diff --git a/frontend/charm/src/charm.py b/frontend/charm/src/charm.py
index 7894d422..d3f2451d 100755
--- a/frontend/charm/src/charm.py
+++ b/frontend/charm/src/charm.py
@@ -7,11 +7,11 @@
"""Test Observer frontend charm."""
import logging
+import sys
from typing import Tuple
import ops
from charms.nginx_ingress_integrator.v0.nginx_route import require_nginx_route
-from ops.framework import StoredState
from ops.model import (
ActiveStatus,
BlockedStatus,
@@ -26,8 +26,6 @@
class TestObserverFrontendCharm(ops.CharmBase):
"""The frontend charm operates serving the frontend through nginx."""
- _stored = StoredState()
-
def __init__(self, *args):
super().__init__(*args)
self.pebble_service_name = "test-observer-frontend"
@@ -48,8 +46,6 @@ def __init__(self, *args):
self._on_rest_api_relation_broken,
)
- self._stored.set_default(backend_hostname=None, backend_port=None)
-
self._setup_ingress()
def _setup_ingress(self):
@@ -94,20 +90,12 @@ def _config_is_valid(self, config) -> Tuple[bool, str]:
def _on_rest_api_relation_update(self, event):
api_hostname = event.relation.data[event.app].get("hostname")
api_port = event.relation.data[event.app].get("port")
- logger.debug(f"API hostname: {api_hostname} (app: {event.app})")
-
- if self.unit.is_leader():
- self._stored.backend_hostname = api_hostname
- self._stored.backend_port = api_port
-
+ logger.debug(f"API hostname: {api_hostname}, port: {api_port} (app: {event.app})")
self._update_layer_and_restart(event)
def _on_rest_api_relation_broken(self, event):
- logger.debug("REST API relation broken -> removing backend hostname")
-
- if self.unit.is_leader():
- self._stored.backend_hostname = None
- self._stored.backend_port = None
+ logger.debug("REST API relation broken")
+ self._update_layer_and_restart(event)
def nginx_config(self, base_uri: str) -> str:
"""Return a config where the backend port `base_uri` is adjusted."""
@@ -132,30 +120,96 @@ def nginx_config(self, base_uri: str) -> str:
}}
"""
+ def nginx_503_config(self) -> str:
+ """Return a config for the situation when the backend is not yet available."""
+ return """
+ server {
+ listen 80 default_server;
+ server_name _;
+ return 503;
+ error_page 503 @maintenance;
+
+ location @maintenance {
+ rewrite ^(.*)$ /503.html break;
+ root /usr/share/nginx/html;
+ }
+ }
+ """
+
+ def html_503(self) -> str:
+ """Return a 503 response page."""
+ return """
+
+
+ 503 Service Unavailable
+
+
+ 503 Service Unavailable
+ Backend not yet configured.
+
+
+ """
+
def _update_layer_and_restart(self, event):
self.unit.status = MaintenanceStatus(f"Updating {self.pebble_service_name} layer")
+ api_relation = next(iter(self.model.relations["test-observer-rest-api"]), None)
+
+ if api_relation is None:
+ if self.container.can_connect():
+ self.container.add_layer(
+ self.pebble_service_name, self._pebble_layer, combine=True
+ )
+ self.container.push(
+ "/etc/nginx/sites-available/test-observer-frontend",
+ self.nginx_503_config(),
+ make_dirs=True,
+ )
+ self.container.push(
+ "/usr/share/nginx/html/503.html",
+ self.html_503(),
+ make_dirs=True,
+ )
+ self.container.restart(self.pebble_service_name)
+ self.unit.status = MaintenanceStatus(
+ "test-observer-rest-api relation not connected."
+ )
+ else:
+ self.unit.status = WaitingStatus(
+ "Waiting for Pebble for API to set maintenance state"
+ )
+
+ return
+
+ relation_data = api_relation.data[api_relation.app]
+ if not relation_data:
+ self.unit.status = WaitingStatus("Waiting for test observer api relation data")
+ sys.exit()
+
+ hostname = api_relation.data[api_relation.app]["hostname"]
+ port = api_relation.data[api_relation.app]["port"]
+
scheme = self.config["test-observer-api-scheme"]
- hostname = self._stored.backend_hostname
- port = self._stored.backend_port
+
+ logger.info(f"Hostname: {hostname} (from relation: {hostname})")
+ logger.info(f"Port: {port} (from relation: {port})")
if int(port) == 80 or int(port) == 443:
base_uri = f"{scheme}{hostname}"
else:
base_uri = f"{scheme}{hostname}:{port}"
- self.container.push(
- "/etc/nginx/sites-available/test-observer-frontend",
- self.nginx_config(base_uri=base_uri),
- make_dirs=True,
- )
-
if self.container.can_connect():
self.container.add_layer(self.pebble_service_name, self._pebble_layer, combine=True)
+ self.container.push(
+ "/etc/nginx/sites-available/test-observer-frontend",
+ self.nginx_config(base_uri=base_uri),
+ make_dirs=True,
+ )
self.container.restart(self.pebble_service_name)
self.unit.status = ActiveStatus()
else:
- self.unit.status = WaitingStatus("Waiting for Pebble for API")
+ self.unit.status = WaitingStatus("Waiting for Pebble for API to set available state")
@property
def _pebble_layer(self):