Switch State
name
Unique State name. Must follow the Serverless Workflow Naming Convention
string
yes
type
State type
string
yes
dataConditions
Defined if the Switch state evaluates conditions and transitions based on state data.
array
yes (if eventConditions is not defined)
eventConditions
Defined if the Switch state evaluates conditions and transitions based on arrival of events.
array
yes (if dataConditions is not defined
stateDataFilter
State data filter
object
no
onErrors
States error handling and retries definitions
array
no
timeouts
State specific timeout settings
object
no
defaultCondition
Default transition of the workflow if there is no matching data conditions or event timeout is reached. Can be a transition or end definition
object
yes
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
Example:
Switch states can be viewed as workflow gateways: they can direct transitions of a workflow based on certain conditions. There are two types of conditions for switch states:
Data-based conditions
Event-based conditions
These are exclusive, meaning that a switch state can define one or the other condition type, but not both.
At times multiple defined conditions can be evaluated to true by runtime implementations. Conditions defined first take precedence over conditions defined later. This is backed by the fact that arrays/sequences are ordered in both JSON and YAML. For example, let's say there are two true conditions: A and B, defined in that order. Because A was defined first, its transition will be executed, not B's.
In case of data-based conditions definition, switch state controls workflow transitions based on the states data. If no defined conditions can be matched, the state transitions is taken based on the defaultCondition property. This property can be either a transition to another workflow state, or an end definition meaning a workflow end.
For event-based conditions, a switch state acts as a workflow wait state. It halts workflow execution until one of the referenced events arrive, then making a transition depending on that event definition. If events defined in event-based conditions do not arrive before the states eventTimeout property expires, state transitions are based on the defined defaultCondition property.
The timeouts property can be used to define state specific timeout settings. Switch states can define the stateExecTimeout setting. If eventConditions is defined, the switch state can also define the eventTimeout property. For more information on workflow timeouts reference the Workflow Timeouts section.
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