feat: run with gunicorn instead of flask

Each worker now uses its own registry instead of the global REGISTRY
to avoid duplicate metric registration, since metrics are served
from the database.

Dockerfile

@@ -4,14 +4,16 @@ ENV APP="bc"
 ENV APP_BASE="/srv"
 ENV SHELL="/bin/bash"
 ENV FLASK_APP="${FLASK_APP:-app}"
-ENV FLASK_RUN_HOST="${FLASK_RUN_HOST:-0.0.0.0}"
-ENV FLASK_RUN_PORT="${FLASK_RUN_PORT:-5000}"
+ENV GUNICORN_RUN_HOST="${GUNICORN_RUN_HOST:-0.0.0.0}"
+ENV GUNICORN_RUN_PORT="${GUNICORN_RUN_PORT:-5000}"
 ENV PYTHONPATH="${APP_BASE}/env/lib/python3.11/site-packages"
 ENV PATH="${APP_BASE}/env/bin:/usr/local/bin:/usr/bin:/bin:/sbin:/usr/sbin:/home/${APP}/.local/bin"
 
 ARG CONTAINER_UID="${CONTAINER_UID:-1000}"
 ARG CONTAINER_GID="${CONTAINER_GID:-1000}"
 
+ENV GUNICORN_WORKERS="${GUNICORN_WORKERS:-4}"
+
 RUN apt-get update && \
     apt-get install --no-install-recommends -y \
     curl \
@@ -47,10 +49,11 @@ USER ${APP}
 
 WORKDIR ${APP_BASE}/${APP}
 COPY --chown=${APP}:${APP} . ${APP_BASE}/${APP}
+RUN chmod +x ${APP_BASE}/${APP}/run_gunicorn.sh
 
 RUN python3 -m venv ${APP_BASE}/env && \
     ${APP_BASE}/env/bin/pip install --no-cache-dir -r requirements.txt && \
-    ${APP_BASE}/env/bin/pip install --no-cache-dir psycopg2-binary
+    ${APP_BASE}/env/bin/pip install --no-cache-dir psycopg2-binary gunicorn
 
 RUN rm -rf frontend && \
     git clone https://gitlab.com/guardianproject-ops/bypass-censorship/portal-frontend.git frontend && \
@@ -58,3 +61,5 @@ RUN rm -rf frontend && \
     mkdir -p ${APP_BASE}/${APP}/app/static/ui && \
     cp -r dist/* ${APP_BASE}/${APP}/app/static/ui && \
     rm -rf frontend /tmp/* /var/tmp/*
+
+ENTRYPOINT ["./run_gunicorn.sh"]

app/__init__.py

@@ -5,7 +5,7 @@ from typing import Iterator
 import yaml
 from flask import Flask, redirect, url_for, send_from_directory
 from flask.typing import ResponseReturnValue
-from prometheus_client import make_wsgi_app, REGISTRY, Metric
+from prometheus_client import make_wsgi_app, Metric, CollectorRegistry
 from prometheus_client.metrics_core import GaugeMetricFamily, CounterMetricFamily
 from prometheus_client.registry import Collector
 from sqlalchemy import text
@@ -106,9 +106,10 @@ class AutomationCollector(Collector):
 
 
 if not_migrating() and 'DISABLE_METRICS' not in os.environ:
-    REGISTRY.register(DefinedProxiesCollector())
-    REGISTRY.register(BlockedProxiesCollector())
-    REGISTRY.register(AutomationCollector())
+    registry = CollectorRegistry()
+    registry.register(DefinedProxiesCollector())
+    registry.register(BlockedProxiesCollector())
+    registry.register(AutomationCollector())
 
 
 @app.route('/ui')

run_gunicorn.sh

@@ -0,0 +1,4 @@
+#!/bin/sh
+
+flask db upgrade
+gunicorn "$FLASK_APP".__init__:app -w "$GUNICORN_WORKERS" --access-logfile=- -b "$GUNICORN_RUN_HOST:$GUNICORN_RUN_PORT"