Orchestrate Saga

These actions provide ability to coordinate end-to-end API calls, locally executing or distributing microservice steps across the platform.

Orchestrate Saga Actions

StartSaga

Initiates execution of a new saga, using sagaPath or sagaId parameter of the requesting event, or the request metadata path if not defined. The request is accepted only if there is an active saga matching this path.

When called from within another saga, following event metadata fields are applicable for this action:

Table

Field	Definition	Example	Default
Input Element	Json path for the input in request event payload	parameters	-
Output Element	Json path for the output in response event payload	result	-

JSON Schema

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "eventMeta": {
      "type": "object",
      "properties": {
        "inputElement": {
          "type": "string",
          "definition": "Json path for the input in request event payload",
          "example": "parameters",
          "default": null
        },
        "outputElement": {
          "type": "string",
          "definition": "Json path for the output in response event payload",
          "example": "result",
          "default": null
        }
      }
    }
  }
}

With the following event metadata parameters:

Table

Parameter	Definition	Example	Default
Saga	ID of the saga to call	list_customers	-
Saga Path	Path of the saga to call	/ListCustomers
Saga Path Path	Json path of the input payload element that specifies saga path to call	data.saga	-
Fire Forget	Whether specific call to saga should work async (in case saga itself is not configured as such)	true	false
Input Pattern	JMESPath pattern to apply on data input	-	-
Output Pattern	JMESPath pattern to apply on data output, before returning response	-	-

JSON Schema

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "eventMeta": {
      "type": "object",
      "properties": {
        "parameters": {
          "type": "object",
          "properties": {
            "sagaId": {
              "type": "string",
              "definition": "ID of the saga to call",
              "example": "list_customers",
              "default": null
            },
            "sagaPath": {
              "type": "string",
              "definition": "Path of the saga to call",
              "example": "/ListCustomers",
              "default": null
            },
            "sagaPathPath": {
              "type": "string",
              "definition": "Json path of the input payload element that specifies saga path to call",
              "example": "data.saga",
              "default": null
            },
            "fireForget": {
              "type": "string",
              "definition": "Whether specific call to saga should work async (in case saga itself is not configured as such)",
              "default": "false"
            },
            "inputPattern": {
              "type": "string",
              "definition": "JMESPath pattern to apply on data input",
              "example": null,
              "default": null
            },
            "outputPattern": {
              "type": "string",
              "definition": "JMESPath pattern to apply on data output, before returning response",
              "example": null,
              "default": null
            }
          }
        }
      }
    }
  }
}

Nested sagas should only be used within the same runner as they do not replicate original event payload and metadata during execution for stateless distribution.

StepSaga

Executes the next action after a saga step is completed by an event runner, using the saga id and step id in event saga metadata.

Unlike the other event handlers, SagaEventHandler is rarely called from within saga flows, as it acts as a coordinator rather than a simple task executor.