Multiple Lambda functions from the sam.yml file possible?

[joelfogue]

I have a situation where I have multiple lambda functions within our API Gateway's API.
I'm new to AWS and learning as much as I can.
I am wondering, how would I change the template yaml (sam.yaml) so that we can deploy to any number of lambda functions and not just one as is the case in this lab.
Would you create multiple index.js file per lambda function?

• so index1.js -> will map to first lambda function
• index2.js -> second lambda function;
• etc....

And how do I update the sam.yaml file to reflect this change?

Here's a snippet code of what I'm trying to accomplish:

Resources:
  HelloWorld:
    Type: AWS::Serverless::Function
    Properties:
      Handler: index.handler
      Runtime: nodejs4.3
      Role:
        Fn::ImportValue:
          !Join ['-', [!Ref 'ProjectId', !Ref 'AWS::Region', 'LambdaTrustRole']]
      Events:
        GetEvent:
          Type: Api
          Properties:
            Path: /
            Method: get
        PostEvent:
          Type: Api
          Properties:
            Path: /
            Method: post

.... and more endpoints here to hit more lambda functions? So do I create multiple index.js to map to each individual lambda function?

[andrewryan1906]

Guys,

I have the same question.

Really trying to learn serverless and questions like these - on best practices - is making it super difficult. Would love some direction here.

[dfloresgonz]

any help

[jairoVera]

As far as I am aware, you can have multiple JS files, each containing a handler to a different Lambda. The files don't have to be in the same directory! You can also define the 2nd Lambda function in the same SAM template yaml file where you defined the 1st Lambda function.

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: Outputs the time

Resources:
  TimeFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: firstsample/firstsample.handler   # firstsample.js file is in firstsample direcotory
      Role: !GetAtt BasicAWSLambdaRole.Arn
      Runtime: nodejs6.10
      CodeUri: ./                          # Look for code in the same directory as the output SAM file
      Events:
        MyTimeApi:
          Type: Api
          Properties:
            Path: /TimeResource
            Method: GET
  
  SecondSampleFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: secondsample.handler                  # didn't have to include secondsample directory
      Role: !GetAtt BasicAWSLambdaRole.Arn
      Runtime: nodejs6.10
      CodeUri: ./secondsample           # code is in the secondsample directory, located in same directory
      Events:
        MyTimeApi:
          Type: Api
          Properties:
            Path: /TextResource
            Method: GET

[red8888]

This is the top google result for "sam template multiple functions". Be nice to have airoVera's solution in the official docs if thats the way we should be doing this.

And how does this work with aws cloudformation package and aws cloudformation deploy ? Do I need to run that for each lambda/CodeUri?

[joeyshub]

@red8888 what I do is having my repo structure as below. I used Jenkins pipeline to do 'npm install' for my lambda functions, FYR.

├── 00_DEVOPS-test1
│   ├── index.js
│   ├── package.json
│   ├── package-lock.json
│   └── README.md
├── 00_DEVOPS-test2
│   ├── index.js
│   ├── package.json
│   ├── package-lock.json
│   └── README.md
├── Jenkinsfile
├── packaged.yaml
├── README.md
└── template.yaml

[hugoprudente]

@red8888, using the @jairoVera approach, as both AWS::Serverless::Function are on the same template only one sam package | aws cloudformation package must be executed, same for the deploy.

Regarding the first code if you have a main.js that check the origin of the request and it can route it Post to index-1.js and the Get to index-2.js using the main.js handler and directing to 2 "subhandlers"

[deleugpn]

@jairoVera do you know if that approach will generate 1 or 2 API Gateways?

[sam-mundle]

It will generate two separate API gateways but the issue is (at least when generating a testing environment locally) if you create separate functions that have separate handler files both of the handler files will be written into the build folder for BOTH Lambda functions. I'm not sure if this would happen when deploying though.

[sertaco]

It seems SAM is intended for one lambda per application. For multi-function applications, there is Nested application method.

[red8888]

SAM does support multiple functions, the right way to do it is with the sam build command which pulls deps for all functions and creates a package that will be deployed as a "serverless application"

Maybe someone from the SAM team can reiterate this?

[estebansolo]

@deleugpn it will generate two API Gateways, but you can add the API Gateway resource and It will create just one

Transform: AWS::Serverless-2016-10-31
Description: Outputs the time

Resources:
  ApiResource:
    Type: AWS::Serverless::Api
    Properties:
      StageName: prod  
  
  TimeFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: firstsample/firstsample.handler   # firstsample.js file is in firstsample direcotory
      Role: !GetAtt BasicAWSLambdaRole.Arn
      Runtime: nodejs6.10
      CodeUri: ./                          # Look for code in the same directory as the output SAM file
      Events:
        MyTimeApi:
          Type: Api
          Properties:
            Path: /TimeResource
            Method: GET
            RestApiId: !Ref ApiResource
  
  SecondSampleFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: secondsample.handler                  # didn't have to include secondsample directory
      Role: !GetAtt BasicAWSLambdaRole.Arn
      Runtime: nodejs6.10
      CodeUri: ./secondsample           # code is in the secondsample directory, located in same directory
      Events:
        MyTimeApi:
          Type: Api
          Properties:
            Path: /TextResource
            Method: GET
            RestApiId: !Ref ApiResource```

[MatteoGioioso]

And how about shared libraries and code?

[estebansolo]

You can use Layers

[debendraoli]

@jairoVera is life saver, I was banging on this problem for a week.

I have 13 serverless functions having go1.x and python run times and dependent to each others, previously I was managing the code bases and aws services manually, it was so pain, accidentally I discovered sam and I introduced one template file for all the functions but build sam was unable to find the code bases.

I specified CodeUri where my codes points.

Now I can easily debug locally, build and deploy in one click. :-)

[javiortizmol]

@jairoVera is life saver, I was banging on this problem for a week.

I have 13 serverless functions having go1.x and python run times and dependent to each others, previously I was managing the code bases and aws services manually, it was so pain, accidentally I discovered sam and I introduced one template file for all the functions but build sam was unable to find the code bases. Now I can easily debug locally, build and deploy in one click. :-)

So works or no? "but build sam was unable to find the code bases. Now I can easily debug locally, build and deploy in one click"