What is AWS Simple Workflow Service?
AWS Simple Workflow Service (SWF) is a workflow orchestration service that enables coordination of tasks across distributed application components. The service tracks workflow state, distributes tasks to workers, and coordinates flow between different components.
SWF was designed for complex, long-running workflows where developers need full control over workflow logic. However, for most new use cases, AWS recommends Step Functions as a more modern alternative.
Core Features
- Track workflow state over arbitrary time periods
- Distribute tasks to deciders and activity workers
- Support for human and automated tasks
- Signals for external events and approvals
- Guaranteed task execution with retry logic
Typical Use Cases
Media Processing Pipelines: Complex processing workflows with many steps running over hours or days, coordinating various encoding and analysis tasks.
Order Fulfillment: Multi-step processes with manual approval steps that can take weeks and need to react to external events.
Legacy Workflows: Existing SWF implementations that run reliably and don’t require migration.
Benefits
- Unlimited workflow runtime possible
- Full control over workflow logic in code
- Reliable execution with at-least-once guarantee
- Support for complex branching logic
Integration with innFactory
As an AWS Reseller, innFactory supports you with AWS SWF: assessment of existing workflows, migration to Step Functions where appropriate, optimization of SWF implementations, and architecture consulting for workflow requirements.
Typical Use Cases
Frequently Asked Questions
What is the difference between SWF and Step Functions?
SWF is an older service with more flexibility in workflow logic but requires custom code for deciders and activity workers. Step Functions is newer, fully managed, and uses declarative workflow definitions. AWS recommends Step Functions for new projects.
When should I still use SWF?
SWF makes sense for existing implementations, when workflows need to run longer than one year, or when workflow logic is too complex to be modeled in Step Functions.
How long can SWF workflows run?
SWF workflows can theoretically run indefinitely, while Step Functions Standard Workflows are limited to one year. For very long-running processes, SWF may be the better choice.
Does SWF support human approvals?
Yes, SWF can wait for external signals, enabling human approval steps. The workflow pauses until a signal is received.