PLEASE! I've been trying to find some inbox module for ejabberd like MongooseIm's but without success
I would like to know if there are any, and if not, can I adapt MongooseIm's mod_inbox in ejabberd or is it better to switch to MongooseIm?
EDITED:
or how can I create a similar implementation on the client with 0313 - MAM and 0013 - Offline messages that give me the same or approximate result. Please help, I'm breaking my head, I don't want to change the ejabberd but if necessary, no problem
Disclaimer: I'm on MongooseIM core team.
It's not clear how much you've invested in deploying and integrating ejabberd. If the integration is only on XMPP level, then MongooseIM is mostly a drop-in replacement. You can just grab a MongooseIM container or a prebuilt package and be done with it.
If you have, on the other hand, invested in metrics gathering, deployment pipelines, infrastructure as code, etc, then switching might cost you a bit more effort due to some differences in how the projects are built from source, report stats, format logs. The switch is still relatively easy, but there's some overhead involved.
If you're comfortable programming in Erlang, then porting mod_inbox won't be a big problem (it's a matter of a few days at most). If you don't have Erlang experience and hiring is not an option, then better stick to prebuilt MongooseIM container images / packages.
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I am new to this, what is a best approach to implement microservices?
I found fw like seneca but it is little bit confusing...
Is there any tut how to create jwt auth, mongodb and other staff in microservices?
Take a look on Docker.
With docker-compose you can play with several services with an easy integration without worrying about the IP addresses to connect them.
Also if you add nginx to your stack, it's gonna be very easy to scale those services, there are several videos and tutorials that you can lookup to help you get started.
I've heard aboutseneca, but I haven't used, I think you shouldn't depend on a specific framework because one of the ideas behind of Microservices is the low coupling.
To make the jump into the real micro-services world is not trivial. It's not about plumbing some APIs, but a radical change in architecture thinking that, well, at the beginning will make you a bit uncomfortable (e.g. every service with its own database) :)
The best book I have read so far about micro-services is The Tao of Microservices, by Richard Rodger the author of Seneca himself. It exposes very well the shift from monolithic and object-oriented software towards micro-services.
I have personally struggled a bit with Seneca because of the average quality of documentation (inconsistencies, etc...). I would rather recommend Hemera, which took its inspiration from the message-pattern approach from Seneca, but is better documented and much more production-ready.
1) Build services and deploy it with Docker Containers
2) Let them communicate via gRPC coz it is really fast for inter services communication.
3) Use error reporter like Bugsnag or Rollbar. Error reporting is really important to catch error quickly.
4) Integrate tracing using opentracing or opencensus. Tracing is important too because it will be so hard to monitor all microservices with logs only.
I think about technology stack for my project and I think about using ejabberd. The project will look like classic multi-user dungeon RPG where players will move across the world from one location to another (locations looks exactly like chat rooms), and they also will figth each other as well as creatures with AI in turn-based mode.
I never used ejabberd, but I have some experience in writing server applications using erlang.
Is ejabberd an overkill for this kind of game? It has a lot of features that I won't need ever. However it is well-known to erlang developers and is also very stable and mature. Is ejabberd worth using it as kind of transport layer for my online game, or I should better invent my own wheel, something tiny and simple?
I have several years of commercial experience, using ejabberd for things like this. So, my take:
Pros:
It is certainly technically capable.
It is quite easy to grok.
It is very easy to extend and modify.
If you update it regularly, it will solve two really important aspects. A. network security (this is extremely important thing for me); and B.properly done authentication. These two alone are enough of a reason to use it.
It is surprisingly fast.
It gives you chat, presence and friends list for free.
It gives you MUC (rooms) for free. With all the things like permissions solved quite well.
Cons:
Don't really expect to find any usable documentation. Source is mostly your only friend.
Don't really expect to find a community. It's a lonely path. There is a room - ejabberd#conference.jabber.ru but it's very quiet (and almost empty). Most of the people there are not developers, but just ejabberd users. Mailing list is a bit better, but usually not enough to find you the answer you seek.
The source code per-se is not the best example of an erlang project. If you want to learn how to write big, modular, distributed erlang software, better have a look at something like Riak.
The internal APIs are not very stable (they change quite a lot with releases). Because of this, I recommend writing your software as a separate erlang application, connecting to ejabberd as an external XMPP component. Thus you will be guaranteed that you communicate over a stable protocol (XMPP). Of course, you cannot escape having to write some internal stuff as well. Authentication and Roster (friend list) modules are the first that come to mind. This combination is quite hard to maintain and update, especially if you need hot code loading, but it's yet the best solution for me. Try to keep the "in-ejabberd" code to the viable minimum.
That being said, there is only one (to my knowledge) usable XMPP erlang library. It's called exmpp and is developed by the same company as ejabberd (ProcessOne). It's not yet considered stable. I have been using it for quite some time, and for now there are no problems, but you never know. It is also mostly undocumented (or was, when I was learning it).
I'm trying to write a scalable interactive chat application for an existing high traffic website. It needs to be scalable on day 1, and chat's concurrency and multi-broadcast issues make it a tricky thing to scale.
My initial plan was to write the whole thing in rails and refactor the chat server into erlang later.
Although I am an experienced PHP dev and sysadmin, both node.js and RoR are new and extremely alien technologies to me, so I could use a little help understanding the core concepts and applications in this scenario. With so many new technologies, it is hard to understand them all.
Firstly, I recommend you review http://ajaxim.com/. The software is a pre-packaged version of what you want that relies on Node JS (far easier than rolling your own).
If you still want to write something yourself and have no experience with either technology, I recommend you review some introductory materials:
Node JS and Rails
The two sources are not free but will give you a quick one hour crash course on each technology.
You can also have a look at http://pusherapp.com ! This is if you want to implement a chat app right away.
If on the other hand, you want to implement one all by yourself, Node.js + Socket.io is your best bet. However, if you want chat rooms and stuff, have a look at this:
http://github.com/shripadk/express-juggernaut-demo
This demo app uses Express.JS framework and Juggernaut 2.
I would suggest going for only Node.js if you are building apps that require high concurrency. Its fairly easy to implement a chat room using Node.js compared to other server-side languages (mainly thanks to modules like socket.io). The event-driven architecture of Node.js makes it really easy to implement such stuff. The only catch with Node is that you have to think everything asynchronous! If you are good at Javascript then Node.js should be easy to learn.
How can i write a cloud-aware application? e.g. an application that takes benefit of being deployed on cloud. Is it same as an application that runs or a vps/dedicated server? if not then what are the differences? are there any design changes? What are the procedures that i need to take if i am to migrate an application to cloud-aware?
Also i am about to implement a web application idea which would need features like security, performance, caching, and more importantly free. I have been comparing some frameworks and found that django has least RAM/CPU usage and works great in prefork+threaded mode, but i have also read that django based sites stop to respond with huge load of connections. Other frameworks that i have seen/know are Zend, CakePHP, Lithium/Cake3, CodeIgnitor, Symfony, Ruby on Rails....
So i would leave this to your opinion as well, suggest me a good free framework based on my needs.
Finally thanks for reading the essay ;)
I feel a matrix moment coming on... "what is the cloud? The cloud is all around us, a prison for your program..." (what? the FAQ said bring your sense of humour...)
Ok so seriously, what is the cloud? It depends on the implementation but usual features include scalable computing resource and a charge per cpu-hour, storage area etc. So yes, it is a bit like developing on your VPS/a normal server.
As I understand it, Google App Engine allows you to consume as much as you want. The back-end resource management is done by Google and billed to you and you pay for what you use. I believe there's even a free threshold.
Amazon EC2 exposes an API that actually allows you to add virtual machine instances (someone correct me please if I'm wrong) having pre-configured them, deploy another instance of your web app, talk between private IP ranges if you wish (slicehost definitely allow this). As such, EC2 can allow you to act like a giant load balancer on the front-end passing work off to a whole number of VMs on the back end, or expose all that publicly, take your pick. I'm not sure on the exact detail because I didn't build the system but that's how I understand it.
I have a feeling (but I know least about Azure) that on Azure, resource management is done automatically, for you, by Microsoft, based on what your app uses.
So, in summary, the cloud is different things depending on which particular cloud you choose. EC2 seems to expose an API for managing resource, GAE and Azure appear to be environments which grow and shrink in the background based on your use.
Note: I am aware there are certain constraints developing in GAE, particularly with Java. In a minute, I'll edit in another thread where someone made an excellent comment on one of my posts to this effect.
Edit as promised, see this thread: Cloud Agnostic Architecture?
As for a choice of framework, it really doesn't matter as far as I'm concerned. If you are planning on deploying to one of these platforms you might want to check framework/language availability. I personally have just started Django and love it, having learnt python a while ago, so, in my totally unbiased opinion, use Django. Other developers will probably recommend other things, based on their preferences. What do you know? What are you most comfortable with? What do you like the most? I'd go with that. I chose Django purely because I'm not such a big fan of PHP, I like Python and I was comfortable with the framework when I initially played around with it.
Edit: So how do you write cloud-aware code? You design your software in such a way it fits on one of these architectures. Again, see the cloud-agnostic thread for some really good discussion on ways of doing this. For example, you might talk to some services on GAE which scale. That they are on GAE (example) doesn't really matter, you use loose coupling ideas. In essence, this is just a step up from the web service idea.
Also, another feature of the cloud I forgot to mention is the idea of CDN's being provided for you - some cloud implementations might move your data around the globe to make it more efficient to serve, or just because that's where they've got space. If that's an issue, don't use the cloud.
I cannot answer your question - I'm not experienced in such projects - but I can tell you one thing... both CakePHP and CodeIgniter are designed for PHP4 - in other words: for really old technology. And it seems nothing is going to change in their case. Symfony (especially 2.0 version which is still in heavy beta) is worth considering, but as I said on the very beginning - I can not support this with my own experience.
For designing applications for deployment for the cloud, the main thing to consider if recoverability. If your server is terminated, you may lose all of your data. If you're deploying on Amazon, I'd recommend putting all data that you need persisted onto an Elastic Block Storage (EBS) device. This would be data like user generated content/files, the database files and logs. I also use the EBS snapshot on a 5 day rotation so that's backed up itself. That said, I've had a cloud server up on AWS for over a year without any issues.
As for frameworks, I'm giving Grails a try at the minute and I'm quite enjoying it. Built to be syntactically similar to Rails but runs on the JVM. It means you can take advantage of all the Java goodness, like threading, concurrency and all the great libraries out there to build your web application.
I am a newbie to Erlang and am trying to make a switch to Erlang for our latest project. Since this is going to be a real-time chat (long polled) system for file sharing on the fly, I realized after a bit of digging around that Erlang would be the most appropriate choice, because of high concurrency, plus people also suggested to use Yaws since it can handle upto 50k parallel connections.
Although, it sounds awesome, but since I am a newbie (both to erlang and comet applications), I am unable to understand the right technology stack / architecture of how this would work. Also, because of relatively less documentation, I am unable to figure out how the individual pieces would fit together (web server, application layer, DB, message queue) for such an application. The application is going to run off a desktop client only (no web presence required), and so we need to build a REST api for the functionalities.
It would be great, if someone could point me in the right direction to proceed.
Thanks
Nitrogen has a very slick Comet feature built-in. It will work with the three most popular Erlang web servers, including the one you're already considering, YAWS.
Nitrogen doesn't do anything in particular about data storage. It's not one of those web frameworks that insists on managing the DB for you. You're free to use Mnesia or whatever else you like. If this bothers you, you might consider Erlyweb instead. It doesn't do Comet for you like Nitrogen does, but it's more of the manage-everything-for-me sort of web framework.
You could use:
ejabberd as the XMPP server
mnesia as the database
YAWS as the WEB server
Message Queue : you can implement that in Erlang or use an enterprise solution such as RabbitMQ
The all new Zotonic application may inspire you. It's a webapp running off mochiweb for HTTP service with webmachine for the REST API. And it's using good ol' PostgreSQL as database.
It has comet support implemented.