1 files changed, 114 insertions, 0 deletions
diff --git a/ice_validator/preload/engine.py b/ice_validator/preload/engine.py
new file mode 100644
index 0000000..488766d
--- /dev/null
+++ b/ice_validator/preload/engine.py
@@ -0,0 +1,114 @@
+import importlib
+import inspect
+import os
+import pkgutil
+import shutil
+from itertools import chain
+from pathlib import Path
+from typing import List, Type
+
+from preload.data import AbstractPreloadDataSource
+from preload.generator import AbstractPreloadGenerator
+from preload.model import get_heat_templates, Vnf
+from tests.helpers import get_output_dir
+
+
+def create_preloads(config, exitstatus):
+    """
+    Create preloads in every format that can be discovered by get_generator_plugins
+    """
+    if config.getoption("self_test"):
+        return
+    print("+===================================================================+")
+    print("|                      Preload Template Generation                  |")
+    print("+===================================================================+")
+
+    preload_dir = os.path.join(get_output_dir(config), "preloads")
+    if os.path.exists(preload_dir):
+        shutil.rmtree(preload_dir)
+    plugins = PluginManager()
+    available_formats = [p.format_name() for p in plugins.preload_generators]
+    selected_formats = config.getoption("preload_formats") or available_formats
+    preload_source = None
+    if config.getoption("preload_source"):
+        preload_source_path = Path(config.getoption("preload_source"))
+        source_class = plugins.get_source_for_id(
+            config.getoption("preload_source_type")
+        )
+        preload_source = source_class(preload_source_path)
+
+    heat_templates = get_heat_templates(config)
+    vnf = None
+    for plugin_class in plugins.preload_generators:
+        if plugin_class.format_name() not in selected_formats:
+            continue
+        vnf = Vnf(heat_templates)
+        generator = plugin_class(vnf, preload_dir, preload_source)
+        generator.generate()
+    if vnf and vnf.uses_contrail:
+        print(
+            "\nWARNING: Preload template generation does not support Contrail\n"
+            "at this time, but Contrail resources were detected. The preload \n"
+            "template may be incomplete."
+        )
+    if exitstatus != 0:
+        print(
+            "\nWARNING: Heat violations detected. Preload templates may be\n"
+            "incomplete or have errors."
+        )
+
+
+def is_implementation_of(class_, base_class):
+    """
+    Returns True if the class is an implementation of AbstractPreloadGenerator
+    """
+    return (
+        inspect.isclass(class_)
+        and not inspect.isabstract(class_)
+        and issubclass(class_, base_class)
+    )
+
+
+def get_implementations_of(class_, modules):
+    """
+    Returns all classes that implement ``class_`` from modules
+    """
+    members = list(
+        chain.from_iterable(
+            inspect.getmembers(mod, lambda c: is_implementation_of(c, class_))
+            for mod in modules
+        )
+    )
+    return [m[1] for m in members]
+
+
+class PluginManager:
+    def __init__(self):
+        self.preload_plugins = [
+            importlib.import_module(name)
+            for finder, name, ispkg in pkgutil.iter_modules()
+            if name.startswith("preload_") or name == "preload"
+        ]
+        self.preload_generators: List[
+            Type[AbstractPreloadGenerator]
+        ] = get_implementations_of(AbstractPreloadGenerator, self.preload_plugins)
+        self.preload_sources: List[
+            Type[AbstractPreloadDataSource]
+        ] = get_implementations_of(AbstractPreloadDataSource, self.preload_plugins)
+
+    def get_source_for_id(self, identifier: str) -> Type[AbstractPreloadDataSource]:
+        for source in self.preload_sources:
+            if identifier == source.get_identifier():
+                return source
+        raise RuntimeError(
+            "Unable to find preload source for identifier {}".format(identifier)
+        )
+
+    def get_source_for_name(self, name: str) -> Type[AbstractPreloadDataSource]:
+        for source in self.preload_sources:
+            if name == source.get_name():
+                return source
+        raise RuntimeError("Unable to find preload source for name {}".format(name))
+
+
+PLUGIN_MGR = PluginManager()