cloud-event 1.1.2

by Serious Business

Subscribe to Cloud Events webhook subscriptions (such as from Azure EventGrid) and report them to a chat room.

Subscribe to events in your cloud infrastructure such as deployment slot failover!

It's helpful to know when important events happen in your cloud infrastructure. The cloud-event skill can help. It allows you to subscribe to cloud events and report them into chat. It is capable of supporting events in all cloud providers, but currently only has built in support for Azure App Service events.

For example, suppose you use Blue Green deployments using Slots in Azure. You can subscribe to slot swaps to know when your deployments succeed or fail.

Subscribing to events is pretty easy. I posted a video walkthrough on YouTube or you can follow the instructions below.

First, install and save the skill!
Then, attach the skill to a chat channel. For example, in our #ops room I ran the command: @abbot attach cloud-event.
When you attach the skill, it'll give you a URL to grab the HTTP Trigger URL. You'll need this in a moment.
Go to Azure Event Grid Subscriptions in the Azure Portal and create a new subscription.
1. For the "Event Schema" choose "Cloud Event Schema 1.0".
2. For the "Topic Types" choose "App Services."
3. For "Endpoint Type" choose "Web Hook" and supply the HTTP Trigger URL for the skill you created when you attached the skill.

And that's it! Now when the events you subscribed to occur, you'll get a notification in chat.

This skill supports the Cloud Events WebHook Spec v1.0. for subscribing to cloud events so it can be adapted to any cloud hosting provider. Over time I plan to add support for all kinds of events.

Run @abbot attach cloud-event in the chat room that should receive these events, then supply the trigger URL as the webhook URL to the event source.

The following commands work in chat:

* @abbot cloud-event list - List all the trigger URLs used as webhooks.
* @abbot cloud-event list {triggerUrl} - lists the allowed origins for the specified trigger URL. Instead of the URL, you can specify the number of the trigger URL in the list ex. @abbot list 2.
* @abbot cloud-event remove {triggerUrl} - removes all allowed origins for that trigger URL. No webhook requests at that URL will be accepted. You can specify the number of the trigger to remove as well: @abbot remove 2.
* @abbot cloud-event remove {triggerUrl} {origin} - removes the specific allowed origin for the trigger URL. You can specify the order of the trigger instead of the trigger URL. Ex. @abbot cloud-event remove 2 example.com removes example.com from the allowed origin for the second trigger.

/* ------------------------------------------------------------------------------------------------
Use this skill to subscribe to cloud events such as Azure Event Grid using the 
Cloud Events WebHook Spec v1.0.1: https://github.com/cloudevents/spec/blob/v1.0.1/http-webhook.md
--------------------------------------------------------------------------------------------------- */

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

if (Bot.IsChat) {
    // This section describes the chat interactions
    var (cmd, arg, origin) = Bot.Arguments;
    
    Task reply = (cmd, arg, origin) switch {
        (IMissingArgument, _, _) => ReplyWithHelp(),
        ({Value: "list"}, IMissingArgument, _) => ReplyWithListTriggersWithAllowedOrigins(),
        ({Value: "list"}, var triggerArg, IMissingArgument) => ReplyWithListOfAllowedWebHooks(triggerArg),
        ({Value: "remove"}, var triggerArg, IMissingArgument) => RemoveAllAllowedOriginsAndReply(triggerArg),
        ({Value: "remove"}, var triggerArg, var originArg) => RemoveAllowedOriginAndReply(triggerArg, originArg.Value),
        _ => ReplyWithLackOfUnderstanding()
    };
    
    await reply;
    return;
}

/* -----------------------------------------------
The following methods handle webhook interactions.
-------------------------------------------------- */
if (Bot.Request.HttpMethod == HttpMethod.Options) {
    await HandleValidationOptionsRequest();
    return;
}

if (Bot.Request.IsJson) {
    string origin = Bot.Request.Headers.Origin;
    if (origin is not {Length: > 0}) {
        // Azure Cloud Events are not sending the Origin header, even though the spec requires it. They send this instead.
        // I've reported this to the proper authorities.
        origin = Bot.Request.Headers.WebHookRequestOrigin;
    }

    var allowedOrigins = await GetAllowedOrigins();
    if (!allowedOrigins.Contains(origin)) {
        await Bot.ReplyAsync($"Rejected origin `{origin}`.");
        return;
    }
    
    var cloudEvent = GetCloudEvent();
    
    Task reply = cloudEvent.Type switch {
        "Microsoft.Web.AppUpdated" => ReplyWithAppUpdatedMessage(cloudEvent),
        "Microsoft.EventGrid.SubscriptionDeletedEvent" => Bot.ReplyAsync($"Azure EventGrid Subscription `{cloudEvent.Data.ToObject<SubscriptionData>().EventSubscriptionId}` deleted. This message came from {Bot.SkillUrl}"),
        _ when cloudEvent.Type.StartsWith("Microsoft.Web.Slot") => ReplyWithSlotSwapMessage(cloudEvent),
        _ => Bot.ReplyAsync($"Received an unknown event. Version: `{Bot.VersionInfo.ProductVersion}`. You may want to check the Activity logs for the trigger to see what's up. This message came from {Bot.SkillUrl}.")
    };
    
    await reply;
    return;
}

await Bot.ReplyAsync("Received an unknown Cloud Event request. You may want to check the Activity logs to see what's up. This message came from {Bot.SkillUrl}..");

Task ReplyWithSlotSwapMessage(CloudEvent cloudEvent) {
    var slotSwapData = cloudEvent.Data.ToObject<SlotSwapData>();
    if (cloudEvent.Type.StartsWith("Microsoft.Web.SlotSwap")) {
        string action = cloudEvent.Type switch {
                "Microsoft.Web.SlotSwapCompleted" => "completed",
                "Microsoft.Web.SlotSwapStarted" => "started",
                "Microsoft.Web.SlotSwapFailed" => "failed",
                "Microsoft.Web.SlotSwapWithPreviewStarted" => "started with preview",
                "Microsoft.Web.SlotSwapWithPreviewCancelled" => "cancelled with preview",
                _ => cloudEvent.Type
            };
        
        // https://docs.microsoft.com/en-us/azure/event-grid/event-schema-app-service?tabs=cloud-event-schema
        // says we should get "siteName" but the actual payload has "name". I've also reported this to the 
        // proper authorities.
        var siteName = slotSwapData.SiteName ?? slotSwapData.Name;
        return Bot.ReplyAsync($"{siteName}: Swap from {slotSwapData.SourceSlot} to {slotSwapData.TargetSlot} {action}. Version: `{Bot.VersionInfo.ProductVersion}`.  This message came from {Bot.SkillUrl}.");
    }
    return Bot.ReplyAsync("Something happened with an app service but I don't know what.");
}

Task ReplyWithAppUpdatedMessage(CloudEvent cloudEvent) {
    var appUpdatedData = cloudEvent.Data.ToObject<AppUpdatedData>();
    var siteName = appUpdatedData.SiteName ?? appUpdatedData.Name;
    return Bot.ReplyAsync($"{siteName}: Update {appUpdatedData.AppEventTypeDetail.Action}. Version: `{Bot.VersionInfo.ProductVersion}`.  This message came from {Bot.SkillUrl}.");
}

public CloudEvent GetCloudEvent() {
    // It's possible to subscribe to event batches, hence this haaaaack.
    if (Bot.Request.RawBody.StartsWith('[')) {
        var list = Bot.Request.DeserializeBodyAs<List<CloudEvent>>();
        if (list is null or not { Count: 1 }) {
            return default;
        }
        return list.Single();
    }
    return Bot.Request.DeserializeBodyAs<CloudEvent>();
}

public class CloudEvent {
    public string Id { get; set; }
    public string Source { get; set; }
    public string SpecVersion { get; set; }
    public string Type { get; set; }
    public string DataSchema { get; set; }
    public string Subject { get; set; }
    public DateTimeOffset Time { get; set; }
    public JObject Data { get; set; }
}

public class AppServiceData {
    public string Name { get; set; }
    // https://docs.microsoft.com/en-us/azure/event-grid/event-schema-app-service?tabs=cloud-event-schema says we should get "siteName" but in 
    // my testing I'm getting "name"
    public string SiteName { get; set; }
    public string ClientRequestID { get; set; }
    public string CorrelationRequestId { get; set; }
    public string RequestId { get; set; }
    public string Address { get; set; }
    public string Verb { get; set; }
}

public class AppUpdatedData : AppServiceData {
    public AppEventTypeDetail AppEventTypeDetail { get; set; }
}

public class AppEventTypeDetail {
    public string Action { get; set; }
}

public class SlotSwapData : AppServiceData
{
    public string SourceSlot { get; set; }
    public string TargetSlot { get; set; }
}

public class SubscriptionData {
    public string EventSubscriptionId { get; set; }
}

// Handles the validation request: https://github.com/cloudevents/spec/blob/v1.0.1/http-webhook.md#41-validation-request
async Task HandleValidationOptionsRequest() {
    // This is the origin that is requesting permission to send requests to this trigger.
    string origin = Bot.Request.Headers.WebHookRequestOrigin;
    
    // We want to save that this origin may send events to this specific trigger. Multiple origins may be 
    // allowed to post to the same trigger so we use the trigger URL as the key.
    await AddToAllowedOrigins(origin);
    
    // Respond that this origin is allowed. This part of the spec.
    Bot.Response.Headers.WebHookAllowedOrigin = origin;
    Bot.Response.Headers.WebHookAllowedRate = 120;
    
    // And we should report to the room that it all went to plan.
    await Bot.ReplyAsync($"Validated that {origin} may deliver cloud events to this channel.");
}

/* ----------------------------------------------
The following methods handle chat interactions.
------------------------------------------------- */

async Task ReplyWithListTriggersWithAllowedOrigins() {
    var allTriggers = await GetAllTriggers();
    var triggerList = allTriggers.Select(subscription => subscription.Key.ToLowerInvariant())
        .ToOrderedList();
    if (!triggerList.Any()) {
        await Bot.ReplyAsync("There are no allowed origins for this skill. `{Bot} help {Bot.SkillName}` for help using this skill.");
        return;
    } 
    await Bot.ReplyAsync($"These are the triggers for this skill that allow WebHooks. `{Bot} {Bot.SkillName} list #` or `{Bot} {Bot.SkillName} list {{url}}` to see which origins are allowed for that trigger:\n{triggerList}");
}

async Task ReplyWithListOfAllowedWebHooks(IArgument triggerArg) {
    var triggerUrl = await GetTriggerUrlFromArgument(triggerArg);
    var allowedOrigins = await GetAllowedOrigins(triggerUrl);
    if (allowedOrigins is null or {Count: 0}) {
        await Bot.ReplyAsync($"There are no origins allowed to post to {triggerUrl}. That sounds like a bug in this skill.");
        return;
    }
    await Bot.ReplyAsync($"These are the webhooks allowed to post to {triggerUrl}:\n{allowedOrigins.ToMarkdownList()}");
}

Task ReplyWithHelp() {
    return Bot.ReplyAsync(GetHelpMessage());
}

Task ReplyWithLackOfUnderstanding() {
    return Bot.ReplyAsync($"Sorry, I did not understand that. {GetHelpMessage()}");
}

async Task RemoveAllAllowedOriginsAndReply(IArgument triggerArg) {
    var triggerUrl = await GetTriggerUrlFromArgument(triggerArg);
    await Bot.Brain.DeleteAsync(triggerUrl);
    await Bot.ReplyAsync($"Removed all webhooks allowed to post to {triggerUrl}. You may still want to go to the source and delete the webhook registration.");
    return;    
}

async Task RemoveAllowedOriginAndReply(IArgument triggerArg, string origin) {
    var triggerUrl = await GetTriggerUrlFromArgument(triggerArg);
    var removed = await Bot.Brain.RemoveFromHashSetAsync(triggerUrl, origin);
    if (removed) {
        await Bot.ReplyAsync($"I removed {origin} from the list of webooks allowed to post to {triggerUrl}. You may still want to go to the source and delete the webhook registration.");
        return;
    }
    await Bot.ReplyAsync($"The origin {origin} was not in the list of allowed origins that may post to {triggerUrl}.");
}

string GetHelpMessage() {
    return $"`{Bot} help {Bot.SkillName}` to learn how to use this skill.";
}

async Task<IReadOnlyList<ISkillDataItem>> GetAllTriggers() {
    var allTriggers = await Bot.Brain.GetAllAsync();
    return allTriggers
        .Where(item => !item.Key.Equals("Log", StringComparison.OrdinalIgnoreCase))
        .ToList();
}

async Task<string> GetTriggerUrlFromArgument(IArgument triggerArg) {
    var position = triggerArg.ToInt32(); // Attempt to convert to int, otherwise return null.
    if (position.HasValue) {
        var allSubscriptions = await GetAllTriggers();
        return allSubscriptions[position.Value - 1].Key.ToLowerInvariant();
    }
    return triggerArg.Value.ToLowerInvariant();
}

Task<HashSet<string>> GetAllowedOrigins() {
    return GetAllowedOrigins(Bot.Request.Url.ToString());
}

Task<HashSet<string>> GetAllowedOrigins(string url) {
    return Bot.Brain.GetHashSetAsync<string>(url);
}

Task AddToAllowedOrigins(string origin) {
    var triggerUrl = Bot.Request.Url.ToString();
    return Bot.Brain.AddToHashSetAsync(triggerUrl, origin);
}

Version	Created	Author	Release Notes	Installs
1.1.2	5/4/2024	haacked	Remove the custom trigger logging. Abbot now has first-class support for trigger logging!	0
1.0.2	3/4/2024	haacked	No code changes. Updated a couple of comments to clarify why the code does some odd things.	0
1.0.1	3/4/2024	haacked	Fixed a bug when listing the list of triggers with active web hook subscriptions.	0
1.0.0	3/4/2024	haacked	✨ This is the initial version of the cloud-event skill. It supports AppService `SlotSwap` and `AppUpdated` events. More events to come in the future.	1

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Last updated: Tuesday, 04 May 2024 16:35
Installs: 1 total install
Language: CSharp
License: MIT License

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