Install & Compatibility
Where this runs
tested against v10.8.1 · pip install
no network on importno background threads
Install × environment matrix
Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux
muslpy 3.10–3.95 runs
installs and imports cleanly · install 0.0s · import 0.000s · 23.9MB
glibcpy 3.10–3.95 runs
installs and imports cleanly · install 2.6s · import 0.000s · 24MB
22MB installed
● package 22MB
Code
Verified usage
Verified import paths — ran on the pinned version, not inferred.
Construct
✓ from constructs import Construct
✗ from aws_cdk.core import Construct
While aws_cdk.core.Construct was common in CDK v1, in CDK v2 and constructs v10, the base class is directly imported from 'constructs'.
Node
✓ from constructs import Node
This example demonstrates how to define and instantiate custom constructs using the `constructs` library. It shows how constructs form a hierarchical tree, how to access their `Node` for metadata and path information, and how to define a simple root scope for demonstration purposes. In a real application, `MyRootApp` would typically be `aws_cdk.App` or an `aws_cdk.Stack`.
from constructs import Construct, Node
class MyRootApp(Construct):
def __init__(self, scope: Construct, id: str):
super().__init__(scope, id)
class MyComponent(Construct):
def __init__(self, scope: Construct, id: str, value: str):
super().__init__(scope, id)
self.node.add_metadata('custom_value', value)
print(f"Created component: {self.node.path} with value: {value}")
print(f"Node ID: {self.node.id}, Parent ID: {self.node.scope.node.id}")
# To demonstrate, we create a root construct
# In a real CDK application, this would typically be an `App` or `Stack`.
# For pure `constructs` library usage, we can create a base construct as root.
root = MyRootApp(None, "MyApplication") # Root construct has no parent scope
# Instantiate custom components within the root scope
component1 = MyComponent(root, "FirstComponent", "Hello")
component2 = MyComponent(root, "SecondComponent", "World")
# Accessing attributes of a child construct
print(f"\nMetadata for {component1.node.id}: {component1.node.metadata}")
Debug
Known issues
breakingThe `constructs` library underwent a major version jump from 3.x to 10.x, aligning with AWS CDK v2. This introduced significant breaking changes in API surface and overall architecture, making direct migration from 3.x applications to 10.x non-trivial.fixReview the CDK v2 migration guide for a full list of changes. For `constructs` specifically, be aware of changes to base class imports (`from constructs import Construct` instead of `from aws_cdk.core import Construct`).
affects: 3.x to 10.x
gotchaConfusion between `constructs` and `aws-cdk-lib`: `constructs` provides the fundamental programming model and base `Construct` class, while AWS-specific resources (e.g., S3 buckets, EC2 instances) are provided by `aws-cdk-lib`. It's a common mistake to look for AWS resources directly within the `constructs` package.fixAlways import AWS-specific resources from `aws_cdk.aws_*` modules within `aws-cdk-lib` (e.g., `from aws_cdk import aws_s3`). `constructs` is for the core object model and custom construct definitions.
affects: All versions (especially 10.x+)
gotcha`jsii` compatibility issues: `constructs` relies heavily on `jsii` for its multi-language capabilities. Mismatches or issues with the `jsii` runtime (either its version or environment setup) can lead to difficult-to-diagnose runtime errors, especially when mixing `constructs` versions or other `jsii`-based libraries.fixEnsure that the `jsii` version installed is compatible with your `constructs` version (it's specified as a dependency). When encountering obscure errors, try reinstalling `jsii` or ensuring your Python environment is clean and correctly configured.
affects: All versions
Errors
Common errors & fixes
ModuleNotFoundError: No module named 'constructs'
The `constructs` package is not installed in your Python environment or there is a typo in the import statement.
fixInstall the `constructs` library using pip: `pip install constructs`
TypeError: 'str' object is not callable
This common Python error occurs when a variable, often named 'str', shadows a built-in function or when a string variable is mistakenly invoked with parentheses as if it were a function in your `constructs` code.
fixRename any variables named 'str' to avoid conflict with the built-in `str()` function and ensure you are not appending parentheses `()` to string variables or `constructs` properties that are not functions.
AttributeError: module 'constructs' has no attribute 'ISynthesisSession'
This error typically indicates a version mismatch between your `constructs` library and the `aws-cdk-lib` or other CDK-related libraries. The specific interface `ISynthesisSession` might have moved, been renamed, or been removed in a newer or older version of `constructs` that is incompatible with your CDK version.
fixEnsure that your `constructs` and `aws-cdk-lib` (or other CDK libraries) versions are compatible. Often, upgrading both to their latest compatible versions or aligning them as per the AWS CDK documentation resolves this. For Python, this usually means `pip install --upgrade constructs aws-cdk-lib`.
TypeError: Argument of type 'Construct' is not assignable to parameter of type 'Construct'
This error occurs in TypeScript/JavaScript CDK projects (often surfacing as a build error) when multiple, incompatible versions of the `constructs` library are present in your project's dependency tree, leading to different `Construct` types being recognized, which causes type checking to fail.
fixResolve dependency conflicts by ensuring a single, consistent version of the `constructs` library is used across your project and its dependencies. This often involves updating `package.json` to use a specific version for `constructs` and running `npm install` or `yarn install` to refresh dependencies.
Upgrade
Version history
10.8.1latest on PyPI · released Aug 3, 2026
Audit
Dependencies
jsiirequiredRequired for cross-language compatibility and runtime interaction with TypeScript-defined constructs.