"""

Code generator for dbt to Feast imports.

This module generates Python code files containing Feast object definitions

(Entity, DataSource, FeatureView) from dbt model metadata.

"""

import logging

from typing import Any, List, Optional, Set

from jinja2 import BaseLoader, Environment

from feast.dbt.mapper import map_dbt_type_to_feast_type

from feast.dbt.parser import DbtModel

from feast.types import (

Array,

Bool,

Bytes,

Float32,

Float64,

Int32,

Int64,

String,

UnixTimestamp,

)

logger = logging.getLogger(__name__)

# Template for generating a complete Feast definitions file

FEAST_FILE_TEMPLATE = '''"""

Feast feature definitions generated from dbt models.

Source: {{ manifest_path }}

Project: {{ project_name }}

Generated by: feast dbt import

"""

from datetime import timedelta

from feast import Entity, FeatureView, Field

{% if type_imports %}

from feast.types import {{ type_imports | join(', ') }}

{% endif %}

{% if data_source_type == 'bigquery' %}

from feast.infra.offline_stores.bigquery_source import BigQuerySource

{% elif data_source_type == 'snowflake' %}

from feast.infra.offline_stores.snowflake_source import SnowflakeSource

{% elif data_source_type == 'file' %}

from feast.infra.offline_stores.file_source import FileSource

{% endif %}

# =============================================================================

# Entities

# =============================================================================

{% for entity in entities %}

{{ entity.var_name }} = Entity(

name="{{ entity.name }}",

join_keys=["{{ entity.join_key }}"],

description="{{ entity.description }}",

tags={{ entity.tags }},

)

{% endfor %}

# =============================================================================

# Data Sources

# =============================================================================

{% for source in data_sources %}

{% if data_source_type == 'bigquery' %}

{{ source.var_name }} = BigQuerySource(

name="{{ source.name }}",

table="{{ source.table }}",

timestamp_field="{{ source.timestamp_field }}",

description="{{ source.description }}",

tags={{ source.tags }},

)

{% elif data_source_type == 'snowflake' %}

{{ source.var_name }} = SnowflakeSource(

name="{{ source.name }}",

database="{{ source.database }}",

schema="{{ source.schema }}",

table="{{ source.table }}",

timestamp_field="{{ source.timestamp_field }}",

description="{{ source.description }}",

tags={{ source.tags }},

)

{% elif data_source_type == 'file' %}

{{ source.var_name }} = FileSource(

name="{{ source.name }}",

path="{{ source.path }}",

timestamp_field="{{ source.timestamp_field }}",

description="{{ source.description }}",

tags={{ source.tags }},

)

{% endif %}

{% endfor %}

# =============================================================================

# Feature Views

# =============================================================================

{% for fv in feature_views %}

{{ fv.var_name }} = FeatureView(

name="{{ fv.name }}",

entities=[{{ fv.entity_var }}],

ttl=timedelta(days={{ fv.ttl_days }}),

schema=[

{% for field in fv.fields %}

Field(name="{{ field.name }}", dtype={{ field.dtype }}{% if field.description %}, description="{{ field.description }}"{% endif %}),

{% endfor %}

],

online={{ fv.online }},

source={{ fv.source_var }},

description="{{ fv.description }}",

tags={{ fv.tags }},

)

{% endfor %}

'''

def _get_feast_type_name(feast_type: Any) -> str:

"""Get the string name of a Feast type for code generation."""

if isinstance(feast_type, Array):

# Safely get base_type. Should always exist since Array.__init__ sets it.

# Example: Array(String) -> base_type = String

base_type = getattr(feast_type, "base_type", None)

if base_type is None:

logger.warning(

"Array type missing 'base_type' attribute. "

"This indicates a bug in Array initialization. Falling back to String."

)

base_type = String

base_type_name = _get_feast_type_name(base_type)

return f"Array({base_type_name})"

# Map type objects to their names.

# Note: ImageBytes and PdfBytes are excluded since dbt manifests only expose

# generic BYTES type without semantic information about binary content.

type_map = {

String: "String",

Int32: "Int32",

Int64: "Int64",

Float32: "Float32",

Float64: "Float64",

Bool: "Bool",

UnixTimestamp: "UnixTimestamp",

Bytes: "Bytes",

}

return type_map.get(feast_type, "String")

def _make_var_name(name: str) -> str:

"""Convert a name to a valid Python variable name."""

# Replace hyphens and spaces with underscores

var_name = name.replace("-", "_").replace(" ", "_")

# Ensure it starts with a letter or underscore

if var_name and var_name[0].isdigit():

var_name = f"_{var_name}"

return var_name

def _escape_description(desc: Optional[str]) -> str:

"""Escape a description string for use in Python code."""

if not desc:

return ""

# Escape quotes and newlines

return desc.replace("\\", "\\\\").replace('"', '\\"').replace("\n", " ")

class DbtCodeGenerator:

"""

Generates Python code for Feast objects from dbt models.

This class creates complete, importable Python files containing

Entity, DataSource, and FeatureView definitions.

Example::

generator = DbtCodeGenerator(

data_source_type="bigquery",

timestamp_field="event_timestamp",

ttl_days=7

)

code = generator.generate(

models=models,

entity_column="user_id",

manifest_path="target/manifest.json",

project_name="my_project"

)

with open("features.py", "w") as f:

f.write(code)

"""

def __init__(

self,

data_source_type: str = "bigquery",

timestamp_field: str = "event_timestamp",

ttl_days: int = 1,

):

self.data_source_type = data_source_type.lower()

self.timestamp_field = timestamp_field

self.ttl_days = ttl_days

# Set up Jinja2 environment

self.env = Environment(

loader=BaseLoader(),

trim_blocks=True,

lstrip_blocks=True,

)

self.template = self.env.from_string(FEAST_FILE_TEMPLATE)

def generate(

self,

models: List[DbtModel],

entity_column: str,

manifest_path: str = "",

project_name: str = "",

exclude_columns: Optional[List[str]] = None,

online: bool = True,

) -> str:

"""

Generate Python code for Feast objects from dbt models.

Args:

models: List of DbtModel objects to generate code for

entity_column: The entity/primary key column name

manifest_path: Path to the dbt manifest (for documentation)

project_name: dbt project name (for documentation)

exclude_columns: Columns to exclude from features

online: Whether to enable online serving

Returns:

Generated Python code as a string

"""

excluded = {entity_column, self.timestamp_field}

if exclude_columns:

excluded.update(exclude_columns)

# Collect all Feast types used for imports

type_imports: Set[str] = set()

# Prepare entity data

entities = []

entity_var = _make_var_name(entity_column)

entities.append(

{

"var_name": entity_var,

"name": entity_column,

"join_key": entity_column,

"description": "Entity key for dbt models",

"tags": {"source": "dbt"},

}

)

# Prepare data sources and feature views

data_sources = []

feature_views = []

for model in models:

# Check required columns exist

column_names = [c.name for c in model.columns]

if self.timestamp_field not in column_names:

continue

if entity_column not in column_names:

continue

# Build tags

tags = {"dbt.model": model.name}

for tag in model.tags:

tags[f"dbt.tag.{tag}"] = "true"

# Data source

source_var = _make_var_name(f"{model.name}_source")

source_data = {

"var_name": source_var,

"name": f"{model.name}_source",

"timestamp_field": self.timestamp_field,

"description": _escape_description(model.description),

"tags": tags,

}

if self.data_source_type == "bigquery":

source_data["table"] = model.full_table_name

elif self.data_source_type == "snowflake":

source_data["database"] = model.database

source_data["schema"] = model.schema

source_data["table"] = model.alias

elif self.data_source_type == "file":

source_data["path"] = f"/data/{model.name}.parquet"

data_sources.append(source_data)

# Feature view fields

fields = []

for column in model.columns:

if column.name in excluded:

continue

feast_type = map_dbt_type_to_feast_type(column.data_type)

type_name = _get_feast_type_name(feast_type)

# Track base type for imports. For Array types, import both Array and base type.

# Example: Array(Int64) requires imports: Array, Int64

if isinstance(feast_type, Array):

type_imports.add("Array")

base_type = getattr(feast_type, "base_type", None)

if base_type is None:

logger.warning(

"Array type missing 'base_type' attribute while generating imports. "

"This indicates a bug in Array initialization. Falling back to String."

)

base_type = String

base_type_name = _get_feast_type_name(base_type)

type_imports.add(base_type_name)

else:

type_imports.add(type_name)

fields.append(

{

"name": column.name,

"dtype": type_name,

"description": _escape_description(column.description),

}

)

# Feature view

fv_var = _make_var_name(f"{model.name}_fv")

feature_views.append(

{

"var_name": fv_var,

"name": model.name,

"entity_var": entity_var,

"source_var": source_var,

"ttl_days": self.ttl_days,

"fields": fields,

"online": online,

"description": _escape_description(model.description),

"tags": tags,

}

)

# Sort type imports for consistent output

sorted_types = sorted(type_imports)

# Render template

return self.template.render(

manifest_path=manifest_path,

project_name=project_name,

data_source_type=self.data_source_type,

type_imports=sorted_types,

entities=entities,

data_sources=data_sources,

feature_views=feature_views,

)

def generate_feast_code(

models: List[DbtModel],

entity_column: str,

data_source_type: str = "bigquery",

timestamp_field: str = "event_timestamp",

ttl_days: int = 1,

manifest_path: str = "",

project_name: str = "",

exclude_columns: Optional[List[str]] = None,

online: bool = True,

) -> str:

"""

Convenience function to generate Feast code from dbt models.

Args:

models: List of DbtModel objects

entity_column: Primary key column name

data_source_type: Type of data source (bigquery, snowflake, file)

timestamp_field: Timestamp column name

ttl_days: TTL in days for feature views

manifest_path: Path to manifest for documentation

project_name: Project name for documentation

exclude_columns: Columns to exclude from features

online: Whether to enable online serving

Returns:

Generated Python code as a string

"""

generator = DbtCodeGenerator(

data_source_type=data_source_type,

timestamp_field=timestamp_field,

ttl_days=ttl_days,

)

return generator.generate(

models=models,

entity_column=entity_column,

manifest_path=manifest_path,

project_name=project_name,

exclude_columns=exclude_columns,

online=online,

)