Implementation:Infiniflow Ragflow Singleton Decorator

Knowledge Sources	Infiniflow_Ragflow
Domains	Design_Patterns, Infrastructure
Last Updated	2026-02-12 06:00 GMT

Overview

Concrete tool providing a process-aware singleton decorator that ensures only one instance per class per process provided by the RAGFlow common library.

Description

The singleton decorator function creates a per-process singleton pattern using the process ID as a cache key. This ensures that each forked worker process gets its own singleton instance while preventing duplicate instantiation within the same process.

Usage

Apply this decorator to connection or service classes that should be instantiated only once per process, such as database connection pools or cache clients.

Code Reference

Source Location

• Repository: Infiniflow_Ragflow
• File: common/decorator.py
• Lines: 1-27

Signature

def singleton(cls, *args, **kw):
    """Process-aware singleton decorator. One instance per class per process."""

Import

from common.decorator import singleton

I/O Contract

Inputs

Name	Type	Required	Description
cls	type	Yes	The class to make singleton

Outputs

Name	Type	Description
returns	function	A wrapper that returns the cached instance

Usage Examples

from common.decorator import singleton

@singleton
class DatabaseConnection:
    def __init__(self):
        self.conn = create_connection()

# Both calls return the same instance within a process
db1 = DatabaseConnection()
db2 = DatabaseConnection()
assert db1 is db2

Related Pages

• Environment:Infiniflow_Ragflow_Python_Runtime