Proof of Concept for Golang and AWS Lambda Service

Prerequisites

1. Install Golang
2. Instal AWS CLI
3. AWS Go SDK - go get github.com/aws/aws-sdk-go
4. AWS Lambda SDK - go get github.com/aws/aws-lambda-go/lambda
5. Excel SDK - go get github.com/360EntSecGroup-Skylar/excelize

Setup IAM role for lambda function

{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": { "Service": "lambda.amazonaws.com" }, "Action": "sts:AssumeRole" } ] }

aws iam create-role --role-name lambda-testx-executor \ --assume-role-policy-document file:///tmp/trust-policy.json

Output as follows { "Role": { "RoleName": "lambda-testx-executor", "AssumeRolePolicyDocument": { "Version": "2012-10-17", "Statement": [ { "Principal": { "Service": "lambda.amazonaws.com" }, "Effect": "Allow", "Action": "sts:AssumeRole" } ] }, "RoleId": "SOME-ID", "Path": "/", "Arn": "arn:aws:iam::SOME-ID:role/lambda-testx-executor", "CreateDate": "2019-09-27T08:14:03Z" } }

Copy ARN (Amazon Resource Name) from results - for create-function listed below

Specify role permissions

aws iam attach-role-policy --role-name lambda-testx-executor \ --policy-arn arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole

Add S3 role policy

aws iam put-role-policy --role-name lambda-testx-executor \ --policy-name s3-item-crud-role \ --policy-document file:///tmp/privilege-policy.json

{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Action": [ "s3:ListAllMyBuckets", "s3:GetBucketLocation", "s3:GetObject", "s3:PutObject", "s3:ListBucket", "s3:DeleteBucket", "s3:CreateBucket" ], "Resource": "*" } ] }

Build Lambda Go program

env GOOS=linux GOARCH=amd64 go build -o /tmp/main testx && zip -j /tmp/main.zip /tmp/main

Lambda Create Function

aws lambda create-function --function-name testx --runtime go1.x \ --role arn:aws:iam::SOME-ID:role/lambda-testx-executor \ --handler main --zip-file fileb:///tmp/main.zip

Invoke Lambda Service

aws lambda invoke --function-name testx /tmp/output.json

Output is as follows

{
  "treasure-map.xlsx": "Excel File",
  "treasure1": "The Tollow, Anno 1401 in Germany, Störtebeker’s Golden Grave",
  "treasure10": "Isla Robinson Crusoe, Anno 1715 in Chile",
  "treasure2": "Gardiners Island, Anno 1699 in New York State, USA",
  "treasure3": "Oak Island, Anno 1795 in Nova Scotia, Canada, The Unknown Treasure",
  "treasure4": "Isla de Coco, 1820 in Panama, The famous treasure of Lima on Cocos Island",
  "treasure5": "Norman Island, Anno 1883 in the British Virgin Islands, Stevenson’s Treasure Island - The Ultimate Legend",
  "treasure6": "Ailsa Craig, Anno in the 17th century in Scotland",
  "treasure7": "Frégate Island, Anno 1730 in the Seychelles",
  "treasure8": "St. Joseph Atoll, Anno 1721 in the Seychelles, Concerning the Treasure of the St. Joseph Atoll",
  "treasure9": "Tupai, Anno 1822 in French Polynesia"
}

Re-deploy Lambda Service

aws lambda update-function-code --function-name testx --zip-file fileb:///tmp/main.zip

Delete Lambda Service - when needed

aws lambda delete-function --function-name testx

Query Cloudwatch logs

aws logs filter-log-events --log-group-name /aws/lambda/testx \ --filter-pattern "ERROR"

TODO

• Create Serverless Gateway/REST API
• Create unit tests and document code
• Create Terraform code to deploy Lambda function
• Create CircleCI build pipeline
• Cron Lambda function