take latest changes from upstream

Author: meetchandan

README.md

@@ -1,65 +1,46 @@
-# Python framework for Cadence Workflow Service
+# Intro: Fault-Oblivious Stateful Python Code
 
-[Cadence](https://github.com/uber/cadence) is a workflow engine developed at Uber Engineering. With this framework, workflows and activities managed by Cadence can be implemented in Python code.
+cadence-python allows you to create Python functions that have their state (local variables etc..) implicitly saved such that if the process/machine fails the state of the function is not lost and can resume from where it left off. 
 
-## Status / TODO
+This programming model is useful whenever you need to ensure that a function runs to completion. For example:
 
-cadence-python is still under going heavy development. It should be considered EXPERIMENTAL at the moment. A production
-version is targeted to be released in ~~September of 2019~~ ~~January 2020~~ March 2020.
+- Business logic involving multiple micro services
+- CI/CD pipelines
+- Data pipelines
+- RPA
+- ETL
+- Marketing automation / Customer journeys / Customer engagement
+- Zapier/IFTTT like end user automation.
+- Chat bots
+- Multi-step forms
+- Scheduler/Cron jobs
 
-1.0
-- [x] Tchannel implementation
-- [x] Python-friendly wrapper around Cadence's Thrift API
-- [x] Author activities in Python
-- [x] Start workflows (synchronously)
-- [x] Create workflows
-- [x] Workflow execution in coroutines
-- [x] Invoke activities from workflows
-- [x] ActivityCompletionClient heartbeat, complete, complete_exceptionally
-- [x] Activity heartbeat, getHeartbeatDetails and doNotCompleteOnReturn
-- [x] Activity retry
-- [x] Activity getDomain(), getTaskToken(), getWorkflowExecution()
-- [x] Signals
-- [x] Queries
-- [x] Async workflow execution
-- [x] await
-- [x] now (currentTimeMillis)
-- [x] Sleep
-- [x] Loggers
-- [x] newRandom
-- [x] UUID
-- [x] Workflow Versioning
-- [x] WorkflowClient.newWorkflowStub(Class workflowInterface, String workflowId);
+Behind the scenes, cadence-python uses [Cadence](https://github.com/uber/cadence) as its backend. 
 
-1.1
-- [ ] ActivityStub and Workflow.newUntypedActivityStub
-- [ ] Classes as arguments and return values to/from activity and workflow methods
-- [ ] WorkflowStub and WorkflowClient.newUntypedWorkflowStub
-- [ ] Custom workflow ids through start() and new_workflow_stub()
-- [ ] ContinueAsNew
-- [ ] Compatibility with Java client
-- [ ] Compatibility with Golang client
+For more information about the fault-oblivious programming model refer to the Cadence documentation [here](https://cadenceworkflow.io/docs/03_concepts/01_workflows)
 
-2.0
-- [ ] Sticky workflows
+## Install Cadencce
 
-Post 2.0:
-- [ ] sideEffect/mutableSideEffect
-- [ ] Parallel activity execution
-- [ ] Timers
-- [ ] Cancellation Scopes
-- [ ] Child Workflows
-- [ ] Explicit activity ids for activity invocations
+```
+wget https://raw.githubusercontent.com/uber/cadence/master/docker/docker-compose.yml
+docker-compose up
+```
 
-## Installation
+## Register `sample` domain
 
 ```
-pip install cadence-client
+docker run --network=host --rm ubercadence/cli:master --do sample domain register -rd 1
 ```
 
-## Hello World Sample
+## Installation cadence-python
 
 ```
+pip install cadence-client==1.0.0b3
+```
+
+## Hello World Sample
+
+```python
 import sys
 import logging
 from cadence.activity_method import activity_method
@@ -82,7 +63,7 @@ class GreetingActivities:
 # Activities Implementation
 class GreetingActivitiesImpl:
     def compose_greeting(self, greeting: str, name: str):
-        return greeting + " " + name + "!"
+        return f"{greeting} {name}!"
 
 
 # Workflow Interface
@@ -99,6 +80,9 @@ class GreetingWorkflowImpl(GreetingWorkflow):
         self.greeting_activities: GreetingActivities = Workflow.new_activity_stub(GreetingActivities)
 
     async def get_greeting(self, name):
+        # Place any Python code here that you want to ensure is executed to completion.
+        # Note: code in workflow functions must be deterministic so that the same code paths
+        # are ran during replay.
         return await self.greeting_activities.compose_greeting("Hello", name)
 
 
@@ -118,4 +102,56 @@ if __name__ == '__main__':
     worker.stop()
     print("Workers stopped...")
     sys.exit(0)
-```
+``` 
+
+## Status / TODO
+
+cadence-python is still under going heavy development. It should be considered EXPERIMENTAL at the moment. A production
+version is targeted to be released in ~~September of 2019~~ ~~January 2020~~ ~~March 2020~~ April 2020.
+
+1.0
+- [x] Tchannel implementation
+- [x] Python-friendly wrapper around Cadence's Thrift API
+- [x] Author activities in Python
+- [x] Start workflows (synchronously)
+- [x] Create workflows
+- [x] Workflow execution in coroutines
+- [x] Invoke activities from workflows
+- [x] ActivityCompletionClient heartbeat, complete, complete_exceptionally
+- [x] Activity heartbeat, getHeartbeatDetails and doNotCompleteOnReturn
+- [x] Activity retry
+- [x] Activity getDomain(), getTaskToken(), getWorkflowExecution()
+- [x] Signals
+- [x] Queries
+- [x] Async workflow execution
+- [x] await
+- [x] now (currentTimeMillis)
+- [x] Sleep
+- [x] Loggers
+- [x] newRandom
+- [x] UUID
+- [x] Workflow Versioning
+- [x] WorkflowClient.newWorkflowStub(Class workflowInterface, String workflowId);
+
+1.1
+- [ ] ActivityStub and Workflow.newUntypedActivityStub
+- [ ] Classes as arguments and return values to/from activity and workflow methods
+- [ ] WorkflowStub and WorkflowClient.newUntypedWorkflowStub
+- [ ] Custom workflow ids through start() and new_workflow_stub()
+- [ ] ContinueAsNew
+- [ ] Compatibility with Java client
+- [ ] Compatibility with Golang client
+
+2.0
+- [ ] Sticky workflows
+
+Post 2.0:
+- [ ] sideEffect/mutableSideEffect
+- [ ] Local activity
+- [ ] Parallel activity execution
+- [ ] Timers
+- [ ] Cancellation Scopes
+- [ ] Child Workflows
+- [ ] Explicit activity ids for activity invocations
+
+

cadence/activity_loop.py

@@ -6,20 +6,22 @@
 from cadence.cadence_types import PollForActivityTaskRequest, TaskListMetadata, TaskList, PollForActivityTaskResponse
 from cadence.conversions import json_to_args
 from cadence.workflowservice import WorkflowService
-from cadence.worker import Worker
+from cadence.worker import Worker, StopRequestedException
 
 logger = logging.getLogger(__name__)
 
 
 def activity_task_loop(worker: Worker):
-    service: WorkflowService = WorkflowService.create(worker.host, worker.port)
+    service: WorkflowService = WorkflowService.create(worker.host, worker.port, timeout=worker.get_timeout())
     worker.manage_service(service)
     logger.info(f"Activity task worker started: {WorkflowService.get_identity()}")
     try:
         while True:
             if worker.is_stop_requested():
                 return
             try:
+                service.set_next_timeout_cb(worker.raise_if_stop_requested)
+
                 polling_start = datetime.datetime.now()
                 polling_request = PollForActivityTaskRequest()
                 polling_request.task_list_metadata = TaskListMetadata()
@@ -32,6 +34,8 @@ def activity_task_loop(worker: Worker):
                 task, err = service.poll_for_activity_task(polling_request)
                 polling_end = datetime.datetime.now()
                 logger.debug("PollForActivityTask: %dms", (polling_end - polling_start).total_seconds() * 1000)
+            except StopRequestedException:
+                return
             except Exception as ex:
                 logger.error("PollForActivityTask error: %s", ex)
                 continue
@@ -75,4 +79,8 @@ def activity_task_loop(worker: Worker):
                 process_end = datetime.datetime.now()
                 logger.info("Process ActivityTask: %dms", (process_end - process_start).total_seconds() * 1000)
     finally:
+        try:
+            service.close()
+        except:
+            logger.warning("service.close() failed", exc_info=1)
         worker.notify_thread_stopped()

cadence/activity_method.py

@@ -54,6 +54,8 @@ async def stub_activity_fn(self, *args):
             assert self._decision_context
             assert stub_activity_fn._execute_parameters
             parameters = copy.deepcopy(stub_activity_fn._execute_parameters)
+            if hasattr(self, "_activity_options") and self._activity_options:
+                self._activity_options.fill_execute_activity_parameters(parameters)
             if self._retry_parameters:
                 parameters.retry_parameters = self._retry_parameters
             parameters.input = args_to_json(args).encode("utf-8")
@@ -80,3 +82,24 @@ async def stub_activity_fn(self, *args):
         raise Exception("activity_method must be called with arguments")
     else:
         return wrapper
+
+
+@dataclass
+class ActivityOptions:
+    schedule_to_close_timeout_seconds: int = None
+    schedule_to_start_timeout_seconds: int = None
+    start_to_close_timeout_seconds: int = None
+    heartbeat_timeout_seconds: int = None
+    task_list: str = None
+
+    def fill_execute_activity_parameters(self, execute_parameters: ExecuteActivityParameters):
+        if self.schedule_to_close_timeout_seconds is not None:
+            execute_parameters.schedule_to_close_timeout_seconds = self.schedule_to_close_timeout_seconds
+        if self.schedule_to_start_timeout_seconds is not None:
+            execute_parameters.schedule_to_start_timeout_seconds = self.schedule_to_start_timeout_seconds
+        if self.start_to_close_timeout_seconds is not None:
+            execute_parameters.start_to_close_timeout_seconds = self.start_to_close_timeout_seconds
+        if self.heartbeat_timeout_seconds is not None:
+            execute_parameters.heartbeat_timeout_seconds = self.heartbeat_timeout_seconds
+        if self.task_list is not None:
+            execute_parameters.task_list = self.task_list

cadence/connection.py

@@ -1,11 +1,10 @@
 from __future__ import annotations
 
 import getpass
-import os
 import socket
 from dataclasses import dataclass
 from io import BytesIO
-from typing import IO, List, Union, Optional, Dict
+from typing import IO, List, Union, Optional, Dict, Callable
 
 from cadence.frames import InitReqFrame, Frame, Arg, CallReqFrame, CallReqContinueFrame, CallResFrame, \
     CallResContinueFrame, FrameWithArgs, CallFlags, ErrorFrame
@@ -300,19 +299,23 @@ class TChannelConnection:
     s: socket.socket
 
     @classmethod
-    def open(cls, host: object, port: object) -> TChannelConnection:
+    def open(cls, host: object, port: object, timeout: int = None) -> TChannelConnection:
         s: socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        s.settimeout(timeout)
         s.connect((host, port))
         return cls(s)
 
     def __init__(self, s: socket):
         self.s = s
         self.file = self.s.makefile("rwb")
-        self.wrapper = IOWrapper(self.file)
+        self.wrapper = IOWrapper(self.file, socket_=s)
         self.current_id = -1
 
         self.handshake()
 
+    def set_next_timeout_cb(self, cb: Callable):
+        self.wrapper.set_next_timeout_cb(cb)
+
     def new_id(self):
         self.current_id += 1
         return self.current_id
@@ -340,6 +343,7 @@ def read_frame(self):
 
     def close(self):
         self.s.close()
+        self.wrapper.close()
 
     def call_function(self, call: ThriftFunctionCall) -> ThriftFunctionResponse:
         frames = call.build_frames(self.new_id())

cadence/constants.py

@@ -1,3 +1,7 @@
 
 CODE_OK = 0x00
 CODE_ERROR = 0x01
+
+# This should be at least 60 seconds because Cadence will reply after 60 seconds when polling
+# if there is nothing pending
+DEFAULT_SOCKET_TIMEOUT_SECONDS = 120