Revert "Feature 11071: Modular OSM installation. Remove charms, juju and lxd"

This reverts commit a0f0d8ef4f2aa0dd227ecb651002490b66498bab.

Change-Id: I92394e4074dad4e457c107c58e4ebc17d507f8b2
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/installers/charm/juju-simplestreams-operator/src/charm.py b/installers/charm/juju-simplestreams-operator/src/charm.py
new file mode 100755
index 0000000..555aab0
--- /dev/null
+++ b/installers/charm/juju-simplestreams-operator/src/charm.py
@@ -0,0 +1,249 @@
+#!/usr/bin/env python3
+# Copyright 2022 Canonical Ltd.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+# For those usages not covered by the Apache License, Version 2.0 please
+# contact: legal@canonical.com
+#
+# To get in touch with the maintainers, please contact:
+# osm-charmers@lists.launchpad.net
+#
+#
+# Learn more at: https://juju.is/docs/sdk
+
+"""Juju simpletreams charm."""
+
+import logging
+import subprocess
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Any, Dict
+
+from charms.nginx_ingress_integrator.v0.ingress import IngressRequires
+from charms.observability_libs.v1.kubernetes_service_patch import KubernetesServicePatch
+from charms.osm_libs.v0.utils import (
+    CharmError,
+    check_container_ready,
+    check_service_active,
+)
+from lightkube.models.core_v1 import ServicePort
+from ops.charm import ActionEvent, CharmBase
+from ops.main import main
+from ops.model import ActiveStatus, Container
+
+SERVICE_PORT = 8080
+
+logger = logging.getLogger(__name__)
+container_name = "server"
+
+
+@dataclass
+class ImageMetadata:
+    """Image Metadata."""
+
+    region: str
+    auth_url: str
+    image_id: str
+    series: str
+
+
+class JujuSimplestreamsCharm(CharmBase):
+    """Simplestreams Kubernetes sidecar charm."""
+
+    def __init__(self, *args):
+        super().__init__(*args)
+        self.ingress = IngressRequires(
+            self,
+            {
+                "service-hostname": self.external_hostname,
+                "service-name": self.app.name,
+                "service-port": SERVICE_PORT,
+            },
+        )
+        event_handler_mapping = {
+            # Core lifecycle events
+            self.on["server"].pebble_ready: self._on_server_pebble_ready,
+            self.on.update_status: self._on_update_status,
+            self.on["peer"].relation_changed: self._push_image_metadata_from_relation,
+            # Action events
+            self.on["add-image-metadata"].action: self._on_add_image_metadata_action,
+        }
+
+        for event, handler in event_handler_mapping.items():
+            self.framework.observe(event, handler)
+
+        port = ServicePort(SERVICE_PORT, name=f"{self.app.name}")
+        self.service_patcher = KubernetesServicePatch(self, [port])
+        self.container: Container = self.unit.get_container(container_name)
+        self.unit.set_workload_version(self.unit.name)
+
+    @property
+    def external_hostname(self) -> str:
+        """External hostname property.
+
+        Returns:
+            str: the external hostname from config.
+                If not set, return the ClusterIP service name.
+        """
+        return self.config.get("external-hostname") or self.app.name
+
+    # ---------------------------------------------------------------------------
+    #   Handlers for Charm Events
+    # ---------------------------------------------------------------------------
+
+    def _on_server_pebble_ready(self, _) -> None:
+        """Handler for the config-changed event."""
+        try:
+            self._push_configuration()
+            self._configure_service()
+            self._push_image_metadata_from_relation()
+            # Update charm status
+            self._on_update_status()
+        except CharmError as e:
+            logger.debug(e.message)
+            self.unit.status = e.status
+
+    def _on_update_status(self, _=None) -> None:
+        """Handler for the update-status event."""
+        try:
+            check_container_ready(self.container)
+            check_service_active(self.container, container_name)
+            self.unit.status = ActiveStatus()
+        except CharmError as e:
+            logger.debug(e.message)
+            self.unit.status = e.status
+
+    def _push_image_metadata_from_relation(self, _=None):
+        subprocess.run(["rm", "-rf", "/tmp/simplestreams"])
+        subprocess.run(["mkdir", "-p", "/tmp/simplestreams"])
+        image_metadata_dict = self._get_image_metadata_from_relation()
+        for image_metadata in image_metadata_dict.values():
+            subprocess.run(
+                [
+                    "files/juju-metadata",
+                    "generate-image",
+                    "-d",
+                    "/tmp/simplestreams",
+                    "-i",
+                    image_metadata.image_id,
+                    "-s",
+                    image_metadata.series,
+                    "-r",
+                    image_metadata.region,
+                    "-u",
+                    image_metadata.auth_url,
+                ]
+            )
+        subprocess.run(["chmod", "555", "-R", "/tmp/simplestreams"])
+        self.container.push_path("/tmp/simplestreams", "/app/static")
+
+    def _on_add_image_metadata_action(self, event: ActionEvent):
+        relation = self.model.get_relation("peer")
+        try:
+            if not relation:
+                raise Exception("charm has not been fully initialized. Try again later.")
+            if not self.unit.is_leader():
+                raise Exception("I am not the leader!")
+            if any(
+                prohibited_char in param_value
+                for prohibited_char in ",; "
+                for param_value in event.params.values()
+            ):
+                event.fail("invalid params")
+                return
+
+            image_metadata_dict = self._get_image_metadata_from_relation()
+
+            new_image_metadata = ImageMetadata(
+                region=event.params["region"],
+                auth_url=event.params["auth-url"],
+                image_id=event.params["image-id"],
+                series=event.params["series"],
+            )
+
+            image_metadata_dict[event.params["image-id"]] = new_image_metadata
+
+            new_relation_data = []
+            for image_metadata in image_metadata_dict.values():
+                new_relation_data.append(
+                    f"{image_metadata.image_id};{image_metadata.series};{image_metadata.region};{image_metadata.auth_url}"
+                )
+            relation.data[self.app]["data"] = ",".join(new_relation_data)
+        except Exception as e:
+            event.fail(f"Action failed: {e}")
+            logger.error(f"Action failed: {e}")
+
+    # ---------------------------------------------------------------------------
+    #   Validation and configuration and more
+    # ---------------------------------------------------------------------------
+
+    def _get_image_metadata_from_relation(self) -> Dict[str, ImageMetadata]:
+        if not (relation := self.model.get_relation("peer")):
+            return {}
+
+        image_metadata_dict: Dict[str, ImageMetadata] = {}
+
+        relation_data = relation.data[self.app].get("data", "")
+        if relation_data:
+            for image_metadata_string in relation_data.split(","):
+                image_id, series, region, auth_url = image_metadata_string.split(";")
+                image_metadata_dict[image_id] = ImageMetadata(
+                    region=region,
+                    auth_url=auth_url,
+                    image_id=image_id,
+                    series=series,
+                )
+
+        return image_metadata_dict
+
+    def _configure_service(self) -> None:
+        """Add Pebble layer with the ro service."""
+        logger.debug(f"configuring {self.app.name} service")
+        self.container.add_layer(container_name, self._get_layer(), combine=True)
+        self.container.replan()
+
+    def _push_configuration(self) -> None:
+        """Push nginx configuration to the container."""
+        self.container.push("/etc/nginx/nginx.conf", Path("files/nginx.conf").read_text())
+        self.container.make_dir("/app/static", make_parents=True)
+
+    def _update_ingress_config(self) -> None:
+        """Update ingress config in relation."""
+        ingress_config = {
+            "service-hostname": self.external_hostname,
+            "max-body-size": self.config["max-body-size"],
+        }
+        if "tls-secret-name" in self.config:
+            ingress_config["tls-secret-name"] = self.config["tls-secret-name"]
+        logger.debug(f"updating ingress-config: {ingress_config}")
+        self.ingress.update_config(ingress_config)
+
+    def _get_layer(self) -> Dict[str, Any]:
+        """Get layer for Pebble."""
+        return {
+            "summary": "server layer",
+            "description": "pebble config layer for server",
+            "services": {
+                container_name: {
+                    "override": "replace",
+                    "summary": "server service",
+                    "command": 'nginx -g "daemon off;"',
+                    "startup": "enabled",
+                }
+            },
+        }
+
+
+if __name__ == "__main__":  # pragma: no cover
+    main(JujuSimplestreamsCharm)