Method get_or_compute

codeclash/viewer/app.py:164–209

Get cached value or compute it, preventing concurrent computation Args: key: Cache key compute_fn: Function to call if cache miss (should take no arguments) timeout_seconds: Cache timeout in seconds Returns: Cached or computed value

(self, key: str, compute_fn, timeout_seconds: int | None = None)

                    del self._compute_locks[key]

    def get_or_compute(self, key: str, compute_fn, timeout_seconds: int | None = None) -> Any:
        """Get cached value or compute it, preventing concurrent computation

        Args:
            key: Cache key
            compute_fn: Function to call if cache miss (should take no arguments)
            timeout_seconds: Cache timeout in seconds

        Returns:
            Cached or computed value
        """
        # First check: see if we have cached value
        cached_value = self.get(key, timeout_seconds)
        if cached_value is not None:
            logger.debug(f"Cache hit for key '{key}'")
            return cached_value

        # Get per-key lock to prevent concurrent computation
        compute_lock = self._get_compute_lock(key)

        # Check if we're waiting for another thread
        if compute_lock.locked():
            logger.info(f"Cache key '{key}' is being computed by another request, waiting...")

        try:
            with compute_lock:
                # Second check: another thread might have computed it while we waited for lock
                cached_value = self.get(key, timeout_seconds)
                if cached_value is not None:
                    logger.info(
                        f"✓ Duplicate computation prevented for key '{key}' - using result from another request"
                    )
                    return cached_value

                # Compute the value
                logger.info(f"Cache miss for key '{key}', computing value...")
                value = compute_fn()

                # Store in cache
                self.set(key, value)
                logger.info(f"✓ Computed and cached value for key '{key}'")

                return value
        finally:
            # Cleanup compute lock to avoid memory leak
            self._cleanup_compute_lock(key)


# Global cache instance