Source code for planai.cached_task

# Copyright 2024 Niels Provos
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import argparse
import hashlib
import logging
import sys
import threading
from typing import List

from diskcache import Cache
from pydantic import Field, PrivateAttr

from .task import Task, TaskWorker


[docs] class CachedTaskWorker(TaskWorker): cache_dir: str = Field("./cache", description="Directory to store the cache") cache_size_limit: int = Field( 25_000_000_000, description="Cache size limit in bytes" ) _cache: Cache = PrivateAttr() _lock: threading.Lock = PrivateAttr(default_factory=threading.Lock) def __init__(self, **data): super().__init__(**data) self._cache = Cache(self.cache_dir, size_limit=self.cache_size_limit) def _pre_consume_work(self, task: Task): with self.work_buffer_context(task): self.pre_consume_work(task) cache_key = self._get_cache_key(task) result = self._cache.get(cache_key) if result is not None: cached_results, _ = result logging.info("Cache hit for %s with key: %s", self.name, cache_key) self._publish_cached_results(cached_results, task) else: logging.info("Cache miss for %s with key: %s", self.name, cache_key) self.consume_work(task) input_task, outputs = self._local.ctx.get_input_and_outputs() self._set_cache(input_task, outputs) self.post_consume_work(task)
[docs] def pre_consume_work(self, task: Task): """ This method is called before consuming the work item. It will be called even if the task has been cached. It can be used for state manipulation, e.g. changing state for a class specific cache key. Args: task (Task): The work item to be consumed. Returns: None """ pass
[docs] def post_consume_work(self, task: Task): """ This method is called after consuming a work item in the task. It will be called even if the task has been cached. It can be used for state manipulation, e.g. changing state for a class specific cache key. Args: task (Task): The work item that was consumed. Returns: None """ pass
def _get_cache_key(self, task: Task) -> str: """Generate a unique cache key for the input task.""" task_dict = task.model_dump() task_str = str(sorted(task_dict.items())) # Ensure consistent ordering task_str += f" - {self.name}" # Include the task name to avoid collisions for output_type in self.output_types: task_str += f" - {output_type.__name__}" if extra_key := self.extra_cache_key(task): task_str += f" - {extra_key}" return hashlib.sha1(task_str.encode()).hexdigest()
[docs] def extra_cache_key(self, task: Task) -> str: """Can be implemented by subclasses to provide additional cache key information.""" return ""
def _publish_cached_results(self, cached_results: List[Task], input_task: Task): """Publish cached results.""" for result in cached_results: super().publish_work(result, input_task=input_task) def _set_cache(self, input_task: Task, cached_results: List[Task]): cache_key = self._get_cache_key(input_task) try: self._cache.set(cache_key, [cached_results, input_task]) logging.info("Task %s cached results for key: %s", self.name, cache_key) except Exception as e: logging.error("Error caching results for key %s: %s", cache_key, str(e))
def main(): parser = argparse.ArgumentParser( description="Read and print entries from a diskcache." ) parser.add_argument( "--output_task_filter", help="Filter for output task type", default=None ) parser.add_argument("cache_dir", help="Directory of the diskcache to read") args = parser.parse_args() try: cache = Cache(args.cache_dir) print(f"Reading cache from: {args.cache_dir}") print("-----------------------------") if len(cache) == 0: print("The cache is empty.") else: for key in cache: value, input = cache.get(key) if args.output_task_filter: if not any( [task.name == args.output_task_filter for task in value] ): continue print(f"Key: {key}") print(f"Value: {value}") print(f"Input: {input.name}: {str(input)[:100]}...") print("-----------------------------") except Exception as e: print(f"Error reading cache: {str(e)}", file=sys.stderr) sys.exit(1) if __name__ == "__main__": main()