This logic app performs the following analysis on an incoming message, evaluates the state of the contract, and triggers an SMS alert using Twilio.
Specifically –
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It identifies if the message is of type ContractInsertedOrUpdated
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If true, it identifies if this is an update to an existing contract or a new contract
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If an update, it identifies if the action executed was named “IngestTelemetry”
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If true, it will cycle through the parameters in the message to find the parameter named “State”
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Once found, it evaluates the value of the current contract state.
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It then triggers an SMS Alert using the Twilio service
This sample takes a dependency on a third-party service provided by Twilio.
The pre-requisites for this sample include -
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A Twilio account
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A verified Twilio phone number that can send SMS
Twilio offers free trial accounts via their website.
Note - If you are using a Twilio trial account, you can only send SMS to verified phone numbers.
This sample is designed to work with the RefrigeratedTransportation application but can be easily adapted to other contracts by making changes to the name of the action (“IngestTelemetry”) or the logic related to identifying the states.
Other samples will further extend this to send alerts via Outlook, SMS (Twilio), and voice (Twilio).
Navigate to the Azure portal at http://portal.azure.com
Click the + symbol in the upper left corner of the screen to add a new resource.
Search for and select Logic App and then click Create.
Name the logic app “ExecuteBasedOnStateAfterSpecificAction”.
Specify the same resource group as your Azure Blockchain Workbench deployment.
Click the Create button.
A logic app is initiated by a trigger.
In this scenario, the trigger will be an event from Azure Blockchain Workbench delivered via the Event Grid.
Within the Logic App Designer, select the trigger “When an Event Grid event occurs”.
Within the Logic App Designer, click the Sign In button for the action that was added.
Select the Azure Active Directory Tenant that the Azure Blockchain Workbench was deployed to in the drop-down list and either sign-in using your credentials or connect using a Service Principal.
For this basic sample, you will sign in using your credentials.
Clicking Sign In will display a login dialog.
Once connected successfully, the trigger will show a check mark in a green circle as demonstrated below.
Click the Continue button.
Next select the subscription for the Azure Blockchain Workbench, specify a Resource Type of “Microsoft.EventGrid.Topics” and the resource name for the Event Grid topic in the resource group for the Azure Blockchain Workbench deployment.
Click the “+ New Step” button.
Click More and click the Add a Switch Case
For the Switch, there is an “On” field that identifies what value will be evaluated.
Click the text box and then select “Subject” which contains the name of the message type being delivered.
In the Case message on the right, enter the value of ContractInsertedOrUpdated.
Click the “…” in the upper right of the case and select Rename.
Rename the case to ContractInsertedOrUpdated.
Add the action “Data Operations – Parse Json” to the case.
In the Content field, select Body.
In the Schema field, enter the following –
{
"properties": {
"data": {
"properties": {
"ActionName": {
"type": "string"
},
"BlockId": {
"type": "number"
},
"ChainId": {
"type": "number"
},
"ContractAddress": {
"type": "string"
},
"ContractId": {
"type": "number"
},
"IsTopLevelUpdate": {
"type": "boolean"
},
"IsUpdate": {
"type": "boolean"
},
"OperationName": {
"type": "string"
},
"OriginatingAddress": {
"type": "string"
},
"Parameters": {
"items": {
"properties": {
"Name": {
"type": "string"
},
"Value": {
"type": "string"
}
},
"required": [
"Name",
"Value"
],
"type": "object"
},
"type": "array"
},
"TopLevelInputParams": {
"type": "array"
},
"TransactionHash": {
"type": "string"
}
},
"type": "object"
},
"dataVersion": {
"type": "string"
},
"eventTime": {
"type": "string"
},
"eventType": {
"type": "string"
},
"id": {
"type": "string"
},
"metadataVersion": {
"type": "string"
},
"subject": {
"type": "string"
},
"topic": {
"type": "string"
}
},
"type": "object"
}
Click the “More” link and then select “add a condition”.
Click in the box at the left of the condition. It will display the Dynamic Content window, select “IsUpdate” from the Dynamic Content list.
Set the condition to “is equal to”.
Set the condition value to true.
This identifies that this is an update to a contract and not the creation of a new contract.
Click the three dots in the upper right corner of the Condition action and select Rename. Rename this action to “Check to See If This is a New Contract or an Action”
In the “If true” section, click More and select “add a switch case”.
Click inside the “On” field and select “ActionName” from the dynamic properties dialog.
Click the three dots in the upper right of the action, select Rename, and name it “Check to See What Action Was Executed”
In the choice on the right, set the “Equals” field to IngestTelemetry.
Click the three dots in the upper right, select Rename and name this “Check to see if this is the IngestTelemetry action from our device”
Click “… More” and select “Add for each”
In the “For each” action, click in the “Select an output from previous steps” field and select Parameters from the Dynamic Properties dialog.
Next click on the “More” button and select “add a switch case”.
Right-click the three dots in the upper corner of the action and select Rename. Rename this to “Determine what parameter this is”
Click on the newly created item on the left, and set the “Equals” field value to State
Click on the three dots in the upper right of the action and select Rename. Rename this to “Confirm this is the State parameter”
Underneath that action, click the “More” link and then “add new switch case”.
In the “On” field, click it select Value from the dynamic properties.
For the item on the left of the switch case, set the Equals property to Created
Click on the three dots in the corner of this case and select Rename. Rename it to “In the Created state”
Click the (+) in the center of the switch case to add a new case.
For the new case, set the Equals property to InTransit
Click on the three dots in the corner of this case and select Rename. Rename it to “In the InTransit state”
Click the (+) in the center of the switch case to add a new case.
For the new case, set the Equals property to Completed
Click on the three dots in the corner of this case and select Rename. Rename it to “In the Completed state”
Click the (+) in the center of the switch case to add a new case.
For the new case, set the Equals property to OutOfCompliance
Click on the three dots in the corner of this case and select Rename. Rename it to “In the OutOfCompliance state”
You can now add logic that takes action based on the state after a specific action. In this sample, if after a device provides telemetry that it is now in an out of compliance state there may be a desire to send an alert.
In the case for the “In the OfferPlaced state”, click “Add an action”
Select Twilio – Send Text SMS (SMS)
Populate the properties for the action, providing the phone number assigned by Twilio, your message, and the target phone number to call.
Note – You can use Dynamic Content in any of these values, allowing for dynamic alerts specific to the context of any contract.
Save your Logic App
You can test this functionality by taking the following steps –
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Navigate to the overview page of for the logic app in the portal and confirm that it is enabled (if it is not, click on the “disabled” link at the top of the screen to transition the logic app to an enabled state).
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Deploy the RefrigeratedTransportation sample application in Azure Blockchain Workbench.
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Add members to the new application for the roles of Owner, Counterparty, Device, and Observer.
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Create a new contract instance. Specify values of 1 and 15 for both the minimum and maximum values for temperature and humidity.
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Transfer responsibility to a party in the Counterparty role.
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Log out of Workbench and log in as the account associated with the Device
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Navigate to the contract you created within Workbench.
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Take the action of “IngestTelemetry” and enter values of 50 for both temperature and humidity.
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The logic app should now be triggered and the code will be executed. Receiving the alert indicates that the logic app has executed successfully. If you’d like to look at the execution of the logic app to send the alert, navigate to the logic app in the portal. At the bottom of the screen, you will detail for Runs history
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Click on the most recent execution of your logic app in the list.
This will show details on the trigger and actions executing within the logic app and allow you to validate success or troubleshoot reasons for failure.
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Once making changes in your logic app, you can navigate back to this same screen and click “Resubmit” and it will call the current version of your logic app with the values provided by the previous run.
In many workflows, there is a need to execute logic based on a state change that may occur after a specific action is taken on a smart contract.
The logic app created in this sample facilitates this need by –
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Identifying if the message is of type ContractInsertedOrUpdated
-
If true, it identifies if this is an update to an existing contract or a new contract
-
If the message represents a contract update, it identifies if the action executed was named “IngestTelemetry”
-
If that is true, it will cycle through the parameters in the message to find the parameter named “State”
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Once found, it evaluates the value of the current contract state and triggers an alert when appropriate.