Request support for an independent archive directory

[WangJincheng4869]

Core requirements

New configuration item: "Archive Directory"

Basic rules

1. You can choose a directory different from the one where logs are written for archiving and exporting
2. Archiving can be stored using date directories. For example: 2026-05-18 or 2026/05/18

Usage scenario

In the server, real-time logs are written to the local disk, and when archiving, they are archived to a network disk similar to NAS. This approach can reduce the latency of log writing and lower storage costs.

[Delgan]

Hi.

Such behavior is already relatively easy to implement using a custom compression function. I don't think it need to be a built-in configuration option, since it is quite specific demand.

import gzip
import shutil
from datetime import datetime
from pathlib import Path

from loguru import logger


def archive(log_path: str) -> None:
    src = Path(log_path)
    dst = Path("nas_archives") / datetime.now().strftime("%Y/%m/%d") / f"{src.name}.gz"
    dst.parent.mkdir(parents=True, exist_ok=True)
    with open(src, "rb") as f_in, gzip.open(dst, "wb") as f_out:
        shutil.copyfileobj(f_in, f_out)
    src.unlink()


logger.add("app.log", rotation="1 KB", compression=archive)

for i in range(50):
    logger.info("message number {}", i)

[WangJincheng4869]

@Delgan Hello, after doing this, do I also need to implement a function for log rotation deletion (such as automatically deleting logs older than six months)?

---

您好，这样做之后是不是日志轮转删除（比如自动删除半年的日志）是否也需要自己实现一个函数？

[Delgan]

@WangJincheng4869 Yes, you likely need to also implements a custom function to delete the archives. See explanation about the retention attribute in the docs. Otherwise, using retention="6 months" would likely not find the moved files.

Not tested example:

import gzip
import shutil
from datetime import datetime, timedelta
from pathlib import Path

from loguru import logger


def archive(log_path: str) -> None:
    src = Path(log_path)
    dst = Path("nas_archives") / datetime.now().strftime("%Y/%m/%d") / f"{src.name}.gz"
    dst.parent.mkdir(parents=True, exist_ok=True)
    with open(src, "rb") as f_in, gzip.open(dst, "wb") as f_out:
        shutil.copyfileobj(f_in, f_out)
    src.unlink()


def delete(logs: list[str]) -> None:
    cutoff = datetime.now().timestamp() - timedelta(days=6 * 30).total_seconds()
    for archive_path in Path("nas_archives").glob("**/*.gz"):
        if archive_path.stat().st_mtime < cutoff:
            archive_path.unlink()


logger.add("app.log", rotation="1 KB", compression=archive, retention=delete)

for i in range(50):
    logger.info("message number {}", i)