Build lightweight AI agent admin
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@@ -0,0 +1,405 @@
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"""
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循环节点
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支持两种循环模式：
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1. for_each - 遍历数组，对每个元素执行循环体
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2. while - 条件循环，满足条件时持续执行
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"""
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import ast
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import json
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import logging
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import operator
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from typing import Any, Dict, List
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from ..base import BaseNode, NodeContext, NodeResult
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from ..registry import NodeRegistry
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logger = logging.getLogger(__name__)
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@NodeRegistry.register
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class LoopNode(BaseNode):
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"""
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循环节点
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支持 for_each 和 while 两种循环模式
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"""
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node_type = 'loop'
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node_name = '循环'
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node_category = 'logic'
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node_icon = 'repeat'
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node_description = '循环执行一组节点，支持遍历数组或条件循环'
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supports_branches = True
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inputs = [
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{
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'name': 'items',
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'type': 'array',
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'description': '要遍历的数组（for_each 模式）',
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},
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]
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outputs = [
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{
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'name': 'results',
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'type': 'array',
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'description': '每次循环的结果数组',
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},
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{
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'name': 'current_item',
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'type': 'any',
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'description': '当前循环项（循环体内可用）',
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},
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{
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'name': 'current_index',
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'type': 'number',
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'description': '当前循环索引（从 0 开始）',
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},
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]
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# 支持的操作符（用于 while 条件判断）
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OPERATORS = {
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'eq': operator.eq, # 等于
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'ne': operator.ne, # 不等于
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'gt': operator.gt, # 大于
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'gte': operator.ge, # 大于等于
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'lt': operator.lt, # 小于
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'lte': operator.le, # 小于等于
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'is_empty': lambda a, _: not a, # 为空
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'is_not_empty': lambda a, _: bool(a), # 不为空
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'is_true': lambda a, _: bool(a), # 为真
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'is_false': lambda a, _: not bool(a), # 为假
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}
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def execute(self, context: NodeContext) -> NodeResult:
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"""
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执行循环节点
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循环节点本身只负责初始化循环状态，实际的循环执行由 WorkflowService 处理
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"""
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try:
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loop_mode = self.config.get('loop_mode', 'for_each')
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max_iterations = self.config.get('max_iterations', 100)
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if loop_mode == 'for_each':
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return self._init_for_each(context, max_iterations)
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elif loop_mode == 'while':
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return self._init_while(context, max_iterations)
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else:
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return NodeResult(
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success=False,
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error=f'不支持的循环模式: {loop_mode}',
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)
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except Exception as e:
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logger.exception(f'循环节点执行失败: {e}')
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return NodeResult(
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success=False,
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error=str(e),
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)
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def _init_for_each(self, context: NodeContext, max_iterations: int) -> NodeResult:
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"""初始化 for_each 循环"""
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items_var = self.config.get('items_variable', '')
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logger.info(f'[LoopNode] 初始化 for_each 循环，items_variable={items_var}')
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# 解析数组变量
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items = self._resolve_variable(items_var, context)
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logger.info(f'[LoopNode] 解析后的 items 类型: {type(items).__name__}, 值: {items}')
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# 如果是字符串，尝试解析为 JSON 或 Python 字面量
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if isinstance(items, str):
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try:
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items = json.loads(items)
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logger.info(f'[LoopNode] JSON 解析成功，items={items}')
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except json.JSONDecodeError:
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# 尝试使用 ast.literal_eval 解析 Python 字面量（如 str() 输出的列表）
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try:
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items = ast.literal_eval(items)
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logger.info(f'[LoopNode] Python 字面量解析成功，items={items}')
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except (ValueError, SyntaxError):
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# 尝试按逗号分割（仅当不是列表/字典格式时）
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if not (items.strip().startswith('[') or items.strip().startswith('{')):
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items = [item.strip() for item in items.split(',') if item.strip()]
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logger.info(f'[LoopNode] 按逗号分割，items={items}')
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else:
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logger.error(f'[LoopNode] 无法解析 items 字符串: {items[:200]}...')
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return NodeResult(
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success=False,
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error=f'无法解析 items 变量，格式不正确',
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)
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if not isinstance(items, (list, tuple)):
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error_msg = f'items 必须是数组，当前类型: {type(items).__name__}, 值: {items}, items_variable={items_var}'
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logger.error(f'[LoopNode] {error_msg}')
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return NodeResult(
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success=False,
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error=error_msg,
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)
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# 检查数组是否为空
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if len(items) == 0:
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logger.warning(f'[LoopNode] items 数组为空，items_variable={items_var}')
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# 返回成功但不执行循环体
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# 限制最大迭代次数
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if len(items) > max_iterations:
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logger.warning(f'数组长度 {len(items)} 超过最大迭代次数 {max_iterations}，将被截断')
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items = list(items)[:max_iterations]
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return NodeResult(
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success=True,
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output={
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'items': list(items),
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'total_count': len(items),
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},
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output_variables={
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'_loop_items': list(items),
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'_loop_index': 0,
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'_loop_total': len(items),
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'_loop_mode': 'for_each',
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'_loop_results': [],
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},
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metadata={
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'is_loop': True,
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'loop_mode': 'for_each',
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'total_iterations': len(items),
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'max_iterations': max_iterations,
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},
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)
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def _init_while(self, context: NodeContext, max_iterations: int) -> NodeResult:
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"""初始化 while 循环"""
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# 检查初始条件
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condition_met = self._evaluate_condition(context)
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return NodeResult(
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success=True,
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output={
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'condition_met': condition_met,
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},
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output_variables={
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'_loop_index': 0,
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'_loop_mode': 'while',
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'_loop_condition_met': condition_met,
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'_loop_results': [],
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'_loop_max_iterations': max_iterations,
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},
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metadata={
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'is_loop': True,
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'loop_mode': 'while',
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'condition_met': condition_met,
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'max_iterations': max_iterations,
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},
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)
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def check_continue(self, context: NodeContext) -> bool:
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"""
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检查是否继续循环
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由 WorkflowService 在每次循环迭代后调用
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"""
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loop_mode = context.get_variable('_loop_mode')
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current_index = context.get_variable('_loop_index', 0)
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max_iterations = self.config.get('max_iterations', 100)
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# 检查最大迭代次数
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if current_index >= max_iterations:
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logger.warning(f'达到最大迭代次数 {max_iterations}，停止循环')
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return False
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if loop_mode == 'for_each':
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total = context.get_variable('_loop_total', 0)
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return current_index < total
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elif loop_mode == 'while':
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return self._evaluate_condition(context)
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return False
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def get_current_item(self, context: NodeContext) -> Any:
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"""获取当前循环项（for_each 模式）"""
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items = context.get_variable('_loop_items', [])
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index = context.get_variable('_loop_index', 0)
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if 0 <= index < len(items):
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return items[index]
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return None
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def increment_index(self, context: NodeContext) -> int:
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"""增加循环索引"""
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current_index = context.get_variable('_loop_index', 0)
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new_index = current_index + 1
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context.set_variable('_loop_index', new_index)
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return new_index
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def add_result(self, context: NodeContext, result: Any) -> None:
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"""添加循环结果"""
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results = context.get_variable('_loop_results', [])
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results.append(result)
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context.set_variable('_loop_results', results)
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def _resolve_variable(self, variable: str, context: NodeContext) -> Any:
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"""解析变量引用，支持多层路径访问"""
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if not isinstance(variable, str):
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return variable
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# 如果是空字符串，返回 None
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if not variable.strip():
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return None
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# 检查是否是 {{...}} 格式的变量引用
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if not (variable.startswith('{{') and variable.endswith('}}')):
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# 不是变量引用，直接返回原始字符串值（可能是硬编码的 JSON 数组或逗号分隔的值）
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return variable
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# 使用 resolve_template 解析变量，它支持多层路径访问（如 node.key.subkey）
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resolved = context.resolve_template(variable)
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# 如果解析结果与原始变量相同，说明变量不存在或解析失败
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if resolved == variable:
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return None
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# 如果解析结果是字符串，尝试解析为 JSON
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if isinstance(resolved, str):
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try:
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import json
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return json.loads(resolved)
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except (json.JSONDecodeError, TypeError):
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return resolved
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return resolved
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def _evaluate_condition(self, context: NodeContext) -> bool:
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"""评估 while 条件"""
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conditions = self.config.get('conditions', [])
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logic = self.config.get('condition_logic', 'and') # and 或 or
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if not conditions:
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return False # 无条件默认不继续
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results = []
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for condition in conditions:
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result = self._evaluate_single_condition(condition, context)
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results.append(result)
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if logic == 'or':
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return any(results)
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else: # and
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return all(results)
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def _evaluate_single_condition(self, condition: Dict, context: NodeContext) -> bool:
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"""评估单个条件"""
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variable = condition.get('variable', '')
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op_name = condition.get('operator', 'eq')
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value = condition.get('value', '')
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# 解析变量和值
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left_val = self._resolve_variable(variable, context)
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right_val = self._resolve_variable(value, context) if value else None
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# 获取操作符函数
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op_func = self.OPERATORS.get(op_name, operator.eq)
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try:
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# 特殊处理不需要右值的操作符
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if op_name in ['is_empty', 'is_not_empty', 'is_true', 'is_false']:
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return op_func(left_val, None)
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# 尝试类型转换
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if isinstance(left_val, (int, float)) and isinstance(right_val, str):
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try:
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if '.' in right_val:
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right_val = float(right_val)
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else:
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right_val = int(right_val)
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except ValueError:
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pass
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return op_func(left_val, right_val)
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except Exception as e:
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logger.warning(f'条件评估失败: {e}')
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return False
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@classmethod
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def get_config_schema(cls) -> Dict[str, Any]:
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"""获取配置 Schema"""
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return {
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'type': 'object',
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'properties': {
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'loop_mode': {
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'type': 'string',
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'title': '循环模式',
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'enum': ['for_each', 'while'],
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'enumNames': ['遍历数组 (For Each)', '条件循环 (While)'],
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'default': 'for_each',
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},
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'items_variable': {
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'type': 'string',
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'title': '数组变量',
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'description': '要遍历的数组变量名（for_each 模式）',
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},
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'item_variable_name': {
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'type': 'string',
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'title': '循环项变量名',
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'description': '当前循环项的变量名，默认为 item',
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'default': 'item',
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},
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'index_variable_name': {
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'type': 'string',
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'title': '索引变量名',
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'description': '当前索引的变量名，默认为 index',
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'default': 'index',
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},
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'conditions': {
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'type': 'array',
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'title': '循环条件',
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'description': 'while 模式的循环条件',
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'items': {
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'type': 'object',
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'properties': {
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'variable': {
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'type': 'string',
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'title': '变量',
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},
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'operator': {
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'type': 'string',
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'title': '操作符',
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'enum': list(cls.OPERATORS.keys()),
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'default': 'eq',
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},
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'value': {
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'type': 'string',
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'title': '比较值',
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},
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},
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},
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},
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'condition_logic': {
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'type': 'string',
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'title': '条件逻辑',
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'enum': ['and', 'or'],
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'enumNames': ['全部满足 (AND)', '任一满足 (OR)'],
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'default': 'and',
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},
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'max_iterations': {
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'type': 'integer',
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'title': '最大迭代次数',
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'description': '防止无限循环，默认 100 次',
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'default': 100,
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'minimum': 1,
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'maximum': 10000,
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},
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'output_variable': {
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'type': 'string',
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'title': '输出变量名',
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'description': '存储所有循环结果的变量名',
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'default': 'loop_results',
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},
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},
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}
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