Conditions

You can use a switch block as a selection mechanism that allows the value of an expression to control the flow of a workflow's execution. If a value matches, that condition's statement is executed.

If no matching expression is found, the workflow looks for an optional default condition: - condition: true. This should be the last condition in the switch block as they are evaluated in order and the first match found is executed. If there is neither a match nor a default condition, the workflow continues execution with the step that immediately follows.

Each switch block can include a maximum of 50 conditions. Each expression must evaluate to true or false. (Learn how to define and use expressions.)

For example, you can control the order of a workflow's execution by using a switch block to jump between steps based on a conditional expression:

YAML

 - STEP_NAME_A:  switch:  - condition: ${EXPRESSION_A}  next: STEP_NAME_B  - condition: ${EXPRESSION_B}  next: STEP_NAME_C  - condition: true  next: STEP_NAME_C  next: STEP_NAME_D

JSON

 [  {  "STEP_NAME_A": {  "switch": [  {  "condition": "${EXPRESSION_A}",  "next": "STEP_NAME_B"  },  {  "condition": "${EXPRESSION_B}",  "next": "STEP_NAME_C"  }  {  "condition": true,  "next": "STEP_NAME_C"  }  ],  "next": "STEP_NAME_D"  }  }  ]

You can also nest multiple steps inside a switch block:

YAML

 - STEP_NAME_A:  switch:  - condition: ${EXPRESSION}  steps:  - STEP_NAME_B:  ...  - STEP_NAME_C:  ...  next: STEP_NAME_D

JSON

 [  {  "STEP_NAME_A": {  "switch": [  {  "condition": "${EXPRESSION}",  "steps": [  {  "STEP_NAME_B": {  ...  }  },  {  "STEP_NAME_C": {  ...  }  }  ]  }  ],  "next": "STEP_NAME_D"  }  }  ]

Note that the steps block is optional. It can contain the following:

For more information about defining a workflow's order of execution, see Jumps and Control the order of execution in a workflow.

Samples

These samples demonstrate the syntax.

Conditional jumps to specific steps

You might want a workflow to jump to a specific step when a condition is met. These two samples execute steps depending on the value returned by the first step of the workflow.

YAML

- first_step:  call: http.get  args:  url: https://www.example.com/callA  result: first_result - where_to_jump:  switch:  - condition: ${first_result.body.SomeField < 10}  next: small  - condition: ${first_result.body.SomeField < 100}  next: medium  next: large - small:  call: http.get  args:  url: https://www.example.com/SmallFunc  next: end - medium:  call: http.get  args:  url: https://www.example.com/MediumFunc  next: end - large:  call: http.get  args:  url: https://www.example.com/LargeFunc  next: end

JSON

[  {  "first_step": {  "call": "http.get",  "args": {  "url": "https://www.example.com/callA"  },  "result": "first_result"  }  },  {  "where_to_jump": {  "switch": [  {  "condition": "${first_result.body.SomeField < 10}",  "next": "small"  },  {  "condition": "${first_result.body.SomeField < 100}",  "next": "medium"  }  ],  "next": "large"  }  },  {  "small": {  "call": "http.get",  "args": {  "url": "https://www.example.com/SmallFunc"  },  "next": "end"  }  },  {  "medium": {  "call": "http.get",  "args": {  "url": "https://www.example.com/MediumFunc"  },  "next": "end"  }  },  {  "large": {  "call": "http.get",  "args": {  "url": "https://www.example.com/LargeFunc"  },  "next": "end"  }  } ]

YAML

- getCurrentTime:  call: http.get  args:  url: https://timeapi.io/api/Time/current/zone?timeZone=Europe/Amsterdam  result: currentTime - conditionalSwitch:  switch:  - condition: ${currentTime.body.dayOfWeek == "Friday"}  next: friday  - condition: ${currentTime.body.dayOfWeek == "Saturday" or currentTime.body.dayOfWeek == "Sunday"}  next: weekend  next: workWeek - friday:  return: "It's Friday! Almost the weekend!" - weekend:  return: "It's the weekend!" - workWeek:  return: "It's the work week."

JSON

[  {  "getCurrentTime": {  "call": "http.get",  "args": {  "url": "https://timeapi.io/api/Time/current/zone?timeZone=Europe/Amsterdam"  },  "result": "currentTime"  }  },  {  "conditionalSwitch": {  "switch": [  {  "condition": "${currentTime.body.dayOfWeek == \"Friday\"}",  "next": "friday"  },  {  "condition": "${currentTime.body.dayOfWeek == \"Saturday\" or currentTime.body.dayOfWeek == \"Sunday\"}",  "next": "weekend"  }  ],  "next": "workWeek"  }  },  {  "friday": {  "return": "It's Friday! Almost the weekend!"  }  },  {  "weekend": {  "return": "It's the weekend!"  }  },  {  "workWeek": {  "return": "It's the work week."  }  } ]

Switch structure with embedded steps

A switch structure can also be used to support direct execution of steps when a condition is met, without jumping to other steps. This improves the readability of a workflow by reducing the number of steps in the workflow definition.

YAML

- step1:  assign:  - a: 1 - step2:  switch:  - condition: ${a==1}  steps:  - stepA:  assign:  - a: ${a+7}  - stepB:  return: ${"increase a to:"+string(a)} - step3:  return: ${"default a="+string(a)}

JSON

[  {  "step1": {  "assign": [  {  "a": 1  }  ]  }  },  {  "step2": {  "switch": [  {  "condition": "${a==1}",  "steps": [  {  "stepA": {  "assign": [  {  "a": "${a+7}"  }  ]  }  },  {  "stepB": {  "return": "${\"increase a to:\"+string(a)}"  }  }  ]  }  ]  }  },  {  "step3": {  "return": "${\"default a=\"+string(a)}"  }  } ]