feat: abstract around base package manager

lib/charms/hpc_libs/v0/slurm_ops.py

@@ -73,6 +73,7 @@ def _on_install(self, _) -> None:
 from collections.abc import Mapping
 from enum import Enum
 from typing import Any, Optional
+from abc import ABC, abstractmethod
 
 import yaml
 
@@ -84,7 +85,7 @@ def _on_install(self, _) -> None:
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 5
+LIBPATCH = 6
 
 # Charm library dependencies to fetch during `charmcraft pack`.
 PYDEPS = ["pyyaml>=6.0.1"]
@@ -124,20 +125,6 @@ def format_key(key: str) -> str:
     return _kebabize.sub(r"-", key).lower()
 
 
-def install() -> None:
-    """Install Slurm."""
-    # FIXME: Pin slurm to the stable channel
-    _snap("install", "slurm", "--channel", "latest/candidate", "--classic")
-
-
-def version() -> str:
-    """Get the current version of Slurm installed on the system."""
-    info = yaml.safe_load(_snap("info", "slurm"))
-    if (ver := info.get("installed")) is None:
-        raise SlurmOpsError("unable to retrive snap info. Ensure slurm is correctly installed")
-    return ver.split(maxsplit=1)[0]
-
-
 def _call(cmd: str, *args: str, stdin: Optional[str] = None) -> str:
     """Call a command with logging.
 
@@ -175,7 +162,6 @@ def _mungectl(*args: str, stdin: Optional[str] = None) -> str:
     """
     return _call("slurm.mungectl", *args, stdin=stdin)
 
-
 class ServiceType(Enum):
     """Type of Slurm service to manage."""
 
@@ -196,10 +182,100 @@ def config_name(self) -> str:
 
         return self.value
 
+class ServiceManager(ABC):
+    """Control a Slurm service."""
+
+    @abstractmethod
+    def enable(self) -> None:
+        """Enable service."""
+        pass
+
+    @abstractmethod
+    def disable(self) -> None:
+        """Disable service."""
+        pass
+
+    @abstractmethod
+    def restart(self) -> None:
+        """Restart service."""
+        pass
+
+    @abstractmethod
+    def active(self) -> bool:
+        """Return True if the service is active."""
+        pass
+
+class ConfigurationManager(ABC):
+    """Control configuration of a Slurm component."""
+
+    def get_options(self, *keys: str) -> Mapping[str, Any]:
+        """Get given configurations values for Slurm component."""
+        configs = {}
+        for key in keys:
+            config = self.get(key)
+            target = key.rsplit(".", maxsplit=1)[-1]
+            configs[target] = config
+
+        return configs
+
+    @abstractmethod
+    def get(self, key: Optional[str] = None) -> Any:
+        """Get specific configuration value for Slurm component."""
+        pass
+
+    @abstractmethod
+    def set(self, config: Mapping[str, Any]) -> None:
+        """Set configuration for Slurm component."""
+        pass
+
+    @abstractmethod
+    def unset(self, *keys: str) -> None:
+        """Unset configuration for Slurm component."""
+        pass
+
+
+class SlurmOpsManager(ABC):
+    @abstractmethod
+    def install(self) -> None:
+        """Install Slurm."""
+        pass
+
+    @abstractmethod
+    def version(self) -> str:
+        """Get the current version of Slurm installed on the system."""
+        pass
+
+    @abstractmethod
+    def service_for(self, service: ServiceType) -> ServiceManager:
+        pass
+
+    @abstractmethod
+    def configuration_manager_for(self, service: ServiceType) -> ConfigurationManager:
+        pass
 
-class ServiceManager:
+class SnapManager(SlurmOpsManager):
+    def install(self) -> None:
+        # FIXME: Pin slurm to the stable channel
+        _snap("install", "slurm", "--channel", "latest/candidate", "--classic")
+
+    def version(self) -> str:
+        info = yaml.safe_load(_snap("info", "slurm"))
+        if (ver := info.get("installed")) is None:
+            raise SlurmOpsError("unable to retrive snap info. Ensure slurm is correctly installed")
+        return ver.split(maxsplit=1)[0]
+
+    def service_for(self, service: ServiceType) -> ServiceManager:
+        return _SnapServiceManager(service)
+
+    def configuration_manager_for(self, service: ServiceType) -> ConfigurationManager:
+        return _SnapConfigurationManager(service.config_name)
+
+class _SnapServiceManager(ServiceManager):
     """Control a Slurm service."""
 
+    def __init__(self, service: ServiceType) -> None:
+        self._service = service
+
     def enable(self) -> None:
         """Enable service."""
         _snap("start", "--enable", f"slurm.{self._service.value}")
@@ -224,22 +300,12 @@ def active(self) -> bool:
         return "inactive" not in services[f"slurm.{self._service.value}"]
 
 
-class ConfigurationManager:
-    """Control configuration of a Slurm component."""
+class _SnapConfigurationManager(ConfigurationManager):
+    """Control configuration of a Slurm component using Snap"""
 
     def __init__(self, name: str) -> None:
         self._name = name
 
-    def get_options(self, *keys: str) -> Mapping[str, Any]:
-        """Get given configurations values for Slurm component."""
-        configs = {}
-        for key in keys:
-            config = self.get(key)
-            target = key.rsplit(".", maxsplit=1)[-1]
-            configs[target] = config
-
-        return configs
-
     def get(self, key: Optional[str] = None) -> Any:
         """Get specific configuration value for Slurm component."""
         key = f"{self._name}.{key}" if key else self._name
@@ -257,13 +323,12 @@ def unset(self, *keys: str) -> None:
         _snap("unset", "slurm", *args)
 
 
-class MungeManager(ServiceManager):
+class MungeManager:
     """Manage `munged` service operations."""
 
-    def __init__(self) -> None:
-        service = ServiceType.MUNGED
-        self._service = service
-        self.config = ConfigurationManager(service.config_name)
+    def __init__(self, ops_manager: SlurmOpsManager) -> None:
+        self.service = ops_manager.service_for(ServiceType.MUNGED)
+        self.config = ops_manager.configuration_manager_for(ServiceType.MUNGED)
 
     def get_key(self) -> str:
         """Get the current munge key.
@@ -286,18 +351,18 @@ def generate_key(self) -> None:
         _mungectl("key", "generate")
 
 
-class PrometheusExporterManager(ServiceManager):
+class PrometheusExporterManager:
     """Manage `slurm-prometheus-exporter` service operations."""
 
-    def __init__(self) -> None:
-        self._service = ServiceType.PROMETHEUS_EXPORTER
+    def __init__(self, ops_manager: SlurmOpsManager) -> None:
+        self.service = ops_manager.service_for(ServiceType.PROMETHEUS_EXPORTER)
 
 
-class SlurmManagerBase(ServiceManager):
+class SlurmManagerBase:
     """Base manager for Slurm services."""
 
-    def __init__(self, service: ServiceType) -> None:
-        self._service = service
+    def __init__(self, service: ServiceType, ops_manager: SlurmOpsManager) -> None:
+        self.service = ops_manager.service_for(service)
         self.config = ConfigurationManager(service.config_name)
         self.munge = MungeManager()
         self.exporter = PrometheusExporterManager()