Include constants.py and update dispatch

dispatch

@@ -16,14 +16,13 @@ then
 		yum -y install epel-release
 		yum -y install wget gcc make tar bzip2-devel zlib-devel xz-devel openssl-devel libffi-devel sqlite-devel ncurses-devel
 
-		export PYTHON_VERSION=3.8.16		
-		CHARM_DIR=$PWD
+		export PYTHON_VERSION=3.8.16
 		wget https://www.python.org/ftp/python/${PYTHON_VERSION}/Python-${PYTHON_VERSION}.tar.xz -P /tmp
 		tar xvf /tmp/Python-${PYTHON_VERSION}.tar.xz -C /tmp
 		cd /tmp/Python-${PYTHON_VERSION}
 		./configure --enable-optimizations
 		make -C /tmp/Python-${PYTHON_VERSION} -j $(nproc) altinstall		
-		cd $CHARM_DIR
+		cd $OLDPWD
 		rm -rf /tmp/Python*
 
 	elif [[ $ID == 'ubuntu' ]]

lib/charms/operator_libs_linux/v0/juju_systemd_notices.py

@@ -173,12 +173,8 @@ def __init__(self, charm: CharmBase, services: List[str]) -> None:
             self._charm.on.define_event(f"service_{service}_started", ServiceStartedEvent)
             self._charm.on.define_event(f"service_{service}_stopped", ServiceStoppedEvent)
 
-    def subscribe(self, python_bin: str) -> None:
-        """Subscribe charmed operator to observe status of systemd services.
-        
-        Args:
-            python_bin: Path of Python's binary file.
-        """
+    def subscribe(self) -> None:
+        """Subscribe charmed operator to observe status of systemd services."""
         _logger.debug("Generating systemd notice hooks for %s", self._services)
         start_hooks = [Path(f"hooks/service-{service}-started") for service in self._services]
         stop_hooks = [Path(f"hooks/service-{service}-stopped") for service in self._services]
@@ -191,7 +187,6 @@ def subscribe(self, python_bin: str) -> None:
         _logger.debug("Starting %s daemon", self._service_file.name)
         if self._service_file.exists():
             _logger.debug("Overwriting existing service file %s", self._service_file.name)
-
         self._service_file.write_text(
             textwrap.dedent(
                 f"""
@@ -204,7 +199,7 @@ def subscribe(self, python_bin: str) -> None:
                 Restart=always
                 WorkingDirectory={self._charm.framework.charm_dir}
                 Environment="PYTHONPATH={self._charm.framework.charm_dir / "venv"}"
-                ExecStart={python_bin} {__file__} {self._charm.unit.name}
+                ExecStart=/usr/bin/python3 {__file__} {self._charm.unit.name}
 
                 [Install]
                 WantedBy=multi-user.target

src/charm.py

@@ -7,7 +7,6 @@
 import logging
 from pathlib import Path
 
-import distro
 from charms.fluentbit.v0.fluentbit import FluentbitClient
 from charms.operator_libs_linux.v0.juju_systemd_notices import (
     ServiceStartedEvent,
@@ -48,12 +47,6 @@ def __init__(self, *args, **kwargs):
         self._slurmd = Slurmd(self, "slurmd")
         self._systemd_notices = SystemdNotices(self, ["slurmd"])
 
-        # use an specific python version for CentOS 7
-        if distro.id() == "centos":
-            self._python_bin = "/usr/bin/env python3.8"
-        else:
-            self._python_bin = "/usr/bin/python3"
-
         event_handler_bindings = {
             self.on.install: self._on_install,
             self.on.upgrade_charm: self._on_upgrade,
@@ -91,12 +84,12 @@ def _on_install(self, event):
         successful_installation = self._slurm_manager.install(
             self.config.get("custom-slurm-repo"), nhc_path
         )
-        slurmd.override_service(self._python_bin)
+        slurmd.override_service()
         logger.debug(f"### slurmd installed: {successful_installation}")
 
         if successful_installation:
             self._stored.slurm_installed = True
-            self._systemd_notices.subscribe(self._python_bin)
+            self._systemd_notices.subscribe()
         else:
             self.unit.status = BlockedStatus("Error installing slurmd")
             event.defer()

src/constants.py

@@ -0,0 +1,20 @@
+#!/usr/bin/python3
+# Copyright 2023 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.
+
+"""File containing constants to be used in the charm."""
+
+import distro
+
+DISTRO_ID = distro.id()

src/utils/slurmd.py

@@ -28,6 +28,7 @@
 from pathlib import Path
 
 import charms.operator_libs_linux.v1.systemd as systemd
+from constants import DISTRO_ID
 
 _logger = logging.getLogger(__name__)
 
@@ -59,18 +60,15 @@ def override_default(host: str, port: int) -> None:
         textwrap.dedent(
             f"""
             SLURMD_OPTIONS="--conf-server {host}:{port}"
-            PYTHONPATH={Path.cwd() / "lib"}
+            PYTHONPATH={Path.cwd() / "lib"}:{Path.cwd() / "venv"}
             """
         ).strip()
     )
 
 
-def override_service(python_bin: str) -> None:
+def override_service() -> None:
     """Override the default slurmd systemd service file.
 
-    Args:
-        python_bin: Path of Python's binary file.
-
     Notes:
         This method makes an invokes `systemd daemon-reload` after writing
         the overrides.conf file for slurmd. This invocation will reload
@@ -80,6 +78,12 @@ def override_service(python_bin: str) -> None:
     if not (override_dir := Path("/etc/systemd/system/slurmd.service.d")).is_dir():
         override_dir.mkdir()
 
+    # use an specific python version for CentOS 7
+    if DISTRO_ID == "centos":
+        python_bin = "/usr/bin/env python3.8"
+    else:
+        python_bin = "/usr/bin/python3"
+
     overrides = override_dir / "99-slurmd-charm.conf"
     overrides.write_text(
         textwrap.dedent(

tests/unit/utils/test_slurmd.py

@@ -48,14 +48,14 @@ def test_overwrite_default(self, _) -> None:
     @patch("charms.operator_libs_linux.v1.systemd._systemctl")
     def test_override_service_no_service_d(self, *_) -> None:
         """Test override_service(...) when slurmd.service.d does not exist."""
-        slurmd.override_service(python_bin="/usr/bin/python3")
+        slurmd.override_service()
 
     @patch("pathlib.Path.is_dir", return_value=True)
     @patch("pathlib.Path.write_text")
     @patch("charms.operator_libs_linux.v1.systemd._systemctl")
     def test_override_service_yes_service_d(self, *_) -> None:
         """Test override_service(...) when slurmd.service.d exists."""
-        slurmd.override_service(python_bin="/usr/bin/python3")
+        slurmd.override_service()
 
     @patch("datetime.timedelta", return_value=datetime.timedelta(-1))
     def test_start_slurmd_service_fail(self, _) -> None: