Inject State

Parameter	Description	Type	Required
name	Unique State name. Must follow the Serverless Workflow Naming Convention	string	yes
type	State type	string	yes
data	JSON object which can be set as state's data input and can be manipulated via filter	object	yes
stateDataFilter	State data filter	object	no
transition	Next transition of the workflow after injection has completed	string or object	yes (if end is not defined)
compensatedBy	Unique name of a workflow state which is responsible for compensation of this state	string	no
usedForCompensation	If true, this state is used to compensate another state. Default is false	boolean	no
metadata	Metadata information	object	no
end	Is this state an end state	boolean or object	yes (if transition is not defined)

JSON	YAML
{ "name":"hello", "type":"inject", "data": { "result": "Hello" }, "transition": "world" }	name: hello type: inject data: result: Hello transition: world

Inject state can be used to inject static data into state data input. Inject state does not perform any actions. It is very useful for debugging, for example, as you can test/simulate workflow execution with pre-set data that would typically be dynamic in nature (e.g., function calls, events).

The inject state data property allows you to statically define a JSON object which gets added to the states data input. You can use the filter property to control the states data output to the transition state.

Here is a typical example of how to use the inject state to add static data into its states data input, which then is passed as data output to the transition state:

JSON	YAML
{ "name":"simple-inject-state", "type":"inject", "data": { "person": { "fname": "John", "lname": "Doe", "address": "1234 SomeStreet", "age": 40 } }, "transition": "greet-person-state" }	name: simple-inject-state type: inject data: person: fname: John lname: Doe address: 1234 SomeStreet age: 40 transition: greet-person-state

The data output of the "SimpleInjectState" which then is passed as input to the transition state would be:

{
 "person": {
      "fname": "John",
      "lname": "Doe",
      "address": "1234 SomeStreet",
      "age": 40
 }
}

If the inject state already receives a data input from the previous transition state, the inject data should be merged with its data input.

You can also use the filter property to filter the state data after data is injected. Let's say we have:

JSON

YAML

{ "name":"simple-inject-state", "type":"inject", "data": { "people": [ { "fname": "John", "lname": "Doe", "address": "1234 SomeStreet", "age": 40 }, { "fname": "Marry", "lname": "Allice", "address": "1234 SomeStreet", "age": 25 }, { "fname": "Kelly", "lname": "Mill", "address": "1234 SomeStreet", "age": 30 } ] }, "stateDataFilter": { "output": "${ {people: [.people[] | select(.age < 40)]} }" }, "transition": "greet-person-state" }

name: simple-inject-state type: inject data: people: - fname: John lname: Doe address: 1234 SomeStreet age: 40 - fname: Marry lname: Allice address: 1234 SomeStreet age: 25 - fname: Kelly lname: Mill address: 1234 SomeStreet age: 30 stateDataFilter: output: "${ {people: [.people[] | select(.age < 40)]} }" transition: greet-person-state

In which case the states data output would include only people whose age is less than 40:

{
  "people": [
    {
      "fname": "Marry",
      "lname": "Allice",
      "address": "1234 SomeStreet",
      "age": 25
    },
    {
      "fname": "Kelly",
      "lname": "Mill",
      "address": "1234 SomeStreet",
      "age": 30
    }
  ]
}

You can change your output path easily during testing, for example change the expression to:

${ {people: [.people[] | select(.age >= 40)]} }

This allows you to test if your workflow behaves properly for cases when there are people whose age is greater or equal 40.

Note that transition and end properties are mutually exclusive, meaning that you cannot define both of them at the same time.