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
           }
         ]
       },
   }