Deploy lambda function using AWS CLI

Prerequisites - AWS CLI & AWS Shell

AWS Command Line Interface(CLI) is used in this post to deploy the Lambda function. CLI needs to be installed and configured locally in order to use it.

AWS Shell helps with auto-completion, fuzzy searching, and more.

How to deploy it on AWS

We're uploading the Go binary file into AWS Lambda as a .zip file. In order to build for Linux, we're using the following command.

GOOS=linux GOARCH=amd64 go build -o main main.go
zip main.zip main

Creating IAM roles & policies.

Create the assume-role-policy.json file:

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

Create an IAM role

iam create-role --role-name role-lambda-shopify --assume-role-policy-document file://assume-role-policy.json

{
    "Role": {
        "Path": "/",
        "RoleName": "role-lambda-shopify",
        "RoleId": "AROARKDOZJ3E6FZQIORPR",
        "Arn": "arn:aws:iam::090426658505:role/role-lambda-shopify",
        "CreateDate": "2022-06-25T21:30:57Z",
        "AssumeRolePolicyDocument": {
            "Version": "2012-10-17",
            "Statement": [
                {
                    "Effect": "Allow",
                    "Principal": {
                        "Service": "lambda.amazonaws.com"
                    },
                    "Action": "sts:AssumeRole"
                }
            ]
        }
    }
}

Let's attach permission to this role. AWSLambdaBasicExecutionRole gives permission to write logs to cloudWatch.

iam attach-role-policy --role-name role-lambda-shopify --policy-arn arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole

Create an SNS topic

sns create-topic --name shopify-stock-notification


```json:response
{
    "TopicArn": "arn:aws:sns:ap-southeast-2:090426658505:shopify-stock-notification"
}

To subscribe to the SNS topic:

sns subscribe --topic-arn arn:aws:sns:ap-southeast-2:090426658505:shopify-stock-notification --protocol email --notification-endpoint test@hotmail.com

we're going to attach an inline policy that grants access to the Lambda function to trigger SNS notification.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "sns:Publish",
      "Resource": "arn:aws:sns:ap-southeast-2:090426658505:shopify-stock-notification"
    }
  ]
}

iam put-role-policy --role-name role-lambda-shopify --policy-name publish-to-sns --policy-document file://sns-policy-for-lambda.json

Create/Update Lambda function

lambda create-function --function-name function-lambda-shopify-stock --zip-file fileb://main.zip --handler main --runtime go1.x --role arn:aws:iam::090426658505:role/role-lambda-shopify

{
    "FunctionName": "function-lambda-shopify-stock",
    "FunctionArn": "arn:aws:lambda:ap-southeast-2:090426658505:function:function-lambda-shopify-stock",
    "Runtime": "go1.x",
    "Role": "arn:aws:iam::090426658505:role/role-lambda-shopify",
    "Handler": "main",
    "CodeSize": 6662556,
    "Description": "",
    "Timeout": 3,
    "MemorySize": 128,
    "LastModified": "2022-06-25T22:04:02.491+0000",
    "CodeSha256": "uLsOQEp4VCFi294HpbKyl1i60uLGUIBwmpI2cg0wdeU=",
    "Version": "$LATEST",
    "TracingConfig": {
        "Mode": "PassThrough"
    },
    "RevisionId": "1ff52d69-6429-49d8-ba7f-492886e9aee3",
    "State": "Pending",
    "StateReason": "The function is being created.",
    "StateReasonCode": "Creating",
    "PackageType": "Zip",
    "Architectures": [
        "x86_64"
    ],
    "EphemeralStorage": {
        "Size": 512
    }
}

To add environmental variable to Lambda function:

lambda update-function-configuration --function-name function-lambda-shopify-stock --environment "Variables={SHOPIFY_API_KEY=<your-shopify-key>, SHOPIPY_API_PASSWORD=<your-shopify-password>, SHOPIFY_SHOPIFY_DOMAIN=c<your-shopify-domain>}”

To update the Lambda function:

lambda update-function-code --function-name function-lambda-shopify-stock --zip-file fileb://main.zip

To invoke the Lambda function and store the output to a text file:

lambda invoke --function-name function-lambda-shopify-stock output.txt

EventBridge scheduler

EventBridge rule let you create a cron that triggers the Lambda function.