# Docker
docker version
# (...)

# Rust
cargo --version
# -> cargo 1.82.0 (8f40fc59f 2024-08-21)

# Zig (for cross-compiling lambda binaries)
zig version
# -> 0.13.0

# AWS
aws --version
# -> aws-cli/2.17.0 Python/3.11.8 Darwin/23.6.0 exe/x86_64

# AWS login
# you might need to run extra commands to get temporary credentials if you use AWS organizations
# details on how to configure your CLI here: https://docs.aws.amazon.com/cli/latest/userguide/getting-started-quickstart.html
aws sts get-caller-identity
# ->
# {
#     "UserId": "AROATBJTMBXWT2ZAVHYOW:luciano",
#     "Account": "208950529517",
#     "Arn": "arn:aws:sts::208950529517:assumed-role/AWSReservedSSO_AdministratorAccess_d0f4d19d5ba1f39f/luciano"
# }

# Cargo Lambda
cargo lambda --version
# -> cargo-lambda 1.4.0 (e3bd536 2024-09-07Z)

# SAM
sam --version
# -> SAM CLI, version 1.126.0

cargo lambda new itsalive

// src/main.rs

use aws_lambda_events::event::eventbridge::EventBridgeEvent;
use lambda_runtime::{run, service_fn, tracing, Error, LambdaEvent};

async fn function_handler(event: LambdaEvent<EventBridgeEvent>) 
  -> Result<(), Error> {
    dbg!(event);
    Ok(())
}

#[tokio::main]
async fn main() -> Result<(), Error> {
    tracing::init_default_subscriber();

    run(service_fn(function_handler)).await
}

{
  "version": "0",
  "id": "53dc4d37-cffa-4f76-80c9-8b7d4a4d2eaa",
  "detail-type": "Scheduled Event",
  "source": "aws.events",
  "account": "123456789012",
  "time": "2015-10-08T16:53:06Z",
  "region": "us-east-1",
  "resources": [
    "arn:aws:events:us-east-1:123456789012:rule/my-scheduled-rule"
  ],
  "detail": {}
}

cargo lambda watch

cargo lambda invoke --data-file "events/eventbridge.json"

cargo lambda build --arm64 --release
cargo lambda release

# template.yml

AWSTemplateFormatVersion: 2010-09-09
Transform: AWS::Serverless-2016-10-31

Resources:
  
  HealthCheckLambda:
    Type: AWS::Serverless::Function
    Metadata:
      BuildMethod: rust-cargolambda
    Properties:
      CodeUri: .
      Handler: bootstrap
      Runtime: provided.al2023
      Architectures:
        - arm64
      MemorySize: 256
      Timeout: 70
      Events:
        ScheduledExecution:
          Type: Schedule
          Properties:
            Schedule: rate(30 minutes)

sam validate --lint \
  && sam build --beta-features \
  && sam deploy --guided

cargo add reqwest \
  --no-default-features \
  --features "rustls-tls,http2"

// src/main.rs

async fn function_handler(_event: LambdaEvent<EventBridgeEvent<Value>>) -> Result<(), Error> {
    let start = Instant::now();
    let resp = reqwest::get("https://loige.co").await;
    let duration = start.elapsed();
    match resp {
        Ok(resp) => {
            let status = resp.status().as_u16();
            let success = resp.status().is_success();
            dbg!(status);
            dbg!(success);
            dbg!(duration);
        }
        Err(e) => {
            eprintln!("The request failed: {}", e);
        }
    }

    Ok(())
}

# template.yml

Resources:
# ...
  HealthChecksTable:
    Type: AWS::DynamoDB::Table
    DeletionPolicy: Delete
    UpdateReplacePolicy: Delete
    Properties:
      BillingMode: PAY_PER_REQUEST
      KeySchema:
        - AttributeName: "Id"
          KeyType: "HASH"
        - AttributeName: "Timestamp"
          KeyType: "RANGE"
      AttributeDefinitions:
        - AttributeName: "Id"
          AttributeType: "S"
        - AttributeName: "Timestamp"
          AttributeType: "S"

# template.yml

Resources:
# ...
  HealthCheckLambda:
    Type: AWS::Serverless::Function
    # ...
    Properties:
      # ...
      Environment:
        Variables:
          TABLE_NAME: !Ref HealthChecksTable
      Policies:
        - DynamoDBWritePolicy:
            TableName: !Ref HealthChecksTable

cargo add aws-config aws-sdk-dynamodb

let table_name = env::var("TABLE_NAME").expect("TABLE_NAME not set");

let config = aws_config::defaults(BehaviorVersion::latest())
  .load()
  .await;
let dynamodb_client = aws_sdk_dynamodb::Client::new(&config);

let timestamp = event
  .payload
  .time
  .unwrap()
  .format("%+")
  .to_string();

let mut item = HashMap::new();
item.insert(
	"Id".to_string(),
	AttributeValue::S(format!("https://loige.co#{}", timestamp)),
);
item.insert("Timestamp".to_string(), AttributeValue::S(timestamp));

let success = match resp {
  Ok(resp) => {
    let status = resp.status().as_u16();
    item.insert("Status".to_string(), AttributeValue::N(status.to_string()));
    item.insert(
    	"Duration".to_string(),
    	AttributeValue::N(duration.as_millis().to_string()),
  	);
  	resp.status().is_success()
  }
  Err(e) => {
  	item.insert("Error".to_string(), AttributeValue::S(e.to_string()));
  	false
  }
};

item.insert("Success".to_string(), AttributeValue::Bool(success));

let insert_result = dynamodb_client
  .put_item()
  .table_name(table_name.as_str())
  .set_item(Some(item))
  .send()
  .await?;

tracing::info!("Insert result: {:?}", insert_result);

sam validate --lint \
  && sam build --beta-features \
  && sam deploy

sam delete