I've got an intermediate amount of experience programming in Java and a fairly advanced amount of experience programming web applications in other languages. I'm currently in the process of learning some of the Java web frameworks (Spring MVC, Struts.)
Where I work, we have a number of individual Java web applications, deployed in separate contexts and as separate wars. A few of the oldest are servlets, many are Struts 1, and the new ones will be Spring 3.
Most of the existing applications have inconsistent or no branding (graphics/decoration), and one of the things I am looking into is applying a consistent header and footer across multiple sites that we can maintain in one place. Ideally it wouldn't even have to be on the same server as the web applications. To be clear-- whereever I configure my template, I want to be able to configure http://some.other.server/template instead of WEB-INF/template.
I would like to use SiteMesh or something with the same "decorating" approach but I researched it, and apparently the only way this has been done in SiteMesh 2 was done by someone who forked the code and customized it to allow remote templates to be imported. (I found this information on the Sitemesh3 Google group.)
I'm at the beginning of designing this solution so I suppose we could use anything like Velocity, Freemarker, Tiles. However, where I work we are slow to update old apps and conservative in adopting new technologies, so I have to prove a solution has good community support, works with Struts 1 and Spring 3 MVC, and is fairly trustworthy and stable.
Velocity has a concept of "resource loader", i.e. an interface for finding template files which can be configured. There is already a loader for URL-based resources. See the Velocity Documentation for Resource Loaders. It also has basic support for caching.
If you need something a bit more sophisticated it should also be fairly easy to provide your own implementation of a resource loader, I did that for one of my projects and it works fine.
Related
I've read articles and posts about what a project and an app is for Django, and basically end up using the typical example of Pool and Users, however a real program generally use a complex relational database, therefore its design gravitates around this RDB; and the eternal conflict raises once again about: which ones to consider an application and which one to consider components of that application?
Let's take as an example this RDB (courtesy of Visual Paradigm):
I could consider the whole set as an application or to consider every entity as an application, the outlook looks gray. The only thing I'm sure is about this:
$ django-admin startproject movie_rental
So I wish to learn from the expertise of all of you: What approach (not necessarily those mentioned before) would you use to create applications based on this RDB for a Django project?
Thanks in advance.
PS1: MORE DETAILS RELATED ABOUT MY REQUEST
When programming something I follow this steps:
Understand the context what you are going to program about,
Identify the main actors and objects in this context,
If needed, make an UML diagram,
Design a solid-relational-database diagram, (solid=constraints, triggers, procedures, etc.)
Create the relational database,
Start coding... suffer and enjoy
When I learn something new I hope they follow these same steps to understand where they want to go with their actions.
When reading articles and posts (and viewing videos), almost all of them omit the steps 1 to 5 (because they choose simple demo apps), and when programming they take the easy route, and don't show other situations or the many supposed features that Django offers (reusability, pluggability, etc).
When doing this request, I wish to know what criteria is used for experienced programmers in Django to determine what applications to create based on this sample RDB diagram.
With the (2) answers obtained so far, "application" for...
brandonris1 is about features/services
Jeff Hui is about implementing entities of a DB
James Bennett is about every action on a object, he likes doing a lot of apps
Conclusion so far: Django application is a personal creed.
My initial request was about creating applications, but as models are mentioned, I have this another question: is with a legacy relational database (as showed in the picture) possible to create a Django project with multiple apps? this is because in every Django demo project showed, every app created has a model with their own tables, giving the impression that tables do not interact with those of other applications.
I hope my request is more clear. Thanks again for your help.
It seems you are trying to decide between building a single monolithic application vs microservices. Both approaches have their pros and cons.
For example, a single monolithic application is a good solution if you have a small amount of support resources and do not need to be able to develop new features in fast sprints across the different areas of the application (i.e. Film Management Features vs Staff Management Features)
One major downside to large monolithic applications is that eventually their feature sets grow too large and with each new feature, you have a significant amount of regression testing which will need to be done to ensure there aren't any negative repercussions in other areas of the application.
Your other option is to go with a microservice strategy. In this case, you would divide these entities amongst a series of smaller services and provide them each methods to integrate/communicate with each other (APIs).
Example:
- Film Service
- Customer Service
- Staff Service
The benefits of this approach is it allows you to separate capabilities and features by specific service areas thus reducing risk and regression testing across the application when new features are deployed or there is a catastrophic issue (i.e. DB goes down).
The downside to this approach is that under true microservice architecture, all resources are separated therefore you need to have unique resources (ie Databases, servers) for each service thus increasing your operating cost.
Either of these options is a good option but is totally dependent on your support model and expected volumes. Hope this helps.
ADDITIONAL DETAIL:
After reading through your additional details, since this DB already exists and my assumption is that you cannot migrate it, you still have the same choice as to whether or not you follow a monolithic application or a microservices architecture.
For both approaches, you would need to connect your django webapp the the specific DB you are already using. I can't speak for every connector out there but I know that the MySQL connector allows django to read from the pre-existing db to systematically generate the models.py file for the application. As a part of that connector, there is a model variable which allows you to define whether or not Django is responsible for actually managing the DB tables themselves.
The only thing this changes from an architecture perspective is how many times do you want to code this connection?
If you only want to do it once and completely comply with the DRY method, you can build a monolithic application knowing that as new features become required, application wide regression testing will be an absolute requirement.
If you want ultimate flexibility for future changes with this collection of features and don't mind recoding the migration across multiple apps while reducing the need for application wide regression testing as new features become required, a microservice architecture strategy is more appropriate.
We currently have a monolithic web application built with Scala (scalatra for the Rest APIs) for the backend and AngularJS for the front end. The application is deployed at AWS. We are going to build a new component, which we would like to build it as an independent microservice. And this component will have its own data repository which may not be the same type of DB. It will also be built with Scala as well, but Akka for the Rest APIs. The current application is built with DB module, domain module, and web service API module and front end/client module.
What is a good approach of a smooth journey? We possibly need to set up a micro service architecture first, such as an API gateway service along with others.
Too many ways, too many approaches, too many best practices. It really all depends on the analysis of your application, trying to figure out where the natural breaks are.
One place I start is looking at the data model. Lots of people advocate each microservice having its own database. Well, that's fine and dandy, but that can really be difficult to achieve without breaking things all over the place. But if you get lucky and there's a place where the data segregates nicely, than see what services would go with it and try breaking it out.
If you do not adhere to the separate database mentality, then I start with the low-hanging fruit, often times nothing more than simple CRUD operations with just a little business logic mixed in, providing some of the basic support for other larger-grained services to come. Of course, this becomes more iterative, not sure your organization will like it.
Which brings me to methodology. Organizations who've created monolithic applications often have methodologies that support them, whereas microservices require a much different approach to application development. Is your organization ready for that?
Needless to say, there's no right answer. I've gone to many conferences where these concepts are high on the interest list and the fact is there's no silver bullet, everyone has different ideas of what is right, and there's exceptions galore. You're just going to have to bite the bullet and cross your fingers, unfortunately.
I'm currently working with a team of developers on a company project to create a centralized repository of product and pricing information. This will be built for both internal company use and external client use. On top of the basic features of storing product and pricing information we also need to build up an infrastructure to accommodate:
REST API endpoints
Dev/Staging/Deployment workflows (particularly for performing updates on records in a live environment)
Logging
Analytics
Reporting
Security (authentication and authorization).
Going over the list, it reads like a very common set of requirements for a web application and I doubt my company is breaking any sort of new ground. SO, is there any particular resources (frameworks, technology stacks, articles, books) that can help me understand how other web applications are tackling these problems?
A bit of background on the team. The team has worked on a handful of small-to-medium sized web applications using PHP, Mongo and MySQL for the backend, and basic HTML, CSS, JQuery on the frontend. The team is familiar with design patterns (i.e.Gang of Four) but to date have not worked on anything requiring all of the elements listed above
It's probably worth playing around with a solid Web development framework like Zend, Yii or even Ruby on Rails or Django, which are not PHP frameworks, but are fairly mature and well structured. Even if you do not plan to use that framework for development you'll get some great ideas for how to structure your web applications, how to implement logging and common web security features.
As far as deployment and workflows go, you may want to give Extreme Programming a read if you haven't already. It describes what many developers today considered to be a fairly classic agile project management methodology, but it also gets into important practices such as testing and continuous integration, which in my opinion are incredibly important components of the development workflow. If you're starting from scratch as a team you'll benefit enormously from implementing a solid agile methodology -- or at the very least from a solid foundation in testing and continuous integration.
For examples of REST style applications you may want to see how popular open source implementations work. Some of these frameworks will have a REST structure built in, but there are many open source options, some of which are discussed here.
For analytics, Google has quite a bit of documentation here.
As far as reporting goes, I'm not clear on what you need, but if you're talking about log parsers and bug or downtime reporters there are some excellent tools out there, including continuous integration automation tools such as Atlassian's Bamboo that will provide some reporting assistance. These can help you with part of the reporting process, but from my experience a large, complex web application can benefit from custom reporting elements, considered as part of the development process from the beginning. It's not that difficult to parse logs programmatically, I don't think there's a one size fits all implementation.
As a side note, Atlassian has some excellent development tools if you're willing to pay for them, but open source alternatives shouldn't be difficult to find, such as the ubiquitous Trac for ticket tracking, and basic project management with an integrated wiki.
I can't say I know of a single, comprehensive location that provides you all the information you need (at least not yet!), but hopefully you'll glean something interesting from this answer. Starting on some serious web development projects with a fresh team (if I interpreted your situation correctly) can be a really enjoyable challenge. Good luck!
Please excuse the noobiness of my question. I am mostly searching here for some directions and buzzwords to start digging from.
I spent some time developing an application in Python
Basically, it takes a bunch of images and creates a video out of it.
It i quite simple, and uses only a few libraries (opencv and nunmpy mostly).
I designed a small gui in gtk, but I think that it would be a good idea to offer the service over the web.
I think I could reuse some of my core and design a front end that people could access in their browser.
I only need a few data to get it running (images, an email)
The thing is my web dev skills are really close to 0, and I don't exactly know where to start from .
I don't plan on having hundreds of people a day on the platform.
People would connect, feed me with the data (link to a dropbox folder, google drive, whatever) and I would send them a message where it's finished.
If you could provide me with some names or links so that I could touch the field, I'd be really glad.
CGI is a fine option, but if you already have Python experience Django is definitely worth checking out (it falls in the category of rhooligan's #3 except it uses Python!). Django completely takes care of all of the database backend details for you, which is a benefit over simple CGI. It also provides easy-to-use pre-defined classes for handling file uploads, images, etc. It also has a great tutorial that will get you up and running. Just be careful about whether you're using version 1.3, 1.4, or the latest dev version, because some aspects of the framework have changed fairly quickly. Make sure that you're always looking at the right version of the docs.
Another handy service to keep in mind for doing something like image processing through a web app is a hosted cloud computing service provider like PiCloud. Unless you already have a private web server with lots of memory and processing power, these cloud services that charge by the ms are really cool. They also give you 1000s of cores which could allow you to do lot's of concurrent processing. They provide a nice Python API, and it has numpy and opencv pre-installed in both v2.6 and v2.7. (They use PyOpenCV, but you also have root access to install anything you want, so you can set up the "cv2" interface if that's what you're using--actually I just looked at your GitHub and it looks like you're using the old "cv" interface. You can also install any application you want on PiCloud--it doesn't have to be Python.)
You could start by looking into the Python CGI module and see if it will work for you. Then you'll need to do the following steps:
Decide on a webserver and install it, Apache is probably a good starting point.
Design the UI. Wireframe things out on paper paper. Figure out how you'd ideally want the users to go through your site and what you want on each page/view.
Your decision in #2 drives all the decisions from this point out. These days, most web applications are a combination of Web 1.0 and JSON/REST "services" (there's a couple of buzzwords for ya!). JQuery is a popular and widely used JavaScript library for developing the front end of your site. That would be another thing to look at. JQuery is completely independent from the back end and can be used with any type of back end (PHP, Ruby, Perl, .NET, etc)
We have a (AJAX heavy) web application hosted in cloud across servers and we need to monitor the availability of this service. Requires logging in to the application with a username-password, perform some searches as that user etc.
Since we plan to use Nagios for some other monitoring tasks, we decided to use Nagios for web application monitoring too.
I came across three such solutions:
Webinject: I don't feel like using this. Project not under active development. It was last released in Jan 2006. I can't see any support/help available. Also I suspect how will it behave with Ajax.
Cucumber-Nagios:
I tried using this. It involves many Ruby components and found that you have to have in-depth knowledge of Ruby platform to make all these components work together. I am not a Ruby guy and having tough time making all these components work together. Also even this project is not under active development and I don't see support/help options available. I posted a bug 4 days back and don't see any response yet.
Selenium plugin for Nagios: Haven't tried it yet. Will try now.
Any more solutions available?
Also, since I don't see any good actively developed solutions for monitoring web applications using Nagios, I suspect if it's really a good approach to use Nagios for this? If not, what alternatives do I have? In short what is the best approach to monitor web applications availability?
Edit 1: We can't afford the Nagios XI paid version and will prefer open source solutions.
If not, what alternatives do I have?
Although Nagios was one of options that we've considered, we've chosen OpenNMS for monitoring purposes. Rationale for our decision is that OpenNMS is highly reliable and configurable free open-source tool and additionally, most of our applications are Java-based; OpenNMS offers integration with JMX. However, bear in mind that if you're demanding very complex tests for your Web site maybe it's better to look elsewhere. OpenNMS can be set to check for HTTP status codes etc., but if you're looking for complex scenarios take a look at:
Apache JMeter (we're using it mainly during the testing phase)
Selenium (can be well used even in production phase)