Distributed systems are the backbone of modern application architectures. They enable scalability and modularity, but they also introduce challenges. Distributed transactions in a microservices-based architecture exemplify this. How do you ensure reliability amid failures? How can you debug a problem that spans multiple services? Developers often struggle to answer these questions, as progress slows in response to increasing system complexity.
Temporal transforms microservices orchestration by providing a fundamentally better approach for developing distributed applications. In this blog post, you’ll explore common pitfalls in managing distributed transactions and learn how Temporal simplifies them.
Microservices Application Example
The illustration above represents an e-commerce application that uses four steps to process orders:
1. Fraud Check: To protect the business against theft, the application first contacts the fraud service, which evaluates the order details and flags fraudulent transactions.
2. Prepare Shipment: If the order passes the fraud check, the application contacts the inventory service to reserve the items ordered by the customer.
3. Charge Customer: The application contacts the payment service to charge the customer for the products in their order currently available in inventory.
4. Ship Order: The application contacts the shipping service, which generates a shipping label and schedules a driver to deliver the shipment to the customer.
Orchestrating Microservices the Hard Way
Here are some of the challenges that developers face when coordinating transactions across multiple services:
- Ephemeral State: Processes may end prematurely due to unexpected failures, leading to incomplete transactions or debugging nightmares.
- Lack of Visibility: State is strewn across multiple services, making it difficult to understand progress and diagnose problems in the application.
- Limited Reliability: Service outages may cause interruptions, often requiring manual intervention and potentially leading to failures in other parts of the system.
Conventional Approaches and Their Shortcomings
Teams have adopted various strategies to address these problems, including:
1. Stateful Services: Each service maintains its own database to track state. While this ensures data isn't lost, it introduces multiple state machines that must be managed and synchronized, adding complexity to the system.
2. Event Stores or Messaging Systems: Tools such as Kafka can provide protection against service outages by decoupling the service that produces a message from the service that consumes it. However, this can further reduce the lack of visibility in the overall system, especially after adding dead letter queues to deal with failures.
Clearly, these approaches mitigate certain risks but often introduce new problems.
Orchestrating Microservices the Durable Way
The defining characteristic of a distributed application is the increased potential for failure. Temporal addresses this by providing Durable Execution—crash-proof execution—through an abstraction known as a Workflow. A Workflow is a function or method that defines your business logic using a standard programming language, such as Java, Go, or Python. Unlike other methods or functions in those languages, it can overcome both software and hardware failures.
Here is how Temporal simplifies distributed transactions by directly addressing these challenges:
Eliminate Ephemeral State Issues: Temporal Workflows automatically persist state at every step, eliminating the risk of losing it if the process crashes.
Gain Visibility Into Execution: Temporal’s Event History records the application’s progress and results. This is accessible via a convenient web-based user interface, delivering insights into both current and past behavior of each execution.
Improve Reliability: Temporal enables automatic retries to address service outages and intermittent failures, with retry policies you can customize to align with business requirements.
Centralize Orchestration Logic: Temporal Workflows define the overall business logic in one place. This simplifies updates, debugging, and enhances clarity and maintainability.
Key Components of Temporal Design
Temporal’s design introduces abstractions that simplify handling distributed transactions:
1. Workflows:
- Each Workflow Execution has a unique ID. These are user-defined values, typically corresponding to a business-level identifier (such as an order number or account name), providing better traceability.
- Temporal’s design ensures that no more than one Workflow Execution with a given ID will be running at any given point in time, which protects against duplicate processing.
2. Activities:
- Activities encapsulate operations that may fail, such as database queries or calls to external services
- Built-in retry policies ensure that even error-prone steps succeed reliably.
- Activities support modularity by enabling reuse across Workflows.
- Activities enable cross-team collaboration even when teams don’t share a common programming language. Each Activity can be written in any language that Temporal supports, even a different one from the Workflow itself.
3. Event History:
- Temporal stores the execution history of Workflows as a series of events, visible in the Temporal Web UI.
- This history enables Workflows to be reset to any prior state, allowing for easy debugging and error recovery.
- It also serves as a rich audit trail for compliance and observability.
These components address common pain points in distributed transactions, enhancing system reliability and manageability.
Temporal in Action
Temporal ensures that if any step fails — e.g., a payment gateway timeout occurs — the system automatically retries or resets to the previous state without losing progress. Instead of many disconnected events sent to multiple systems run by different teams, Temporal collects events related to a specific transaction into that Workflow’s Event History. This consolidation allows any team to see all events related to a process in one place.
For example, events like validating an account, credit or debit transactions, or checking for fraud— which are typically scattered across services — are collected into a single Workflow. Real-world transactions often involve more complex and varied events. By consolidating these events into Workflows, Temporal enhances visibility and simplifies operations.
Why Choose Temporal?
Temporal doesn’t just address the challenges of distributed transactions — it fundamentally changes how developers design and manage systems. By abstracting away infrastructure complexities, Temporal empowers teams to focus on business logic rather than plumbing.
The result? Systems that are simpler, more reliable, and easier to evolve over time.
Ready to simplify your microservices architecture? Try Temporal today.