digraph G {
    // This diagram uses the AWS PNG icon set Light_BG style
    // symlink the folder here as 'icons'
    
    rankdir=LR
    ranksep="1.5"
    layout=dot
    
    subgraph cluster_triggers {

        graph[style=invis]

        api_gateway [
            group=a
            shape=none
            label=""
            xlabel="API Gateway"
            fontname="Arial"
            fixedsize=true width=1 height=1
            image="icons/Networking_and_Content_Delivery/Amazon-API-Gateway_light-bg.png"
        ]

        cloudwatch [
            group=a
            shape=none label=""
            xlabel="CloudWatch" fontname="Arial"
            fixedsize=true width=1 height=1
            image="icons/Management_and_Governance/Amazon-CloudWatch.png"
        ]
    }

    subgraph cluster_middle {

        graph[style=invis]

        subgraph cluster_database {
            label="Database"
            fontname="Arial"
            graph[style=dashed]
        
            dynamo_db [
                shape=none
                label=""
                xlabel="Dynamo DB"
                fontname="Arial"
                fixedsize=true width=1 height=1
                image="./icons/Database/Amazon-DynamoDB_light-bg.png"
            ]
            ddb_table_watcher [
                shape=none label=""
                xlabel="Watcher" fontname="Arial"
                fixedsize=true width=1 height=1
                image="./icons/Database/Amazon-DynamoDB_Table_light-bg.png"
            ]
        }

        lambda_watcher_run [
            shape=none label=""
            xlabel="Watcher Run" fontname="Arial"
            fixedsize=true width=1 height=1
            image="icons/Compute/AWS-Lambda_light-bg.png"
        ]

        sqs [
            shape=none label=""
            xlabel="SQS" fontname="Arial"
            fixedsize=true width=1 height=1
            image="icons/Application_Integration/Amazon-Simple-Queue-Service-SQS_light-bg.png"
        ]

        lambda_scheduled_watcher_runs [
            shape=none label=""
            xlabel="Scheduled Watcher Runs" fontname="Arial"
            fixedsize=true width=1 height=1
            image="icons/Compute/AWS-Lambda_light-bg.png"
        ]
    }

    ses [
        shape=none label=""
        xlabel="SES" fontname="Arial"
        fixedsize=true width=1 height=1
        image="icons/Customer_Engagement/Amazon-Simple-Email-Service-SES_light-bg.png"
    ]

// connections

    api_gateway -> ddb_table_watcher [
        label="Create/List/Delete" fontname="Arial"
        constraint=false
    ]
    api_gateway -> lambda_watcher_run [
        label="GET /{id}/run" fontname="Arial"
    ]
    lambda_watcher_run -> ddb_table_watcher [
        constraint=false
    ]
    sqs -> lambda_watcher_run [
        constraint=false
    ]
    lambda_scheduled_watcher_runs -> sqs [
        constraint=false
    ]
    cloudwatch -> lambda_scheduled_watcher_runs [
        label="rate(6 hours)" fontname="Arial"
        constraint=false
    ]
    lambda_watcher_run -> ses
}