Lambda Runner - VSCode Extension

This VSCode extension provides a simple way to invoke AWS Lambda functions defined in both template.yaml (SAM) and serverless.yml (Serverless Framework) files directly from the editor. The extension adds CodeLens options to invoke local Lambda functions with pre-configured test files, environment variables, and runtime parameters.

Features

Automatic Function Detection:
- The extension detects AWS Lambda functions defined in either template.yaml or serverless.yml.
- For each detected function, a CodeLens ("Run This Function") is displayed above the function definition.
Dynamic Test File Selection:
- The extension looks for test files (JSON format) in a test-data folder in the root of the workspace.
- Users are prompted to select a test file to simulate an event for the Lambda function.
Environment Selection:
- Users can choose between different environments (e.g., Preprod or Prod).
Region Input:
- The extension prompts users to input the AWS region where the function will be invoked. Default region is set to ap-south-1.
Environment Variables Management:
- The extension looks for env.json and envProd.json files in the workspace for configuring environment-specific variables during invocation.
SAM and Serverless Framework Support:
- Supports both the AWS SAM CLI (sam local invoke) and the Serverless Framework (serverless invoke local) for local function invocations.
Command Execution in Terminal:
- All commands are executed in a new VSCode terminal, allowing users to see the output of the Lambda function execution in real-time.

How It Works

Detecting Functions:
- The extension uses regular expressions to detect functions in template.yaml and serverless.yml.
  - For SAM (template.yaml) files:
    - Functions are identified by the Type: AWS::Serverless::Function and their associated handler.
    - Regex: (\w+):\s*Type:\s*AWS::Serverless::Function\s*Properties:\s*Handler:\s*([^\s]+)
      - This captures two groups:
        
        The function name (first capture group: (\w+)).
        
        The handler (second capture group: ([^\s]+)).
    - Example Function Definition:
```
MyFunction:
  Type: AWS::Serverless::Function
  Properties:
    Handler: index.handler
    ...
```
  - For Serverless (serverless.yml) files:
    - Functions are identified by the functions key and the corresponding handler.
    - Regex: (\w+):\s*handler:\s*([^\s]+)
      - This captures two groups:
        
        The function name (first capture group: (\w+)).
        
        The handler (second capture group: ([^\s]+)).
    - Example Function Definition:
```
functions:
  myFunction:
    handler: index.handler
    ...
```
- For each detected function, the extension checks if the handler is defined. If the handler is valid, a CodeLens with the option to "Run This Function" is displayed above the function definition.
CodeLens Options:
- After detecting a function, the extension adds a CodeLens above the function, showing:
  - "Run This Function" if the function has a valid handler.
  - "Handler Not Defined" if the handler is missing or undefined.
Running Functions:
- When you click the CodeLens to run a function:
  1. Test File Selection: You are prompted to select a test file from the test-data folder (only .json files are displayed).
  2. Environment Selection: You are prompted to choose the environment (Preprod or Prod).
  3. Region Input: You are asked to enter the AWS region (default is ap-south-1).
  4. Environment Variables: Depending on the selected environment, the extension looks for env.json or envProd.json files in the workspace.
  5. Command Execution: The selected SAM/Serverless function is executed with the selected test file, environment, and region via the terminal.

Assumptions

Test Files:
- The extension assumes that all test files are in JSON format and are located in the test-data folder at the root of the workspace.
- If the folder does not exist, the extension will create it automatically and ask you to add test files.
Environment Variables Files:
- The extension expects env.json for Preprod and envProd.json for Prod, located at the root of the workspace. If these files do not exist, it will fall back to env.json.

When Do Options Appear?

Run This Function (CodeLens):
- This option appears above any function definition in template.yaml or serverless.yml.
- The option only appears if the function has a valid handler defined.
Test File Selection:
- This option appears once you initiate the function invocation. It will list all .json test files from the test-data folder for you to choose from.
Environment Selection:
- After selecting a test file, you will be prompted to choose the environment (Preprod or Prod).
Region Input:
- After selecting the environment, you will be prompted to enter the AWS region for the Lambda function execution.

Prerequisites

AWS SAM CLI if you are using SAM templates (template.yaml).
Serverless Framework CLI if you are using Serverless Framework (serverless.yml).
A test-data folder with test event JSON files.
Optional: env.json and envProd.json for environment-specific variables.

Installation

Clone or download the extension.
Open the folder in VSCode.
Run the extension in a development environment using F5 in VSCode.

Usage

Open a workspace that includes a template.yaml or serverless.yml file.
Add a test-data folder at the root of the workspace and add JSON files representing the test events.
Open any template.yaml or serverless.yml file.
A CodeLens will appear above the Lambda function declarations with the option to "Run This Function".
Click the CodeLens to initiate the function invocation process.

Contributing

Feel free to submit issues and pull requests for new features or bug fixes.

lambda-run

rishabhDMonkey2412