I'm planing on having my database stored in Cloudant.
Is it safe to use local CouchDB during development, testing and staging of our application with knowledge that everything works locally should also work on Cloudant?
Certainly. Cloudant is API compatible with the Apache CouchDB API with a few subtle distinctions, all of which are documented at http://docs.cloudant.com. Some highlights are:
we disable temporary views (they would be expensive for you at scale!)
for our distributed system, we have extend the update_seq from an integer to a string
your re-reduce code will nearly always be called, so we recommend using exclusively built-in reduce methods
we have fully integrated lucence indexing/search
we have multi-stage mapreduce processing via "dbcopy"
I do a very similar process. You don't need the same versions, it will actually be very different no matter how you look at it. Cloudant is very cool, and have made a lot of alterations and additions to their system. So, if you are looking at developing views, attachments, etc, then you can develop those locally on your dev project. Once your dev project looks good, I would have those checked into the staging/qa server, which I like to use Cloudant for as well. Thats where you need to get everyones code working together. after that is done, you can fire off a replicator to replicate your staging to production.
No matter how you look at it though, or how you envision the process being, you are going to want to take a close look at the going from dev to QA. There are ways to go about it so that everyone can dev on their own, and merge up. I personally like to use github. I hope this helps you out in your tasks.
Related
I want to know following things so that I can fix my server architecture and make it more flexible.
Is it good to store home feed data [ex: Facebook homeFeed] to the variable for future manipulation or just fetch data related to homeFeed and manipulate everything which needs to be done on run time.
Please note that data set of home feed can contain anything. [ not developed yet ]
Is there any limit to request to MongoDB at any given time which can create a delay in data processing?
Are node.js and MongoDB a good option for social network development?
If you know anything related to social network development then please share the pros and cons.
Is it good to store home feed data [ex: Facebook homeFeed] to the variable for future manipulation or just fetch data related to homeFeed and manipulate everything which needs to be done on run time.
You can (and sometimes should) pre-compute home feed data for certain users (for example those who are the most active). You don't store that in a variable though, you cache the results with something like Redis.
Generating the home feed on a "request" basis is also possible and good.
Both approaches require careful thinking about your system's architecture, performance, scalability, robustness, fault-tolerance, etc...
Is there any limit to request to MongoDB at any given time. which can create a delay in data processing?
Yes. A MongoDB instance (or any other database) has limited resources. Look at the Sharding and Replication docs of MongoDB for more info about how to work with MongoDb at scale.
Are node.js and MongoDB are a good option for social network development.
Node.js and MongoDb are a good combinations for quick prototyping, you can get productive fairly quickly. Any language(s) you are familiair with is/are a good choice here, since your focus seems to be on architecture. Go, Java and PHP are good candidates too.
In the real world social networks are built with a lot more tools than that. Since the teams use various programming languages, databases and frameworks depending on the task at hand.
I have an app that I would like to create. But I am not sure how to go about it. I am using node.js and would like to use couchdb, but if something like mongodb or riak would be a better choice them im willing to hear ideas. But, i have a site, say
cool.com
and on there is a couchdb instance, as well as a site to manage a store. say a shopping cart. the db houses all the store's items and data. The app itself has an admin backend to manage that data and can change items. What i would like to be able to do, is have the ability to have the user be disconnected from the internet, and still have the admin backend work. I realize for this to work I need to use a client side framework with my models/routes/controllers/whatever. But what I am not sure of, is how to let the site function while offline. couchdb if installed locally can sync the data from local to remote when back online, and if the admin user is on the computer, i could have them install couch. but that could be messy.
Also, what if the admin user is on a tablet or a phone? Would I need to have an actual mobile app and a desktop app to do this? is there some way I can set this up so it is seamless the the end user. I would also like this to be offline for end users too, but the bigger audience is the admin.
Another use case, instore POS system. and the power goes out. But the POS system can be loaded from the web onto a tablet and they can still make card based sales if the wifi is out, because the app is available offline.
Im just not sure how to do this. lets assume i need a client framrwork that can handle the data as well as the backend. something like ember, or angular. theres also all in one stacks like meteor and derby js, but those arent fully offline,but are for the appearance of real time. though meteor does have mini mongo so it might be worth looking into.
I was hoping someone could help me figure out how I would get this setup to work, preferrably with couch, but other nosql's would work too if I can have a way to sync the data.
I'm not sure if it would work for you, but I have been thinking of such an application for quite a long time now and been doing some research on what's possible. The best solution I could come up with is using a server with a couchdb and writing the application clientside based. Then for the data storage use pouchdb and synchronize the pouchdb regularly with your serverside couchdb if the app is online. I know pouch is in an early stage and not production ready but if you are willing to put some work into it I'd say it's doable.
If you want clients that work seemless as they go offline and come online (like a POS with the power out) then I would recommend making the app primarily work off local storage with a background publishing or synchronization to the cloud.
Local storage options could be everything from something light like sqlite, sqlexpress, firebird to no sql options like mongo, couchdb etc...
But for the client or device, consider the ease of configuration and weight of the option. You also need to consider the type of clients - do you have many platforms varying from devices to PCs? You don't want something that has a heavy config and runtime footprint. That's fine on the service side.
On the service side, consider the nature of your data and whether it's fitted better for transactional/relational systems (banking etc...) or eventually consistent/non transactional (no-sql) documents. Don't forget hybrid as an option. Also consider the service platform - for example, node goes well with mongodb (json objects front to back) ...
The device and service storage options can be different (and likely should be) separate by service interfaces (soap, rest/http, sockets etc...).
It's hard to have a one size fits all solution but often something light weight like sqlite on the device or client makes for ease of installation/config while scalability on the service side with something like sqlserver/mysql or couchdb/mongodb makes sense.
Some links to read:
http://www.mongodb.org/display/DOCS/Comparing+Mongo+DB+and+Couch+DB
http://www.sqlite.org/
http://blogs.msdn.com/b/sqlexpress/archive/2011/07/12/introducing-localdb-a-better-sql-express.aspx
You're question is pretty wide open and there's no one size fits all solution. Hopefully I provided some options to think about.
There's an interesting project out there called AppJs (http://appjs.com/), which packages Node.JS and Chrominium as a desktop environment. It's currently very fresh (very little documentation), but it appears to be straight forward enough (you'll be using the same tools as you would for your online application).
As for synchronising the offline and online environments. I doubt you can rely on CouchDB in the way that you envisage. CouchDB mobile support is not as comprehensive as some of the documentation suggests. So in this sense, it would be no different to using SQL/Mongo/Punchcards.
You might have more luck with designing a suitable serialisation scheme based on XML or JSON (or just plain text), and passing files between the online and offline installations.
Edit - Since writing this, Node Webkit - http://nwjs.io/ - is clearly the most obvious replacement for App.js. It has a very simple API, and some great features.
Is there an easy way to manage offline data with a web app, and synchronize with a server when there is a connection? I have been looking at Meteor, CouchDB and the likes, but still not sure what would be the least painfull way.
I could of course implement it myself with sockets or something similar, but if something is already made for the purpose, I don't see a reason to do it again.
I'm planning to work with Node as the server.
Thanks
You're talking about two things; 1) How to store/persist data if/when offline (storage mechanism), and 2) How to synchronize with a server when online (communication mechanism). The answer to 1 is some kind of local storage, and there any several ways of doing that (localstorage, websql, filesystem APIs etc) depending on your platform. The answer to 2 really depend on how urgent your synchronization needs are, but in general you can use HTTP itself with periodic (long-) polling, websockets and similar.
On top of both storage and communication mechanisms there are numerous libraries that make the job simpler, like Meteor (communication) and CouchDB (storage), but also many many more. There are even libraries that take care of the actual synchronization mechanism (with possible conflict resolution as well), but this very much depends on your actual application.
Updated: This framework looks promising, but I haven't tested it myself:
http://blog.nateps.com/announcing-racer-experimental-realtime-model
You might want to look at cloud services as well. These are best if you are developing a new application as they push you more to a serverless model, and of course you have to be happy using a service.
Simperium (simperium) is an interesting cloud service - the only one I can find today that does syncing (unlike Firebase and Spire.io who are similar in other respects), and for iOS it includes offline storage, while for JavaScript clients you'd need to cover the local storage yourself using HTML5 features. Backbone.js seems to have some support for this, and Simperium can integrate with Backbone, using a similar API style.
For non-cloud services, Derbyjs (derbyjs) is an open source project that includes Racer, a data synchronization library (mentioned by the earlier answer) - both are under rapid development and not yet complete, but look interesting if your timescales allow, and don't require a cloud service. There is a comparison of Derbyjs to Meteor that is useful - although it's written by the Derbyjs developers it's not too biased.
I also looked at CouchDB, which has some interesting built-in replication features, but I didn't like its use of indexes that are updated lazily when a query needs them (or by a batch process), and I wasn't happy with exposing the server DB directly to clients to enable replication/sync. Generally I think it's best to decouple the client side local storage from the server side DB, and of course for a web app it would be hard to use CouchDB on the client.
So we've starting using couchdb at work. Writing javascript functions in futon is no fun. I want to be able to write them in a text editor. I'd also like to be able to easily write my functions, push them to a dev database, and then push them to test/prod. Help?!
http://couchapp.org
Even if you aren't creating a typical couchapp (a web application served from CouchDB), I've found it to be a useful tool for the needs you describe.
A minimal couchapp allows you to organize each of your view, list, show, filter, and update functions as their own .js file, in a directory structure that makes sense. It takes care of JSON-encoding during a push, and assembling all of the files into a _design document. This allows you to easily use typical version control practices. It also supports other SCM practices, like enabling configurations for pushing to different environments. This avoids most of the hassles of Futon, which is not a very practical tool for managing your JavaScript functions in CouchDB.
I'm hoping someone can validate or correct my conclusions here.
I'm looking into writing a small side project. I want to create a desktop application for taking notes that will synchronise to a web-server so that multiple installations can be kept in step and data shared and also so that it can be accessed via a browser if necessary.
I've kind of been half-listening to the noises about CouchDB and I've heard mention of "offline functionality", of desktop-couchdb and of moves to utilise its ability to handle intermittent communications to enable distributed applications in the mobile market. This all led me to believe that it might be an interesting option to look at for providing my data storage and also handling my synchronisation needs, but after spending some time looking around for info on how to get started my conclusion is that I've got completely the wrong end of the stick and the reality is that:
There's no way of packaging up a CouchDB instance, distributing it as part of a desktop application and running it in the context of that application to provide local storage and synchronisation to a central database.
Am I correct here? If so is there any technology out there that does this sort of thing or am I left just rolling my own local storage and maybe still using CouchDB on the server?
Update (2012/05): check out the new TouchDB projects from Couchbase if you are targeting Mac OS X and/or iOS or Android. These actually use SQLite under the hood (at least for now) but can replicate to/from a "real" CouchDB server. Another clientside alternative that is finally starting to mature is PouchDB, which runs in IndexedDB capable browser engines. Using these or using them to inspire similar port to another desktop platform is now becoming a better-trod path.
Original answer:
There's no way of packaging up a
CouchDB instance, distributing it as
part of a desktop application and
running it in the context of that
application to provide local storage
and synchronisation to a central
database.
At this point in time, your statement is practically correct although it is possible to include CouchDB in an app — for an example see CouchDBX.app which is a thin wrapper around a prefixed bundle of CouchDB and all its dependencies.
The easiest way to build a CouchDB app is to assume that the user will already have a CouchDB server running. This is easier than it sounds, especially with Couchone's hosting or a prebuilt app like CouchDBX on OS X or DesktopCouch on Ubuntu. This latter is especially interesting, because if I understand correctly it is included by default with Ubuntu these days, and automatically spins up a CouchDB server per-user when you query its port via D-Bus. Something similar could (and should) be done on OS X using launchd and Bonjour.
So as you write, you either would design your app to store data in a local format and optionally sync with a CouchDB service you provide or you'd have to build and bundle all of Erlang, SpiderMonkey and CouchDB together with your app along with some scripts to make sure it was running when needed. This is possible but obviously neither of these are ideal, and believe me you're not the only one wanting a simpler solution for desktop-oriented apps!