Prototyped dnf_appstream custom promise type

I wasn't looking at the ticket prior to implementation, likely missing things.

Ticket: CFE-3653

Author: nickanderson

promise-types/dnf_appstream/dnf_appstream.py

@@ -0,0 +1,223 @@
+#!/usr/bin/python3
+#
+# Custom promise type to manage DNF AppStream modules
+# Uses cfengine_module_library.py library.
+#
+# Use it in the policy like this:
+# promise agent dnf_appstream
+# {
+#   interpreter => "/usr/bin/python3";
+#   path => "$(sys.inputdir)/dnf_appstream.py";
+# }
+# bundle agent main
+# {
+#   dnf_appstream:
+#       "nodejs"
+#         state => "enabled",
+#         stream => "12";
+# }
+
+import dnf
+import re
+from cfengine_module_library import PromiseModule, ValidationError, Result
+
+
+class DnfAppStreamPromiseTypeModule(PromiseModule):
+    def __init__(self, **kwargs):
+        super(DnfAppStreamPromiseTypeModule, self).__init__(
+            name="dnf_appstream_promise_module", version="0.0.1", **kwargs
+        )
+
+        # Define all expected attributes with their types and validation
+        self.add_attribute("state", str, required=True, default="enabled",
+                          validator=lambda x: self._validate_state(x))
+        self.add_attribute("stream", str, required=False)
+        self.add_attribute("profile", str, required=False)
+
+    def _validate_state(self, value):
+        if value not in ("enabled", "disabled", "installed", "removed"):
+            raise ValidationError("state attribute must be 'enabled', 'disabled', 'installed', or 'removed'")
+
+    def _validate_module_name(self, name):
+        # Validate module name to prevent injection
+        if not re.match(r'^[a-zA-Z0-9_.-]+$', name):
+            raise ValidationError(f"Invalid module name: {name}. Only alphanumeric, underscore, dot, and dash characters are allowed.")
+
+    def _validate_stream_name(self, stream):
+        # Validate stream name to prevent injection
+        if stream and not re.match(r'^[a-zA-Z0-9_.-]+$', stream):
+            raise ValidationError(f"Invalid stream name: {stream}. Only alphanumeric, underscore, dot, and dash characters are allowed.")
+
+    def validate_promise(self, promiser, attributes, meta):
+        # Validate promiser (module name)
+        if not isinstance(promiser, str):
+            raise ValidationError("Promiser must be of type string")
+
+        self._validate_module_name(promiser)
+
+        # Validate stream if provided
+        if "stream" in attributes:
+            self._validate_stream_name(attributes["stream"])
+
+    def evaluate_promise(self, promiser, attributes, meta):
+        module_name = promiser
+        state = attributes.get("state", "enabled")
+        stream = attributes.get("stream", None)
+        profile = attributes.get("profile", None)
+
+        # Construct the module specification
+        module_spec = module_name
+        if stream:
+            module_spec += ":" + stream
+        if profile:
+            module_spec += "/" + profile
+
+        try:
+            # Create a DNF base object
+            base = dnf.Base()
+
+            # Read configuration
+            base.conf.assumeyes = True
+
+            # Read repository information
+            base.read_all_repos()
+
+            # Fill the sack (package database)
+            base.fill_sack(load_system_repo='auto')
+
+            # Access the module base
+            module_base = base.module_base
+            if module_base is None:
+                self.log_error("DNF modules are not available")
+                return Result.NOT_KEPT
+
+            # Check current state of the module
+            current_state = self._get_module_state(module_base, module_name, stream)
+
+            # Determine what action to take based on desired state
+            if state == "enabled":
+                if current_state == "enabled":
+                    self.log_verbose(f"Module {module_name} is already enabled")
+                    return Result.KEPT
+                else:
+                    return self._enable_module(module_base, module_spec)
+            elif state == "disabled":
+                if current_state == "disabled":
+                    self.log_verbose(f"Module {module_name} is already disabled")
+                    return Result.KEPT
+                else:
+                    return self._disable_module(module_base, module_spec)
+            elif state == "installed":
+                if current_state in ["installed", "enabled"]:
+                    # For "installed" state, if it's already installed or enabled,
+                    # we need to install packages from it
+                    # But if it's already installed with packages, we're done
+                    if self._is_module_installed_with_packages(base, module_name, stream):
+                        self.log_verbose(f"Module {module_name} is already installed with packages")
+                        return Result.KEPT
+                    else:
+                        # Module is enabled but packages are not installed
+                        return self._install_module(module_base, module_spec)
+                else:
+                    # Module is not enabled, need to install (which will enable and install packages)
+                    return self._install_module(module_base, module_spec)
+            elif state == "removed":
+                if current_state == "removed" or current_state == "disabled":
+                    self.log_verbose(f"Module {module_name} is already removed or disabled")
+                    return Result.KEPT
+                else:
+                    return self._remove_module(module_base, module_spec)
+
+        except Exception as e:
+            self.log_error(f"Error managing module {module_name}: {str(e)}")
+            return Result.NOT_KEPT
+
+    def _get_module_state(self, module_base, module_name, stream):
+        """Get the current state of a module using DNF Python API"""
+        try:
+            # List all modules to check the current state
+            module_list, _ = module_base._get_modules(module_name)
+
+            for module in module_list:
+                # Check if this is the stream we're looking for (if specified)
+                if stream and module.stream != stream:
+                    continue
+
+                # Check the module state
+                if module.status == "enabled":
+                    return "enabled"
+                elif module.status == "disabled":
+                    return "disabled"
+                elif module.status == "installed":
+                    return "installed"
+
+            # If we get here, module is not found or not in the specified stream
+            return "removed"
+
+        except Exception as e:
+            self.log_error(f"Error getting module state for {module_name}: {str(e)}")
+            return "unknown"
+
+    def _is_module_installed_with_packages(self, base, module_name, stream):
+        """Check if the module packages are actually installed on the system"""
+        try:
+            # Check if packages from the module are installed
+            # This is a more complex check that requires examining installed packages
+            # to see if they are from the specified module
+            return False  # Simplified for now - would need more complex logic
+        except Exception:
+            return False
+
+    def _enable_module(self, module_base, module_spec):
+        """Enable a module using DNF Python API"""
+        try:
+            module_base.enable([module_spec])
+            module_base.base.resolve()
+            module_base.base.do_transaction()
+            self.log_verbose(f"Module {module_spec} enabled successfully")
+            return Result.REPAIRED
+        except Exception as e:
+            self.log_error(f"Failed to enable module {module_spec}: {str(e)}")
+            return Result.NOT_KEPT
+
+    def _disable_module(self, module_base, module_spec):
+        """Disable a module using DNF Python API"""
+        try:
+            module_base.disable([module_spec])
+            module_base.base.resolve()
+            module_base.base.do_transaction()
+            self.log_verbose(f"Module {module_spec} disabled successfully")
+            return Result.REPAIRED
+        except Exception as e:
+            self.log_error(f"Failed to disable module {module_spec}: {str(e)}")
+            return Result.NOT_KEPT
+
+    def _install_module(self, module_base, module_spec):
+        """Install a module (enable + install default packages) using DNF Python API"""
+        try:
+            # Enable and install the module
+            module_base.install([module_spec])
+            module_base.base.resolve()
+            module_base.base.do_transaction()
+            self.log_verbose(f"Module {module_spec} installed successfully")
+            return Result.REPAIRED
+        except Exception as e:
+            self.log_error(f"Failed to install module {module_spec}: {str(e)}")
+            return Result.NOT_KEPT
+
+    def _remove_module(self, module_base, module_spec):
+        """Remove a module using DNF Python API"""
+        try:
+            # Get list of packages from the module to remove
+            module_base.remove([module_spec])
+            module_base.base.resolve()
+            module_base.base.do_transaction()
+            self.log_verbose(f"Module {module_spec} removed successfully")
+            return Result.REPAIRED
+        except Exception as e:
+            self.log_error(f"Failed to remove module {module_spec}: {str(e)}")
+            return Result.NOT_KEPT
+
+
+if __name__ == "__main__":
+    DnfAppStreamPromiseTypeModule().start()