Add support for Lambda Tenants (#608)

Address https://github.com/awslabs/swift-aws-lambda-runtime/issues/605

NEW Lambda Tenant isolation capability: 
https://docs.aws.amazon.com/lambda/latest/dg/tenant-isolation.html 


# Add Support for Lambda Tenant Isolation Mode

## Summary

This PR adds support for AWS Lambda's tenant isolation mode to the Swift
AWS Lambda Runtime, enabling developers to build multi-tenant
applications with strict execution environment isolation per tenant.

## Changes

### Runtime Support
- Added `tenantID` property to `LambdaContext` to expose the tenant
identifier
- Extended `InvocationMetadata` to capture the
`Lambda-Runtime-Aws-Tenant-Id` header
- Added `AmazonHeaders.tenantID` constant for the tenant ID header
- Added trace logging for invocation headers to aid debugging

### New Example: MultiTenant
A complete working example demonstrating tenant isolation mode:
- **Request tracking system** that maintains separate counters and
histories per tenant
- **Actor-based storage** (`TenantDataStore`) for thread-safe tenant
data management
- **Immutable data structures** (`TenantData`) following Swift best
practices
- **API Gateway integration** with tenant ID passed via query parameter
- **SAM template** configured with `TenancyConfig.TenantIsolationMode:
PER_TENANT`
- **Comprehensive documentation** covering architecture, deployment,
testing, and best practices

### Testing
- Added unit test for tenant ID extraction from invocation headers
- Integrated MultiTenant example into CI/CD pipeline

### Documentation
The example includes detailed documentation on:
- When to use tenant isolation (user code execution, sensitive data
processing)
- How tenant isolation works (dedicated environments, no cross-tenant
reuse)
- Concurrency limits and scaling considerations
- Pricing implications
- Security best practices
- CloudWatch monitoring with tenant dimensions

## Files Changed
- `Sources/AWSLambdaRuntime/LambdaContext.swift` - Added tenantID
property
- `Sources/AWSLambdaRuntime/ControlPlaneRequest.swift` - Capture tenant
ID from headers
- `Sources/AWSLambdaRuntime/Utils.swift` - Added tenantID header
constant
- `Sources/AWSLambdaRuntime/Lambda.swift` - Pass tenant ID to context
- `Sources/AWSLambdaRuntime/LambdaRuntimeClient+ChannelHandler.swift` -
Added trace logging
- `Tests/AWSLambdaRuntimeTests/InvocationTests.swift` - Added tenant ID
test
- `Examples/MultiTenant/*` - New complete example with SAM template
- `.github/workflows/pull_request.yml` - Added MultiTenant to CI
pipeline

## Testing Instructions

1. Build and deploy the example:
   bash
  cd Examples/MultiTenant
  swift package archive --allow-network-connections docker
  sam deploy --guided
  

2. Test with different tenants:
   bash
curl
"https://<api-id>.execute-api.<region>.amazonaws.com/Prod?tenant-id=
alice"
curl
"https://<api-id>.execute-api.<region>.amazonaws.com/Prod?tenant-id=
bob"
  


3. Verify isolation by checking that each tenant maintains separate
request counts

## Related Documentation
- [AWS Lambda Tenant
Isolation](https://docs.aws.amazon.com/lambda/latest/dg/tenant-isolation.html)
- [AWS Blog: Streamlined Multi-Tenant Application
Development](https://aws.amazon.com/blogs/aws/streamlined-multi-tenant-application-development-with-tenant-isolation-mode-in-aws-lambda/)

---------

Co-authored-by: Sebastien Stormacq <stormacq@amazon.lu>
Co-authored-by: Tim Condon <0xTim@users.noreply.github.com>
This commit is contained in:
Sébastien Stormacq
2025-11-21 21:14:15 +01:00
committed by GitHub
parent 0305cb31b8
commit 2abe7eb7de
15 changed files with 680 additions and 2 deletions
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samconfig.toml
template.yaml
Makefile
Dockerfile
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response.json
samconfig.toml
Makefile
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// swift-tools-version:6.2
import PackageDescription
// needed for CI to test the local version of the library
import struct Foundation.URL
let package = Package(
name: "swift-aws-lambda-runtime-example",
platforms: [.macOS(.v15)],
products: [
.executable(name: "MultiTenant", targets: ["MultiTenant"])
],
dependencies: [
// during CI, the dependency on local version of swift-aws-lambda-runtime is added dynamically below
.package(url: "https://github.com/awslabs/swift-aws-lambda-runtime.git", from: "2.0.0"),
.package(url: "https://github.com/awslabs/swift-aws-lambda-events.git", from: "1.0.0"),
],
targets: [
.executableTarget(
name: "MultiTenant",
dependencies: [
.product(name: "AWSLambdaRuntime", package: "swift-aws-lambda-runtime"),
.product(name: "AWSLambdaEvents", package: "swift-aws-lambda-events"),
]
)
]
)
if let localDepsPath = Context.environment["LAMBDA_USE_LOCAL_DEPS"],
localDepsPath != "",
let v = try? URL(fileURLWithPath: localDepsPath).resourceValues(forKeys: [.isDirectoryKey]),
v.isDirectory == true
{
// when we use the local runtime as deps, let's remove the dependency added above
let indexToRemove = package.dependencies.firstIndex { dependency in
if case .sourceControl(
name: _,
location: "https://github.com/awslabs/swift-aws-lambda-runtime.git",
requirement: _
) = dependency.kind {
return true
}
return false
}
if let indexToRemove {
package.dependencies.remove(at: indexToRemove)
}
// then we add the dependency on LAMBDA_USE_LOCAL_DEPS' path (typically ../..)
print("[INFO] Compiling against swift-aws-lambda-runtime located at \(localDepsPath)")
package.dependencies += [
.package(name: "swift-aws-lambda-runtime", path: localDepsPath)
]
}
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# Multi-Tenant Lambda Function Example
This example demonstrates how to build a multi-tenant Lambda function using Swift and AWS Lambda's tenant isolation mode. Tenant isolation ensures that execution environments are dedicated to specific tenants, providing strict isolation for processing tenant-specific code or data.
## Overview
This example implements a request tracking system that maintains separate counters and request histories for each tenant. The Lambda function:
- Accepts requests from multiple tenants via API Gateway
- Maintains isolated execution environments per tenant
- Tracks request counts and timestamps for each tenant
- Returns tenant-specific data in JSON format
## What is Tenant Isolation Mode?
AWS Lambda's tenant isolation mode routes requests to execution environments based on a customer-specified tenant identifier. This ensures that:
- **Execution environments are never reused across different tenants** - Each tenant gets dedicated execution environments
- **Data isolation** - Tenant-specific data remains isolated from other tenants
- **Firecracker virtualization** - Provides workload isolation at the infrastructure level
### When to Use Tenant Isolation
Use tenant isolation mode when building multi-tenant applications that:
- **Execute end-user supplied code** - Limits the impact of potentially incorrect or malicious user code
- **Process tenant-specific data** - Prevents exposure of sensitive data to other tenants
- **Require strict isolation guarantees** - Such as SaaS platforms for workflow automation or code execution
## Architecture
The example consists of:
1. **TenantData** - Immutable struct tracking tenant information:
- `tenantID`: Unique identifier for the tenant
- `requestCount`: Total number of requests from this tenant
- `firstRequest`: Unix timestamp (seconds since epoch) of the first request
- `requests`: Array of individual request records
2. **TenantDataStore** - Actor-based storage providing thread-safe access to tenant data across invocations
3. **Lambda Handler** - Processes API Gateway requests and manages tenant data
## Code Structure
```swift
// Immutable tenant data structure
struct TenantData: Codable {
let tenantID: String
let requestCount: Int
let firstRequest: String
let requests: [TenantRequest]
func addingRequest() -> TenantData {
// Returns new instance with incremented count
}
}
// Thread-safe tenant storage using Swift actors
actor TenantDataStore {
private var tenants: [String: TenantData] = [:]
subscript(id: String) -> TenantData? {
tenants[id]
}
func update(id: String, data: TenantData) {
tenants[id] = data
}
}
// Lambda handler extracts tenant ID from context
let runtime = LambdaRuntime {
(event: APIGatewayRequest, context: LambdaContext) -> APIGatewayResponse in
guard let tenantID = context.tenantID else {
return APIGatewayResponse(statusCode: .badRequest, body: "No Tenant ID provided")
}
// Process request for this tenant
let currentData = await tenants[tenantID] ?? TenantData(tenantID: tenantID)
let updatedData = currentData.addingRequest()
await tenants.update(id: tenantID, data: updatedData)
return try APIGatewayResponse(statusCode: .ok, encodableBody: updatedData)
}
```
## Configuration
### SAM Template (template.yaml)
The function is configured with tenant isolation mode and API Gateway parameter mapping in the SAM template:
```yaml
# API Gateway REST API with parameter mapping
MultiTenantApi:
Type: AWS::Serverless::Api
Properties:
StageName: Prod
DefinitionBody:
openapi: 3.0.1
paths:
/:
get:
parameters:
- name: tenant-id
in: query
required: true
x-amazon-apigateway-integration:
type: aws_proxy
httpMethod: POST
uri: !Sub arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${MultiTenantLambda.Arn}/invocations
# Map query parameter to Lambda tenant header
requestParameters:
integration.request.header.X-Amz-Tenant-Id: method.request.querystring.tenant-id
# Lambda function with tenant isolation
MultiTenantLambda:
Type: AWS::Serverless::Function
Properties:
Runtime: provided.al2023
Architectures:
- arm64
# Enable tenant isolation mode
TenancyConfig:
TenantIsolationMode: PER_TENANT
```
### Key Configuration Points
- **TenancyConfig.TenantIsolationMode**: Set to `PER_TENANT` to enable tenant isolation
- **Parameter Mapping**: API Gateway maps the `tenant-id` query parameter to the `X-Amz-Tenant-Id` header required by Lambda
- **REST API**: Uses REST API (not HTTP API) to support request parameter mapping
- **OpenAPI Definition**: Defines the integration using OpenAPI 3.0 specification for fine-grained control
- **Immutable property**: Tenant isolation can only be enabled when creating a new function
- **Required tenant-id**: All invocations must include a tenant identifier
### Why Parameter Mapping is Required
Lambda's tenant isolation feature requires the tenant ID to be passed via the `X-Amz-Tenant-Id` header. When using API Gateway:
1. **Client sends request** with `tenant-id` as a query parameter
2. **API Gateway transforms** the query parameter into the `X-Amz-Tenant-Id` header
3. **Lambda receives** the header and routes to the appropriate tenant-isolated environment
This mapping is configured in the `x-amazon-apigateway-integration` section using:
```yaml
requestParameters:
integration.request.header.X-Amz-Tenant-Id: method.request.querystring.tenant-id
```
## Deployment
### Prerequisites
- Swift (>=6.2)
- Docker (for cross-compilation to Amazon Linux)
- AWS SAM CLI (>=1.147.1)
- AWS CLI configured with appropriate credentials
### Build and Deploy
1. **Build the Lambda function**:
```bash
swift package archive --allow-network-connections docker
```
2. **Deploy using SAM**:
```bash
sam deploy --guided
```
3. **Note the API Gateway endpoint** from the CloudFormation outputs
## Testing
### Using API Gateway
The tenant ID is passed as a query parameter. API Gateway automatically maps it to the `X-Amz-Tenant-Id` header:
```bash
# Request from tenant "alice"
curl "https://your-api-id.execute-api.us-east-1.amazonaws.com/Prod?tenant-id=alice"
# Request from tenant "bob"
curl "https://your-api-id.execute-api.us-east-1.amazonaws.com/Prod?tenant-id=bob"
# Multiple requests from the same tenant will reuse the execution environment
for i in {1..5}; do
curl "https://your-api-id.execute-api.us-east-1.amazonaws.com/Prod?tenant-id=alice"
done
```
### Using AWS CLI (Direct Lambda Invocation)
For direct Lambda invocation without API Gateway:
```bash
# Synchronous invocation
aws lambda invoke \
--function-name MultiTenantLambda \
--tenant-id alice \
response.json
# View the response
cat response.json
```
### Expected Response
```json
{
"tenantID": "alice",
"requestCount": 3,
"firstRequest": "1705320000.123456",
"requests": [
{
"requestNumber": 1,
"timestamp": "1705320000.123456"
},
{
"requestNumber": 2,
"timestamp": "1705320075.789012"
},
{
"requestNumber": 3,
"timestamp": "1705320150.345678"
}
]
}
```
**Note**: Timestamps are Unix epoch times (seconds since January 1, 1970) for cross-platform compatibility.
## How Tenant Isolation Works
1. **Request arrives** with a tenant identifier (via query parameter, header, or direct invocation)
2. **Lambda routes the request** to an execution environment dedicated to that tenant
3. **Environment reuse** - Subsequent requests from the same tenant reuse the same environment (warm start)
4. **Isolation guarantee** - Execution environments are never shared between different tenants
5. **Data persistence** - Tenant data persists in memory across invocations within the same execution environment
## Important Considerations
### Concurrency and Scaling
- Lambda imposes a limit of **2,500 tenant-isolated execution environments** (active or idle) for every 1,000 concurrent executions
- Each tenant can scale independently based on their request volume
- Cold starts occur more frequently due to tenant-specific environments
### Pricing
- Standard Lambda pricing applies (compute time and requests)
- **Additional charge** when Lambda creates a new tenant-isolated execution environment
- Price depends on allocated memory and CPU architecture
- See [AWS Lambda Pricing](https://aws.amazon.com/lambda/pricing) for details
### Limitations
Tenant isolation mode is **not supported** with:
- Function URLs
- Provisioned concurrency
- SnapStart
### Supported Invocation Methods
- ✅ Synchronous invocations
- ✅ Asynchronous invocations
- ✅ API Gateway event triggers
- ✅ AWS SDK invocations
## Security Best Practices
1. **Execution role applies to all tenants** - Use IAM policies to restrict access to tenant-specific resources
2. **Validate tenant identifiers** - Ensure tenant IDs are properly authenticated and authorized
3. **Implement tenant-aware logging** - Include tenant ID in CloudWatch logs for audit trails
4. **Set appropriate timeouts** - Configure function timeout based on expected workload
5. **Monitor per-tenant metrics** - Use CloudWatch to track invocations, errors, and duration per tenant
## Monitoring
### CloudWatch Metrics
Lambda automatically publishes metrics with tenant dimensions:
- `Invocations` - Number of invocations per tenant
- `Duration` - Execution time per tenant
- `Errors` - Error count per tenant
- `Throttles` - Throttled requests per tenant
### Accessing Metrics
```bash
# Get invocation count for a specific tenant
aws cloudwatch get-metric-statistics \
--namespace AWS/Lambda \
--metric-name Invocations \
--dimensions Name=FunctionName,Value=MultiTenant Name=TenantId,Value=alice \
--start-time 2024-01-15T00:00:00Z \
--end-time 2024-01-15T23:59:59Z \
--period 3600 \
--statistics Sum
```
## Learn More
- [AWS Lambda Tenant Isolation Documentation](https://docs.aws.amazon.com/lambda/latest/dg/tenant-isolation.html)
- [Configuring Tenant Isolation](https://docs.aws.amazon.com/lambda/latest/dg/tenant-isolation-configure.html)
- [Invoking Tenant-Isolated Functions](https://docs.aws.amazon.com/lambda/latest/dg/tenant-isolation-invoke.html)
- [AWS Blog: Streamlined Multi-Tenant Application Development](https://aws.amazon.com/blogs/aws/streamlined-multi-tenant-application-development-with-tenant-isolation-mode-in-aws-lambda/)
- [Swift AWS Lambda Runtime](https://github.com/swift-server/swift-aws-lambda-runtime)
## License
This example is part of the Swift AWS Lambda Runtime project and is licensed under Apache License 2.0.
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//===----------------------------------------------------------------------===//
//
// This source file is part of the SwiftAWSLambdaRuntime open source project
//
// Copyright SwiftAWSLambdaRuntime project authors
// Copyright (c) Amazon.com, Inc. or its affiliates.
// Licensed under Apache License v2.0
//
// See LICENSE.txt for license information
// See CONTRIBUTORS.txt for the list of SwiftAWSLambdaRuntime project authors
//
// SPDX-License-Identifier: Apache-2.0
//
//===----------------------------------------------------------------------===//
import AWSLambdaEvents
import AWSLambdaRuntime
#if canImport(FoundationEssentials)
import FoundationEssentials
#else
import Foundation
#endif
let tenants = TenantDataStore()
let runtime = LambdaRuntime {
(event: APIGatewayRequest, context: LambdaContext) -> APIGatewayResponse in
// Extract tenant ID from context
guard let tenantID = context.tenantID else {
return APIGatewayResponse(statusCode: .badRequest, body: "No Tenant ID provided")
}
// Get or create tenant data
let currentData = await tenants[tenantID] ?? TenantData(tenantID: tenantID)
// Add new request
let updatedData = currentData.addingRequest()
// Store updated data
await tenants.update(id: tenantID, data: updatedData)
return try APIGatewayResponse(statusCode: .ok, encodableBody: updatedData)
}
try await runtime.run()
actor TenantDataStore {
private var tenants: [String: TenantData] = [:]
subscript(id: String) -> TenantData? {
tenants[id]
}
// subscript setters can't be called from outside of the actor
func update(id: String, data: TenantData) {
tenants[id] = data
}
}
struct TenantData: Codable {
struct TenantRequest: Codable {
let requestNumber: Int
let timestamp: String
}
let tenantID: String
let requestCount: Int
let firstRequest: String
let requests: [TenantRequest]
init(tenantID: String) {
self.init(
tenantID: tenantID,
requestCount: 0,
firstRequest: "\(Date().timeIntervalSince1970)",
requests: []
)
}
func addingRequest() -> TenantData {
let newCount = requestCount + 1
let newRequest = TenantRequest(
requestNumber: newCount,
timestamp: "\(Date().timeIntervalSince1970)"
)
return TenantData(
tenantID: tenantID,
requestCount: newCount,
firstRequest: firstRequest,
requests: requests + [newRequest]
)
}
private init(
tenantID: String,
requestCount: Int,
firstRequest: String,
requests: [TenantRequest]
) {
self.tenantID = tenantID
self.requestCount = requestCount
self.firstRequest = firstRequest
self.requests = requests
}
}
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AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: SAM Template for Multi Tenant Lambda Example
# This is an example SAM template for the purpose of this project.
# When deploying such infrastructure in production environment,
# we strongly encourage you to follow these best practices for improved security and resiliency
# - Enable access logging on API Gateway
# See: https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-logging.html)
# - Ensure that AWS Lambda function is configured for function-level concurrent execution limit
# See: https://docs.aws.amazon.com/lambda/latest/dg/lambda-concurrency.html
# https://docs.aws.amazon.com/lambda/latest/dg/configuration-concurrency.html
# - Check encryption settings for Lambda environment variable
# See: https://docs.aws.amazon.com/lambda/latest/dg/configuration-envvars-encryption.html
# - Ensure that AWS Lambda function is configured for a Dead Letter Queue(DLQ)
# See: https://docs.aws.amazon.com/lambda/latest/dg/invocation-async-retain-records.html#invocation-dlq
# - Ensure that AWS Lambda function is configured inside a VPC when it needs to access private resources
# See: https://docs.aws.amazon.com/lambda/latest/dg/configuration-vpc.html
# Code Example: https://github.com/awslabs/swift-aws-lambda-runtime/tree/main/Examples/ServiceLifecycle%2BPostgres
Resources:
# API Gateway REST API
MultiTenantApi:
Type: AWS::Serverless::Api
Properties:
StageName: Prod
DefinitionBody:
openapi: 3.0.1
info:
title: MultiTenant API
version: 1.0.0
paths:
/{proxy+}:
x-amazon-apigateway-any-method:
parameters:
- name: tenant-id
in: query
required: true
schema:
type: string
- name: proxy
in: path
required: true
schema:
type: string
x-amazon-apigateway-request-validator: params-only
x-amazon-apigateway-integration:
type: aws_proxy
httpMethod: POST
uri: !Sub arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${MultiTenantLambda.Arn}/invocations
requestParameters:
integration.request.header.X-Amz-Tenant-Id: method.request.querystring.tenant-id
/:
x-amazon-apigateway-any-method:
parameters:
- name: tenant-id
in: query
required: true
schema:
type: string
x-amazon-apigateway-request-validator: params-only
x-amazon-apigateway-integration:
type: aws_proxy
httpMethod: POST
uri: !Sub arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${MultiTenantLambda.Arn}/invocations
requestParameters:
integration.request.header.X-Amz-Tenant-Id: method.request.querystring.tenant-id
x-amazon-apigateway-request-validators:
params-only:
validateRequestParameters: true
validateRequestBody: false
# Lambda function
MultiTenantLambda:
Type: AWS::Serverless::Function
Properties:
CodeUri: .build/plugins/AWSLambdaPackager/outputs/AWSLambdaPackager/MultiTenant/MultiTenant.zip
Timeout: 60
Handler: swift.bootstrap # ignored by the Swift runtime
Runtime: provided.al2023
MemorySize: 128
Architectures:
- arm64
# https://docs.aws.amazon.com/lambda/latest/dg/tenant-isolation-configure.html#tenant-isolation-cfn
TenancyConfig:
TenantIsolationMode: PER_TENANT
Environment:
Variables:
# by default, AWS Lambda runtime produces no log
# use `LOG_LEVEL: debug` for lifecycle and event handling information
# use `LOG_LEVEL: trace` for detailed input event information
LOG_LEVEL: trace
Events:
RootPath:
Type: Api
Properties:
RestApiId: !Ref MultiTenantApi
Path: /
Method: ANY
ProxyPath:
Type: Api
Properties:
RestApiId: !Ref MultiTenantApi
Path: /{proxy+}
Method: ANY
# Permission for API Gateway to invoke Lambda
MultiTenantLambdaPermission:
Type: AWS::Lambda::Permission
Properties:
FunctionName: !Ref MultiTenantLambda
Action: lambda:InvokeFunction
Principal: apigateway.amazonaws.com
SourceArn: !Sub arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:${MultiTenantApi}/*/*
Outputs:
# print API Gateway endpoint
APIGatewayEndpoint:
Description: API Gateway endpoint URL
# https://docs.aws.amazon.com/lambda/latest/dg/tenant-isolation-invoke.html#tenant-isolation-invoke-apigateway
Value: !Sub "https://${MultiTenantApi}.execute-api.${AWS::Region}.amazonaws.com/Prod?tenant-id=seb"