https://github.com/oieduardorabelo/aws-sam-nested-applications-single-package-json

AWS SAM Nested Applications with single package.json to all lambda handlers
https://github.com/oieduardorabelo/aws-sam-nested-applications-single-package-json

amazon-api-gateway aws aws-lambda aws-sam aws-sam-cli aws-sam-example aws-sam-nested-applications serverless typescript

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AWS SAM Nested Applications with single package.json to all lambda handlers

• Host: GitHub
• URL: https://github.com/oieduardorabelo/aws-sam-nested-applications-single-package-json
• Owner: oieduardorabelo
• Created: 2023-03-08T05:47:52.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2023-03-08T08:27:37.000Z (over 1 year ago)
• Last Synced: 2024-04-14T19:10:11.169Z (7 months ago)
• Topics: amazon-api-gateway, aws, aws-lambda, aws-sam, aws-sam-cli, aws-sam-example, aws-sam-nested-applications, serverless, typescript
• Language: TypeScript
• Homepage:
• Size: 195 KB
• Stars: 7
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# AWS SAM Nested Applications with single package.json

This is an example of using AWS SAM with nested applications sharing a single `package.json`.

We have a Rest API TypeScript application (`apps/rest-api/handlers`) that uses `dependencies` from the root `package.json`.

We have a DynamoDB Stream with a TypeScript lambda consumer (`apps/dynamodb/handlers`) that uses `dependencies` from the root `package.json`.

Any application can define its own TypeScript Lambda and use the root `package.json`.

The parent AWS SAM application is defined in `./template.yaml` and child applications are defined in `./apps/*/template.yaml`.

## Benefits

This enables the developer to use a single `package.json` and share it across the entire application. `esbuild` will be packing each lambda handler bundling the correct dependencies imported by each handler.

## Drawback

You need to define `--base-dir` for every AWS SAM CLI command that have it as an option.

When using `sam sync` chaging the source code of one lambda with sync all lambdas of that stack. For example, `apps/rest-api` is a stack with 2 lambdas. If you change the source code of one lambda, all 2 lambdas will be synced.

## Conventions on how to use

We have a few conventions:

1. The `package.json` is located in the root of the project

2. The `CodeUri` of any lambda is always `./`

3. Definitions for lambda handlers entry points are defined using the full relative path of the project root

4. When running `sam build` from the root of the project, we need to define `--base-dir .` to make sure that `esbuild` will be able to find the `package.json` in the root of the project and resolve all relative paths correctly

For example:

```yaml

Resources:

    GetBooksFunction:

        Type: AWS::Serverless::Function

        Properties:

            CodeUri: ./

            Handler: get-books.handler

            # ...

        Metadata:

            # ...

            BuildProperties:

                # ...

                EntryPoints:

                    - apps/rest-api/handlers/get-books.ts

```

**Important:** The `--base-dir` must be defined for every AWS SAM CLI command that have it as an option.

## Deploying to AWS

You can use any AWS SAM CLI command, make sure you include `--base-dir .` when running from the root of the project.

With `sync`:

```bash

sam sync --base-dir .

```

With `deploy`:

```

sam build --base-dir .

sam deploy

```

## Running locally

You can run it locally as you would normally do with AWS SAM CLI.

With `local start-api`:

```bash

sam build --base-dir .

sam local start-api

```

With `local invoke`:

```bash

sam build --base-dir .

sam local invoke StackRestApi/GetCategoriesFunction

```