsRequestId(),
    'path' => $event['path'] ?? '/'
]));

Deployment

Serverless Configuration

# serverless.yml
service: symfony-lambda-api

provider:
  name: aws
  runtime: php-82
  memorySize: 512
  timeout: 20

package:
  individually: true
  exclude:
    - '**/node_modules/**'
    - '**/.git/**'

functions:
  api:
    handler: public/index.php
    events:
      - http:
          path: /{proxy+}
          method: ANY

Deploy and Validate

# 1. Install Bref
composer require bref/bref --dev

# 2. Test locally (validate before deploy)
sam local invoke -e event.json

# 3. Deploy
vendor/bin/bref deploy

# 4. Verify deployment
aws lambda invoke --function-name symfony-lambda-api-api \
  --payload '{"path": "/", "httpMethod": "GET"}' /dev/stdout

Symfony Full Configuration

# serverless.yml for Symfony
service: symfony-lambda-api

provider:
  name: aws
  runtime: php-82
  stage: ${self:custom.stage}
  region: ${self:custom.region}
  environment:
    APP_ENV: ${self:custom.stage}
    APP_DEBUG: ${self:custom.isLocal}
  iam:
    role:
      statements:
        - Effect: Allow
          Action:
            - dynamodb:GetItem
            - dynamodb:PutItem
          Resource: '*'

functions:
  web:
    handler: public/index.php
    timeout: 30
    memorySize: 1024
    events:
      - http:
          path: /{proxy+}
          method: ANY

  console:
    handler: bin/console
    timeout: 300
    events:
      - schedule: rate(1 day)

plugins:
  - ./vendor/bref/bref

custom:
  stage: dev
  region: us-east-1
  isLocal: false

Constraints and Warnings

Lambda Limits

• Deployment package: 250MB unzipped maximum (50MB zipped)
• Memory: 128MB to 10GB
• Timeout: 29 seconds (API Gateway), 15 minutes for async
• Concurrent executions: 1000 default

PHP-Specific Considerations

• Cold start: PHP has moderate cold start; use Bref for optimized runtimes
• Dependencies: Keep composer.json minimal; use Lambda Layers for shared deps
• PHP version: Use PHP 8.2+ for best Lambda performance
• No local storage: Lambda containers are ephemeral; use S3/DynamoDB for persistence

Common Pitfalls

1. Large vendor folder - Exclude dev dependencies; use --no-dev
2. Session storage - Don't use local file storage; use DynamoDB
3. Long-running processes - Not suitable for Lambda; use ECS instead
4. Websockets - Use API Gateway WebSockets or AppSync instead

Security Considerations

• Never hardcode credentials; use IAM roles and SSM Parameter Store
• Validate all input data
• Use least privilege IAM policies
• Enable CloudTrail for audit logging
• Set proper CORS headers

Examples

Example 1: Create a Symfony Lambda API

Input: "Create a Symfony Lambda REST API using Bref for a todo application"

Process:

1. Initialize Symfony project with composer create-project
2. Install Bref: composer require bref/bref
3. Configure serverless.yml
4. Set up routes in config/routes.yaml
5. Test locally: sam local invoke
6. Deploy: vendor/bin/bref deploy
7. Verify: aws lambda invoke --function-name <name> --payload '{}'

Output: Complete Symfony project structure with REST API, DynamoDB integration, deployment configuration

Example 2: Optimize Cold Start for Symfony

Input: "My Symfony Lambda has 5 second cold start, how do I optimize it?"

Process:

1. Analyze services loaded at startup
2. Disable unused Symfony features (validation, annotations)
3. Use lazy loading for heavy services
4. Optimize composer autoload
5. Measure: Deploy and invoke to verify cold start < 2s

Output: Refactored Symfony configuration with cold start < 2s

Example 3: Deploy with GitHub Actions

Input: "Configure CI/CD for Symfony Lambda with Serverless Framework"

Process:

1. Create GitHub Actions workflow
2. Set up PHP environment with composer
3. Run PHPUnit tests
4. Deploy with Serverless Framework
5. Validate: Check Lambda function exists and responds

Output: Complete .github/workflows/deploy.yml with multi-stage pipeline and test automation

References

• Bref Lambda - Complete Bref setup, Symfony integration, routing
• Raw PHP Lambda - Minimal handler patterns, caching, packaging
• Serverless Deployment - Serverless Framework, SAM, CI/CD pipelines
• Testing Lambda - PHPUnit, SAM Local, integration testing