To reduce file size when deploying to AWS Lambda with Serverless Framework, we recommend npm install serverless —global.

[Prerequisites] Don't include serverless in node_modules

Why was I adding it to package.json?

Just to include it in package.json and manage it under git, I was installing serverless with:

npm install serverless --save

Since official documentation and many technical blogs recommend npm install serverless —global, I think including it in package.json is the minority approach.

Why do I want to reduce file size?

For two reasons: “speeding up” serverless deploy and “saving network traffic”.

While this wasn’t noticeable with good network environments, both points became concerning when developing in tethering environments, so I decided to improve it.

uninstall serverless & global install

Remove it from package.json with npm uninstall —save, then globally install with npm install —global.

npm uninstall serverless --save

npm install serverless --global
# npm install [email protected] --global

[Before] serverless local install

When serverless was locally installed, the .zip file was 66.57 MB including other node modules.

$ $(npm bin)/serverless deploy --verbose

Serverless: Packaging service...
Serverless: Excluding development dependencies...
Serverless: Creating Stack...
Serverless: Checking Stack create progress...
CloudFormation - CREATE_IN_PROGRESS - AWS::CloudFormation::Stack - aws-nodejs-dev
CloudFormation - CREATE_IN_PROGRESS - AWS::S3::Bucket - ServerlessDeploymentBucket
CloudFormation - CREATE_IN_PROGRESS - AWS::S3::Bucket - ServerlessDeploymentBucket
CloudFormation - CREATE_COMPLETE - AWS::S3::Bucket - ServerlessDeploymentBucket
CloudFormation - CREATE_COMPLETE - AWS::CloudFormation::Stack - aws-nodejs-dev
Serverless: Stack create finished...
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading artifacts...
Serverless: Uploading service .zip file to S3 (66.57 MB)...

# Takes time with poor internet connection… ⏳

[After] serverless global install

When changing serverless to global install, the .zip file was 56.59 MB including other node modules. I was able to reduce file size by about 10 MB.

$ serverless deploy --verbose

Serverless: Packaging service...
Serverless: Excluding development dependencies...
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading artifacts...
Serverless: Uploading service .zip file to S3 (56.59 MB)...

# 66.57 - 56.59 = 9.98 MB file size reduction

That’s all from the Gemba where we want to reduce node_modules file size and speed up serverless deploy.