Apologies if something similar has been asked in the future but my search didn't return, what I would consider, directly related.
I am trying to implement a service with its backend in AWS EC2/S3 and front-end in iPhone and the service is more or less like a todo-list. This is not a novel idea but will help me in a class I teach about IT infrastructure.
Unfortunately I have access to only my own iPhone and I cannot demonstrate scalability over AWS, etc.
Is there a way/software tool/framework to simulate virtual users for this app that can send requests to the AWS servers pretending to be from different accounts/apps?
The simulator should send requests just like my actual iphone app would send if I were to add an item to the list or delete or edit.
I understand stress testing is a well established topic but here I want to just simulate multiple users and demonstrate scalability instead of trying to push the Web service to its limits. Neither am I sure if this completely overlaps with traffic simulation.
Any help will be deeply appreciated.
You might be able to do it using Apache JMeter. That depends on what you have going on on the backend. But it supports the following server types:
Web - HTTP, HTTPS
SOAP
Database via JDBC
LDAP
JMS
Mail - SMTP(S), POP3(S) and IMAP(S)
Native commands or shell scripts
You should be able to wire something together with that.
http://jmeter.apache.org/
http://www.opensourcetesting.org/performance.php
I've used it at various points to simulate VERY heavy loads for my services running in AWS/EC2.
Apache Benchmark is a very convenient tool for doing HTTP load testing -- you can have it make concurrent requests to simulate multiple users. It's main advantage over other tools is that it's simple and easy to get started with. If your backend listens on HTTP, it might be worth trying ab before investing any time in something more complex.
Related
I need to make TCP based decentralised chat app for local network. By decentralised I mean there is no central server. Each entity on a network should have server/client architecture. When app starts it should check which user is online ( already running the app ). My question is how can i check that? Can i do it by trying to connect via connect() function from socket library? I'm new to programming, especially socket programing, so if it's a dumb question sorry in advance.
You should definitely study how other decentralized applications do this. There are lots of techniques.
Each instance of the application should, as part of its server functionality, track the addresses of other instances of the application. Each instance should, as part of its client functionality, keep track of a few instances it can connect to. Prefer instances that have been around for a long time.
The software should include a list of servers that have been running for a long time and are expected to typically be available. You may wish to include a fallback method such DNS, maintained by anyone willing to keep a list of well-known servers offering access through a well-known port. The fallback method can also be IRC or HTTP.
If you want to stay decentralized, you might want to try multicasting or broadcasting a request packet to all hosts on the network to discover other instances of your chat application.
Something similar has been implemented in Pidgin, named Bonjour. It works quite nicely and provides chatting capabilities on a local network. More specifically, it is defined as a Serverless Messaging part of XMPP.
If you are looking for code examples, have a look at one of my projects where I use multicast to discover hosts on the local network that provide a specific service: Headers and implementation.
I have a client company with a simple web application (Python Flask) and I need to add a phone notification functionality to it.
The main requirement is that the app should call users, play a certain sound file and accept some tone input ("Hello! This is an automated message from your WebApp account. You have a meeting with $John today at $5pm. Please press 1 to confirm").
The other requirement is that the solution should be relatively cheap and fast to market.
I have done some research already and it seems that there are a few consequent steps to achieve that:
Set up an Asterisk or a FreeSwitch server;
Set up a SIP account;
Write some business logic for the Asterisk server which allows to make calls and play sounds via a SIP account;
Write an API at the Asterisk server and expose it to the Python Flask web app.
Do I miss something here? Can any of the steps be omitted anyhow? Can I do it simpler?
the fastest way to get it working is to use one of the cloud voice services with speech synthesiser. Here's a short list to check out:
Twilio
Tropo
Plivo
Here I listed some details.
Those services charge you per minute, plus you may have to pay some monthly fee.
If you want to run an independent and standalone service, I would recommend FreeSWITCH instead of Asterisk. It's got reach integration possibilities and API. You will need to read the FreeSWITCH book in order to understand how it works and how to build your service.
I agree with Stanislav Sinyagin on the cloud based solutions, but I would add one more, Voxeo Prophecy. Tropo is from Voxeo, but they have offered Prophecy as a solution for a lot longer and it supports the open standards CCXML and VoiceXML. The advantage of CCXML for outbound notification applications is you have a lot more control of the notification process.
The Prophecy platform has excellent call progress analysis (CPA) which will allow you to determine whether a machine or a human answered and handle the call accordingly. For example, it does not make sense to ask a machine to "...press one to confirm". Instead you may want to leave a message that provides a call back number for the user to confirm with after they have listened to the voice message. The CPA can be used to leave a message on a machine at the correct time (when the greeting message has stopped) so that you do not get clipped messages in the voice mail. CPA will also allow you to provide detailed reports on who was notified and for those that did not it can tell you whether it was a bad number (received a SIT tone), a modem or fax answered, or ring-no-answer (pretty rare these days). These type of details can factor into your retry process for failed notifications.
The other advantage to using Prophecy and open standards is your application will be portable to other IVR systems that are VoiceXML/CCXML compatible if you ever want to migrate. Tropo, Twilio, and Plivo all use proprietary API's which does not allow you to move your applications to other services. Prophecy is also available as a software solution so that if you want to take it out of the cloud you can run it on premise. You can get a two port version for free to try it out.
There is excellent documentation on developing outbound notification systems on Voxeo's developer site. Take a look at the CCXML documentation in section F on Outbound Dialing.
Not sure which development languages you are familiar with, but if you are used to ASP.NET MVC there is an open source project called VoiceModel that makes it easier to develop VoiceXML applications. The other advantage of VoiceModel is that you develop your application once and it will run on any VoiceXML compatible platform and Tropo. They are currently working on adding outbound notification support in this project that will work for both Tropo and VoiceXML.
Third party solutions listed are your easy choice. Running your own asterisk is also suitable for what you want to do, but i think for only this much it would be overkill, from an operational perspective.
In asterisk, you can originate a call that has the 2 variables you need with an (basic-authenticated) HTTP request. You will also need some settings and a tiny dialplan. Setting up the SIP account is easier or more difficult, depending on the documentation from the provider. Most of them have detailed documentation for configuring asterisk (not so much so for freeswitch). Keeping the damn thing alive is what's gonna get to you :)
how can i measure stress testing for the iPhone app ?
i need stress testing not performance testing, for example 100 users access the database of the app which is on the server at the same time.
any help?
thanks in advance
First, you need to decide if you need to test the client-side (iPhone) app, the server-side code, or both.
Testing ONLY the server-side, might make this much easier - especially if it is using HTTP to communicate with the server and exchanges data via a text-based format (XML, JSON, etc). There are many web load testing tools available which can handle this scenario. Using our Load Tester product, for example, you would configure the proxy settings on your iPhone to point to our software running on a local machine. Then start a recording and use the application. Load Tester will record the messages exchanged with the server. You can then replay the scenario, en masse, to simulate many users hitting your server simultaneously. The process, at a high level, is the same with most of the web load testing tools.
Of course, the requests to the server can't be replayed exactly as recorded - they'll need to be customized to accurately simulate multiple users. How much customization is needed will depend on the kind of data being exchanged, the complexity of the scenario and the ability of the tool to automatically configure dynamic fields (and this is one area where the abilities of the tools vary greatly).
Hope that helps!
A basic simulation would involve running your unit tests on OS X, using many simultaneous unit test processes (with unique simulated users, and other variables).
If you need more 'stress', add machines - you'll likely end up hitting io or network limits from one machine relatively early on.
We're looking for some java api to use as middleware/bus to make java processes running on different hosts communicate.
The scenario is the following:
- we have a web application we want to use to monitor the different java processes running on different hosts
- we want all the different processes to be able to communicate with the web application, pushing their own status to the central web app
- we want the web app to be able to poll the different processes in order to receive updates about their status
We were thinking to use something like jgroups, while we wouldn't like to use jms.
Do anyone suggest any alternative? Even better if advantages/disavantages are highlighted..
thanks
It sounds like you need a messaging system such as RabbitMQ http://www.rabbitmq.com/ or ActiveMQ http://activemq.apache.org/ . Rabbit has been gaining a lot of popularity recently and is straightforward to use (see http://www.rabbitmq.com/getstarted.html for example).
I'm looking for advice on the best way to implement some kind of bi-directional communication between a "server-side" application, written in Objective-C and running on a mac, and a client application running on an iPhone.
To cut a long story short, I'm adapting an existing library for use in a client-server environment. The library (which runs on the server) is basically a search engine which provides periodic results, and additionally can provide updates for any of those results at a later date. In an ideal world therefore I would be able to achieve the following with my hypothetical networking solution:
Start queries on the server.
Have the server "push" results to the client as they arrive.
Have the server "push" updates to individual results to the client as they arrive.
If I was writing this client to run on another Mac, I might well look at using Distributed Objects to mask the fact that the server was actually running remotely, but DO is not available on an iPhone.
If I was writing a more generic client-server application I would probably look at using HTTP to provide some kind of RESTful interface to searches, but this solution does not lend itself well to asynchronous updates and additionally what I am proposing does not fit well with the "stateless" tennet of REST: I would have to model my protocol so I "created" a search resource that I could subsequently query the state of and I would have to poll for updates to it.
One suggestion someone made was to make use of something like BLIP to provide me with a two-way pipe between the client and the server and implement my own "proxy" type objects for the server-side resources that knew how to fetch data from the server and additionally were addressable so that the server could push updates to them. Whilst BLIP provides the low-level messaging framework needed to communicate bi-directionally it still leaves me with a few questions:
How will I manage the lifetime of the objects on the server? I can have a message type that "creates" a search object, but when should that object be destroyed?
How well with this perform on an iPhone: if I have a persistent connection to the server will this drain the batteries too fast? This question is also pertinent in the HTTP world: most async updates are done using a COMET type hack which again requires a persistent connection.
So right now I'm still completely unsure what the best way to go is: I've done a lot of searching and reading but have not settled on any solution. I'm asking here on SO because I'm sure that there are many of you out there who have already solved this problem.
How have you gone about achieving real-time bidirectional networking between the iPhone and an Objective-C server-side app?