Dict to Schema Example

examples/dict_to_schema/README.md

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+# Dict to Schema
+
+This example demonstrates how to automatically convert Python dictionary literals into Pydantic models. The codemod makes this process simple by handling all the tedious manual updates automatically.
+
+## How the Conversion Script Works
+
+The script (`run.py`) automates the entire conversion process in a few key steps:
+
+1. **Codebase Loading**
+   ```python
+   codebase = Codebase.from_repo("modal-labs/modal-client")
+   ```
+   - Loads your codebase into Codegen's intelligent code analysis engine
+   - Provides a simple SDK for making codebase-wide changes
+   - Supports any Git repository as input
+
+2. **Dictionary Detection**
+   ```python
+   if "{" in global_var.source and "}" in global_var.source:
+       dict_content = global_var.value.source.strip("{}")
+   ```
+   - Automatically identifies dictionary literals in your code
+   - Processes both global variables and class attributes
+   - Skips empty dictionaries to avoid unnecessary conversions
+
+3. **Schema Creation**
+   ```python
+   class_name = global_var.name.title() + "Schema"
+   model_def = f"""class {class_name}(BaseModel):
+       {dict_content.replace(",", "\n    ")}"""
+   ```
+   - Generates meaningful model names based on variable names
+   - Converts dictionary key-value pairs to class attributes
+   - Maintains proper Python indentation
+
+4. **Code Updates**
+   ```python
+   global_var.insert_before(model_def + "\n\n")
+   global_var.set_value(f"{class_name}(**{global_var.value.source})")
+   ```
+   - Inserts new Pydantic models in appropriate locations
+   - Updates dictionary assignments to use the new models
+   - Automatically adds required Pydantic imports
+
+
+## Common Conversion Patterns
+
+### Global Variables
+```python
+# Before
+config = {"host": "localhost", "port": 8080}
+
+# After
+class ConfigSchema(BaseModel):
+    host: str = "localhost"
+    port: int = 8080
+
+config = ConfigSchema(**{"host": "localhost", "port": 8080})
+```
+
+### Class Attributes
+```python
+# Before
+class Service:
+    defaults = {"timeout": 30, "retries": 3}
+
+# After
+class DefaultsSchema(BaseModel):
+    timeout: int = 30
+    retries: int = 3
+
+class Service:
+    defaults = DefaultsSchema(**{"timeout": 30, "retries": 3})
+```
+
+## Running the Conversion
+
+```bash
+# Install Codegen
+pip install codegen
+
+# Run the conversion
+python run.py
+```
+
+## Learn More
+
+- [Pydantic Documentation](https://docs.pydantic.dev/)
+- [Codegen Documentation](https://docs.codegen.com)
+
+## Contributing
+
+Feel free to submit issues and enhancement requests!

examples/dict_to_schema/run.py

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+import codegen
+from codegen import Codebase
+
+
+@codegen.function("dict-to-pydantic-schema")
+def run(codebase: Codebase):
+    """Convert dictionary literals to Pydantic models in a Python codebase.
+
+    This codemod:
+    1. Finds all dictionary literals in global variables and class attributes
+    2. Creates corresponding Pydantic models
+    3. Updates the assignments to use the new models
+    4. Adds necessary Pydantic imports
+    """
+    # Track statistics
+    files_modified = 0
+    models_created = 0
+
+    # Iterate through all files in the codebase
+    for file in codebase.files:
+        needs_imports = False
+        file_modified = False
+
+        # Look for dictionary assignments in global variables
+        for global_var in file.global_vars:
+            try:
+                if "{" in global_var.source and "}" in global_var.source:
+                    dict_content = global_var.value.source.strip("{}")
+                    if not dict_content.strip():
+                        continue
+
+                    # Convert dict to Pydantic model
+                    class_name = global_var.name.title() + "Schema"
+                    model_def = f"""class {class_name}(BaseModel):
+    {dict_content.replace(",", "\n    ")}"""
+
+                    print(f"\nConverting '{global_var.name}' to schema")
+                    print("\nOriginal code:")
+                    print(global_var.source)
+                    print("\nNew code:")
+                    print(model_def)
+                    print(f"{class_name}(**{global_var.value.source})")
+                    print("-" * 50)
+
+                    # Insert model and update assignment
+                    global_var.insert_before(model_def + "\n\n")
+                    global_var.set_value(f"{class_name}(**{global_var.value.source})")
+                    needs_imports = True
+                    models_created += 1
+                    file_modified = True
+            except Exception as e:
+                print(f"Error processing global variable {global_var.name}: {str(e)}")
+
+        # Look for dictionary assignments in class attributes
+        for cls in file.classes:
+            for attr in cls.attributes:
+                try:
+                    if "{" in attr.source and "}" in attr.source:
+                        dict_content = attr.value.source.strip("{}")
+                        if not dict_content.strip():
+                            continue
+
+                        # Convert dict to Pydantic model
+                        class_name = attr.name.title() + "Schema"
+                        model_def = f"""class {class_name}(BaseModel):
+    {dict_content.replace(",", "\n    ")}"""
+
+                        print(f"\nConverting'{attr.name}' to schema")
+                        print("\nOriginal code:")
+                        print(attr.source)
+                        print("\nNew code:")
+                        print(model_def)
+                        print(f"{class_name}(**{attr.value.source})")
+                        print("-" * 50)
+
+                        # Insert model and update attribute
+                        cls.insert_before(model_def + "\n\n")
+                        attr.set_value(f"{class_name}(**{attr.value.source})")
+                        needs_imports = True
+                        models_created += 1
+                        file_modified = True
+                except Exception as e:
+                    print(f"Error processing attribute {attr.name} in class {cls.name}: {str(e)}")
+
+        # Add imports if needed
+        if needs_imports:
+            file.add_import_from_import_string("from pydantic import BaseModel")
+
+        if file_modified:
+            files_modified += 1
+
+    print("\nModification complete:")
+    print(f"Files modified: {files_modified}")
+    print(f"Schemas created: {models_created}")
+
+
+if __name__ == "__main__":
+    print("Initializing codebase...")
+    codebase = Codebase.from_repo("modal-labs/modal-client")
+
+    print("Running codemod...")
+    run(codebase)