release-tweeter

release-tweeter

Description

API to tweet the latest release tag version using AWS Lambda(Golang) & API Gateway.

Local

You can test AWS Lambda & API Gateway locally with AWS SAM (Serverless Application Model).

prerequisites

• install aws-sam-cli. Docker is also required. Follow the instruction here.
• set environment variables to sample-env.json.
  • You have to go to the Twitter Apps page and create new app by yourself. Then you can get Access Token, Access Token Secret, Consumer Key (API Key) and Consumer Secret (API Secret).
  • REPO is your repository name on the GitHub. For example, if you want to notice the latest release on this repository to your followers, you have to set toshi0607/gig to REPO.

hosting

# start up API Gateway and Lambda with Docker
$ sam local start-api --env-vars sample-env.json

2018/05/26 11:46:50 Connected to Docker 1.37
2018/05/26 11:46:51 Fetching lambci/lambda:go1.x image for go1.x runtime...
go1.x: Pulling from lambci/lambda
Digest: sha256:79a06e00e85fd2951ad60ee2290590241e8173df5c307134fda061f4a3272bac
Status: Image is up to date for lambci/lambda:go1.x

Mounting main (go1.x) at http://127.0.0.1:3000/ [POST]

You can now browse to the above endpoints to invoke your functions.
You do not need to restart/reload SAM CLI while working on your functions,
changes will be reflected instantly/automatically. You only need to restart
SAM CLI if you update your AWS SAM template.


# request to the localhost from another tab
$ curl -XPOST http://127.0.0.1:3000/
v0.1.4 # and post twitter account's timeline

Production

prerequisites

You have to prepare credentials with proper policies.

• AWSLambdaFullAccess (should be limited)
• AmazonS3FullAccess (should be limited)
• CloudWatchLogsFullAccess (should be limited)
• AmazonAPIGatewayAdministrator (should be limited)
• AWSXrayFullAccess (should be limited)

In addition to the above, I added group policy for AWS CloudFormation. It's because sam deploy command is alias of aws cloudformation deploy.

Also, sam package command generates CloudFormation template from template.yml.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "Stmt**********",
            "Effect": "Allow",
            "Action": [
                "cloudformation:CreateChangeSet",
                "cloudformation:ExecuteChangeSet",
                "cloudformation:DescribeStackEvents",
                "cloudformation:DeleteStack",
                "iam:CreateRole",
                "iam:AttachRolePolicy",
                "iam:DetachRolePolicy",
                "iam:DeleteRole"
            ],
            "Resource": [
                "*"
            ]
        }
    ]
}

if you're using credentials you can't change policies by yourself by default, you can add another user profiles.

$ aws configure --profile user2
AWS Access Key ID [None]: AKIAI44QH8DHBEXAMPLE
AWS Secret Access Key [None]: je7MtGbClwBF/2Zp9Utk/h3yCo8nvbEXAMPLEKEY
Default region name [None]: us-east-1
Default output format [None]: text

if you skip entering output format, default output (json) is used.

$ cat ~/.aws/credentials
[default]
aws_access_key_id = AKI********
aws_secret_access_key = ********
[user2]
aws_access_key_id = AKIAI44QH8DHBEXAMPLE
aws_secret_access_key = je7MtGbClwBF/2Zp9Utk/h3yCo8nvbEXAMPLEKEY
region=us-east-1
output=text

and you can specify profiles explicitly

$ aws [some sub command] --profile user2

check the official site in detail.

deploy

1. make a s3 bucket

$ aws s3 mb s3://lambda-release-tweeter --profile private

• an S3 bucket is required. so make a bucket for the release-tweeter you're going to host for the first time
• AWS management console is also avilable to make a bucket instead of the AWS Cli
• a buekcet name (lambda-release-tweeter in this case) should be unique globally.

1. prepare artifacts for deploy

$ sam package --profile private \
  --template-file template.yml \
  --s3-bucket lambda-release-tweeter \
  --output-template-file packaged.yml

• if you use default credentials, you don't have to use --profile private

1. deploy artifacts

$ sam deploy --profile private \
  --template-file ./packaged.yml \
  --stack-name stack-release-tweeter \
  --capabilities CAPABILITY_IAM \
  --parameter-overrides REPO=$REPO \
    TWITTER_ACCESS_TOKEN=$TWITTER_ACCESS_TOKEN \
    TWITTER_ACCESS_TOKEN_SECRET=$TWITTER_ACCESS_TOKEN_SECRET \
    TWITTER_CONSUMER_KEY=$TWITTER_CONSUMER_KEY \
    TWITTER_CONSUMER_SECRET=$TWITTER_CONSUMER_SECRET

• --parameter-overrides option is requred because we shouldn't write qredentials to the template.yml.
• you have to set 5 environment variables in this case. you can pass value of REPO, TWITTER_ACCESS_TOKEN, TWITTER_ACCESS_TOKEN_SECRET, TWITTER_CONSUMER_KEY and TWITTER_CONSUMER_SECRET directly instead.
• a stack name (stack-release-tweeter in this case) should be unique globally.