SAM Template Generator

Generates a SAM Template for API Gateway and lambdas written in go. Generates test and build script for each function.

Expects folder structure to match the desired API Gateway structure.

For example to create an API Gateway with a GET resource at path /biscuits, add the handler to the function at biscuits/get. A PUT would then go at biscuits/put.

Example folder structure and API Gateway result:

Outputs

govet_gotest.sh Script to test all functions

gobuild.sh Script to build all functions, outputs a mirrored directory structure with built binaries

template.yml SAM template to create API Gateway and Lambda functions

Usage

Install the npm package npm install samtemplategenerator --save

const generate = require('samtemplategenerator');
generate(templatePath, pathToFunctions, outputDirectory);

Input parameters

Template Path

Path to templates

SamTemplateGenerator expects 2 templates in the directory base.yml and function.yml

Templates

• base.yml will appear once at the top of the file
• For each function, function.yml will be parsed and the tokens replaced for that function

Tokens

For a function at /biscuits/get

Token name	Description	Example
Name	The name of the resource in the SAM template	biscuitsget
CodeUri	Location of code binary after build	bin/biscuits/
Handler	Which binary to use in folder	/get
Path	Location of resource	/biscuits
Method	Http Method	get

Examples

base.yml

AWSTemplateFormatVersion: 2010-09-09
Transform: AWS::Serverless-2016-10-31
Parameters:
  SecurityGroupIds: 
    Type: List<AWS::EC2::SecurityGroup::Id>
    Description: Security Group IDs that Lambda will use
  VpcSubnetIds: 
    Type: List<AWS::EC2::Subnet::Id>
    Description: VPC Subnet IDs that Lambda will use (min 2 for HA)

Resources:
  DfdApi:
    Type: AWS::Serverless::Api
    Properties:
      StageName: Prod
      Cors:
        AllowHeaders: "'Content-Type,Authorization'"
        AllowMethods: "'OPTIONS,POST,GET,PUT,DELETE'"
        AllowOrigin: "'*'"
      Auth:
        Authorizers:
          CognitoAuthorizer:
            UserPoolArn: arn:aws:cognito-idp:eu-west-2:<account-id>:userpool/eu-west-2_1234abcd

function.yml

  {{Name}}:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: bin{{CodeUri}}/
      Handler: {{Handler}}
      Runtime: go1.x
      Tracing: Active
      Role: arn:aws:iam::<account-id>:role/api-lambda-role
      Events:
        GetEvent:
          Type: Api
          Properties:
            RestApiId: !Ref DfdApi
            Path: {{Path}}
            Method: {{Method}}
            Auth:
              Authorizer: CognitoAuthorizer
      Policies:
        - VPCAccessPolicy: {}
        # This policy gives permission for Lambdas to create/manage ENIs
        # SAM Policy templates you can use: https://github.com/awslabs/serverless-application-model/blob/develop/examples/2016-10-31/policy_templates/all_policy_templates.yaml
      VpcConfig:
        SecurityGroupIds: !Ref SecurityGroupIds
        SubnetIds: !Ref VpcSubnetIds