What tools will come in handy to debug and monitor SaaS services built on WCF in production environment ?
FYI - No access to the actual server whatsoever. No remoting in, and no access to the file system.
There are dozens of 'dotcom-monitors' (eg site24x7.com) but they can only monitor parameters that are publicly available, like site uptime, response times etc.
If you want to monitor memory usage and other parameters known only from 'inside', then you have two choices: either install some monitoring agent on a server (in most cases it would be a pain).
You can also send 'signals' from your code to some external event handling and notification service. I recommend AlertGrid (http://alert-grid.com) for the latter purpose it is very flexible and extremely easy to integrate.
AlertGrid doesn't require installation, access to the file system etc. it just gathers data you send and allows to build some notification rules. Examples:
you can send some parameter like memory usage and built rule 'if memory_usage > threshold -> send SMS to admin'
you can send data related to your applicatioin. If you have application proceeding orders, you can send number of processed orders in the signal and build notification rules around that
If you have some logic trigerred periodically (cron, windows service) you can send signal each time your logic is executed to check if it is executed on a scheduled basis.
(I am a developer in AlertGrid's team, in case of any question, please feel free to ask.)
What exactly do you want to monitor? If you only care about availability then good old ping might be enough :)
Related
I'm trying to manage a FHIR workflow based on API Rest for resources CRUD (as Patient, Practitioner and so on).
For workflow handling among different systems I want to use task resource, but I don't want to manage the Subscription resource and it's architecture.
So I have a doubt about manage of notifications.
The correct way is: the different systems must apply a polling operation on server to know if there's a task resource to consume? Or is it the server to warn the different systems?
The server FHIR I want to use is R4.
EDIT
We want to create a interoperability platform about the exchange of data among three systems. Every system is already in production developed by different software house and we can't work on them.
Every system, actually, hasn't got a server FHIR (as the Option B of Workflow architecture).
Every system is available about communication in HL7 v.3 / FHIR
So we want to add a layer with FHIR Server as the below image.
In this case:
if System A sends to FHIR server a resource (i.e. Appointment) then System B take this appointment to process in its environment. How works the schema of communication?
The FHIR workflow communication patterns page defines a number of architecture alternatives. One possibility is to create the Task on the fulfiller's system. In that case, no need for polling or subscription. If the Task is created on the placer's system or an intermediary system and you're sticking with pure REST, then the fulfilling system will need to either have a subscription that will result in them receiving a notification about the Task or they'll have to poll. Other non-RESTful options include POSTing to a "process task" operation on the fulfilling system or sending a FHIR message to the fulfilling system.
Is it possible to subscribe to mail events on an IBM Domino server?
I need a service similar to the one provided by Microsoft Exchange Event Notification, where you can subscribe to events and get notified when there are changes - eg. arrival of a new e-mail. I need the solution to be server side, since I can't rely on users having their client running.
Unfortunately, as per my comment above, there is no pre-packaged equivalent to the push, pull and streaming subscription services that EWS supports. A Notes client can get notifications via Notes RPC protocol, and there's also obviously some technology in IBM's Notes Traveler mobile product, but nothing that I'm aware of as a pre-packed web service or even as a notifications API. You would have to build it. There are a variety of ways you could go about it.
For push or streaming subscriptions, one way would be with a Notes C API plugin using the Extension Manager, running on the server and monitoring the mailboxes. You might be able to use a DSAPI plugin into Domino's HTTP stack to manage the incoming connections and feed the data out to subscribers, but honestly I have no idea if Domino's HTTP stack can handle the persistent connections that are implied in the subscription model. Alternatively, the Extension Manager plugin could quickly send the data over to code written in any other language that you want, running on any web stack that. Of course, you'll have to deal with security through all the linked-together parts.
For pull subscriptions, I guess it's really more of a polling archiecture, with state saved somewhere so that only changes since the last call will be delivered. You have any number of options for that. You could use Domino's built-in HTTP server, obviously, so you could write your own Domino-hosted web service for this. You could also use the Domino Data Service, which is a REST API, to do this -- with all necessary state information being stored on the client-side. (On quick look, I don't see a good option for getting all new docs since a specified date-time via Domino Data Service, but it might be possible.)
I do worry a bit about scalability of any custom solution for this. My understanding is that Microsoft has quite a bit of caching and optimization in their services in order to address scale. Obviously, you can build whatever you need for that into your own web service, but it will likely add a lot of effort.
All
I am looking for a bit of inspiration here, a client has requested me to build a simple remote process monitoring application with capability for smtp notification, when monitored processes go down or come back on-line. Can anyone point me in the direction of some sample code to get me started. I have briefly looked at .net remoting as a potential development path, from my understanding of how this works, the remoting architecture would require both a client and remote server component, (though I am not a 100% sure on this one), however if this is the case, then it will not fit the bill, as one of the fundamental requirements is that no additional software can be deployed on the servers which are to be monitored.
Alternatively, if you know of a finished 'lightweight' product out there, which would deliver this sort of functionality then this would probably work as well.
Kind Regards
Paul J.
Net-SNMP actually has the ability to monitor processes and send out notifications now. If you look in the snmpd.conf manual page (http://www.net-snmp.org/docs/man/snmpd.conf.html) under "process monitoring" (http://www.net-snmp.org/docs/man/snmpd.conf.html#lbAR) and "disman event-mib" support (http://www.net-snmp.org/docs/man/snmpd.conf.html#lbAX) to get the two features you need. Also the notification sending support (http://www.net-snmp.org/docs/man/snmpd.conf.html#lbAW).
I don't remember the windows support for it and how well it works though (it looks like you're aiming for windows).
I have a vb.net 2.0 winforms project that is full of all kinds of business reports (generated with Excel interop calls) that can be run "on-demand". Some of these reports filter through lots of data and take a long time to run - especially on our older machines around the office.
I'd like to have a system where a report request can be made from the client machines, some listener sees it, locates a server with low-load, runs the report on that server, and emails the result to the user that requested it.
How can I design such a change? All our reports take different parameters, and I can't seem to figure out how to deal with this. Does each generator need to inherit from a "RemoteReport" class that does this work? Do I need to use a service on one of our servers to listen for these requests?
One approach you could take is to create a database that the clients can connect to, and have the client add a record that represents a report request, including the necessary parameters which could be passed in an xml field.
You can then have a service that periodically checks this database for new requests, and depending on how many other requests are current processing, submit the request to the least busy server.
The server would then be able to run the report and email the file to the user.
This is by no means a quick solution and will likely take some time to design the various elements and get them to work together, but its not impossible, especially considering that it has the possibility to scale rather well (adding more available/more powerful servers).
I developed a similar system where a user can submit a request for data from a web interface, that would get picked up by a request manager service that would delegate the request to the appropriate server based on the type of request, while providing progress indication to the client.
How about write a web service that accepts reporting requests. On completion the reports could be emailed to the users. The web service can provide a Status method that allows your WinForms app to interrogate the current status of the report requests.
I'm playing around with windows azure and I would like to build a clouded server application that receives messages from many different clients, such as mobile and desktop.
I would like to build the client so that they work while in "offline-mode", i.e. I would like the client to build up a local queue of messages that are sent to the azure server as soon as they get online.
Can I accomplish this using wcf and/or azure queing mechanism, so that I don't have to worry about whether the client is online or offline when I write the code?
You won't need queuing in the cloud to accomplish this. For the client app to be "offline enabled" you need to do queuing on the client. For this there are many options, a local database, xml files, etc. Whenever the app senses network availability you can upload your queue to Azure. And yes, you can use WCF for that.
For the client queue/sync stuff you could take a look at the Sync Framework.
I haven't found a great need for the queue so far. Maybe it's just that I'm not seeing it in my app view. Could also be that the data you can store in the queue is minimal. You basically store short text strings (like record ids), and then you have to do something with the ID when you pull it from the queue, such as look it up, delete it, whatever.
In my app, I didn't use the queue at all, just as Peter suggests. I wrote directly to table storage (accessed via it's REST interface using StorageClient) from the client. If you want to look at a concrete example, take a look at http://www.netalerts.mobi/traffic. Like you, I wanted to learn Azure so I built a small web site.
There's a worker_role that wakes up every 60 seconds. Using one thread, it retrieves any new data from it's source (screen scraping a web page). New entries are stored directly in table storage (no need for a queue). Another thread deletes entries in table storage that are older than a specified threshold (there's no issue with running multiple threads against table storage). And then I'm working on the third thread which is designed to send notifications to handheld devices.
The app itself is a web_role, obviously.