I have created a simple SWF workflow but seem to be receiving multiple notifications of new Decision tasks available. I am using the boto3 python sdk.
There is no good boto3 swf sample code that I can find, so I started from the boto2 sample at http://boto.cloudhackers.com/en/latest/swf_tut.html.
I've created my simple workflow with this script which creates a domain, a workflow, and a single task in that workflow:
#!/usr/bin/python
import boto3
from botocore.exceptions import ClientError
swf = boto3.client('swf')
try:
swf.register_domain(
name="surroundiotest-swf",
description="Surroundio test SWF domain",
workflowExecutionRetentionPeriodInDays="10"
)
except ClientError as e:
print "Domain already exists: ", e.response.get("Error", {}).get("Code")
try:
swf.register_workflow_type(
domain="surroundiotest-swf",
name="testflow",
version="0.1",
description="testworkflow",
defaultExecutionStartToCloseTimeout="250",
defaultTaskStartToCloseTimeout="NONE",
defaultChildPolicy="TERMINATE",
defaultTaskList={"name": "testflow"}
)
print "testflow created!"
except ClientError as e:
print "Workflow already exists: ", e.response.get("Error", {}).get("Code")
try:
swf.register_activity_type(
domain="surroundiotest-swf",
name="testworker",
version="0.1",
description="testworker",
defaultTaskStartToCloseTimeout="NONE",
defaultTaskList={"name": "testflow"}
)
print "testworker created!"
except ClientError as e:
print "Activity already exists: ", e.response.get("Error", {}).get("Code")
my worker code:
#!/usr/bin/python
import boto3
from botocore.client import Config
botoConfig = Config(connect_timeout=50, read_timeout=70)
swf = boto3.client('swf', config=botoConfig)
print "Listening for Worker Tasks"
while True:
task = swf.poll_for_activity_task(
domain='surroundiotest-swf',
taskList={'name': 'testflow'},
identity='worker-1')
if 'taskToken' not in task:
print "Poll timed out, no new task. Repoll"
else:
print "New task arrived"
swf.respond_activity_task_completed(
taskToken=task['taskToken'],
result='success'
)
print "Task Done"
my decider code:
#!/usr/bin/python
import boto3
from botocore.client import Config
botoConfig = Config(connect_timeout=50, read_timeout=70)
swf = boto3.client('swf', config=botoConfig)
print "Listening for Decision Tasks"
while True:
newTask = swf.poll_for_decision_task(
domain='surroundiotest-swf',
taskList={'name': 'testflow'},
identity='decider-1',
reverseOrder=True)
if 'taskToken' not in newTask:
print "Poll timed out, no new task. Repoll"
elif 'events' in newTask:
eventHistory = [evt for evt in newTask['events'] if not evt['eventType'].startswith('Decision')]
lastEvent = eventHistory[-1]
if lastEvent['eventType'] == 'WorkflowExecutionStarted':
print "Dispatching task to worker", newTask['workflowExecution'], newTask['workflowType']
swf.respond_decision_task_completed(
taskToken=newTask['taskToken'],
decisions=[
{
'decisionType': 'ScheduleActivityTask',
'scheduleActivityTaskDecisionAttributes': {
'activityType':{
'name': 'testworker',
'version': '0.1'
},
'activityId': 'activityid-1001',
'input': '',
'scheduleToCloseTimeout': 'NONE',
'scheduleToStartTimeout': 'NONE',
'startToCloseTimeout': 'NONE',
'heartbeatTimeout': 'NONE',
'taskList': {'name': 'testflow'},
}
}
]
)
print "Task Dispatched"
# print json.dumps(newTask, default=json_serial, sort_keys=True, indent=4, separators=(',', ': '))
elif lastEvent['eventType'] == 'ActivityTaskCompleted':
swf.respond_decision_task_completed(
taskToken=newTask['taskToken'],
decisions=[
{
'decisionType': 'CompleteWorkflowExecution',
'completeWorkflowExecutionDecisionAttributes': {
'result': 'success'
}
}
]
)
print "Task Completed!"
When I run these scripts, and submit a request, the decider receives the task and dispatches it, and the worker receives it and executes it. However, the decider is notified of the task on every subsequent poll, so I see output like this from my decider:
Listening for Decision Tasks
Poll timed out, no new task. Repoll
Dispatching task to worker {u'workflowId': u'surroundtest-1001', u'runId': u'23oPrHZ/d9kR43V/hr0ykZCI7Dks/FzLhfDeA9PPWFuPE='} {u'version': u'0.1', u'name': u'testflow'}
Task Dispatched
Dispatching task to worker {u'workflowId': u'surroundtest-1001', u'runId': u'23oPrHZ/d9kR43V/hr0ykZCI7Dks/FzLhfDeA9PPWFuPE='} {u'version': u'0.1', u'name': u'testflow'}
Task Dispatched
Dispatching task to worker {u'workflowId': u'surroundtest-1001', u'runId': u'23oPrHZ/d9kR43V/hr0ykZCI7Dks/FzLhfDeA9PPWFuPE='} {u'version': u'0.1', u'name': u'testflow'}
Task Dispatched
Dispatching task to worker {u'workflowId': u'surroundtest-1001', u'runId': u'23oPrHZ/d9kR43V/hr0ykZCI7Dks/FzLhfDeA9PPWFuPE='} {u'version': u'0.1', u'name': u'testflow'}
Task Dispatched
Dispatching task to worker {u'workflowId': u'surroundtest-1001', u'runId': u'23oPrHZ/d9kR43V/hr0ykZCI7Dks/FzLhfDeA9PPWFuPE='} {u'version': u'0.1', u'name': u'testflow'}
Task Dispatched
It would seem that SWF is not receiving a notification that the decider has dispatched the task, and is continually delivering the task to the decider. Is there some piece of the decider setup I am doing wrong, is there some additional info I need to convey to SWF?
