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# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: Apache-2.0
"""
Purpose
Shows how to use the AWS SDK for Python (Boto3) with AWS Step Functions to
create and manage activities. An activity is used by a state machine to pause its
execution and let external code get current state data and send a response before the
state machine is resumed.
"""
import logging
from botocore . exceptions import ClientError
logger = logging . getLogger ( __name__ )
# snippet-start:[python.example_code.sfn.Activity_full]
# snippet-start:[python.example_code.sfn.Activity_decl]
class Activity :
""" Encapsulates Step Function activity actions. """
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def __init__ ( self , stepfunctions_client ) :
"""
:param stepfunctions_client: A Boto3 Step Functions client.
"""
self . stepfunctions_client = stepfunctions_client
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# snippet-end:[python.example_code.sfn.Activity_decl]
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# snippet-start:[python.example_code.sfn.CreateActivity]
def create ( self , name ) :
"""
Create an activity.
:param name: The name of the activity to create.
:return: The Amazon Resource Name (ARN) of the newly created activity.
"""
try :
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response = self . stepfunctions_client . create_activity ( name = name )
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except ClientError as err :
logger . error (
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" Couldn ' t create activity %s . Here ' s why: %s : %s " ,
name ,
err . response [ " Error " ] [ " Code " ] ,
err . response [ " Error " ] [ " Message " ] ,
)
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raise
else :
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return response [ " activityArn " ]
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# snippet-end:[python.example_code.sfn.CreateActivity]
# snippet-start:[python.example_code.sfn.ListActivities]
def find ( self , name ) :
"""
Find an activity by name. This requires listing activities until one is found
with a matching name.
:param name: The name of the activity to search for.
:return: If found, the ARN of the activity; otherwise, None.
"""
try :
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paginator = self . stepfunctions_client . get_paginator ( " list_activities " )
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for page in paginator . paginate ( ) :
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for activity in page . get ( " activities " , [ ] ) :
if activity [ " name " ] == name :
return activity [ " activityArn " ]
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except ClientError as err :
logger . error (
" Couldn ' t list activities. Here ' s why: %s : %s " ,
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err . response [ " Error " ] [ " Code " ] ,
err . response [ " Error " ] [ " Message " ] ,
)
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raise
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# snippet-end:[python.example_code.sfn.ListActivities]
# snippet-start:[python.example_code.sfn.GetActivityTask]
def get_task ( self , activity_arn ) :
"""
Gets task data for an activity. When a state machine is waiting for the
specified activity, a response is returned with data from the state machine.
When a state machine is not waiting, this call blocks for 60 seconds.
:param activity_arn: The ARN of the activity to get task data for.
:return: The task data for the activity.
"""
try :
response = self . stepfunctions_client . get_activity_task (
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activityArn = activity_arn
)
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except ClientError as err :
logger . error (
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" Couldn ' t get a task for activity %s . Here ' s why: %s : %s " ,
activity_arn ,
err . response [ " Error " ] [ " Code " ] ,
err . response [ " Error " ] [ " Message " ] ,
)
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raise
else :
return response
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# snippet-end:[python.example_code.sfn.GetActivityTask]
# snippet-start:[python.example_code.sfn.SendTaskSuccess]
def send_task_success ( self , task_token , task_response ) :
"""
Sends a success response to a waiting activity step. A state machine with an
activity step waits for the activity to get task data and then respond with
either success or failure before it resumes processing.
:param task_token: The token associated with the task. This is included in the
response to the get_activity_task action and must be sent
without modification.
:param task_response: The response data from the activity. This data is
received and processed by the state machine.
"""
try :
self . stepfunctions_client . send_task_success (
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taskToken = task_token , output = task_response
)
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except ClientError as err :
logger . error (
" Couldn ' t send task success. Here ' s why: %s : %s " ,
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err . response [ " Error " ] [ " Code " ] ,
err . response [ " Error " ] [ " Message " ] ,
)
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raise
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# snippet-end:[python.example_code.sfn.SendTaskSuccess]
# snippet-start:[python.example_code.sfn.DeleteActivity]
def delete ( self , activity_arn ) :
"""
Delete an activity.
:param activity_arn: The ARN of the activity to delete.
"""
try :
response = self . stepfunctions_client . delete_activity (
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activityArn = activity_arn
)
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except ClientError as err :
logger . error (
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" Couldn ' t delete activity %s . Here ' s why: %s : %s " ,
activity_arn ,
err . response [ " Error " ] [ " Code " ] ,
err . response [ " Error " ] [ " Message " ] ,
)
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raise
else :
return response
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# snippet-end:[python.example_code.sfn.DeleteActivity]
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# snippet-end:[python.example_code.sfn.Activity_full]
