Subscription webhook notifications

You can configure Octopus to send message to a Slack Workspace with the following process:

  • Configure Octopus Deploy subscription to send a webhook.
  • Configure a Slack App.
  • Configure a tool to consume the webhook from Octopus and forward a message on to Slack.

A number of technologies can be used to consume the webhook from Octopus. This document uses an Azure Function App. Another alternative is to use Firebase Cloud Functions, and this is described in this blog.

Configure an Octopus subscription to send a webhook

Configure a subscription in Octopus to send any events that occur against the User, User Role, and Scoped User Role documents:

Copy webhook URL

As a starting point, the Payload URL is set to a value on RequestBin, which provides access to the JSON being sent by Octopus before the function is built.

Configure your Slack app

A Slack app must be configured to enable a message to be sent through to Slack.

  1. In Slack, go to Your Apps and click Create New App.

  2. Enter a useful App Name and select the relevant Development Slack Workspace and click Create App: Create a Slack App

  3. Select Incoming Webhooks from the Add features and functionality section: Select Incoming Webhooks

  4. Click Add New Webhook to Workspace: Add New Webhook to Workspace

  5. Select the channel to post the messages to: Select the channel

  6. Copy the webhook URL, this is the value for the SLACK_URI_APIKEY environment variable on the Azure Function App: Copy webhook URL

Create an Azure Function App

Create the Function App in Azure

The Function App can be created via the Azure Portal, and ARM Template or with the Azure CLI .

To use the Azure CLI, create the Resource Group to contain the Function App:

az group create -l westeurope -n OctopusFunctions

Create the storage account for the Function App to use:

az storage account create -n octofuncstorage -g OctopusFunctions --sku Standard_LRS -l westeurope

Now create the Function App itself:

az functionapp create -g OctopusFunctions -n SubscriptionHandler -s octofuncstorage --functions-version 3 --runtime dotnet  --consumption-plan-location westeurope

Write the Function App code

The code for this can be found in the samples repo.

The Octopus subscription has been created and set up to send data to RequestBin. Here’s the resulting JSON payload following creation of a new Service Account user:

    "Timestamp": "2020-04-16T15:19:42.5410789+00:00",
    "EventType": "SubscriptionPayload",
    "Payload": {
        "ServerUri": "",
        "ServerAuditUri": "",
        "BatchProcessingDate": "2020-04-16T15:19:42.3149941+00:00",
        "Subscription": {
            "Id": "Subscriptions-21",
            "Name": "User and User Role Change Alert",
            "Type": "Event",
            "IsDisabled": false,
            "EventNotificationSubscription": {
                "Filter": {
                    "Users": [],
                    "Projects": [],
                    "ProjectGroups": [],
                    "Environments": [],
                    "EventGroups": [
                    "EventCategories": [],
                    "EventAgents": [],
                    "Tenants": [],
                    "Tags": [],
                    "DocumentTypes": [
                "EmailTeams": [],
                "EmailFrequencyPeriod": "01:00:00",
                "EmailPriority": "Normal",
                "EmailDigestLastProcessed": null,
                "EmailDigestLastProcessedEventAutoId": null,
                "EmailShowDatesInTimeZoneId": "UTC",
                "WebhookURI": "",
                "WebhookTeams": [],
                "WebhookTimeout": "00:00:10",
                "WebhookHeaderKey": null,
                "WebhookHeaderValue": null,
                "WebhookLastProcessed": "2020-04-16T15:19:11.3637275+00:00",
                "WebhookLastProcessedEventAutoId": 53624
            "SpaceId": "Spaces-142",
            "Links": {
                "Self": {}
        "Event": {
            "Id": "Events-55136",
            "RelatedDocumentIds": [
            "Category": "Created",
            "UserId": "Users-27",
            "Username": "",
            "IsService": false,
            "IdentityEstablishedWith": "Session cookie",
            "UserAgent": "OctopusClient-js/2020.2.2",
            "Occurred": "2020-04-16T15:19:14.9925786+00:00",
            "Message": "User SubTest Service Account has been created ",
            "MessageHtml": "User <a href='#/configuration/users/Users-322'>SubTest Service Account</a> has been created ",
            "MessageReferences": [
                    "ReferencedDocumentId": "Users-322",
                    "StartIndex": 5,
                    "Length": 23
            "Comments": null,
            "Details": null,
            "SpaceId": null,
            "Links": {
                "Self": {}
        "BatchId": "b2bdb09f-872a-4bc1-8272-ab2334de3660",
        "TotalEventsInBatch": 2,
        "EventNumberInBatch": 1

The items that will be used in the Slack message for this example are:

  • Payload.Event.Message
  • Payload.Event.SpaceId
  • Payload.Event.Username
  • Payload.ServerUri

If you’re using VS Code to write the code, you need to install the Azure Functions Core Tools to enable debugging for your function.

To use these items easily, create a class OctoMessage to hold them:

using System;
using Newtonsoft.Json;

namespace Octopus
    public class OctoMessage
        public string Message {get;set;}
        public string SpaceId {get;set;}

        public string Username {get;set;}

        public string ServerUri{get;set;}

        public string GetSpaceUrl(){
            return string.Format("{0}/app#/{1}",ServerUri,SpaceId);

Add a class SlackClient to take the message data and send it through to Slack:

public class SlackClient
    private readonly Uri _uri;
    private readonly Encoding _encoding = new UTF8Encoding();
    public SlackClient(string slackUrlWithAccessToken)
        _uri = new Uri(slackUrlWithAccessToken);
    public string PostMessage(string text)
        Payload payload = new Payload()
            Text = text
        return PostMessage(payload);
    public string PostMessage(Payload payload)
        string payloadJson = JsonConvert.SerializeObject(payload);
        using (WebClient client = new WebClient())
            var data = new NameValueCollection();
            data["payload"] = payloadJson;
            var response = client.UploadValues(_uri, "POST", data);
            return _encoding.GetString(response);

The main class of the function OctopusSlackHttpTrigger, will receive the HTTP message, take the request message body and deserialize it into an OctoMessage object. Next, it will build the message text and send it through to Slack using a SlackClient object:

public static class OctopusSlackHttpTrigger
    public static async Task<IActionResult> Run(
        [HttpTrigger(AuthorizationLevel.Function, "post", Route = null)] HttpRequest req,
        ILogger log)
        var client = new SlackClient(Environment.GetEnvironmentVariable("SLACK_URI_APIKEY"));

        var data = await new StreamReader(req.Body).ReadToEndAsync();
        var octoMessage = JsonConvert.DeserializeObject<OctoMessage>(data);
        var slackMessage = string.Format(
                                "{0} (by {1}) - <{2}|Go to Octopus>", 

            var responseText = client.PostMessage(text: slackMessage);                
            return new OkObjectResult(responseText);
        catch (System.Exception ex)
            return new BadRequestObjectResult(ex.Message);

Test the Azure App Function

Before pushing this to Azure it can be tested locally. The Run method uses the environment variable SLACK_URI_APIKEY, this is the value copied when the Slack app was configured. In order to use this value when debugging locally, add the value to the local.settings.json file:

  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "",

Hit F5 to compile and run the app, a URL will be output to the terminal to which a POST test request can be sent:

Debug URL

Postman can send a test request, passing in a test JSON payload.


If this is configured correctly, it will return 200 OK, and the message will appear in Slack!

Slack message

Build the Azure App Function

This example uses Github Actions to build the function code, package it, and push it to Octopus, which deploys it to Azure.

Build output

The build YAML can be found in .github/workflows/AzureSlackFunction.yaml in the samples repo.

Deploy the Azure App Function

The Azure Function App created here is deployed to with Octopus, using a deployment target type of Azure web app. For more information see, deploying a package to an Azure web app.

A project has been configured to deploy the Function App.

Octopus Project

The project has two steps:

  1. Deploy the Azure Function App.
  2. Set the environment variable for SLACK_URI_APIKEY.

The project can be viewed in the AzFuncNotifySlack project on our Octopus samples instance.

Test the subscription

If an Octopus user is changed, the change is shown in the audit trail.

Octopus Project

And the message is sent from the subscription webhook to the Azure Function App in Azure and then on to Slack.

Slack message

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Page updated on Sunday, January 1, 2023