How to Filter Docker Containers for Pruning in Python

import json
from datetime import datetime, timedelta


def parse_docker_ps(json_output: str, older_than_hours: int = 24) -> list:
    containers = json.loads(json_output)
    cutoff = datetime.now() - timedelta(hours=older_than_hours)
    return [
        c for c in containers
        if datetime.fromisoformat(c["created_at"]) < cutoff
        and c["status"] == "exited"
    ]


def docker_prune_mock(container_json: str, older_than_hours: int = 24) -> dict:
    to_prune = parse_docker_ps(container_json, older_than_hours)
    return {
        "pruned": [c["id"][:12] for c in to_prune],
        "total_space_freed_mb": round(sum(c["size_mb"] for c in to_prune), 2),
        "containers_remaining": len(json.loads(container_json)) - len(to_prune),
    }


if __name__ == "__main__":
    mock_docker_ps = json.dumps([
        {
            "id": "a1b2c3d4e5f60718aabbccddeeff0011",
            "name": "old_app",
            "status": "exited",
            "created_at": (datetime.now() - timedelta(days=2)).isoformat(),
            "size_mb": 120.5,
        },
        {
            "id": "f6e5d4c3b2a10918ffeeddccbbaa0022",
            "name": "recent_worker",
            "status": "exited",
            "created_at": (datetime.now() - timedelta(hours=2)).isoformat(),
            "size_mb": 45.8,
        },
        {
            "id": "11223344556677889900aabbccddeeff",
            "name": "running_db",
            "status": "running",
            "created_at": (datetime.now() - timedelta(hours=30)).isoformat(),
            "size_mb": 890.1,
        },
    ])
    result = docker_prune_mock(mock_docker_ps, older_than_hours=24)
    print(result)