aws-lambda-go

aws-lambda-go

API:

GET: /books?isbn=xxx POST: /books

JSON record: {"isbn":"978-1420931693","title":"The Republic","author":"Plato"}

How to setup:

1. build an executable with env GOOS=linux GOARCH=amd64 to make sure lambda will be properly invoked:

env GOOS=linux GOARCH=amd64 go build cmd/main.go

zip it: zip -j main.zip main

1. setup aws cli:

install awscli aws configure --profile

You'll need to configure credentials of the IAM user:

AWS Access Key ID [None]: access-key-ID
AWS Secret Access Key [None]: secret-access-key
Default region name [None]: us-east-1
Default output format [None]: json

1. get the lambda package for go:

go get github.com/aws/aws-lambda-go/lambda

1. set up an IAM role for lambda:

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

note the Arn field: "Arn": "arn:aws:iam::[account-id]:role/lambda-books-executor",

1. specify the permissions that the role has:

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

1. deploy the lambda to aws:

aws lambda create-function --function-name books --runtime go1.x \ --role arn:aws:iam::[account-id]:role/lambda-books-executor \ --handler main --zip-file fileb://main.zip

where [account-id] is the id in the arn role of the lambda

1. test deployed lambda: aws lambda invoke --function-name books output.json

2. create a new table in DynamoDB:

aws dynamodb create-table --table-name Books \ --attribute-definitions AttributeName=ISBN,AttributeType=S \ --key-schema AttributeName=ISBN,KeyType=HASH \ --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5

note [TableArn]

1. add items using put-item:

aws dynamodb put-item --table-name Books --item '{"ISBN": {"S": "978-1420931693"}, "Title": {"S": "The Republic"}, "Author": {"S": "Plato"}}'

1. add go package: go get github.com/aws/aws-sdk-go

2. add database code and rebuild + re-zip the file

3. update lambda:

aws lambda update-function-code --function-name books \ --zip-file fileb://main.zip

1. add permissions to run GetItem on a DynamoDB instance and attach it to the lambda-books-executor role:

aws iam put-role-policy --role-name lambda-books-executor \ --policy-name dynamodb-item-crud-role \ --policy-document file://privilege-policy.json

1. set up a way to access the lamdba function over HTTPS using the AWS API Gateway service: aws apigateway create-rest-api --name bookstore

note down [id] - rest-api-id

1. get the id of the root API resource ("/"):

aws apigateway get-resources --rest-api-id [id]

note down [id] - root-path-id

1. create a new resource under the root path:

aws apigateway create-resource --rest-api-id [rest-api-id] \ --parent-id [root-path-id] --path-part books

note down [id] - id

1. register the HTTP method of ANY:

aws apigateway put-method --rest-api-id [rest-api-id] \ --resource-id [id] --http-method ANY \ --authorization-type NONE

1. integrate the resource with our lambda function:

aws apigateway put-integration --rest-api-id [rest-api-id] \ --resource-id [resource-id] --http-method ANY --type AWS_PROXY \ --integration-http-method POST \ --uri arn:aws:apigateway:eu-central-1:lambda:path/2015-03-31/functions/arn:aws:lambda:eu-central-1:[account-id]:function:books/invocations

1. send a test request to the resource:

aws apigateway test-invoke-method --rest-api-id [rest-api-id] --resource-id [resource-id] --http-method "GET"

1. add aws-lambda-go/events package:

go get github.com/aws/aws-lambda-go/events

we can query Cloudwatch for errors:

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

1. deploy:

aws apigateway create-deployment --rest-api-id [rest-api-id] \ --stage-name staging