Replace Flask built-in WSGI server with gunicorn (#2158)

setup/management.sh

@@ -50,7 +50,7 @@ hide_output $venv/bin/pip install --upgrade pip
 # NOTE: email_validator is repeated in setup/questions.sh, so please keep the versions synced.
 hide_output $venv/bin/pip install --upgrade \
 	rtyaml "email_validator>=1.0.0" "exclusiveprocess" \
-	flask dnspython python-dateutil expiringdict \
+	flask dnspython python-dateutil expiringdict gunicorn \
 	qrcode[pil] pyotp \
 	"idna>=2.0.0" "cryptography==37.0.2" psutil postfix-mta-sts-resolver \
 	b2sdk boto3
@@ -90,6 +90,7 @@ rm -f /tmp/bootstrap.zip
 
 # Create an init script to start the management daemon and keep it
 # running after a reboot.
+# Note: Authentication currently breaks with more than 1 gunicorn worker.
 cat > $inst_dir/start <<EOF;
 #!/bin/bash
 # Set character encoding flags to ensure that any non-ASCII don't cause problems.
@@ -98,8 +99,13 @@ export LC_ALL=en_US.UTF-8
 export LANG=en_US.UTF-8
 export LC_TYPE=en_US.UTF-8
 
+mkdir -p /var/lib/mailinabox
+tr -cd '[:xdigit:]' < /dev/urandom | head -c 32 > /var/lib/mailinabox/api.key
+chmod 640 /var/lib/mailinabox/api.key
+
 source $venv/bin/activate
-exec python $(pwd)/management/daemon.py
+export PYTHONPATH=$(pwd)/management
+exec gunicorn -b localhost:10222 -w 1 wsgi:app
 EOF
 chmod +x $inst_dir/start
 cp --remove-destination conf/mailinabox.service /lib/systemd/system/mailinabox.service # target was previously a symlink so remove it first