feat: Refactor log-alert application into modular structure

- Introduced alerters package with base Alerter class and implementations for LogAlerter and GotifyAlerter.
- Created fetchers package with abstract LogFetcher class and implementations for FileLogFetcher, LokiLogFetcher, and ParseableLogFetcher.
- Added filters package with base Filter class and implementations for RegexpFilter and GeolocationFilter.
- Implemented rules package with base AlertRule class and SimpleAlertRule for alerting logic.
- Enhanced configuration handling with utilities for loading and validating JSON configuration.
- Updated logging setup for better logging management.
- Modified main application logic to utilize the new modular structure, improving maintainability and readability.
- Updated config.json and config.schema.json to reflect changes in alerting and fetching configurations.
- Added python-dateutil to requirements for date parsing functionality.

log-alert/rules/simple.py

@@ -0,0 +1,50 @@
+"""Simple AlertRule implementation copied from the previous monolithic implementation."""
+import logging
+import time
+from typing import Dict, Any, Optional
+
+from .base import AlertRule
+from fetchers import LogFetcher
+from filters import RegexpFilter, GeolocationFilter
+from alerters import Alerter
+
+logger = logging.getLogger("log-alert")
+
+
+class SimpleAlertRule(AlertRule):
+    """Represents an alert rule with filters and alert template."""
+
+    def __init__(self, log_fetchers: Dict[str, LogFetcher], alerters: Dict[str, Alerter], config: Dict[str, Any]):
+        self.log_fetcher = log_fetchers[config["log-fetcher"]["name"]]
+        self.fetcher_filters = config["log-fetcher"].get("filters", {})
+        self.check_interval = config.get("check-interval", 60)
+        self.filters = []
+        for filter in config.get("filters", []):
+            if filter["type"] == "regexp":
+                self.filters.append(RegexpFilter(filter["config"]))
+            elif filter["type"] == "geolocation":
+                self.filters.append(GeolocationFilter(filter["config"]))
+            else:
+                raise ValueError(f"Unsupported filter type: {filter['type']}")
+        self.alerter = alerters[config["alerter"]["name"]]
+        self.alert_title = config["alerter"]["title"]
+        self.alert_message = config["alerter"]["message"]
+        self.last_run = time.time() - self.check_interval
+        self.next_run = time.time()
+
+    def run(self) -> None:
+        logs = self.log_fetcher.fetch_logs_time_range(self.fetcher_filters, start_time=self.last_run, end_time=self.next_run)
+        for log_entry in logs:
+            logger.debug(f"Checking log: {log_entry['log']}")
+            for filter in self.filters:
+                log_entry = filter.filter(log_entry)
+                if log_entry is None:
+                    break
+            if log_entry is None:
+                continue
+            title = self.alert_title.format_map(log_entry.get("labels", {}))
+            message = self.alert_message.format_map(log_entry.get("labels", {}))
+            logger.info(f"Sending message: {message}, title: {title}, with params: {log_entry}")
+            self.alerter.send_alert(title, message)
+        self.last_run = self.next_run
+        self.next_run = time.time() + self.check_interval