AWS Solutions Constructs Core

Common errors

• AttributeError: 'CfnBucket' object has no attribute 'bucket_name'

  cause `aws-cdk-lib` version incompatibility. The Solutions Constructs library expects specific CDK API versions.
  fix Check the `aws-solutions-constructs-core` package's `pyproject.toml` or PyPI page for its `Requires-Dist` or `aws-cdk-lib` dependency range. Install a compatible `aws-cdk-lib` version, e.g., `pip install aws-cdk-lib==2.101.0`.

• ModuleNotFoundError: No module named 'aws_solutions_constructs.aws_solutions_constructs_core'

  cause The `aws-solutions-constructs-core` package is either not installed or the import path is incorrect.
  fix Ensure the package is installed: `pip install aws-solutions-constructs-core`. Verify the import statement matches the full module path: `from aws_solutions_constructs.aws_solutions_constructs_core import ...`.

• TypeError: Expected an instance of constructs.Construct, got <aws_cdk.aws_lambda.Function object at ...>

  cause Often arises from a version mismatch between `aws-cdk-lib` and the underlying `constructs` package, or passing an object of the wrong type where a `constructs.Construct` is expected by a Solutions Construct.
  fix Ensure `aws-cdk-lib` and `aws-solutions-constructs-core` are compatible versions, as `aws-cdk-lib` typically handles the `constructs` dependency. When creating new constructs, always pass `self` (the current construct scope) as the first argument.

Warnings

• breaking AWS Solutions Constructs are tightly coupled to specific versions of `aws-cdk-lib`. Mismatched versions can lead to runtime errors, API inconsistencies, or unexpected behavior.
  Fix: Always align your `aws-cdk-lib` version with the `aws-solutions-constructs-core` version (e.g., if constructs is `2.x.y`, install `aws-cdk-lib==2.x.y` or within its specified compatible range). Check the `pyproject.toml` or `setup.py` for exact dependencies.
• gotcha The `aws-solutions-constructs-core` library provides base classes and helper functions. It is not designed to be instantiated directly for full patterns. Instead, it's used to extend or assist with other `aws-solutions-constructs.*` pattern libraries.
  Fix: If you are looking for pre-built, high-level patterns (e.g., API Gateway to Lambda), use specific pattern libraries like `aws-solutions-constructs.aws_apigateway_lambda`. `core` is for building *your own* constructs or using specific helper methods.
• gotcha Solutions Constructs abstracts away many underlying L1/L2 details for simplicity. If you need fine-grained control or access to low-level CloudFormation properties, you might need to use `.node.default_child` or similar, which can bypass the construct's intended abstraction and lead to future compatibility issues.
  Fix: Prefer using the construct's provided properties and methods for configuration. If direct L1/L2 access is critical, carefully review the construct's documentation and consider the implications for future upgrades.

Install

• pip install aws-solutions-constructs-core Install core library

Imports

• SolutionConstruct

  from aws_solutions_constructs.aws_solutions_constructs_core import SolutionConstruct

  Base class for creating new Solutions Constructs patterns.
• add_tags

  from aws_solutions_constructs.aws_solutions_constructs_core import add_tags

  A common utility function to apply tags to any CDK construct.
• build_lambda_function

  from aws_solutions_constructs.aws_solutions_constructs_core import build_lambda_function

  Helper function for consistently creating Lambda functions with common best practices.

Quickstart

This quickstart demonstrates using `aws-solutions-constructs-core.add_tags` to apply standardized tags to a simple AWS Lambda function within an AWS CDK stack. This highlights how core utilities can be directly leveraged alongside standard CDK resources.

import os
from aws_cdk import (
    App,
    Stack,
    aws_lambda as _lambda,
)
from constructs import Construct
from aws_solutions_constructs.aws_solutions_constructs_core import add_tags

class MyCoreUsageStack(Stack):
    def __init__(self, scope: Construct, id: str, **kwargs) -> None:
        super().__init__(scope, id, **kwargs)

        # Create a basic Lambda function
        my_function = _lambda.Function(
            self, "MyFunction",
            runtime=_lambda.Runtime.PYTHON_3_9,
            handler="index.handler",
            code=_lambda.Code.from_inline("def handler(event, context): return 'Hello from Lambda!'")
        )

        # Use a utility from aws_solutions_constructs_core to add tags to the Lambda
        # add_tags is often used implicitly by pattern constructs, but can be used directly.
        add_tags(my_function, {
            "Project": "MyCDKApp",
            "Environment": "Development"
        })

app = App()
MyCoreUsageStack(app, "MyCoreUsageStack", env={
    'account': os.environ.get('CDK_DEFAULT_ACCOUNT', ''),
    'region': os.environ.get('CDK_DEFAULT_REGION', 'us-east-1')
})
app.synth()