My problem is a simple one. I'm working on a project that uses the service bus from Microsoft Azure to send messages asynchronously between different modules on different virtual machines. And a lot of messages are sent through this bus, so we want to have some indicators about it's performance and other usage information. Why? Because when everything is working, users are happy. When the system is slow, we want to show the user some interesting graphs, statistics, meters and other gadgets to give them an indication if there's a problem within Azure or with something else. And to do this, I need data about the usage of the Azure service bus.
So, which Azure API's are available to display what kind of (diagnostic) information about the service bus?
(Users should have no access to Azure itself! They should just see some performance data to re-assure them Azure is working fine. Or else I could look at it and discover some problem with it, fix it and then make users happy again.)
To elaborate what I'm looking for, the Azure website has some nice chart when you click the Monitor of the Azure bus showing you overviews of the number of incoming messages, the number of errors and their types, size information and the number of succesful operations, all based on a specified period. It would be nice if I could receive this data within my project.
The entity metrics API will give you the exact data the portal is using:
http://msdn.microsoft.com/en-us/library/windowsazure/dn163589.aspx
Here's a Subscribe! episode I recorded with Rajat on the topic http://channel9.msdn.com/Blogs/Subscribe/Service-Bus-Namespace-Management-and-Analytics
I've spent quite some time to make the entity metrics API work, so I decided to share the results.
Here is a full C# code example of how to consume those API:
github repository.
It's a small library which wraps the HTTP request into strongly typed .NET classes. You can also grab it from NuGet.
Finally, here is my blog post with the walkthrough.
Related
I’m in need of some second opinions and guidance on how to use Azure Functions in combination with Azure Service Bus in the scenario described below. Coding is not an issue its about selecting the most appropriate method. Sadly, I have not found any good example of this online so now I’m reaching out for some help.
Scenario
I have an ecommerce customer that is sending a few thousand orders a day to an ERP system. The normal day operations are not an issue, but we would like to make the solution more robust to handle for example “Black Friday” surges. Currently the website can hold x amount of orders before that database is full and is forced to close or send order downstream. Currently the website sends order directly into the ERP system and it is this part I want to decouple with Azure Server Bus Queues. With this decoupling we can continue pushing new orders to the queue and consuming these at our own pace in the ERP without flooding any system.
My thoughts about how to set this up
The website can send messages directly to the Service Bus Queue. An Azure Function is bound to trigger on every new message in the queue and will send that message to the ERP system.
Same as above however the website first sends a message to an Azure Function that puts it into the queue.
The website sends messages to the queue like in point 1 or 2. Instead of binding a function to the queue we setup a scheduled function. The function will run frequently and send 1 message to the ERP system per run.
The website sends messages to the queue like in point 1 or 2. Here we do not send messages to the ERP system but instead the ERP system is the one who reads the queue. Do not like this approach but its possible to do and easy to administrate by ERP users.
Questions
If I go with point 1 or 2 above should the function responsible for delivering the message to the ERP system send 1 or multiple orders per trigger?
If I go with point 1 or 2 it should still be possible to flood the ERP system since they most likely trigger at the same time they get put in?
If the ERP system is down and the queue grows, do I need a separate scheduled function to handle the queue until it is empty?
We do not have to discuss the dead letter queue here, that is another topic.
How would you approach this or if you have done a similar solution what method did you use?
Thank you for your guidance much appriciated!
We've learned a lot in the past couple of years working with Azure Functions and Service Bus to solve similar scenarios you mentioned above. You're definitely on the right track regards to wanting to decouple in case of a surge. To give you some peace of mind with your choice to use Azure Service Bus, we normally push hundreds of events a minute through our topics and subscriptions and it holds up pretty well.
Let me just share some of the lessons we learned:
The concurrent number of incoming requests within the same second
was one of our breaking points. The website when written properly
will easily accommodate multiple incoming requests but we learned
about "port exhaustion" related to outbound web requests to our
Azure Function. Review the scope and lifetime of your web client and
the limits of your app service plan / web server.
If you choose to use a consumption plan for your Azure Function, be
aware that it sometimes takes a long time to start. Whatever is
hitting the function will have to implement retries (probably a good
practice anyway).
A Service Bus Message has a size limit (which can be increased, but
there's still a limit). We randomly hit it with one of our payloads
that contains a bulk of information. Know the worst case scenario
payload size you may encounter.
In the event something goes wrong and there are tens of thousands of
messages in the queue, there is no easy way to query what's in
there. Make sure you're fine with that otherwise consider
doing fast writes into a database that can be queried.
The Azure Function can be triggered by Service Bus and can spawn
multiple concurrent executions of the code (which is desired) and
with a limit. Be aware of any limitations with code to update your
ERP. You will have no control over Service Bus triggers.
Be conscious about the function's storage account, functions with
same name will have their trigger settings and locks stepping on
each other (dev vs. prod environment).
Connections to Azure Service Bus will sometimes fail, just the
nature of services hosted in the cloud. It only happens a few times
and recovers after a few seconds.
Consider doing this:
Website -> Azure API Management Gateway -> Azure Function A -> Service Bus -> Azure Function B -> ERP
Azure API Management with AppInsights enabled is a nice extra layer allowing you to secure, monitor, and route to your Function A. In cases where you need to route incoming requests to some emergency bucket it's a life saver.
Consider allowing function 1 to accept an array of your items. Enable AppInsights, add code for telemetry, providing preview of throughput in terms of orders.
Function B with a configurable timer trigger and some app configuration for number of messages to process from the queue. Allows you to throttle flow of data to your ERP. This may be debatable as you won't be able to scale this function out with multiple instances, but I'm assuming the original concern was to control the pace. Also enable same AppInsights, telemetry, logging, etc.
I'm hoping I don't draw too much criticism from this. We learned the hard way and eventually received some really good guidance from Azure architects and engineers later.
My Azure based SaaS system publishes events and I have customers who wish to subscribe to them - webhooks seem undeniably the right architecture (And I'm currently a happy consumer of webhooks). I've found lots of great documentation and case studies on best practices (e.g. http://resthooks.org) however I've not managed to find an existing architecture, framework, project, sample or solution that implements the best practices.
I could build my own solution however I don't want to reinvent the wheel. I was expecting to find an existing framework (e.g. on Github) created by people much smarter than I but haven't had any success.
I currently use a number of Azure services (such as Service Bus, Cosmos, Table Storage) internally and consume using Azure Functions but what I don't have is an architecture for allowing my customers to subscribe to these events.
Specifically I'm looking for best practices and code samples on how to manage potentially millions of subscribers (who are external customers) and the approach to distribute the webhooks out to each of them.
I already understand how to publish and consume webhooks where I am an individual subscriber and there are already some great samples available - https://github.com/aspnet/AspLabs/tree/master/src/WebHooks
Can anyone point me in the right direction? (Preferably to a .NET / C# based solution)
Not sure if this is the 'right' direction but here are my current thoughts on a solution.
We are currently using CosmosDb and are leveraging the change feed to trigger an Azure function execution. The code within the function does a specific task for all tenants in our system. This code will be changed to simply send a new event to the Event Grid topic. A 'in-house' subscription will then be added that will handle what the function code is currently doing today.
We will then follow the subscription management guidance Zapier offers. In a nutshell it is to expose the capability to our customers to subscribe to the events that we publish via a few endpoints. In addition to standard CRUD stuff when a tenant adds/removes a subscription the code will leverage the Event Grid Management SDK to add/remove subscriptions to the appropriate topics within Event Grid (samples here). The subscriptions that get added will have filters set to ensure each tenant only receives their own events.
There are limitations to the number of subscriptions and topics with in Azure (details here). These limitations are acceptable in our case but is something you might need to look into more if you need to reach 1mm subscribers.
Here is how I visualize it:
Not 100% we'll build this but if we do I'll post back here any gotchas we uncover.
Cheers!
I understand that Microservices is about independent loosely coupled services. I have read https://en.wikipedia.org/wiki/Microservices.
When it comes to Azure, I understand there are many components like Azure Service Fabric, AKS and also have the option of deploying containers within Azure VMs using Docker or any other containerization tools. However, since Microservices is about developing atmoic individually scalable services, can this also be achieved by deploying each service as an Azure Web API APP within an App Service Plan and configure Auto-Scale based on Performance metrics (though each API APP may not be individually scalable, they can still be individually manageable in terms of deployment, configuration etc)?
Can someone please suggest if this thought process is correct?
Microservices aren't a platform or technology so if you can make small independently deployable services then they are microservices. Sure - some tech helps but it depends on your situation.
If you only need a few services you probably don't need anything complex. Make sure services are well modeled, own their own data and ideally have a good monitoring and deployment pipeline setup. Design for service failure where possible.
Do you need to scale each part independently? Ideally, you should be able to but do services have very different requirements? You could have many small App service plans but that comes at cost of unused resources so split when you need to.
This question and of course the answers are going to be opinion based, but generally when thinking in terms of micros services, think not in terms as things like loads of API's and VM's etc. Instead think in terms of. When i upload an image, its needs to be resized, and the table updated to give a url for the thumb. or when XXX record is updated in database, Run XXX in order to create a report, or update Azure search. and that each service, just knows how to do a single thing only. I.E Resize an image.
Now one could say. I have a system, A repo library, and some functions library. When an image is posted, I upload, then call this, and that etc.
With Micor services. You would instead just add the image to a queue. Create an azure function that has a queue trigger. that would resize and save both the large and the thumb to storage. this would then either update the database, or in true micro service, it would add a queue to store the new info, another function would watch that queue and insert into the database.
You can use the DB queue from anything. You can use the Blob queue from anything. Your main API, does not care how images are handled. You can change your functions one day to maybe save to dropbox, instead of azure blob. All really easy, with no re-build of the API, because the API does not care.
A good example I use it for is email and SMS. My systems dont know how to send an email, or an SMS. They only know how to add to a queue. My microservices. SendEmail and SendSMS do know how to do it, and I can change how and who i send that content with, really easy. I can tomorrow change from Twilio to send grid, without ever telling the API that i've done it.
On a more complex thing. I have approval, at the moment that approval sends an email or SMS to either user or admin, and that can change over time. So I have an SMS server, Email Service and and approvalService. when approval happens, it just adds a config to the queue, The rest is done by a logic app, that knows to send an email to XXX and an SMS to XXX and then update database. My api, is just a post, that creates a queue.
Basically what I am saying here is to get started, maybe porting an existing app. Start with the workflow stuff, like send an email, resize an image, create a report, create a PDF, email 50 subscribers etc. and take all that code out and put into there own micro service that just knows how to do one thing. Then when you grow with confidence, create a workflow from all of these services with Logic Apps, let azure take care of the rest, thats what they want to do.
I'd like to build a small solution on Azure for practice. I'd be sending data using IOT-HUB from some devices and what I need is some way to interpret this data and do appropriate query to Azure SQL.
Basically I would need a way to have my program running all the time being able to:
listen to events from iot-hub
interpret event information and save/get data to/from database
send a message to some device using iot-hub
Which service would be good for that? Am I able to use Entity Framework?
In ideal solution I'd create a C# program to do what I need and have it running in Azure, waiting for events from iot-hub, having access to my database - is it even possible?
I'm very new (rather completely new) to cloud solutions, so I'd be really grateful for any advices. Currently I feel completely lost in all these Azure services.
There is quite some documentation on Azure IoT and how one can possible architect an IoT solution.
The IoT documentation is the obvious first step to get an overview of what Azure offers. There are some nice 'Getting Started' walkthroughs also
Take a look at this IoT reference architecture. Quite helpful to get an overview.
There are tons of links and interesting examples for Azure IoT. Just google around.
I have been researching on Microsoft Azure Event Hubs. My goal is to figure out a way to provide automatic scalability. This is a experimental work and I am really only trying to know what can I do with Azure event hubs. I do not have access to the Azure platform to test test anything :( .
Well, so far, I found that through REST API and Service Bus Powershell I can add Throughput Units (to increase performance - I am relying on this: Scale Azure Service Bus through Powershell or API) and increase or decrease Event's Expiration time (which might influence capacity - https://msdn.microsoft.com/en-us/library/azure/dn790675.aspx).
The problem is that, presuming that the previous techniques work and I am able to scale event hubs' performance automatically, I still need a way to know when to trigger scalability mechanisms. To know when and how to trigger scalability, I need to work on some functions that rely upon the event hub's metrics (or a way to monitoring it). The problem is that I can't really find any metrics. The only thing that I find is this: https://azure.microsoft.com/en-us/documentation/articles/cloud-services-how-to-monitor/ - Which actually does not solve my problem because although it may present some interesting metrics, it does not serve the purposes of my "application" (which will come if I can prove that I can successfully scale Azure automatically); and this Azure service bus statistics/Monitoring - which's links are not working.
Surely I can find more information about Service Bus Explorer, and surely it may provide some interesting insights over the event hub metrics, I am just wondering if there is something like this: https://github.com/HBOCodeLabs/incubator-storm/blob/master/STORM-UI-REST-API.md that allow me to access some kind of metrics, rather than creating my own metrics
Thanks in advance
Best regards
You can retrieve metrics about Event Hubs (an Event Hub is a Service Bus Entity) using the Service Bus Entity Metrics REST APIs(https://msdn.microsoft.com/library/azure/dn163589.aspx). Using this you can retrieve the same metrics displayed in the portal such as:
Number of incoming messages
Incoming throughput
Outgoing throughput
These should help you determine when you need to scale your application up or down.
This video is useful for getting started https://channel9.msdn.com/Blogs/Subscribe/Service-Bus-Namespace-Management-and-Analytics
If 3rd party services are an option, look into CloudMonix # http://cloudmonix.com
It can monitor Event Hubs (among gazillion other Azure-related things) and execute Azure Automation runbooks (among gazillion other actions) as a reaction to load conditions/throughout of a whole hub or individual partitions and optionally based on any other metrics in your environment.
Your Azure Automation runbooks could have the logic to execute increases in your EH's throughout, etc.
Disclaimer: I'm affiliated with the product.
HTH
Service Bus Explorer is great. I actually use this.
ServiceBus Explorer