Command Line Interface

# Primary command
erdantic [models_or_modules...] --out OUTPUT_FILE [options]

# Alternative module invocation
python -m erdantic [models_or_modules...] --out OUTPUT_FILE [options]

# Main CLI function signature
def main(
    models_or_modules: list[str],
    out: Path,
    terminal_models: list[str] = [],
    termini: list[str] = [],
    limit_search_models_to: list[str] = [],
    dot: bool = False,
    no_overwrite: bool = False,
    quiet: int = 0,
    verbose: int = 0,
    list_plugins: Optional[bool] = False,
    version: Optional[bool] = None,
):
    """Draw entity relationship diagrams (ERDs) for Python data model classes. Diagrams are
    rendered using the Graphviz library. Currently supported data modeling frameworks are Pydantic,
    attrs, and standard library dataclasses.
    """

# Generate diagram from specific model classes
erdantic my.models.User my.models.Post --out models.png

# Generate diagram from an entire module
erdantic my.models --out module_diagram.svg

# Different output formats (inferred from extension)
erdantic my.models --out diagram.png    # PNG image
erdantic my.models --out diagram.svg    # SVG vector
erdantic my.models --out diagram.pdf    # PDF document
erdantic my.models --out diagram.eps    # EPS format

# Generate DOT language representation instead of image
erdantic my.models --dot

# Save DOT to file for external processing
erdantic my.models --dot > models.dot

# Stop analysis at specific models to control diagram complexity
erdantic my.models --terminal-model my.base.BaseEntity --out simplified.png

# Multiple terminal models
erdantic my.models \
  --terminal-model my.base.BaseEntity \
  --terminal-model my.shared.CommonMixin \
  --out controlled.png

# Limit to specific model types only
erdantic my.models --limit-search-models-to pydantic --out pydantic_only.png

# Multiple plugin types
erdantic my.models \
  --limit-search-models-to pydantic \
  --limit-search-models-to dataclasses \
  --out filtered.png

# Quiet operation (suppress most logging)
erdantic my.models --out quiet.png --quiet

# Very quiet (suppress almost all logging)
erdantic my.models --out very_quiet.png -qq

# Verbose logging (show debug information)
erdantic my.models --out debug.png --verbose

# Very verbose logging
erdantic my.models --out very_debug.png -vv

# Prevent accidental overwriting
erdantic my.models --out existing.png --no-overwrite
# This will fail if existing.png already exists

# Show version
erdantic --version

# List available plugins
erdantic --list-plugins

# Analyze multiple modules with terminal models and filtering
erdantic \
  my.user.models \
  my.post.models \
  my.comment.models \
  --terminal-model my.base.TimestampedModel \
  --terminal-model my.base.SoftDeleteModel \
  --limit-search-models-to pydantic \
  --out complex_project.svg \
  --verbose

#!/bin/bash
# Generate documentation diagrams for CI/CD

# Check if output is up to date
if [ "models.png" -ot "my/models.py" ]; then
  echo "Regenerating model diagram..."
  erdantic my.models --out models.png --no-overwrite || {
    echo "Failed to generate diagram"
    exit 1
  }
fi

# Generate diagrams for multiple modules
for module in user post comment admin; do
  erdantic "my.${module}.models" --out "${module}_models.png"
done

# Generate both image and DOT versions
erdantic my.models --out models.svg
erdantic my.models --dot > models.dot

# Module not found
erdantic nonexistent.module --out error.png
# Error: Unable to import 'nonexistent.module'

# Output directory doesn't exist
erdantic my.models --out /nonexistent/dir/diagram.png
# Error: Output directory does not exist

# File exists with --no-overwrite
erdantic my.models --out existing.png --no-overwrite
# Error: existing.png already exists, and you specified --no-overwrite

# Unsupported model type
erdantic my.unsupported.models --out error.png
# Error: Model type not supported, available plugins: [...]

// VS Code task example (.vscode/tasks.json)
{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "Generate ERD",
      "type": "shell", 
      "command": "erdantic",
      "args": ["${workspaceFolder}/models", "--out", "docs/erd.png"],
      "group": "build"
    }
  ]
}

def import_object_from_name(full_obj_name: str) -> Union[ModuleType, object]:
    """Import an object from a fully qualified name.
    
    Args:
        full_obj_name (str): Fully qualified name of object or module to import.
        
    Returns:
        Union[ModuleType, object]: The imported module or object.
        
    Raises:
        ModelOrModuleNotFoundError: If the module or object cannot be imported.
    """

from erdantic.cli import import_object_from_name

# Import a module
my_module = import_object_from_name("my.models")

# Import a specific class
MyModel = import_object_from_name("my.models.MyModel")

# Import a function
my_function = import_object_from_name("my.utils.helper_function")