Saving example

Author: JBris

default.yaml

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+workflow:
+  - UpperHook

extend.yaml

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+workflow:
+  - UpperHook
+  - LowerHook
+  - ReverseHook

plugin_base.py

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+import pluggy
+
+HOOK_NAMESPACE = "data_transformer" 
+PROJECT_NAME = "data_transformer"
+
+hook_spec = pluggy.HookspecMarker(HOOK_NAMESPACE) 
+hook_impl = pluggy.HookimplMarker(HOOK_NAMESPACE)
+
+def get_class(class_name):
+    return globals()[class_name]
+
+class DataTransformerSpecs:
+    @hook_spec
+    def transform(self, data_transformer: 'DataTransformer') -> None:
+        pass
+
+
+class DataTransformer:
+    def __init__(self, data="", hooks=None) -> None:
+        self._pm = pluggy.PluginManager(PROJECT_NAME)
+        self._pm.add_hookspecs(DataTransformerSpecs)
+        self.data = data
+        hooks.reverse()
+        self.hooks = hooks
+        if hooks:
+            self._register_hooks()
+
+    def _register_hooks(self) -> None:
+        for hook in self.hooks:
+            self._pm.register(hook)
+
+    def run(self):
+        self._pm.hook.transform(data_transformer=self)
+        return self.data
+
+
+class UpperHook:
+    @hook_impl
+    def transform(data_transformer):
+        print("inside UpperHook.transform()")
+        data_transformer.data = data_transformer.data.upper()
+        print(data_transformer.data)
+
+class LowerHook:
+    @hook_impl
+    def transform(data_transformer):
+        print("inside LowerHook.transform()")
+        data_transformer.data = data_transformer.data.lower()
+        print(data_transformer.data)
+
+class ReverseHook:
+    @hook_impl
+    def transform(data_transformer):
+        print("inside ReverseHook.transform()")
+        data_transformer.data = data_transformer.data[::-1] 
+        print(data_transformer.data)
+
+if __name__ == "__main__":
+    pe = DataTransformer(
+        data="hello world",
+        hooks=[
+            UpperHook,
+        ],
+    )
+    pe.run()

plugin_extend.py

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+from plugin_base import DataTransformer, get_class
+import yaml
+import sys   
+
+if __name__ == "__main__":
+    yaml_file = "extend.yaml"
+    if len(sys.argv) > 1:
+        yaml_file = sys.argv[1]
+        
+    with open(yaml_file) as stream:
+        config = yaml.safe_load(stream)
+    
+    hook_list = config["workflow"]
+
+    hooks = [
+        get_class(hook_name) for hook_name in hook_list
+    ]
+
+    pe = DataTransformer(
+        data="hello world",
+        hooks=hooks
+    )
+    
+    pe.run()

poetry.lock

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+[tool.poetry]
+name = "pluggy-test-python"
+version = "0.1.0"
+description = ""
+authors = ["James Bristow <jbris@users.noreply.github.com>"]
+readme = "README.md"
+
+[tool.poetry.dependencies]
+python = "^3.10"
+pluggy = "^1.4.0"
+pyyaml = "^6.0.1"
+
+
+[build-system]
+requires = ["poetry-core"]
+build-backend = "poetry.core.masonry.api"