I curently have an application writen in php using the symfony framework. Rather than have seperate installs for customer on a hosted server, I would like to move to as SaaS model with one install for all customers posible running of google code or another cloud based service. I am not tied to PHP though i would like to have the benifits of a good framework.
So the chalenge: If all customers are using the same application we then have fin a way isolating each customers data. Customers do for eample have admin access and can manager their own users and privlages. At a simplistic leve you could just have a organisation identifier in each table take and add that to all database operations. However most application framewors use and ORM of some kind, and I have not been able to find one that will easly / seemlesly facinatate this at a leve the has minimum impact on the application code.
Has anyone looked at this, are there any good aproaches to this problem?
As Itay says, a multi-tenant system is a common requirement. A while back I was doing some research on this problem and came across a pretty good presentation on the different ways to handle this issue, and the pros and cons of each: http://aac2009.confreaks.com/06-feb-2009-14-30-writing-multi-tenant-applications-in-rails-guy-naor.html
This particular presentation is targeted to a Rails audience, but the principles are the same as with any language.
The approach you described is common, and PHP (One of the strengths) will allow you to comparatively easily go into the ORM code and modify it to your needs.
Second approach is to create a separate DB for each organization and a joint DB for shared resources.
A bit of a design challenge (but just a bit).
if you are really big, then you will even need to consider a separate DB server for each organization (I would say this is a serious overkill in 99.99999% of the cases).
This MSDN article gives you a very good overview of Data Architecture in Multi-tenancy: http://msdn.microsoft.com/en-us/library/aa479086.aspx
Related
I am new in microservices. I am coming from monolithic background in current environment i have different kinds services for different purposes like search, file, email, notification. I have taken so many courses but in that the instructor separate each entity and make it's own database also create API for that(like separate shopping cart entity, product entity) it makes no sense, I am not getting what is real world use of microservices or how to make separate component to build it's own microservice.
Can anyone give Real Project example?
Thanks in advance
Read this and this. Also look here and here. I don't think that anyone will give a link to the real working project, so you can try this.
I am not getting what is real world use of microservices
mostly as you heard in all of those tutorials the microservices architecture leverage advantages of:
the smaller services are easy to maintain and develop
easily can scale specific services rather than the whole project(monolith). for example you scale service-1 to 4 instances that request traffic split into these 4 instance and service-2 to 2 instances and go on (load balance). and these services may distributed in to different servers and locations.
if one service failed to work it does not terminate the whole system since they are independent.
services can be reusable for other scenarios or features.
small team can works for each services and its easy to manage both project and development flow.
and also it suffer from disadvantages of
services are simple and small but all as a whole system is complex so designing part are very critical.
poor performance and it requires do some extras to improve the performance (different types of caching on different levels).
transactions are complex and its developments are time costly. imagine simple update should be projected to other services if its required and you have to consider failure and rollback strategy ( SAGA ).
how to make separate component to build it's own microservice
this is the most challenging part of microservices. you need deep study on Domain driven design DDD.
Decompose by subdomain
Decompose by Business Capabilities
Can anyone give Real Project example?
there are many projects the develop microservices with different patterns. I think you have to start your own and make your hands dirty.
I'm trying to make a service architecture which includes two Node.js apps which shares the same database. The overall service architecture looks like below (simplified version)
I'm planning to use Sequelize as an ORM to access the database. As far as I know, if a service uses Sequelize, it needs model to get the structure of data tables. In my case, api and service will access the same database, which means they should share the same Sequelize model.
So here is the question: where should I locate the common Sequelize relevant files? It seems I have two choices:
put them on the upper common location (assuming the project structure is monorepo) so that each apps can use the single same files
maintain copies of files in each apps' project folders. In this case, each apps will be independent(Let's say I want to dockerize each apps) but in case the Sequelize files modified, the same action should be done for the other.
I'm not sure how I understood is correct. Is my question valid? If so, what is the better choice and practice? I appreciate for your answers in advance.
There is no correct answer, it depends on the specific situation, but sharing a database between multiple microservices is a bad design.
Sharing a database means tight coupling at the data level. The direct consequence is that when a service modifies the database table structure, such as deleting the name field of the user table, it may break the APIs of other services and all use the sequelize user model. All services need to update the model definition and modify the implementation code of the API.
If all of your services are maintained by a team, I suggest you choose the first solution, which costs less and is easier to maintain. If your services are maintained by different teams, the two solutions are actually similar, because as long as the table structure is modified, the application layer model needs to be modified or verified whether it still works well.
Therefore, I recommend following the best practices of microservice architecture, first splitting the database vertically according to the business model, and building application APIs on top of it.
Core principles of microservices:
loose coupling
high cohesion
I am working on a monolith system. All of it's code is in one repository (Web API and background workers). System is written in Nodejs and MongoDB (Mongoose) is used as a data store. My goal is to set a new path how project should evolve. At first I was wondering if I could move towards microservices based architecture.
Monolith architecture creates some problems:
If my background workers needs to scale. I have to deploy all the project to the server despite only using a small fraction of it.
All system must be redeployed when code changes. What if payment processor calls webhook while system is being redeployed?
Using microsevices advantages are quite obvious:
Smaller code base for individual microservice. Easier to reason about it.
Ability to select programming tools best for particular use case.
Easier to scale.
Looking at the current code I noticed that Mongoose ODM (Object Document Mapper) models are used across all the project to create, query and update models in database. As a principle of a good programming all such interactions with database should be abstracted. Business logic should not leak into other system layers. I could do that by introducing REPOSITORY pattern (Domain Driven Design). While code is still being shared across web api and it's background workers it is not a hard task to do.
If i decide to extract repositories into standalone microservices than all bunch of problems arise:
Some sort of query language must be introduced to accommodate complex search queries.
Interface must provide a way to iterate over search results (cursor based navigation) without returning all database documents over network.
Since project is in it's early stage and I am the only developer, going to microservices based architecture seems like an overkill. Maybe there are other approaches I should consider?
Extracting business logic and interaction with database into separate repository and sharing among services to avoid complex communication protocols between services?
Based on my experience with working in Microservices for last few years, it seems like an overkill in current scenario but pays off in long-term.
Based on the information stated above, my thoughts are:
Code Structure - Microservices Architecture (MSA) applying in above context means not separating DAO, Business Logic etc. rather is more on the designing system as per business functions. For example, if it is an eCommerce application, then you can shipping, cart, search as separate services, which can further be divided into smaller services. Read it more about domain-driven design here.
Deployment Unit - Keeping microservices apps as an independent deployment unit is a key principle. Hence, keep a vertical slice of the application and package them as Docker Image with Application Code, App Server (if any), Database and OS (Linux etc.)
Communication - With MSA, communication between services become a key and hence general practice is to remain with the message-oriented approach for communication (read about the reactive system and reactive programming for more insight).
PaaS Solution - There are multiple PaaS solutions available, which you can apply so that you don't need to worry about all the other aspects like container management, container orchestration, auto-scaling, configuration management, log management and monitoring etc. See following PaaS solutions:
https://www.nanoscale.io/ by TIBCO
https://fabric8.io/ - by RedHat
https://openshift.io - by RedHat
Cloud Vendor Platforms - AWS, Azure & Google Cloud all of them have specific support for Microservices App from the deployment perspective, which we can use as an alternative solution if you don't want to deploy PaaS solution in your organization.
Hope these pointers will have in understanding the overall landscape so that you can structure your architecture for future need.
I am working on a monolith system... My goal is to set a new path how project should evolve. At first I was wondering if I could move towards microservices based architecture.
In what ways do you need to evolve the project? Will it be mostly bugfixes, adding features, improving performance and/or scalability? Do you anticipate other developers collaborating in the future? Are you currently having maintenance issues? The answers to these questions (and many more) should be considered in guiding your choices.
You seem to be doing your homework around the pros and cons of a microservice architecture, so if you haven't asked yourself why you're even doing this in the first place, now would be good time to do so.
Maybe there are other approaches I should consider?
There's always the good old don't-break-what's-going ;)
In "Implementing Domain-Driven Design", Vernon give detailed examples for integrating bounded context with a messaging or REST based solution, it also mention database integration, but I understand it is not a very clean solution to share database or at least db tables between BC.
But what if the 2 BCs I want to integrate are hosted locally on the same server, is it really a good idea to use a messaging/rest/rpc solution ? (which seems more suitable for a remotely hosted BC to me)
Otherwise, except with DB integration, what are the other alternatives ? Hosting both BC in the same process and calling it directly (still using adapters and translators for clean seperation) ?
Thanks
You could look into using something like 0MQ for inter-process communication on the same server. I've also in the past just hosted things in the same process as you suggest and just used interfaces / in-memory messaging to separate out contexts.
Everything is about trade-offs in the end, so you just need to decide what level of isolation you are willing to accept. The simplest solution would be to separate inside a solution via folders and interfaces, the other end of the spectrum being completely separate servers.
I don't think that location should come into play w.r.t. integration between BCs.
There really are other factors to consider such as guaranteed delivery to the recipient in order to ensure that the processing takes place. This should be required whether or not the two BCs are hosted on the same server.
Another reason to ignore location is that when you need to scale, your architecture should be able to handle it from the get-go.
As tomliversidge mentioned it is possible to use some deployment mechanisms such as non-durable messaging to speed up things but there will definitely be a trade-off and that has to be a conscious decision.
I am fairly new to Azure and mobile services, and all the examples and tutorials I can find for the table and API scripts are fairly simplistic.
If I have some processes that are fairly complex and rely on pulling information from many different tables and processing contingent on that data, should I be doing that somewhere other than the API scripts? I am new to node.js as well so maybe that's the problem but I was wondering if there is a more appropriate place for business logic, such as some bridge I need to add to my stack?
There are a lot of examples of how to use MSSql object which is used to query tables and Node in general available. A healthy search will reveal just about anything you need. Since you said you are new to Node.js consider using the .NET backend instead. It is based on Entity Framework and there are lots of Entity framework examples out there for you too. Finally, there are some really good examples of complex logic being used in the back ends in the sample code available: http://azure.microsoft.com/en-us/develop/mobile/ios-samples/ (pick your client OS) and here: http://azure.microsoft.com/blog/topics/mobile/ and here: http://blogs.msdn.com/b/azuremobile/
Let us know if you have specific questions!