Lambda Insights layer not added for single function deployments

[dennisholmer]

Description

The Lambda Insights plugin only runs during full stack deployments (sls deploy) but not during single function deployments (sls deploy function -f functionName). This means functions deployed individually don't get the Lambda Insights layer attached, even when defaultLambdaInsights: true is configured globally.

Configuration

custom:
  lambdaInsights:
    defaultLambdaInsights: true

Expected Behavior

When running sls deploy function -f myFunction, the Lambda Insights layer should be added to the function, just like it would during a full sls deploy.

Actual Behavior

• sls deploy: ✅ Lambda Insights layer is added correctly
• sls deploy function -f myFunction: ❌ Lambda Insights layer is NOT added

Root Cause

The plugin only hooks into before:package:setupProviderConfiguration, which is part of the full deployment lifecycle. Single function deployments use a different lifecycle (deploy:function:* hooks) that doesn't include this hook.

Reproduction Steps

1. Configure defaultLambdaInsights: true in serverless.yml
2. Run sls deploy - verify function has Lambda Insights layer in AWS Console
3. Make a code change to a single function
4. Run sls deploy function -f myFunction
5. Check AWS Console - Lambda Insights layer is missing

Suggested Fix

Add the before:deploy:function:packageFunction hook to handle single function deployments:

this.hooks = {
  'before:package:setupProviderConfiguration': this.addLambdaInsights.bind(this),
  'before:deploy:function:packageFunction': this.addLambdaInsights.bind(this), // Add this
};

Environment

• Serverless Framework: 3.x
• Plugin version: 1.6.0
• Node.js version: 20.x

Workaround

Currently, users must run a full sls deploy instead of sls deploy function to ensure Lambda Insights layer is present.