disklru

pip install disklru

Creates a disk based lru (least recently used) cache, backed by sqlite, that you can use in your apps.

Zero dependency package. Only relies on the python standard lib. Cross platform tests.

Usage

from disklru import DiskLRUCache

LRU_CACHE_FILE = "cache.db"
MAX_ENTRIES = 4
cache = DiskLRUCache(LRU_CACHE_FILE, MAX_ENTRIES)
cache.put("key", "value")
assert cache.get("key1") == "val"
cache.clear()

API

class DiskLRUCache:
    """Disk-based LRU cache using SQLite."""

    def get(self, key: str) -> str | None:
        """Returns the value associated with the given key, or None if the key is not in the cache."""

    def compare_and_swap(self, key: str, prev_val: str, new_val: str) -> tuple[bool, str | None]:
        """Performs compare and swap"""

    def get_bytes(self, key: str) -> bytes | None:
        """Returns the bytes values associated with the given key"""

    def get_json(self, key: str) -> Any:
        """Returns the value associated with the given key, or None if the key is not in the cache."""

    def put(self, key: str, value: str) -> None:
        """Sets the value associated with the given key."""

    def put_bytes(self, key: str, value: bytes) ->: None:
        """Sets the byte value associated with the given key."""

    def put_json(self, key: str, val: Any) -> None:
        """Sets the value associated with the given key."""

    def delete(self, key) -> None:
        """Deletes the given key from the cache."""

    def purge(self, timestamp) -> None:
        """Purges all elements less than the timestamp."""

    def clear(self) -> None:
        """Clears the cache."""

    def __del__(self) -> None:
        """Destructor."""
        self.close()

    def close(self) -> None:
        """Closes the connection to the database."""

Development

First install development dependencies:

pip install -e ".[dev]"

Windows

This environment requires you to use git-bash.

Linting

Run ./lint.sh to find linting errors using pylint, flake8, mypy and other tools.

Releases

• 2.0.3 - Added compare_and_swap() for atomic swapping of strings.
• 2.0.2 - contains operator is now defined so that you can do "key" in disklur
• 2.0.1 - max_size is now max_entries
• 2.0.0 - Overhaul - now allows multithreaded access, connection pool, get/put bytes. purge() now takes in a timestamp aware value for purging.