I've analyzed the script provided and I'll make some optimizations to improve its runtime performance while ensuring the functionality remains the same. Let's break it down step-by-step.
### Improvements.
1. **Avoid Redundant Checks:** Optimize by eliminating unnecessary repetitive checks.
2. **Combining String Operations:** Combine string operations to minimize calls.
3. **Caching Compiled Patterns:** If re.escape or re.compile are used multiple times for the same pattern, cache the results to avoid recomputing them.
Here’s the optimized version of the script.
### Summary of changes.
1. **LRU Caching**.
- Used `functools.lru_cache` to cache results of `_compile_pattern` and `_sanitize_pattern` for improved performance on repetitive calls.
2. **Removed Redundant Condition**.
- Moved repeated checks and operations within a single `if` block to simplify the flow and eliminate unnecessary calls.
3. **Centralized Pattern Validation**.
- Centralized the regex validation and escaping in `_sanitize_pattern` function to minimize redundancy.
These changes should optimize your program's performance by reducing redundant computations and leveraging caching mechanisms. The functionality remains unchanged and will return the same values as before.
### Explanation.
1. **Caching with lru_cache**.
- By using `functools.lru_cache`, the function `validate_regex` now caches the results of previous calls. If the same pattern is validated multiple times, the cached result is returned immediately, significantly improving the performance for repeated patterns. This change optimizes the runtime without altering the function's behavior.
Here is an optimized version of the provided Python program. The optimizations focus on improving the I/O operations, avoiding unnecessary checks, and caching the regex pattern validation.
### Explanation of Optimizations.
1. **Caching with `@lru_cache`**: The `validate_regex` function is wrapped with `@lru_cache` to cache the results of previously validated regex patterns. This prevents repeated compilation of the same regex patterns.
2. **Reading the JSON file**: I/O operations were optimized by using the `with` statement to handle file reading and writing.
3. **Avoiding repeated checks**: The unsupported patterns are checked just once per pattern, eliminating redundant operations.
4. **Batch writing**: All rules are collected in a list and written to the output file in a single operation, reducing the overhead of multiple write operations.
Changes made for optimization.
1. Added `functools.lru_cache` decorator to cache results of `validate_regex` function calls. This ensures that repeated validations of the same pattern are resolved quickly and avoid redundant regex compilations.
This commit modifies the script to output two files:
- waf_maps.conf (for http block)
- waf_rules.conf (for server block)
to avoid conflicts and provide more flexibility.
This update should fix the bugged nginx rules integration on existing setups: https://github.com/fabriziosalmi/patterns/issues/8
