metrics: remove circular import

app/metrics.py

@@ -1,16 +1,24 @@
-from typing import Iterator
+from typing import Iterator, Optional
 
+from flask import Flask
 from prometheus_client.metrics_core import GaugeMetricFamily, CounterMetricFamily, Metric
 from sqlalchemy import text
 
-from app import app
 from app.extensions import db
 from app.models.automation import Automation, AutomationState
 
 
+class FlaskCollector:
+    def __init__(self, app=None):
+        self.app: Optional[Flask] = None
+
+    def init_app(self, app):
+        self.app = app
+
+
 class DefinedProxiesCollector:
     def collect(self) -> Iterator[Metric]:
-        with app.app_context():
+        with self.app.app_context():
             conn = db.engine.connect()
             result = conn.execute(text("""
                     SELECT origin.group_id, "group".group_name, proxy.provider, proxy.pool_id, pool.pool_name,
@@ -32,7 +40,7 @@ class DefinedProxiesCollector:
 
 class BlockedProxiesCollector:
     def collect(self) -> Iterator[Metric]:
-        with app.app_context():
+        with self.app.app_context():
             with db.engine.connect() as conn:
                 result = conn.execute(text("""
                         SELECT origin.group_id, "group".group_name, proxy.provider, proxy.pool_id, pool.pool_name,
@@ -56,7 +64,7 @@ class BlockedProxiesCollector:
 
 class AutomationCollector:
     def collect(self) -> Iterator[Metric]:
-        with app.app_context():
+        with self.app.app_context():
             c = GaugeMetricFamily("automation_state", "The automation state (0: idle, 1: running, 2: error)",
                                   labels=['automation_name'])  # type: ignore[no-untyped-call]
             automations = Automation.query.all()