RT-258 Add Prometheus Metrics exports

.gitignore

@@ -127,3 +127,6 @@ dmypy.json
 
 # Pyre type checker
 .pyre/
+
+# Exporter Metrics 
+exporter_metrics

src/vulnrelay/core/conf.py

@@ -27,6 +27,10 @@ class Settings(BaseSettings):
     SCANNERS: list[ScannerOption] = ["grype"]
     SCAN_HOST: bool = False
 
+    # Metric Exporter Settings
+    METRICS_DIR: str = "exporter_metrics"
+    METRICS_FILENAME: str = "vulnrelay.prom"
+
     model_config = SettingsConfigDict(
         env_file=ROOT_DIR / ".env",
     )

src/vulnrelay/metrics/__init__.py

@@ -0,0 +1,4 @@
+from .exporter import MetricExporter
+from .metric import MetricNames
+
+__all__ = ["MetricExporter", "Metric", "MetricNames"]

src/vulnrelay/metrics/exporter.py

@@ -0,0 +1,37 @@
+import os
+import shutil
+from pathlib import Path
+from typing import Any
+
+
+class MetricExporter:
+    def __init__(self, *, metrics: dict[str, Any], path: str) -> None:
+        self.metrics: dict[str, Any] = metrics
+        self.path = path
+        self._check_dir()
+
+    def _get_export_content(self) -> str:
+        return "\n".join([f"{name} {metric}" for name, metric in self.metrics.items()])
+
+    def _check_dir(self) -> None:
+        dir_path = Path(self.path).parent
+        dir_path.mkdir(parents=True, exist_ok=True)
+
+    def export_all(self) -> None:
+        content = self._get_export_content()
+        path = self.path
+        temp_file = f"{path}.tmp"
+
+        with open(temp_file, "w") as file:
+            file.write(content)
+
+        try:
+            shutil.move(temp_file, path)
+        except Exception as e:
+            os.remove(temp_file)
+            raise e
+
+    def save_and_export(self, *, values: dict[str, Any]) -> None:
+        for name, value in values.items():
+            self.metrics[name] = value
+            self.export_all()

src/vulnrelay/metrics/metric.py

@@ -0,0 +1,5 @@
+from enum import Enum
+
+
+class MetricNames(Enum):
+    LAST_SCAN_AND_PUSH = "last_successful_scan_push"

src/vulnrelay/services.py

@@ -1,8 +1,11 @@
 import logging
+import os
 import subprocess
+import time
 from collections.abc import Callable, Iterable
 
 from vulnrelay.core.conf import settings
+from vulnrelay.metrics import MetricExporter, MetricNames
 from vulnrelay.scanners import Scanner
 from vulnrelay.uploader import DefectDojoUploader, Uploader
 
@@ -37,16 +40,27 @@ def get_uploader() -> Uploader:
     )
 
 
+def get_metric_exporter() -> MetricExporter:
+    return MetricExporter(
+        metrics={
+            MetricNames.LAST_SCAN_AND_PUSH.value: None,
+        },
+        path=os.path.join(settings.METRICS_DIR, settings.METRICS_FILENAME),
+    )
+
+
 def run_workflow(
     *,
     images: Iterable[str] | None = None,
     scanner_names: Iterable[str] | None = None,
     get_uploader: Callable[[], Uploader] = get_uploader,
+    get_metric_exporter: Callable[[], MetricExporter] = get_metric_exporter,
     scan_host: bool = True,
 ) -> None:
     images = images or get_running_images()
     scanner_names = scanner_names or settings.SCANNERS
     uploader = get_uploader()
+    metric_exporter = get_metric_exporter()
 
     for scanner_name in scanner_names:
         scanner = Scanner.get_scanner(scanner_name)()
@@ -97,3 +111,10 @@ def run_workflow(
             continue
 
         logger.info("Upload successful")
+
+    try:
+        metric_exporter.save_and_export(
+            values={MetricNames.LAST_SCAN_AND_PUSH.value: int(time.time())},
+        )
+    except Exception:
+        logger.exception("Failed to export metrics!")