forked from platypush/platypush
[procedure] Several improvements to the procedure engine.
- Add `set` statement, which can be used to set context variables within
YAML procedures. Example:
```yaml
procedure.test:
- set:
foo: bar
- action: logger.info
args:
msg: ${bar}
```
- More reliable flow control for nested break/continue/return.
- Propagate changes to context variables also to upstream procedures.
This commit is contained in:
parent
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commit
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GPG key ID:
D90FBA7F76362774
1 changed files with 119 additions and 86 deletions
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@ -1,11 +1,12 @@
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import enum
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import logging
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import re
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from dataclasses import dataclass
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from copy import deepcopy
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from dataclasses import dataclass, field
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from functools import wraps
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from queue import LifoQueue
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from typing import Any, List, Optional
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from typing import Any, Dict, Iterable, List, Optional
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from ..common import exec_wrapper
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from ..config import Config
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@ -23,6 +24,7 @@ class StatementType(enum.Enum):
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BREAK = 'break'
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CONTINUE = 'continue'
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RETURN = 'return'
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SET = 'set'
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@dataclass
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@ -32,7 +34,7 @@ class Statement:
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"""
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type: StatementType
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argument: Optional[str] = None
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argument: Optional[Any] = None
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@classmethod
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def build(cls, statement: str):
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@ -60,8 +62,30 @@ class ReturnStatement(Statement):
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type: StatementType = StatementType.RETURN
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def run(self, *_, **context) -> Any:
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return Response(
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output=Request.expand_value_from_context(
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self.argument, **_update_context(context)
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)
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)
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@dataclass
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class SetStatement(Statement):
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"""
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Models a set variable statement in a procedure.
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"""
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type: StatementType = StatementType.SET
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vars: dict = field(default_factory=dict)
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def run(self, *_, **context):
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return Request.expand_value_from_context(self.argument, **context)
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vars = deepcopy(self.vars) # pylint: disable=redefined-builtin
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for k, v in vars.items():
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vars[k] = Request.expand_value_from_context(v, **context)
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context.update(vars)
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return Response(output=vars)
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class Procedure:
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@ -117,10 +141,20 @@ class Procedure:
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# Check if it's a return statement with a value
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if (
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len(request_config.keys()) == 1
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and list(request_config.keys())[0] == 'return'
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and list(request_config.keys())[0] == StatementType.RETURN.value
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):
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cls._flush_if_statements(reqs, if_config)
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reqs.append(ReturnStatement(argument=request_config['return']))
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reqs.append(
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ReturnStatement(argument=request_config[StatementType.RETURN.value])
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)
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continue
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# Check if it's a variable set statement
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if (len(request_config.keys()) == 1) and (
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list(request_config.keys())[0] == StatementType.SET.value
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):
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cls._flush_if_statements(reqs, if_config)
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reqs.append(SetStatement(vars=request_config[StatementType.SET.value]))
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continue
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# Check if this request is an if-else
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@ -129,6 +163,7 @@ class Procedure:
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m = re.match(r'\s*(if)\s+\${(.*)}\s*', key)
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if m:
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cls._flush_if_statements(reqs, if_config)
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if_count += 1
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if_name = f'{name}__if_{if_count}'
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condition = m.group(2)
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@ -233,86 +268,96 @@ class Procedure:
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pending_if = if_config.get()
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requests.append(IfProcedure.build(**pending_if))
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@staticmethod
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def _find_nearest_loop(stack):
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for proc in stack[::-1]:
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if isinstance(proc, LoopProcedure):
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return proc
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raise AssertionError('break/continue statement found outside of a loop')
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# pylint: disable=too-many-branches,too-many-statements
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def execute(self, n_tries=1, __stack__=None, **context):
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def execute(
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self,
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n_tries: int = 1,
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__stack__: Optional[Iterable] = None,
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new_context: Optional[Dict[str, Any]] = None,
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**context,
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):
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"""
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Execute the requests in the procedure.
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:param n_tries: Number of tries in case of failure before raising a RuntimeError.
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"""
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if not __stack__:
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__stack__ = [self]
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else:
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__stack__.append(self)
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__stack__ = (self,) if not __stack__ else (self, *__stack__)
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new_context = new_context or {}
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if self.args:
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args = self.args.copy()
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for k, v in args.items():
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v = Request.expand_value_from_context(v, **context)
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args[k] = v
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context[k] = v
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args[k] = context[k] = Request.expand_value_from_context(v, **context)
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logger.info('Executing procedure %s with arguments %s', self.name, args)
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else:
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logger.info('Executing procedure %s', self.name)
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response = Response()
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token = Config.get('token')
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context = _update_context(context)
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locals().update(context)
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# pylint: disable=too-many-nested-blocks
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for request in self.requests:
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if callable(request):
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response = request(**context)
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continue
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context['_async'] = self._async
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context['n_tries'] = n_tries
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context['__stack__'] = __stack__
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context['new_context'] = new_context
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if isinstance(request, Statement):
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if isinstance(request, ReturnStatement):
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response = Response(output=request.run(**context))
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response = request.run(**context)
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self._should_return = True
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for proc in __stack__:
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proc._should_return = True # pylint: disable=protected-access
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break
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if isinstance(request, SetStatement):
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rs: dict = request.run(**context).output # type: ignore
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context.update(rs)
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new_context.update(rs)
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locals().update(rs)
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continue
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if request.type in [StatementType.BREAK, StatementType.CONTINUE]:
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loop = self._find_nearest_loop(__stack__)
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if request.type == StatementType.BREAK:
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loop._should_break = True # pylint: disable=protected-access
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else:
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loop._should_continue = True # pylint: disable=protected-access
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for proc in __stack__:
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if isinstance(proc, LoopProcedure):
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if request.type == StatementType.BREAK:
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setattr(proc, '_should_break', True) # noqa: B010
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else:
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setattr(proc, '_should_continue', True) # noqa: B010
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break
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proc._should_return = True # pylint: disable=protected-access
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break
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should_continue = getattr(self, '_should_continue', False)
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should_break = getattr(self, '_should_break', False)
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if isinstance(self, LoopProcedure) and (should_continue or should_break):
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if should_continue:
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setattr(self, '_should_continue', False) # noqa[B010]
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else:
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setattr(self, '_should_break', False) # noqa[B010]
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if self._should_return or should_continue or should_break:
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break
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if token and not isinstance(request, Statement):
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request.token = token
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context['_async'] = self._async
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context['n_tries'] = n_tries
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exec_ = getattr(request, 'execute', None)
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if callable(exec_):
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response = exec_(__stack__=__stack__, **context)
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response = exec_(**context)
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context.update(context.get('new_context', {}))
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if not self._async and response:
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if isinstance(response.output, dict):
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for k, v in response.output.items():
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context[k] = v
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context.update(response.output)
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context['output'] = response.output
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context['errors'] = response.errors
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new_context.update(context)
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locals().update(context)
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if self._should_return:
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break
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@ -333,10 +378,8 @@ class LoopProcedure(Procedure):
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Base class while and for/fork loops.
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"""
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def __init__(self, name, requests, _async=False, args=None, backend=None):
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super().__init__(
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name=name, _async=_async, requests=requests, args=args, backend=backend
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)
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def __init__(self, *args, **kwargs):
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super().__init__(*args, **kwargs)
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self._should_break = False
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self._should_continue = False
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@ -381,6 +424,9 @@ class ForProcedure(LoopProcedure):
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# pylint: disable=eval-used
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def execute(self, *_, **context):
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ctx = _update_context(context)
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locals().update(ctx)
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try:
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iterable = eval(self.iterable)
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assert hasattr(
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@ -388,11 +434,18 @@ class ForProcedure(LoopProcedure):
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), f'Object of type {type(iterable)} is not iterable: {iterable}'
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except Exception as e:
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logger.debug('Iterable %s expansion error: %s', self.iterable, e)
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iterable = Request.expand_value_from_context(self.iterable, **context)
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iterable = Request.expand_value_from_context(self.iterable, **ctx)
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response = Response()
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for item in iterable:
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ctx[self.iterator_name] = item
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response = super().execute(**ctx)
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ctx.update(ctx.get('new_context', {}))
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if response.output and isinstance(response.output, dict):
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ctx = _update_context(ctx, **response.output)
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if self._should_return:
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logger.info('Returning from %s', self.name)
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break
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@ -407,9 +460,6 @@ class ForProcedure(LoopProcedure):
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logger.info('Breaking loop %s', self.name)
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break
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context[self.iterator_name] = item
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response = super().execute(**context)
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return response
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@ -446,41 +496,23 @@ class WhileProcedure(LoopProcedure):
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)
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self.condition = condition
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@staticmethod
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def _get_context(**context):
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for k, v in context.items():
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try:
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context[k] = eval(v) # pylint: disable=eval-used
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except Exception as e:
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logger.debug('Evaluation error for %s=%s: %s', k, v, e)
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if isinstance(v, str):
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try:
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context[k] = eval( # pylint: disable=eval-used
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'"' + re.sub(r'(^|[^\\])"', '\1\\"', v) + '"'
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)
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except Exception as ee:
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logger.warning(
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'Could not parse value for context variable %s=%s: %s',
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k,
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v,
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ee,
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)
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logger.warning('Context: %s', context)
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logger.exception(e)
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return context
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def execute(self, *_, **context):
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response = Response()
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context = self._get_context(**context)
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for k, v in context.items():
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locals()[k] = v
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ctx = _update_context(context)
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locals().update(ctx)
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while True:
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condition_true = eval(self.condition) # pylint: disable=eval-used
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if not condition_true:
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break
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response = super().execute(**ctx)
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ctx.update(ctx.get('new_context', {}))
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if response.output and isinstance(response.output, dict):
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_update_context(ctx, **response.output)
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locals().update(ctx)
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if self._should_return:
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logger.info('Returning from %s', self.name)
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break
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@ -495,13 +527,6 @@ class WhileProcedure(LoopProcedure):
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logger.info('Breaking loop %s', self.name)
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break
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response = super().execute(**context)
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if response.output and isinstance(response.output, dict):
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new_context = self._get_context(**response.output)
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for k, v in new_context.items():
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locals()[k] = v
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return response
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@ -595,20 +620,28 @@ class IfProcedure(Procedure):
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)
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def execute(self, *_, **context):
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for k, v in context.items():
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locals()[k] = v
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ctx = _update_context(context)
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locals().update(ctx)
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condition_true = eval(self.condition) # pylint: disable=eval-used
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response = Response()
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if condition_true:
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response = super().execute(**context)
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response = super().execute(**ctx)
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elif self.else_branch:
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response = self.else_branch.execute(**context)
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response = self.else_branch.execute(**ctx)
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return response
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def _update_context(context: Optional[Dict[str, Any]] = None, **kwargs):
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ctx = context or {}
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ctx = {**ctx.get('context', {}), **ctx, **kwargs}
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for k, v in ctx.items():
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ctx[k] = Request.expand_value_from_context(v, **ctx)
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return ctx
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def procedure(name_or_func: Optional[str] = None, *upper_args, **upper_kwargs):
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name = name_or_func if isinstance(name_or_func, str) else None
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