feat: add slurm_ops and is_container charm libs to project

Signed-off-by: Jason C. Nucciarone <[email protected]>

external/lib/charms/hpc_libs/v0/is_container.py

@@ -0,0 +1,81 @@
+# Copyright 2024 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.
+
+"""Detect if machine is a container instance.
+
+Even though Juju supports using LXD containers as the backing cloud for
+deploying charmed operators, not all HPC applications work within system containers,
+and some need additional configuration. This simple charm library provides utilities
+for identifying the virtualization runtime for a charmed operator.
+
+### Example Usage:
+
+```python3
+from charms.hpc_libs.v0.is_container import is_container
+
+class ApplicationCharm(CharmBase):
+
+    def __init__(self, *args):
+        super().__init__(*args)
+
+        self.framework.observe(self.on.install, self._on_install)
+
+    def _on_install(self, _: InstallEvent) -> None:
+        if is_container():
+            self.unit.status = BlockedStatus("app does not support container runtime")
+
+        # Proceed with installation.
+        ...
+```
+"""
+
+import shutil
+import subprocess
+
+# The unique Charmhub library identifier, never change it
+LIBID = "eb95ad73da1941c0af186ee670f96507"
+
+# Increment this major API version when introducing breaking changes
+LIBAPI = 0
+
+# Increment this PATCH version before using `charmcraft publish-lib` or reset
+# to 0 if you are raising the major API version
+LIBPATCH = 1
+
+
+class UnknownVirtStateError(Exception):
+    """Raise error if unknown virtualization state is returned."""
+
+    @property
+    def message(self) -> str:
+        """Return message passed as argument to exception."""
+        return self.args[0]
+
+
+def is_container() -> bool:
+    """Detect if the machine is a container instance.
+
+    Raises:
+        DetectVirtNotFoundError: Raised if `systemd-detect-virt` is not found on machine.
+    """
+    if shutil.which("systemd-detect-virt") is None:
+        raise UnknownVirtStateError(
+            (
+                "executable `systemd-detect-virt` not found. "
+                + "cannot determine if machine is a container instance"
+            )
+        )
+
+    result = subprocess.run(["systemd-detect-virt", "--container"])
+    return result.returncode == 0