Add nginx config parsing utilities

scripts/nginx_config.py

@@ -0,0 +1,88 @@
+#!/usr/bin/env python3
+"""Utilities for discovering and parsing Nginx configuration files.
+
+This module provides helper functions to locate Nginx configuration files and
+extract key details from ``server`` blocks.  Typical usage::
+
+    from scripts.nginx_config import discover_configs, parse_servers
+
+    files = discover_configs()
+    servers = parse_servers(files)
+    for s in servers:
+        print(s.get("server_name"), s.get("listen"))
+
+The functions intentionally tolerate missing or unreadable files and will simply
+skip over them.
+"""
+
+import os
+import re
+from pathlib import Path
+from typing import Dict, List, Set
+
+DEFAULT_PATHS = [
+    "/etc/nginx/nginx.conf",
+    "/usr/local/etc/nginx/nginx.conf",
+]
+
+INCLUDE_RE = re.compile(r"^\s*include\s+(.*?);", re.MULTILINE)
+SERVER_RE = re.compile(r"server\s*{(.*?)}", re.DOTALL)
+DIRECTIVE_RE = re.compile(r"^\s*(\S+)\s+(.*?);", re.MULTILINE)
+
+
+def discover_configs() -> Set[Path]:
+    """Return a set of all config files reachable from :data:`DEFAULT_PATHS`."""
+
+    found: Set[Path] = set()
+    queue = [Path(p) for p in DEFAULT_PATHS]
+
+    while queue:
+        path = queue.pop()
+        if path in found:
+            continue
+        if not path.exists():
+            continue
+        try:
+            text = path.read_text()
+        except OSError:
+            continue
+        found.add(path)
+        for pattern in INCLUDE_RE.findall(text):
+            pattern = os.path.expanduser(pattern.strip())
+            for included in path.parent.glob(pattern):
+                if included.is_file() and included not in found:
+                    queue.append(included)
+    return found
+
+
+def parse_servers(paths: Set[Path]) -> List[Dict[str, str]]:
+    """Parse ``server`` blocks from the given files.
+
+    Parameters
+    ----------
+    paths:
+        Iterable of configuration file paths.
+    """
+
+    servers: List[Dict[str, str]] = []
+    for p in paths:
+        try:
+            text = Path(p).read_text()
+        except OSError:
+            continue
+        for block in SERVER_RE.findall(text):
+            directives: Dict[str, List[str]] = {}
+            for name, value in DIRECTIVE_RE.findall(block):
+                directives.setdefault(name, []).append(value.strip())
+            entry: Dict[str, str] = {}
+            if "server_name" in directives:
+                entry["server_name"] = " ".join(directives["server_name"])
+            if "listen" in directives:
+                entry["listen"] = " ".join(directives["listen"])
+            if "proxy_cache" in directives:
+                entry["proxy_cache"] = " ".join(directives["proxy_cache"])
+            if "root" in directives:
+                entry["root"] = " ".join(directives["root"])
+            servers.append(entry)
+    return servers
+