Switch States Conditionally in a Flow

This procedure demonstrates how to implement a multi-state flow.

This sample code shows how to design a flow that checks for a resource and updates it. If the resource doesn't exist, the flow creates a new resource.
  1. Open the adapter definition document in Visual Studio Code.
  2. In the flows code section of the document, add code for a flow with GET call to a specific resource.

    In the following code sample, the httpInvoke function implements the GET call. 

    "flows": {   
   "EventRegisterFlow": {
      "id": "EventRegisterFlow",
      "description": "EventRegisterFlow",
      "specVersion": "0.8",
      "version": "0.1",
      "start": "startState",
      "functions": [
        {
          "name": "httpInvoke",
          "type": "custom",
          "operation": "connectivity::rest"
        }
      ],
      "states": [
        {
          "name": "startState",
          "type": "operation",
          "actions": [
            {
              "name": "httpInvoke",
              "functionRef": {
                "refName": "retriveListOfSubscriptionFunc",
                "arguments": {
                  "uri": "${\"https:/\"+\"/\"+.connectionProperties.hostNameTrigger+\"/repos/{owner}/{repo}/hooks\"}",
                  "method": "GET",
                  "parameters": {
                    "owner": "${ .configuration.orgId }",
                    "repo": "${ .configuration.repositoryId }"
                  }
                }
              },
              "actionDataFilter": {
                "results": "${ .body}",
                "toStateData": "${ .subscriptions }"
              }
            }
          ],
          "end": true
        }
         
    }
  3. Add actions to the flow to evaluate if a specific resource exists.

    Sample code:

    "functions": [
  ...
  {
    "name": "SubscriptionExistsFunction",
    "operation": "[.integrationProperties.INTEGRATION_FLOW_URL==.subscriptions[].config.url]|any",
    "type": "expression"
  },
  {
    "name": "getSubscriptionId",
    "type": "expression",
    "operation": "[{subscription:.subscriptions[], INTEGRATION_FLOW_URL:.integrationProperties.INTEGRATION_FLOW_URL}] | map(select(.subscription.config.url==.INTEGRATION_FLOW_URL))[0].subscription.id | tostring"
  }
],
"states": [
  {
    "name": "startState",
    "type": "operation",
    "actions": [
      ...
      {
        "functionRef": "SubscriptionExistsFunction",
        "actionDataFilter": {
          "toStateData": "${ .subscriptionExists }"
        }
      },
      {
        "functionRef": "getSubscriptionId",
        "actionDataFilter": {
          "toStateData": "${ .subscriptionId }"
        }
      }
    ],
    end: true
  }
  4. Add a switch state to transition to another state that can create or register a resource.

    Sample code:

    "flows": {   
   "EventRegisterFlow": {
      "id": "EventRegisterFlow",
      "description": "EventRegisterFlow",
      "specVersion": "0.8",
      "version": "0.1",
      "start": "startState",
      "functions": [
        ...
      ],
      "states": [
        {
          "name": "startState",
          "type": "operation",
          "actions": [
            ...
          ],
           
          "transition": "SwitchBasedOnSubscription"
      
        },
        {
          "name": "SwitchBasedOnSubscription",
          "type": "switch",
          "dataConditions": [
            {
              "condition": "${ .subscriptionExists == true }",
              "transition": "UpdateRepositoryEndpoint"
            },
            {
              "condition": "${ .subscriptionExists == false }",
              "transition": "RegisterRepositoryEvent"
            }
          ],
          "defaultCondition": {
            "transition": "RegisterRepositoryEvent"
          }
        },
         
}
  5. Add termination states that branch from a switch.

    The termination states contain the required actions.

    Sample code:

    "flows": {   
   "EventRegisterFlow": {
      "id": "EventRegisterFlow",
      "description": "EventRegisterFlow",
      "specVersion": "0.8",
      "version": "0.1",
      "start": "startState",
      "functions": [
       ...
      ],
      "states": [
        {
          "name": "startState",
          "type": "operation",
          "actions": [
            ...
          ],
          "transition": "SwitchBasedOnSubscription"
        },
        {
          "name": "SwitchBasedOnSubscription",
          "type": "switch",
          "dataConditions": [
            {
              "condition": "${ .subscriptionExists == true }",
              "transition": "UpdateRepositoryEndpoint"
            },
            {
              "condition": "${ .subscriptionExists == false }",
              "transition": "RegisterRepositoryEvent"
            }
          ],
          "defaultCondition": {
            "transition": "RegisterRepositoryEvent"
          }
        },
        {
          "name": "UpdateRepositoryEndpoint",
          "type": "operation",
          "actions": [
            {
              "name": "UpdateRepositoryEnpointAction",
              "functionRef": {
                "refName": "httpInvoke",
                "arguments": {
                  "uri": "${\"https:/\"+\"/\"+.connectionProperties.hostNameTrigger+\"/repos/{owner}/{repo}/hooks/{subscriptionId}\"}",
                  "parameters": {
                    "owner": "${ .configuration.orgId }",
                    "repo": "${ .configuration.repositoryId }"
                    "subscriptionId": "${ .subscriptionId }"
                  },
                  "method": "POST",
                  "body": "${ { \"name\": \"web\", \"active\": true, \"events\": [.configuration.eventName] } }"
                }
              },
              "actionDataFilter": {
                "results": "${.body}",
                "toStateData": "${ .output }"
              },
              "condition": "${ .subscriptionExists==true }"
            }
          ],
          "end": true
        },
        {
          "name": "RegisterRepositoryEvent",
          "type": "operation",
          "actions": [
            {
               "name": "RepositoryEventRegisterAction",
               "functionRef": {
                "refName": "httpInvoke",
                "arguments": {
                  "uri": "${\"https:/\"+\"/\"+.connectionProperties.hostNameTrigger+\"/repos/{owner}/{repo}/hooks\"}",
                  "parameters": {
                    "owner": "${ .configuration.orgId }",
                    "repo": "${ .configuration.repositoryId }"
                    "subscriptionId": "${ .subscriptionId }"
                  },
                  "method": "POST",
                  "body": "${ { \"name\": \"web\", \"active\": true, \"events\": [.configuration.eventName], \"config\": { \"content_type\": \"json\", \"secret\": .connectionProperties.\"trigger.secret\", \"url\": .integrationProperties.INTEGRATION_FLOW_URL } } }"
                }
              },
              "actionDataFilter": {
                "results": "${.body}",
                "toStateData": "${ .output }"
              },
              "condition": "${ .subscriptionExists==false }"
            }
          ],
          "end": true
        }
      ]
    },
}

    Complete sample code:

    "flows": {    
   "EventRegisterFlow": {
      "id": "EventRegisterFlow",
      "description": "EventRegisterFlow",
      "specVersion": "0.8",
      "version": "0.1",
      "start": "startState",
      "functions": [
        {
          "name": "httpInvoke",
          "type": "custom",
          "operation": "connectivity::rest"
        },
        {
          "name": "SubscriptionExistsFunction",
          "operation": "[.integrationProperties.INTEGRATION_FLOW_URL==.subscriptions[].config.url]|any",
          "type": "expression"
        },
        {
          "name": "getSubscriptionId",
          "type": "expression",
          "operation": "[{subscription:.subscriptions[], INTEGRATION_FLOW_URL:.integrationProperties.INTEGRATION_FLOW_URL}] | map(select(.subscription.config.url==.INTEGRATION_FLOW_URL))[0].subscription.id | tostring"
        }
      ],
      "states": [
        {
          "name": "startState",
          "type": "operation",
          "actions": [
            {
              "name": "httpInvoke",
              "functionRef": {
                "refName": "retriveListOfSubscriptionFunc",
                "arguments": {
                  "uri": "${\"https:/\"+\"/\"+.connectionProperties.hostNameTrigger+\"/repos/{owner}/{repo}/hooks\"}",
                  "method": "GET",
                  "parameters": {
                    "owner": "${ .configuration.orgId }",
                    "repo": "${ .configuration.repositoryId }"
                  }
                }
              },
              "actionDataFilter": {
                "results": "${ .body}",
                "toStateData": "${ .subscriptions }"
              }
            },
            {
              "functionRef": "SubscriptionExistsFunction",
              "actionDataFilter": {
                "toStateData": "${ .subscriptionExists }"
              }
            },
            {
              "functionRef": "getSubscriptionId",
              "actionDataFilter": {
                "toStateData": "${ .subscriptionId }"
              }
            }
          ],
          "transition": "SwitchBasedOnSubscription"
        },
        {
          "name": "SwitchBasedOnSubscription",
          "type": "switch",
          "dataConditions": [
            {
              "condition": "${ .subscriptionExists == true }",
              "transition": "UpdateRepositoryEndpoint"
            },
            {
              "condition": "${ .subscriptionExists == false }",
              "transition": "RegisterRepositoryEvent"
            }
          ],
          "defaultCondition": {
            "transition": "RegisterRepositoryEvent"
          }
        },
        {
          "name": "UpdateRepositoryEndpoint",
          "type": "operation",
          "actions": [
            {
              "name": "UpdateRepositoryEnpointAction",
              "functionRef": {
                "refName": "httpInvoke",
                "arguments": {
                  "uri": "${\"https:/\"+\"/\"+.connectionProperties.hostNameTrigger+\"/repos/{owner}/{repo}/hooks/{subscriptionId}\"}",
                  "parameters": {
                    "owner": "${ .configuration.orgId }",
                    "repo": "${ .configuration.repositoryId }"
                    "subscriptionId": "${ .subscriptionId }"
                  },
                  "method": "POST",
                  "body": "${ { \"name\": \"web\", \"active\": true, \"events\": [.configuration.eventName] } }"
                }
              },
              "actionDataFilter": {
                "results": "${.body}",
                "toStateData": "${ .output }"
              },
              "condition": "${ .subscriptionExists==true }"
            }
          ],
          "end": true
        },
        {
          "name": "RegisterRepositoryEvent",
          "type": "operation",
          "actions": [
            {
               "name": "RepositoryEventRegisterAction",
               "functionRef": {
                "refName": "httpInvoke",
                "arguments": {
                  "uri": "${\"https:/\"+\"/\"+.connectionProperties.hostNameTrigger+\"/repos/{owner}/{repo}/hooks\"}",
                  "parameters": {
                    "owner": "${ .configuration.orgId }",
                    "repo": "${ .configuration.repositoryId }"
                    "subscriptionId": "${ .subscriptionId }"
                  },
                  "method": "POST",
                  "body": "${ { \"name\": \"web\", \"active\": true, \"events\": [.configuration.eventName], \"config\": { \"content_type\": \"json\", \"secret\": .connectionProperties.\"trigger.secret\", \"url\": .integrationProperties.INTEGRATION_FLOW_URL } } }"
                }
              },
              "actionDataFilter": {
                "results": "${.body}",
                "toStateData": "${ .output }"
              },
              "condition": "${ .subscriptionExists==false }"
            }
          ],
          "end": true
        }
      ]
    },
}