feat: Passing resources between stacks (#210)

* resource passing
* fix comment
* Update setup.py

Co-authored-by: Noah Litov <[email protected]>

python/cross-stack-resources/REAMDE.md

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+
+# Passing References Between Stacks!
+
+These two folders contain examples of how to pass resources between stacks.
+
+In each folder, you can run the following commands to synthesize the CDK 
+Applications.
+
+To manually create a virtualenv on MacOS and Linux:
+
+```
+$ python3 -m venv .env
+```
+
+After the init process completes and the virtualenv is created, you can use the following
+step to activate your virtualenv.
+
+```
+$ source .env/bin/activate
+```
+
+If you are a Windows platform, you would activate the virtualenv like this:
+
+```
+% .env\Scripts\activate.bat
+```
+
+Once the virtualenv is activated, you can install the required dependencies.
+
+```
+$ pip install -r requirements.txt
+```
+
+At this point you can now synthesize the CloudFormation template for this code.
+
+```
+$ cdk synth
+```
+
+You can now begin exploring the source code, contained in the hello directory.
+There is also a very trivial test included that can be run like this:
+
+```
+$ pytest
+```
+
+To add additional dependencies, for example other CDK libraries, just add to
+your requirements.txt file and rerun the `pip install -r requirements.txt`
+command.
+
+## Useful commands
+
+ * `cdk ls`          list all stacks in the app
+ * `cdk synth`       emits the synthesized CloudFormation template
+ * `cdk deploy`      deploy this stack to your default AWS account/region
+ * `cdk diff`        compare deployed stack with current state
+ * `cdk docs`        open CDK documentation
+
+Enjoy!

python/cross-stack-resources/native-objects/README.md

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+
+# Native Objects Example For Passing Resources Between Stacks!
+
+One of my favorite parts about CDK is that I don't have to be concerned with how
+the underlying cloudformation expects resources. Ideally the level of
+abstraction that I want to deal with is that I have a Lambda Function in one
+stack and I want to just hand the whole function to other stacks that need it.
+I do not have to worry about whether API Gateway expects a Function Name or a
+Function ARN or some other identifier for a Function, I can simply pass the
+Function Object to the stacks that need it and let CDK handle the details.
+
+In this example we create an AWS Lambda Function in one stack and then make it
+available as a property of that stack for other stacks to consume.
+
+in infrastructure_stack.py:
+```python
+@property
+def main_function(self) -> lambda_.IFunction:
+    return self._function
+```
+
+We later refrence this property in app.py as follows:
+```python
+infra.main_function
+```
+where `infra` is the variable we use to identify our InfrastructureStack.

python/cross-stack-resources/native-objects/app.py

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+#!/usr/bin/env python3
+
+from aws_cdk import core
+
+from native_objects.application_stack import ApplicationStack
+from native_objects.infrastructure_stack import InfrastructureStack
+
+
+app = core.App()
+
+env={'region': 'us-west-2'}
+# Base infrastructure stack, Lambda Functions, DynamoDB Tables, etc....
+infra = InfrastructureStack(app, "infrastructure", env=env)
+
+# Application stack that generally changes independently of the underlying infrastructure stack
+application = ApplicationStack(app, "application", referenced_function=infra.main_function, env=env)
+
+app.synth()

python/cross-stack-resources/native-objects/cdk.json

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+{
+  "app": "python3 app.py"
+}

python/cross-stack-resources/native-objects/native_objects/application_stack.py

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+from aws_cdk import (
+    aws_lambda as lambda_,
+    aws_apigateway as apigw,
+    core
+)
+
+class ApplicationStack(core.Stack):
+
+    def __init__(self, scope: core.Construct, id: str, referenced_function: lambda_.IFunction, **kwargs) -> None:
+        super().__init__(scope, id, **kwargs)
+
+        my_api = apigw.LambdaRestApi(self, "myRestAPI", handler=referenced_function)
+

python/cross-stack-resources/native-objects/native_objects/infrastructure_stack.py

@@ -0,0 +1,25 @@
+from aws_cdk import (
+    aws_lambda as lambda_,
+    core
+)
+
+class InfrastructureStack(core.Stack):
+
+    def __init__(self, scope: core.Construct, id: str, **kwargs) -> None:
+        super().__init__(scope, id, **kwargs)
+
+        my_main_func = lambda_.Function(
+            self,
+            "myMainFunction",
+            code=lambda_.InlineCode("def main(event, context)\n  print('hello, world')"),
+            handler='index.main',
+            runtime=lambda_.Runtime.PYTHON_3_7
+        )
+
+        # We assign the function to a local variable for the Object.
+        self._function = my_main_func
+
+    # Using the property decorator 
+    @property
+    def main_function(self) -> lambda_.IFunction:
+        return self._function

python/cross-stack-resources/native-objects/requirements.txt

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+-e .
+pytest

python/cross-stack-resources/native-objects/setup.py

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+import setuptools
+
+
+with open("README.md") as fp:
+    long_description = fp.read()
+
+
+setuptools.setup(
+    name="native-objects",
+    version="1.0.0",
+
+    description="A python CDK example for passing resources between stacks",
+    long_description=long_description,
+    long_description_content_type="text/markdown",
+
+    author="Richard Boyd",
+
+    package_dir={"": "native_objects"},
+    packages=setuptools.find_packages(where="native_objects"),
+
+    install_requires=[
+        "aws-cdk.core",
+        "aws-cdk.aws_apigateway",
+        "aws-cdk.aws_lambda"
+    ],
+
+    python_requires=">=3.6",
+
+    classifiers=[
+        "Development Status :: 4 - Beta",
+
+        "Intended Audience :: Developers",
+
+        "License :: OSI Approved :: Apache Software License",
+
+        "Programming Language :: JavaScript",
+        "Programming Language :: Python :: 3 :: Only",
+        "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: 3.8",
+
+        "Topic :: Software Development :: Code Generators",
+        "Topic :: Utilities",
+
+        "Typing :: Typed",
+    ],
+)

python/cross-stack-resources/native-objects/source.bat

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+@echo off
+
+rem The sole purpose of this script is to make the command
+rem
+rem     source .env/bin/activate
+rem
+rem (which activates a Python virtualenv on Linux or Mac OS X) work on Windows.
+rem On Windows, this command just runs this batch file (the argument is ignored).
+rem
+rem Now we don't need to document a Windows command for activating a virtualenv.
+
+echo Executing .env\Scripts\activate.bat for you
+.env\Scripts\activate.bat

python/cross-stack-resources/raw-strings/README.md

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+
+# Raw String Example For Passing Resources Between Stacks!
+
+If you're coming from a strong background in cloudformation, you may either
+have a preference for passing resources as strings (the way AWS Cloudformation
+does natively) or your existing infrastructure may already extensively leverage
+imports/exports and you'd like to maintain a consistent paradigm across your
+applications.
+
+In this example we create an AWS Lambda Function in one stack and then make its
+ARN available as a property of that stack for other stacks to consume.
+
+in infrastructure_stack.py:
+```python
+@property
+def main_function_arn(self):
+    return self._function_arn
+```
+
+We later refrence this property in app.py as follows:
+```python
+infra.main_function_arn
+```
+where `infra` is the variable we use to identify our InfrastructureStack.

python/cross-stack-resources/raw-strings/app.py

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+#!/usr/bin/env python3
+
+from aws_cdk import core
+
+from raw_strings.application_stack import ApplicationStack
+from raw_strings.infrastructure_stack import InfrastructureStack
+
+
+app = core.App()
+
+env={'region': 'us-west-2'}
+# Base infrastructure stack, Lambda Functions, DynamoDB Tables, etc....
+infra = InfrastructureStack(app, "infrastructure", env=env)
+
+# Application stack that generally changes independently of the underlying infrastructure stack
+application = ApplicationStack(app, "application", lambda_arn=infra.main_function_arn, env=env)
+
+app.synth()

python/cross-stack-resources/raw-strings/cdk.json

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+{
+  "app": "python3 app.py"
+}

python/cross-stack-resources/raw-strings/raw_strings/application_stack.py

@@ -0,0 +1,14 @@
+from aws_cdk import (
+    aws_lambda as lambda_,
+    aws_apigateway as apigw,
+    core
+)
+
+class ApplicationStack(core.Stack):
+
+    def __init__(self, scope: core.Construct, id: str, lambda_arn: str, **kwargs) -> None:
+        super().__init__(scope, id, **kwargs)
+
+        referenced_function = lambda_.Function.from_function_arn(self, id="LocalNameForFunction", function_arn=lambda_arn)
+        my_api = apigw.LambdaRestApi(self, "myRestAPI", handler=referenced_function)
+

python/cross-stack-resources/raw-strings/raw_strings/infrastructure_stack.py

@@ -0,0 +1,26 @@
+from aws_cdk import (
+    aws_lambda as lambda_,
+    aws_dynamodb as ddb,
+    core
+)
+
+class InfrastructureStack(core.Stack):
+
+    def __init__(self, scope: core.Construct, id: str, **kwargs) -> None:
+        super().__init__(scope, id, **kwargs)
+
+        my_main_func = lambda_.Function(
+            self,
+            "myMainFunction",
+            code=lambda_.InlineCode("def main(event, context)\n  print('hello, world')"),
+            handler='index.main',
+            runtime=lambda_.Runtime.PYTHON_3_7
+        )
+
+        # We assign the function's arn to a local variable for the Object.
+        self._function_arn = my_main_func.function_arn
+
+    # Using the property decorator 
+    @property
+    def main_function_arn(self):
+        return self._function_arn

python/cross-stack-resources/raw-strings/requirements.txt

@@ -0,0 +1,2 @@
+-e .
+pytest

python/cross-stack-resources/raw-strings/setup.py

@@ -0,0 +1,48 @@
+import setuptools
+
+
+with open("README.md") as fp:
+    long_description = fp.read()
+
+
+setuptools.setup(
+    name="raw_strings",
+    version="0.0.1",
+
+    description="A sample CDK Python app",
+    long_description=long_description,
+    long_description_content_type="text/markdown",
+
+    author="author",
+
+    package_dir={"": "raw_strings"},
+    packages=setuptools.find_packages(where="raw_strings"),
+
+    install_requires=[
+        "aws-cdk.core",
+        "aws-cdk.aws_apigateway",
+        "aws-cdk.aws_lambda",
+        "aws-cdk.aws_dynamodb"
+    ],
+
+    python_requires=">=3.6",
+
+    classifiers=[
+        "Development Status :: 4 - Beta",
+
+        "Intended Audience :: Developers",
+
+        "License :: OSI Approved :: Apache Software License",
+
+        "Programming Language :: JavaScript",
+        "Programming Language :: Python :: 3 :: Only",
+        "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: 3.8",
+
+        "Topic :: Software Development :: Code Generators",
+        "Topic :: Utilities",
+
+        "Typing :: Typed",
+    ],
+)

python/cross-stack-resources/raw-strings/source.bat

@@ -0,0 +1,13 @@
+@echo off
+
+rem The sole purpose of this script is to make the command
+rem
+rem     source .env/bin/activate
+rem
+rem (which activates a Python virtualenv on Linux or Mac OS X) work on Windows.
+rem On Windows, this command just runs this batch file (the argument is ignored).
+rem
+rem Now we don't need to document a Windows command for activating a virtualenv.
+
+echo Executing .env\Scripts\activate.bat for you
+.env\Scripts\activate.bat