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Set Variable

"type" : "SET_VARIABLE"

The SET_VARIABLE task allows users to create global workflow variables, and update them with new values.

Variables can be initialized in the workflow definition as well as during the workflow run. Once a variable is initialized it can be read using the expression ${workflow.variables.NAME} by any other task.

It can be overwritten by a subsequent SET_VARIABLE task.


There is a hard barrier for variables payload size in KB defined in the JVM system properties (conductor.max.workflow.variables.payload.threshold.kb) the default value is 256. Passing this barrier will fail the task and the workflow.

Use Cases

For example, you might want to track shared state at the workflow level, and have the state be accessible by any task executed as part of the workflow.


Global variables can be set in inputParameters using the desired variable names and their respective values.


Suppose in a workflow, we have to store a value in a variable and then later in workflow reuse the value stored in the variable just as we do in programming, in such scenarios Set Variable task can be used.

Following is the workflow definition with SET_VARIABLE task.

  "name": "Set_Variable_Workflow",
  "description": "Set a value to a variable and then reuse it later in the workflow",
  "version": 1,
  "tasks": [
      "name": "Set_Name",
      "taskReferenceName": "Set_Name",
      "type": "SET_VARIABLE",
      "inputParameters": {
        "name": "Foo"
      "name": "Read_Name",
      "taskReferenceName": "Read_Name",
      "inputParameters": {
        "saved_name" : "${}"
      "type": "SIMPLE"
  "restartable": true,
  "workflowStatusListenerEnabled": true,
  "schemaVersion": 2

In the above example, it can be seen that the task Set_Name is a Set Variable Task and the variable name is set to Foo and later in the workflow it is referenced by "${}" in another task.