Initial commit

src/charm.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+# Copyright 2026 Valentin Haudiquet
+# See LICENSE file for licensing details.
+
+"""Charm the application."""
+
+import logging
+import time
+
+import ops
+
+# A standalone module for workload-specific logic (no charming concerns):
+import charmed_server
+
+logger = logging.getLogger(__name__)
+
+
+class CharmedServerCharm(ops.CharmBase):
+    """Charm the application."""
+
+    def __init__(self, framework: ops.Framework):
+        super().__init__(framework)
+        framework.observe(self.on.install, self._on_install)
+        framework.observe(self.on.start, self._on_start)
+        framework.observe(self.on.config_changed, self._on_config_changed)
+
+    def _on_install(self, event: ops.InstallEvent):
+        """Install the workload on the machine."""
+        charmed_server.install()
+
+    def _on_start(self, event: ops.StartEvent):
+        """Handle start event."""
+        self.unit.status = ops.MaintenanceStatus("starting workload")
+        self.configure_and_run()
+        version = charmed_server.get_version()
+        if version is not None:
+            self.unit.set_workload_version(version)
+        self.unit.status = ops.ActiveStatus()
+
+    def _on_config_changed(self, event: ops.ConfigChangedEvent) -> None:
+        """Handle config-changed event."""
+        self.configure_and_run()
+
+    def configure_and_run(self) -> None:
+        """Ensure that nginx is running with the correct config."""
+        if not charmed_server.is_installed():
+            return
+        changed = charmed_server.ensure_config()
+        if not charmed_server.is_running():
+            charmed_server.start()
+            self.wait_for_running()
+        elif changed:
+            logger.info("Config changed while nginx is running. Updating nginx config")
+            charmed_server.reload_config()
+
+    def wait_for_running(self) -> None:
+        """Wait for nginx to be running."""
+        for _ in range(3):
+            if charmed_server.is_running():
+                return
+            time.sleep(1)
+        raise RuntimeError("nginx was not running within the expected time")
+
+    def _on_stop(self, event: ops.StopEvent) -> None:
+        """Handle stop event."""
+        charmed_server.stop()
+
+
+if __name__ == "__main__":  # pragma: nocover
+    ops.main(CharmedServerCharm)