digraph system_overview {
    rankdir=LR
    bgcolor="#0a0e17"
    fontname="Helvetica"
    node [fontname="Helvetica" fontsize=11 style=filled color="#1e2a4a" fontcolor="#e8eaf0"]
    edge [fontname="Helvetica" fontsize=9 fontcolor="#8892a8" color="#4a5568"]

    label="Sample app — Lambda + MinIO sandbox"
    labelloc=t
    fontsize=16
    fontcolor="#0066ff"

    subgraph cluster_caller {
        label="Caller"
        style=dashed
        color="#1e2a4a"
        fontcolor="#8892a8"

        invoke [label="invoke.py\n(local) /\nAPI Gateway,\nS3 event,\nStep Functions\n(real AWS)" fillcolor="#243056" shape=box]
    }

    subgraph cluster_lambda {
        label="Lambda execution environment"
        style=dashed
        color="#0066ff"
        fontcolor="#0066ff"

        handler [label="handler(event, context)\nlambda_function.py" fillcolor="#1a1a3a" shape=box]

        subgraph cluster_async {
            label="asyncio.Queue producer / consumer"
            style=dotted
            color="#0066ff"
            fontcolor="#8892a8"

            producer [label="producer\nlist_objects_v2 (paginator)\nfilter *.pdf" fillcolor="#0d1a33" shape=box]
            queue [label="asyncio.Queue\nmaxsize=2000\n(backpressure)" fillcolor="#121829" shape=cylinder]
            consumer [label="consumer\ngenerate_presigned_url\nappend JSONL" fillcolor="#0d1a33" shape=box]
        }

        tmp [label="/tmp/<uuid>.jsonl\nstreamed manifest\n(ephemeral, 512 MB default)" fillcolor="#121829" shape=cylinder fontcolor="#ffc107"]
    }

    subgraph cluster_storage {
        label="Object storage"
        style=dashed
        color="#1e2a4a"
        fontcolor="#8892a8"

        minio [label="MinIO (local)\nor real S3" fillcolor="#1a3a1a" shape=cylinder fontcolor="#00c853"]
        bucket [label="my-company-reports-bucket\n2026/04/*.pdf\nmanifests/<uuid>.jsonl" fillcolor="#121829" shape=folder]
    }

    response [label="response\n{count, manifest_key,\nmanifest_url}\n(< 1 KB; sidesteps 6 MB cap)" fillcolor="#243056" shape=note fontcolor="#00c853"]

    invoke -> handler [label="event"]
    handler -> producer [label="spawn task"]
    handler -> consumer [label="spawn task"]

    producer -> minio [label="LIST"]
    minio -> producer [label="page (1000 keys)" style=dashed]
    producer -> queue [label="key" color="#0066ff"]
    queue -> consumer [label="key"]
    consumer -> minio [label="presign\n(local HMAC)" style=dotted]
    consumer -> tmp [label="JSONL line"]

    tmp -> minio [label="put_object\nmanifests/<uuid>.jsonl"]
    handler -> response [label="return"]
    minio -> bucket [style=invis]
}