Implement Prometheus metrics

src/metrics.py

@@ -0,0 +1,32 @@
+import logging
+
+from prometheus_client import Counter, Histogram, start_http_server
+import time
+
+REQUEST_COUNTER = Counter(
+    name='flaresolverr_request',
+    documentation='Total requests with result',
+    labelnames=['domain', 'result']
+)
+REQUEST_DURATION = Histogram(
+    name='flaresolverr_request_duration',
+    documentation='Request duration in seconds',
+    labelnames=['domain'],
+    buckets=[0, 10, 25, 50]
+)
+
+
+def serve(port):
+    start_http_server(port=port)
+    while True:
+        time.sleep(600)
+
+
+def start_metrics_http_server(prometheus_port: int):
+    logging.info(f"Serving Prometheus exporter on http://0.0.0.0:{prometheus_port}/metrics")
+    from threading import Thread
+    Thread(
+        target=serve,
+        kwargs=dict(port=prometheus_port),
+        daemon=True,
+    ).start()