CDK Examples

Contains sample CDK apps that use Rust Lambda Functions.

Deploy

First, ensure that your AWS profile - which points to the AWS account you want to deploy the CDK app to - is properly set up:

export AWS_PROFILE='my-profile'

After that, cd into one of the sample CDK directories, and install all node dependencies:

cd my-app
npm i

Next, ensure that you have cargo-lambda installed. You will need this to cross-compile Rust code for deployment via cdk. If you don't have cargo-lambda installed, refer to the Getting Started section in docs for more info on getting set up.

Now you can deploy the app with cdk:

Note: on an initial run, it may take a really long time on the compilation step with cargo-lambda. In my case, it sometimes took up to 12 minutes! But don't worry, any subsequent deployments should be overall faster.

npx cdk deploy

Creating a New App

Create a new folder:

mkdir my-app
cd my-app

Run cdk init:

cdk init sample-app --language=typescript

Run cargo init:

cargo init --vcs git && rm -rf .git

Add following lines to the generated .gitignore:

# Rust lambda build directory
.build

For example, using:

echo '\n# Rust lambda build directory\n.build' >> .gitignore

Local Development and Testing

Note: See the New Approach below which obviates the need to update the import statements.

In case it's desirable to uncomment the following import in the lib/ folder of a sample CDK app, for local testing purposes:

import { RustFunction, Settings } from '../../../lib';

You may then potentially run into some import errors when deploying the stack via cdk.

To fix that, run this command from both the project root folder $root, and compare the output when running it from within $root/cdk-examples/my-app:

npm list

To resolve the import issues, you'll need to ensure that certain package versions are the same between the two directories.

For example, here are the important ones you'd need to verify:

├── aws-cdk-lib@2.12.0
├── aws-cdk@2.12.0
├── constructs@10.0.65

New Approach

As per this article I found that explains how a local module can be installed with npm link, this is a slightly different approach to commenting out and then un-commenting an import statement as mentioned above.

This does also have a few unavoidable side-effects, but hopefully such a method should yield an overall better (developer) experience.

Here then, is the updated approach which leverages npm link under the hood to locally install an NPM module.

First, cd into the local directory of a sample CDK app.

Within this folder, run the npm script link (alias: l) to automatically link to the local rust.aws-cdk-lambda module -- i.e. the project folder two levels up:

npm run l

If all is well, you should see that the linking is successful.

To confirm:

npm list

The result should be something like:

...
├── rust.aws-cdk-lambda@1.2.0 -> ./../..
...

That means everything is set up correctly! CDK code should reference the definitions under ../../dist/, i.e. under the root folder.

Next -- open a new terminal window, and from the project root folder $root, run the following command:

npm run watch

This will listen for any changes to the project TypeScript code, and automatically run tsc to down-compile it to JS code, which it places in the dist/ folder.

These changes will also be reflected in the sample CDK project, thanks to npm link which was run earlier.

To unlink the local module and use the remote one installed as a dependency listed in the package.json, simply run the following from the root of a sample CDK app:

npm run ul