Support for while/break/continue/return statemnts - closes #107

This commit is contained in:
Fabio Manganiello 2020-01-09 10:28:02 +01:00
parent 35cefcc9f5
commit 40e65d882f
2 changed files with 227 additions and 48 deletions

View file

@ -138,6 +138,8 @@ class Request(Message):
if callable(context_value):
context_value = context_value()
if isinstance(context_value, range) or isinstance(context_value, tuple):
context_value = [*context_value]
if isinstance(context_value, datetime.date):
context_value = context_value.isoformat()
except Exception as e:

View file

@ -1,3 +1,4 @@
import enum
import logging
import re
@ -9,6 +10,12 @@ from ..message.response import Response
logger = logging.getLogger(__name__)
class Statement(enum.Enum):
BREAK = 'break'
CONTINUE = 'continue'
RETURN = 'return'
class Procedure(object):
""" Procedure class. A procedure is a pre-configured list of requests """
@ -18,7 +25,7 @@ class Procedure(object):
name -- Procedure name
_async -- Whether the actions in the procedure are supposed to
be executed sequentially or in parallel (True or False)
requests -- List of platylist.message.request.Request objects
requests -- List of platypush.message.request.Request objects
"""
self.name = name
@ -26,6 +33,7 @@ class Procedure(object):
self.requests = requests
self.backend = backend
self.args = args or {}
self._should_return = False
for req in requests:
req.backend = self.backend
@ -33,36 +41,18 @@ class Procedure(object):
@classmethod
def build(cls, name, _async, requests, args=None, backend=None, id=None, procedure_class=None, **kwargs):
reqs = []
loop_count = 0
for_count = 0
while_count = 0
if_count = 0
if_config = LifoQueue()
procedure_class = procedure_class or cls
key = None
for request_config in requests:
# Check if this request is a for loop
if len(request_config.keys()) == 1:
key = list(request_config.keys())[0]
m = re.match('\s*(fork?)\s+([\w\d_]+)\s+in\s+(.*)\s*', key)
if m:
loop_count += 1
loop_name = '{}__loop_{}'.format(name, loop_count)
# A 'for' loop is synchronous. Declare a 'fork' loop if you
# want to process the elements in the iterable in parallel
_async = True if m.group(1) == 'fork' else False
iterator_name = m.group(2)
iterable = m.group(3)
loop = LoopProcedure.build(name=loop_name, _async=_async,
requests=request_config[key],
backend=backend, id=id,
iterator_name=iterator_name,
iterable=iterable)
reqs.append(loop)
continue
# Check if it's a break/continue/return statement
if isinstance(request_config, str):
reqs.append(Statement(request_config))
continue
# Check if this request is an if-else
if len(request_config.keys()) >= 1:
@ -100,6 +90,48 @@ class Procedure(object):
if key == 'else':
continue
# Check if this request is a for loop
if len(request_config.keys()) == 1:
key = list(request_config.keys())[0]
m = re.match('\s*(fork?)\s+([\w\d_]+)\s+in\s+(.*)\s*', key)
if m:
for_count += 1
loop_name = '{}__for_{}'.format(name, for_count)
# A 'for' loop is synchronous. Declare a 'fork' loop if you
# want to process the elements in the iterable in parallel
_async = True if m.group(1) == 'fork' else False
iterator_name = m.group(2)
iterable = m.group(3)
loop = ForProcedure.build(name=loop_name, _async=_async,
requests=request_config[key],
backend=backend, id=id,
iterator_name=iterator_name,
iterable=iterable)
reqs.append(loop)
continue
# Check if this request is a while loop
if len(request_config.keys()) == 1:
key = list(request_config.keys())[0]
m = re.match('\s*while\s+\${(.*)}\s*', key)
if m:
while_count += 1
loop_name = '{}__while_{}'.format(name, while_count)
condition = m.group(1).strip()
loop = WhileProcedure.build(name=loop_name, _async=False,
requests=request_config[key],
condition=condition,
backend=backend, id=id)
reqs.append(loop)
continue
request_config['origin'] = Config.get('device_id')
request_config['id'] = id
if 'target' not in request_config:
@ -114,12 +146,25 @@ class Procedure(object):
return procedure_class(name=name, _async=_async, requests=reqs, args=args, backend=backend, **kwargs)
def execute(self, n_tries=1, **context):
@staticmethod
def _find_nearest_loop(stack):
for proc in stack[::-1]:
if isinstance(proc, LoopProcedure):
return proc
raise AssertionError('break/continue statement found outside of a loop')
def execute(self, n_tries=1, __stack__=None, **context):
"""
Execute the requests in the procedure
Params:
n_tries -- Number of tries in case of failure before raising a RuntimeError
"""
if not __stack__:
__stack__ = [self]
else:
__stack__.append(self)
if self.args:
args = self.args.copy()
for k, v in args.items():
@ -134,12 +179,35 @@ class Procedure(object):
token = Config.get('token')
for request in self.requests:
if isinstance(request, Statement):
if request == Statement.RETURN:
self._should_return = True
for proc in __stack__:
proc._should_return = True
break
if request in [Statement.BREAK, Statement.CONTINUE]:
loop = self._find_nearest_loop(__stack__)
if request == Statement.BREAK:
loop._should_break = True
else:
loop._should_continue = True
break
if isinstance(self, LoopProcedure):
if self._should_continue or self._should_break:
if self._should_continue:
# noinspection PyAttributeOutsideInit
self._should_continue = False
break
if token:
request.token = token
context['_async'] = self._async
context['n_tries'] = n_tries
response = request.execute(**context)
response = request.execute(__stack__=__stack__, **context)
if not self._async and response:
if isinstance(response.output, dict):
@ -149,60 +217,171 @@ class Procedure(object):
context['output'] = response.output
context['errors'] = response.errors
if self._should_return:
break
return response or Response()
class LoopProcedure(Procedure):
"""
Base class while and for/fork loops.
"""
def __init__(self, name, requests, _async=False, args=None, backend=None):
super(). __init__(name=name, _async=_async, requests=requests, args=args, backend=backend)
self._should_break = False
self._should_continue = False
class ForProcedure(LoopProcedure):
"""
Models a loop procedure, which expresses a construct similar to a
for loop in a programming language. The 'for' keyword implies a synchronous
loop, i.e. the nested actions will be executed in sequence. Use 'fork'
instead of 'for' if you want to run the actions in parallel.
Example:
Example::
procedure.sync.process_results:
-
action: http.get
args:
url: https://some-service/some/json/endpoint
# Example response: { "results": [ {"id":1, "name":"foo"}, {"id":2,"name":"bar"} ]}
-
for result in ${results}:
-
action: some.custom.action
args:
id: ${result['id']}
name: ${result['name']}
"""
- action: http.get
args:
url: https://some-service/some/json/endpoint
# Example response: { "results": [ {"id":1, "name":"foo"}, {"id":2,"name":"bar"} ]}
- for result in ${results}:
- action: some.custom.action
args:
id: ${result['id']}
name: ${result['name']}
context = {}
"""
def __init__(self, name, iterator_name, iterable, requests, _async=False, args=None, backend=None):
super(). __init__(name=name, _async=_async, requests=requests, args=args, backend=backend)
self.iterator_name = iterator_name
self.iterable = iterable
self.requests = requests
def execute(self, _async=None, **context):
# noinspection PyBroadException
try:
iterable = eval(self.iterable)
if not hasattr(iterable, '__iter__'):
raise RuntimeError
assert hasattr(iterable, '__iter__'), 'Object of type {} is not iterable: {}'.\
format(type(iterable), iterable)
except:
iterable = Request.expand_value_from_context(self.iterable, **context)
response = Response()
# noinspection DuplicatedCode
for item in iterable:
if self._should_return:
logger.info('Returning from {}'.format(self.name))
break
if self._should_continue:
self._should_continue = False
logger.info('Continuing loop {}'.format(self.name))
continue
if self._should_break:
self._should_break = False
logger.info('Breaking loop {}'.format(self.name))
break
context[self.iterator_name] = item
response = super().execute(**context)
return response
class WhileProcedure(LoopProcedure):
"""
Models a while loop procedure.
Example::
procedure.process_results:
- action: http.get
args:
url: https://some-service/some/json/endpoint
# Example response: {"id":1, "name":"foo"}}
- while ${output}:
- action: some.custom.action
args:
id: ${id}
name: ${name}
- action: http.get
args:
url: https://some-service/some/json/endpoint
# Example response: {"id":1, "name":"foo"}}
"""
def __init__(self, name, condition, requests, _async=False, args=None, backend=None):
super(). __init__(name=name, _async=_async, requests=requests, args=args, backend=backend)
self.condition = condition
@staticmethod
def _get_context(**context):
for (k, v) in context.items():
# noinspection PyBroadException
try:
context[k] = eval(v)
except:
if isinstance(v, str):
# noinspection PyBroadException
try:
context[k] = eval('"{}"'.format(re.sub('(^|[^\\\])"', '\1\\"', v)))
except:
pass
return context
# noinspection DuplicatedCode,PyBroadException
def execute(self, _async=None, **context):
response = Response()
context = self._get_context(**context)
for k, v in context.items():
try:
exec('{}={}'.format(k, v))
except:
pass
while True:
condition_true = eval(self.condition)
if not condition_true:
break
if self._should_return:
logger.info('Returning from {}'.format(self.name))
break
if self._should_continue:
self._should_continue = False
logger.info('Continuing loop {}'.format(self.name))
continue
if self._should_break:
self._should_break = False
logger.info('Breaking loop {}'.format(self.name))
break
response = super().execute(**context)
if response.output:
if isinstance(response.output, dict):
new_context = self._get_context(**response.output)
for k, v in new_context.items():
try:
exec('{}={}'.format(k, v))
except:
pass
return response
# noinspection PyBroadException
class IfProcedure(Procedure):
"""
@ -229,8 +408,6 @@ class IfProcedure(Procedure):
cmd: '/path/turn_off_heating.sh'
"""
context = {}
def __init__(self, name, condition, requests, else_branch=None, args=None, backend=None, id=None, **kwargs):
kwargs['_async'] = False
self.condition = condition