Lambda

DevCloud stores function metadata in SQLite and function archives on disk. Function invocations execute through the universal workload runtime (internal/shared/workload), supporting OCI container engines (Docker, Podman, nerdctl), WebAssembly, and host process sandboxing. Management APIs and control-plane calls run without requiring container engines.

Workload Execution Engine

By default, DevCloud executes Python 3.12 (python3.12) and Node.js 22 (nodejs22.x) handlers inside OCI containers.

Container Images

Pull the official AWS runtime images before invoking containerized handlers:

docker pull public.ecr.aws/lambda/python:3.12
docker pull public.ecr.aws/lambda/nodejs:22

Runtime Selection

The workload engine automatically detects available execution environments:

OCI Container Runtime: Automatically discovers podman, docker, or nerdctl from PATH. You can override the engine by setting CONTAINER_RUNTIME:
```
export CONTAINER_RUNTIME=podman
```
WebAssembly (WASM): If handlers are compiled to .wasm binaries or configured for WebAssembly, DevCloud executes them via wasmtime, wasmer, or embedded runtimes, eliminating container daemon overhead.
Process Sandbox: For environments without container runtimes installed, the process runner executes handler code within temporary working directories.

Network Configuration

DEVCLOUD_LAMBDA_NETWORK optionally selects a container network. Handlers can reach DevCloud using an endpoint passed in Environment.Variables:

With a native Linux host: use http://host.docker.internal:4747 (containers receive a host-gateway entry).
When DevCloud runs inside a container: attach both containers to the same network and use the service name, such as http://devcloud:4747.
For Colima on macOS: use http://host.lima.internal:4747.

Host AWS credentials are never inherited; defaults are test/test and region us-east-1. Explicit function environment variables override these defaults.

Supported APIs

These 35 operations are hand-verified at the scope exercised by the compatibility test suite:

Operation	Behaviour
Invoke	Actual handler result; RequestResponse, Event, DryRun and Tail logs
CreateFunction	ZIP archive and configuration including environment variables
ListFunctions / GetFunction / DeleteFunction	Function management lifecycle
UpdateFunctionCode / UpdateFunctionConfiguration	Code and configuration updates
PublishVersion / ListVersionsByFunction	Separate immutable ZIP and configuration snapshots
CreateAlias / GetAlias / UpdateAlias / DeleteAlias / ListAliases	Version references
CreateEventSourceMapping / GetEventSourceMapping / UpdateEventSourceMapping	SQS and DynamoDB Streams mappings and Enabled state
DeleteEventSourceMapping / ListEventSourceMappings	Mapping management lifecycle
AddPermission / GetPolicy / RemovePermission	Stored resource policies
TagResource / UntagResource / ListTags	Function tags

boto3 Example

import io
import zipfile
import boto3

client = boto3.client(
    "lambda",
    endpoint_url="http://localhost:4747",
    aws_access_key_id="test",
    aws_secret_access_key="test",
    region_name="us-east-1",
)

code = io.BytesIO()
with zipfile.ZipFile(code, "w") as archive:
    archive.writestr(
        "index.py",
        "def handler(event, context): return {'executed': True, 'input': event}",
    )

client.create_function(
    FunctionName="my-function",
    Runtime="python3.12",
    Handler="index.handler",
    Role="arn:aws:iam::000000000000:role/test",
    Code={"ZipFile": code.getvalue()},
)

response = client.invoke(
    FunctionName="my-function",
    Payload=b'{"key": "value"}',
)

print("Invoke response:", response["Payload"].read().decode())