Feat/sms 46 bind UI and api to different addresses

CHANGELOG.md

@@ -10,6 +10,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## CI - updates
 
 - Fixed deprecated job versions in the CI
+## [0.10.0] - 2025-08-12
+
+- API and dashboard can now run on separate addresses (#46).
 
 ## [0.9.0] - 2024-05-30
 

cos_alerter/alerter.py

@@ -80,6 +80,13 @@ def reload(self):
             self.data["notify"]["repeat_interval"]
         ).total_seconds()
 
+        # if dashboard address key is missing, set it to None
+        dashboard_addr = None
+        try:
+            dashboard_addr = self.data["dashboard_listen_addr"]
+        except KeyError:
+            self.data["dashboard_listen_addr"] = dashboard_addr
+
         # Static variables. We define them here so it is easy to expose them later as config
         # values if needed.
         base_dir = xdg_base_dirs.xdg_state_home() / "cos_alerter"

cos_alerter/config-defaults.yaml

@@ -45,3 +45,8 @@ log_level: "info"
 # The address to listen on for http traffic.
 # Format HOST:PORT
 web_listen_addr: "0.0.0.0:8080"
+
+# Optional: Separate address for the dashboard UI.
+# If not set, dashboard will be served on the same address as the API.
+# Format HOST:PORT
+# dashboard_listen_addr: "127.0.0.1:8081"

cos_alerter/daemon.py

@@ -16,7 +16,7 @@
 
 from .alerter import AlerterState, config, send_test_notification, up_time
 from .logging import LEVELS, init_logging
-from .server import app
+from .server import create_app
 
 logger = logging.getLogger("cos_alerter.daemon")
 
@@ -98,21 +98,61 @@ def main(run_for: Optional[int] = None, argv: List[str] = sys.argv):
         if not str(e) == "signal only works in main thread of the main interpreter":
             raise  # pragma: no cover
 
-    # Start the web server.
+    # Start the web server(s).
     # Starting in a thread rather than a new process allows waitress to inherit the log level
     # from the daemon. It also facilitates communication over memory rather than files.
     # clear_untrusted_proxy_headers is set to suppress a DeprecationWarning.
-    server_thread = threading.Thread(
-        target=waitress.serve,
-        args=(app,),
-        kwargs={
-            "clear_untrusted_proxy_headers": True,
-            "listen": config["web_listen_addr"],
-        },
-    )
-    server_thread.daemon = True  # Makes this thread exit when the main thread exits.
-    logger.info("Starting the web server thread.")
-    server_thread.start()
+    # If dashboard_lister_addr exists, serve api and dashboard in their own respective addresses
+
+    dashboard_listen_addr = config["dashboard_listen_addr"]
+    web_listen_addr = config["web_listen_addr"]
+
+    if dashboard_listen_addr:
+        logger.info(
+            "Starting API server on %s, dashboard on %s",
+            config["web_listen_addr"],
+            dashboard_listen_addr,
+        )
+
+        # API server
+        api_app = create_app(include_api=True, include_dashboard=False)
+        api_server_thread = threading.Thread(
+            target=waitress.serve,
+            args=(api_app,),
+            kwargs={
+                "clear_untrusted_proxy_headers": True,
+                "listen": web_listen_addr,
+            },
+        )
+        api_server_thread.daemon = True
+        api_server_thread.start()
+
+        # Dashboard server
+        dashboard_app = create_app(include_api=False, include_dashboard=True)
+        dashboard_server_thread = threading.Thread(
+            target=waitress.serve,
+            args=(dashboard_app,),
+            kwargs={
+                "clear_untrusted_proxy_headers": True,
+                "listen": dashboard_listen_addr,
+            },
+        )
+        dashboard_server_thread.daemon = True
+        dashboard_server_thread.start()
+
+    else:
+        logger.info("Starting API server and dashboard on %s", config["web_listen_addr"])
+        app = create_app(include_api=True, include_dashboard=True)
+        server_thread = threading.Thread(
+            target=waitress.serve,
+            args=(app,),
+            kwargs={
+                "clear_untrusted_proxy_headers": True,
+                "listen": web_listen_addr,
+            },
+        )
+        server_thread.daemon = True
+        server_thread.start()
 
     for clientid in config["watch"]["clients"]:
         client_thread = threading.Thread(target=client_loop, args=(clientid,))

cos_alerter/server.py

@@ -12,12 +12,41 @@
 
 from .alerter import AlerterState, config, now_datetime
 
-app = Flask(__name__)
-metrics = PrometheusMetrics(app)
 logger = logging.getLogger(__name__)
 
 
-@app.route("/", methods=["GET"])
+def create_app(include_api: bool = True, include_dashboard: bool = True) -> Flask:
+    """Create Flask app with specified endpoints.
+
+    Args:
+        include_api: Whether to include the /alive API endpoint
+        include_dashboard: Whether to include the / dashboard endpoint
+
+    Returns:
+        Flask application instance
+    """
+    app = Flask(__name__)
+    metrics = PrometheusMetrics(app)  # noqa: F841
+
+    if include_dashboard:
+
+        @app.route("/", methods=["GET"])
+        def dashboard_route():
+            return dashboard()
+
+    if include_api:
+
+        @app.route("/alive", methods=["POST"])
+        def alive_route():
+            return alive()
+
+    @app.before_request
+    def log_request_wrapper():
+        return log_request()
+
+    return app
+
+
 def dashboard():
     """Endpoint for the COS Alerter dashboard."""
     clients = []
@@ -40,7 +69,6 @@ def dashboard():
     return render_template("dashboard.html", clients=clients)
 
 
-@app.route("/alive", methods=["POST"])
 def alive():
     """Endpoint for Alertmanager instances to send their heartbeat alerts."""
     # TODO Decide if we should validate the request.
@@ -74,7 +102,6 @@ def alive():
     return "Success!"
 
 
-@app.before_request
 def log_request():
     """Log every HTTP request."""
     logger.info(

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "cos-alerter"
-version = "0.9.0"
+version = "0.10.0"
 authors = [
   { name="Dylan Stephano-Shachter", email="dylan.stephano-shachter@canonical.com" }
 ]

rockcraft.yaml

@@ -1,7 +1,7 @@
 name: cos-alerter
 summary: A liveness checker for self-monitoring.
 description: Receive regular pings from the cos stack and alert when they stop.
-version: "0.9.0"
+version: "0.10.0"
 base: ubuntu@22.04
 license: Apache-2.0
 platforms:

tests/test_server.py

@@ -9,13 +9,14 @@
 from werkzeug.datastructures import MultiDict
 
 from cos_alerter.alerter import AlerterState, config
-from cos_alerter.server import app
+from cos_alerter.server import create_app
 
 PARAMS = {"clientid": "clientid1", "key": "clientkey1"}
 
 
 @pytest.fixture
 def flask_client():
+    app = create_app()
     return app.test_client()
 
 
@@ -111,3 +112,21 @@ def test_multiple_key_values(flask_client, fake_fs, state_init):
     )
     assert response.status_code == 400
     assert len(response.data) > 0
+
+
+def test_create_app_api_only(fake_fs, state_init):
+    app_instance = create_app(include_api=True, include_dashboard=False)
+    client = app_instance.test_client()
+
+    # Only API endpoint should be available
+    assert client.get("/").status_code == 404
+    assert client.post("/alive", query_string=PARAMS).status_code == 200
+
+
+def test_create_app_dashboard_only(fake_fs, state_init):
+    app_instance = create_app(include_api=False, include_dashboard=True)
+    client = app_instance.test_client()
+
+    # Only dashboard endpoint should be available
+    assert client.get("/").status_code == 200
+    assert client.post("/alive", query_string=PARAMS).status_code == 404