在nodejs中，我可以有每个子文件夹都托管一个AWS Lambda函数的子文件夹吗？

Question

I am trying to implement a serverless application on AWS. I wish to know a good way to organize my codes. Let's say, I want to have multiple lambda functions to be organized under a git repo, each lambda function and it's associated codes are in its own sub-folder.

This is what I have tried, separate sub-folders for each lambda function:

(venv367) dummy@dummy-VirtualBox:~/workspace/serverless-apps/DEVOPS-dailybackup-ebs$ ls -l
total 28
-rw-rw-r-- 1 dummy dummy 4061 Jan 13 19:23 index.js
drwxrwxr-x 3 dummy dummy 4096 Jan 13 19:23 node_modules
-rw-rw-r-- 1 dummy dummy  352 Jan 13 19:23 package.json
-rw-rw-r-- 1 dummy dummy  392 Jan 13 19:23 package-lock.json
-rw-rw-r-- 1 dummy dummy 1220 Jan 14 00:10 README.md

(venv367) dummy@dummy-VirtualBox:~/workspace/serverless-apps/DEVOPS-dailybackup-s3$ ls -l
total 28
-rw-rw-r-- 1 dummy dummy 4061 Jan 13 19:23 index.js
drwxrwxr-x 3 dummy dummy 4096 Jan 13 19:23 node_modules
-rw-rw-r-- 1 dummy dummy  352 Jan 13 19:23 package.json
-rw-rw-r-- 1 dummy dummy  392 Jan 13 19:23 package-lock.json
-rw-rw-r-- 1 dummy dummy 1220 Jan 14 00:10 README.md

In the top level project, I have SAM template.yaml as below

(venv367) dummy@dummy-VirtualBox:~/workspace/serverless-apps$ ls -l
total 16
drwxrwxr-x 3 dummy dummy 4096 Jan 14 05:14 00_DEVOPS-dailybackup-ebs
drwxrwxr-x 3 dummy dummy 4096 Jan 14 05:14 00_DEVOPS-dailybackup-s3
-rw-rw-r-- 1 dummy dummy  702 Jan 14 05:15 packaged.yaml
-rw-rw-r-- 1 dummy dummy 1402 Jan 13 23:45 README.md
-rw-rw-r-- 1 dummy dummy  939 Jan 14 05:15 template.yaml

In the template.yaml, I deploy Lambda functions by specifying Handler with its parent directory

Resources:
    EbsBackupFunction:
        Type: AWS::Serverless::Function 
        Properties:
            Handler: DEVOPS-dailybackup-ebs/index.handler
            Runtime: nodejs8.10
            FunctionName: DEVOPS-dailybackup-ebs

    S3BackupFunction:
        Type: AWS::Serverless::Function 
        Properties:
            Handler: DEVOPS-dailybackup-s3/index.handler
            Runtime: nodejs8.10
            FunctionName: DEVOPS-dailybackup-s3

(1) I haven't look at serverless framework in detail though. Any better approach for managing serverless applications using AWS SAM?

(2) Is there a way to do npm install for nodejs code under each sub-folder other than write a script to do 'cd ${dir} && npm install'

(3) If above is a nasty idea, can you tell me what would you do?

Tks in advance for any helps given.

Answer 1

1. Your method for handling multiple functions is the currently suggested method.

2. Different approaches can be taken based on your CI/CD tool. This is my current buildspec.yml for use with AWS CodeBuild:

version: 0.2
phases:
  pre_build:
    commands:
      - for d in lambdas/*/; do npm --prefix $d install $d; done
  build:
    commands:
      - |
        aws cloudformation package \
          --template-file template.yml \
          --s3-bucket "<bucket name>" \
          --s3-prefix sam \
          --output-template-file packaged.yml
  post_build:
    commands:
      - |
        aws cloudformation deploy \
          --template-file packaged.yml \
          --stack-name "<stack name>" \
          --capabilities CAPABILITY_NAMED_IAM

This allows me to keep my local directory/code repository clean (no node_modules folder) via .gitignore , but dependencies are installed before deploying. Note that including your package-lock.json file is necessary to avoid errors with different package versions.

3. As stated above, this is the same setup that I'm currently using. So far, the only drawbacks I've seen are not being able to update a single function without updating all of them, but because of the way my environment is set up (all functions share the same version number), a change to one function requires changes to the others anyway.

Answer 2

Understand you are using SAM but if you are open to consider serverless framework then that's how you can manage it in your CI/CD pipeline with just one command. All Lambdas will be deployed individually and each function will have dependencies in node_modules that are required by the function

You will need to add following to in your package.json devDependencies.

"devDependencies": {
    "serverless-plugin-optimize": "^4.0.2-rc.1"
 }

serverless-plugin-optimize is used for optimising Lambda code and its dependencies.

Note: When using serverless-plugin-optimize you must ensure that all require(..) are placed above module.exports in your handler.

You will also need serverless framework , you can install it globally.

npm install -g serverless

Repository structure:

devops-backup/
 - node_modules/
 - package.json
 - serverless.yml
 - handlers/
   - s3.js
   - ebs.js

serverless.yml configuration:

service: DevOpsBackup
frameworkVersion: '>=1.2.1 <2.0.0'
provider:
  name: aws
  runtime: nodejs8.10
  region: eu-west-1
  stage: ${opt:stage} # Stage that you define when deploy using `serverless deploy --stage`
  deploymentBucket: ${env:SLS_BUCKET} # Your deployment bucket name. CI must have access to this bucket.

iamRoleStatements:
  - Effect: Allow
    Action:
      - s3:"*"
    Resource: arn:aws:s3:::<bucket_name>
  # Add more permissions as required by the functions

plugins:
  - serverless-plugin-optimize

package:
  individually: true

functions:
  backupEbs:
    handler: handlers/s3.handler
    description: Create user
  backupS3:
    handler: handlers/ebs.handler
    description: Update user

Example s3.js

module.exports.handler = async (event) => {
 // ... your code
}

Deployment

You can deploy all Lambdas using one command, run it from the repository root.

serverless deploy --stage prod -v # prod is the name of stage/env

If your build is successful, you will be able to find you functions in Lambda console.

• DevOpsBackup-prod-backupS3
• DevOpsBackup-prod-backupEbs