/temporal-order-saga-usecases

Order SAGA use case examples

Primary LanguageJavaOtherNOASSERTION

Order Saga Sample

Configuration

The sample is configured by default to connect to a local Temporal Server running on localhost:7233.

To instead connect to Temporal Cloud, set the following environment variables, replacing them with your own Temporal Cloud credentials:

TEMPORAL_ADDRESS=testnamespace.sdvdw.tmprl.cloud:7233
TEMPORAL_NAMESPACE=testnamespace.sdvdw
TEMPORAL_CERT_PATH="/path/to/file.pem"
TEMPORAL_KEY_PATH="/path/to/file.key"

Start a worker

./gradlew -q execute -PmainClass=io.temporal.samples.ordersaga.Worker

Workflow Use Case 1: Split 'Subtract' Traffic with Compensations

Workflow Code

Temporal UI for Compensation Subtract Workflow

  • Splits a list of SKUs into two groups:
    • For processing by the legacy system
    • For processing by the new system
  • The 'subtract' operation is run on each system (in parallel)
  • If a failure in either system occurs, the workflow will run a compensation to 'reverse' the subtract operation in both systems

Run the workflow:

./gradlew -q execute -PmainClass=io.temporal.samples.ordersaga.splittrafficsubtract.Caller

Trigger a saga compensation:

  • Uncomment either of the exceptions in SubtractActivityImpl to cause that system's subtract operation to fail
  • Restart your worker, then re-run the workflow

Workflow Use Case 2: Compensations for failures in Multi-Container Allocation

Workflow Code

Temporal UI for Compensation Allocate Workflow

  • Accepts a quantity of items to allocate across containers
  • Runs getContainerRecommendation with hard-coded results:
    • 4 containers to allocate quantity to
    • Each container has 100 items in it
  • Iterates through the list of containers (sequentially)
    • Allocates 100 items to each container until the quantity is reached and finishes the workflow

Run the workflow (Provide a quantity as an argument using -Parg=<quantity>)

Providing a quantity of 350 will succeed:

./gradlew -q execute -PmainClass=io.temporal.samples.ordersaga.containerallocation.Caller -Parg=350

Trigger a Saga compensation:

  • If the quantity requested is greater than 400, the workflow will fail due to insufficient allocation
    • If an allocation fails, the workflow will run a compensation to 'reverse' the allocations in all containers

Example: Providing a quantity of 470 will fail due to insufficient containers (4 containers have 100 items each):

./gradlew -q execute -PmainClass=io.temporal.samples.ordersaga.containerallocation.Caller -Parg=350