awssl
Python 2.7 package to construct ASL compliant JSON that define State Machines for AWS Step Functions.
Example
from awssl import Pass, StateMachine
s = Pass(
Comment="This is an example of a state in branch",
Name="Pass1",
ResultAsJSON={"Value": 1234},
OutputPath="$.Value",
EndState=True)
sm = StateMachine(
Comment="This is an instance of a State Machine",
StartState=s)
print sm
The ext package provides more complex processing state types, such as For and LimitedParallel, by combining
the core state types appropriately. These require particular Lambda functions to be present, which can be
installed by creating a CloudFormation stack - see the script for details.
import awssl
import awssl.ext
# Declare the Arns for the Lambda functions required by awssl.ext state types
awssl.ext.set_ext_arns(
ForInitializer="arn:aws:lambda:REGION:ACCOUNT_ID:function:FUNCTION_NAME",
ForExtractor="arn:aws:lambda:REGION:ACCOUNT_ID:function:FUNCTION_NAME",
ForConsolidator="arn:aws:lambda:REGION:ACCOUNT_ID:function:FUNCTION_NAME",
ForFinalizer="arn:aws:lambda:REGION:ACCOUNT_ID:function:FUNCTION_NAME",
ForFinalizerParallelIterations="arn:aws:lambda:REGION:ACCOUNT_ID:function:FUNCTION_NAME",
LimitedParallelConsolidator="arn:aws:lambda:REGION:ACCOUNT_ID:function:FUNCTION_NAME")
# Create the branch of concurrent processing to be performed - in this case extraction of the iteration value
p = awssl.Pass(Name="Dummy", EndState=True, OutputPath="$.iteration.Iteration")
# Sometimes we want to throttle concurrent processing - for example to prevent Lambda function throttling
# awssl.ext.LimitedParallel can limit the number of concurrent branches being processed at any given time
parallel = awssl.ext.LimitedParallel(
Name="LimitedParallel",
EndState=True,
Iterations=100,
IteratorPath="$.iteration",
MaxConcurrency=15,
BranchState=p)
# Construct state machine
sm = awssl.StateMachine(Comment="This is a test", StartState=parallel)
print sm
Installation
To install, use pip install awssl.
Documentation
Documentation is available at read the docs.
Coverage
The package provides support for version 1.0 of Amazon Step Language.
No checking is performed for correctness of Paths - these are expected to be valid JsonPath, as implemented by the Step Functions.
Licence
This project is released under the MIT license. See LICENSE for details.
