Flow Services

A Flow Service is the primary unit of logic in Joynare Nexus. It represents a sequence of processing steps defined in a YAML file.

Structure

Every Flow Service lives in a directory named after itself, containing a flow.yaml file.

flows/
  namespace/
    MyService/
      flow.yaml

The YAML Definition

A typical flow.yaml includes:

• name: The service name.
• namespace: The logical grouping.
• pipeline: Metadata defining inputs and outputs.
• steps: An ordered array of processing steps.

Step Types

Joynare Nexus supports several step types to build complex logic:

Type	Purpose
invoke	Calls another service (Built-in, Flow, or Adapter).
map	Directly manipulates pipeline variables (Set, Copy, Drop).
branch	Conditional logic (Switch or Expression modes).
sequence	Groups steps with error handling strategies (Try/Catch).
loop	Iterates over an array in the pipeline.
repeat	Re-executes steps based on count or success/failure.
exit	Terminates a flow, loop, or sequence early.

Example

name: "ProcessOrder"
namespace: "orders"
pipeline:
  input:
    orderId: "string"
steps:
  - name: "FetchData"
    type: "invoke"
    service: "orders:GetOrderById"
    input:
      id: "${orderId}"

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## See Also
- [The Pipeline Concept](./pipeline)
- [Step Types Overview](./control-flow)
- [How to run Flows](../showcase/index)