Imagine there is an application consisting from bunch of microservices. All of these microservices can be developed/deployed completely independently from each other. Each microservice can be "described" with several attributes - e.g. current API version, release version, commit hash etc. Along with that, there are several environments used in development process - e.g. Testing environment (often called Sandbox), Staging environment, Pre-Release environment and obviously Production environment.
Is there a convenient tool/way/approach to track, basically, what attribute is currently deployed to which environment? For instance, get a quick access to information like "what is the current version of Restful API at Pre-Release environment"? Or more complex one - "what was this version two month ago"? And of course see the "global picture" as well?
Theres no ready to use solution on the market yet according to my knowledge.
Some teams are using git ops https://www.twistlock.com/2018/08/06/gitops-101-gitops-use/ to get ahead of the chaos challenge a lot of different micro services usually ship with.
Another technology in a somewhat different, yet related direction are micro service meshes, istio https://istio.io/ being one of them.
There are also test approaches like contract testing or heavy integration tests, that are more expensive, but also provide more confidence.
We are about to embark on a large programme of work to migrate a small number of hugely monolithic 3 tier frameworks into a SOA/Microservice architecture. However there is one thing that I haven't really managed to nail down, version management (note the use of the word management, not control)
One of the core principles of this programme is that each component is absolutely independent, and therefore is designed, developed, built, versioned, deployed, operated, monitored and deprecated independently of all other Consumers and Services. This is the right principle and therefore means that the future holds 15+ clients and 50+ services. In operation we need to quickly and very reliably know all the dependencies. In a world where a service may have 3 or 4 versions of its API in production and a consumer may use 20+ services the dependency tree very quickly becomes large and complex.
So my question is how do you guys manage this? How do you maintain your "enterprise version matrix" (if that is even the correct terminology)?
A common goal of software design seems to be to structure an application so that changes impact a minimal amount of components (i.e compiled assemblies) which can then be published individually. Dependency Inversion Principle is applied so stable components don't depend on volatile ones, classes are packaged in a way again to limit a deployment to a minimal set of components.
So my question is, what is wrong with publishing an entire application in its entirety for each change? Especially if a publish is a completely automated 1-click solution. Surely deploying components individually means I then have to version and manage them individually as mini projects with their own dependencies? A large chunk of 'good design' seems to hang on this one principle that publishing each component separately is a good thing, but why?
What is wrong with publishing an entire application in its entirety
for each change?
I don't think there is anything wrong if you can manage it. It seems this is the approach that Facebook takes:
Because Facebook's entire code base is compiled down to a single
binary executable, the company's deployment process is quite different
from what you'd normally expect in a PHP environment. Rossi told me
that the binary, which represents the entire Facebook application, is
approximately 1.5GB in size. When Facebook updates its code and
generates a new build, the new binary has to be pushed to all of the
company's servers.
Partial deployments can sometimes be useful to maintain a degree of autonomy between component teams but they can result in unexpected behaviours if the particular version-combination of components hasn't been tested.
However, the motivation for modular design is more around ease of change (evolvability, maintainability, low coupling, high cohesion) than the ability to do partial deployments.
I've only got a small amount of experience with A/B testing; but from what I've seen it seems like the standard approach to do an A/B test is to introduce some conditional logic in an application's code. This can be tricky to implement properly (depending on the complexity of the test) and requires extra work both for setup and cleanup.
It got me wondering: are there any frameworks or approaches to A/B testing that simplify matters using, e.g., Git branches? I'm envisioning something at the load balancer level, which directs half of traffic to a server where "master" or "default" has been deployed, and the other half to a server with "experiment" deployed. This way the code itself could always be completely agnostic of any A/B tests going on; and presumably the act of choosing either A or B for full deployment would be a simple flip of a switch.
I'm sure this would not be trivial to set up properly. But still I wonder if it's possible, and if in fact it's already been done.
it's relatively easy to build and definitely doable. you need to implement a deployment system where you deploy all branches starting with "ab_* for an example into different folders on your servers. then at some point in your code you can decide which folder should be included in the actual user session based on your actual test. it's not really a 'framework', it's a simple architecture design pattern you have to add to your own system, i was doing the same in production before.
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We have written a software package for a particular niche industry. This package has been pretty successful, to the extent that we have signed up several different clients in the industry, who use us as a hosted solution provider, and many others are knocking on our doors. If we achieve the kind of success that we're aiming for, we will have literally hundreds of clients, each with their own web site hosted on our servers.
Trouble is, each client comes in with their own little customizations and tweaks that they need for their own local circumstances and conditions, often (but not always) based on local state or even county legislation or bureaucracy. So while probably 90-95% of the system is the same across all clients, we're going to have to build and support these little customizations.
Moreover, the system is still very much a work in progress. There are enhancements and bug fixes happening continually on the core system that need to be applied across all clients.
We are writing code in .NET (ASP, C#), MS-SQL 2005 is our DB server, and we're using SourceGear Vault as our source control system. I have worked with branching in Vault before, and it's great if you only need to keep 2 or 3 branches synchronized - but we're looking at maintaining hundreds of branches, which is just unthinkable.
My question is: How do you recommend we manage all this?
I expect answers will be addressing things like object architecture, web server architecture, source control management, developer teams etc. I have a few ideas of my own, but I have no real experience in managing something like this, and I'd really appreciate hearing from people who have done this sort of thing before.
Thanks!
I would recommend against maintaining separate code branches per customer. This is a nightmare to maintain working code against your Core.
I do recommend you do implement the Strategy Pattern and cover your "customer customizations" with automated tests (e.g. Unit & Functional) whenever you are changing your Core.
UPDATE:
I recommend that before you get too many customers, you need to establish a system of creating and updating each of their websites. How involved you get is going to be balanced by your current revenue stream of course, but you should have an end in mind.
For example, when you just signed up Customer X (hopefully all via the web), their website will be created in XX minutes and send the customer an email stating it's ready.
You definitely want to setup a Continuous Integration (CI) environment. TeamCity is a great tool, and free.
With this in place, you'll be able to check your updates in a staging environment and can then apply those patches across your production instances.
Bottom Line: Once you get over a handful of customers, you need to start thinking about automating your operations and your deployment as yet another application to itself.
UPDATE: This post highlights the negative effects of branching per customer.
Our software has very similar requirements and I've picked up a few things over the years.
First of all, such customizations will cost you both in the short and long-term. If you have control over it, place some checks and balances such that sales & marketing do not over-zealously sell customizations.
I agree with the other posters that say NOT to use source control to manage this. It should be built into the project architecture wherever possible. When I first began working for my current employer, source control was being used for this and it quickly became a nightmare.
We use a separate database for each client, mainly because for many of our clients, the law or the client themselves require it due to privacy concerns, etc...
I would say that the business logic differences have probably been the least difficult part of the experience for us (your mileage may vary depending on the nature of the customizations required). For us, most variations in business logic can be broken down into a set of configuration values which we store in an xml file that is modified upon deployment (if machine specific) or stored in a client-specific folder and kept in source control (explained below). The business logic obtains these values at runtime and adjusts its execution appropriately. You can use this in concert with various strategy and factory patterns as well -- config fields can contain names of strategies etc... . Also, unit testing can be used to verify that you haven't broken things for other clients when you make changes. Currently, adding most new clients to the system involves simply mixing/matching the appropriate config values (as far as business logic is concerned).
More of a problem for us is managing the content of the site itself including the pages/style sheets/text strings/images, all of which our clients often want customized. The current approach that I've taken for this is to create a folder tree for each client that mirrors the main site - this tree is rooted at a folder named "custom" that is located in the main site folder and deployed with the site. Content placed in the client-specific set of folders either overrides or merges with the default content (depending on file type). At runtime the correct file is chosen based on the current context (user, language, etc...). The site can be made to serve multiple clients this way. Efficiency may also be a concern - you can use caching, etc... to make it faster (I use a custom VirtualPathProvider). The largest problem we run into is the burden of visually testing all of these pages when we need to make changes. Basically, to be 100% sure you haven't broken something in a client's custom setup when you have changed a shared stylesheet, image, etc... you would have to visually inspect every single page after any significant design change. I've developed some "feel" over time as to what changes can be comfortably made without breaking things, but it's still not a foolproof system by any means.
In my case I also have no control other than offering my opinion over which visual/code customizations are sold so MANY more of them than I would like have been sold and implemented.
This is not something that you want to solve with source control management, but within the architecture of your application.
I would come up with some sort of plugin like architecture. Which plugins to use for which website would then become a configuration issue and not a source control issue.
This allows you to use branches, etc. for the stuff that they are intended for: parallel development of code between (or maybe even over) releases. Each plugin becomes a seperate project (or subproject) within your source code system. This also allows you to combine all plugins and your main application into one visual studio solution to help with dependency analisys etc.
Loosely coupling the various components in your application is the best way to go.
As mention before, source control does not sound like a good solution for your problem. To me it sounds that is better yo have a single code base using a multi-tenant architecture. This way you get a lot of benefits in terms of managing your application, load on the service, scalability, etc.
Our product using this approach and what we have is some (a lot) of core functionality that is the same for all clients, custom modules that are used by one or more clients and at the core a the "customization" is a simple workflow engine that uses different workflows for different clients, so each clients gets the core functionality, its own workflow(s) and some extended set of modules that are either client specific or generalized for more that one client.
Here's something to get you started on multi-tenancy architecture:
Multi-Tenant Data Architecture
SaaS database tenancy patterns
Without more info, such as types of client specific customization, one can only guess how deep or superficial the changes are. Some simple/standard approaches to consider:
If you can keep a central config specifying the uniqueness from client to client
If you can centralize the business rules to one class or group of classes
If you can store the business rules in the database and pull out based on client
If the business rules can all be DB/SQL based (each client having their own DB
Overall hard coding differences based on client name/id is very problematic, keeping different code bases per client is costly (think of the complete testing/retesting time required for the 90% that doesn't change)...I think more info is required to properly answer (give some specifics)
Layer the application. One of those layers contains customizations and should be able to be pulled out at any time without affect on the rest of the system. Application- and DB-level "triggers" (quoted because they may or many not employ actual DB triggers) that call customer-specific code or are parametrized with customer keys) are very helpful.
Core should never be customized, but you must layer it in somewhere, even if it is simplistic web filtering.
What we have is a a core datbase that has the functionality that all clients get. Then each client has a separate database that contains the customizations for that client. This is expensive in terms of maintenance. The other problem is that when two clients ask for a simliar functionality, it is often done differnetly by the two separate teams. There is currently little done to share custiomizations between clients and make common ones become part of the core application. Each client has their own application portal, so we don't have the worry about a change to one client affecting some other client.
Right now we are looking at changing to a process using a rules engine, but there is some concern that the perfomance won't be there for the number of records we need to be able to process. However, in your circumstances, this might be a viable alternative.
I've used some applications that offered the following customizations:
Web pages were configurable - we could drag fields out of view, position them where we wanted with our own name for the field label.
Add our own views or stored procedures and use them in: data grids (along with an update proc) and reports. Each client would need their own database.
Custom mapping of Excel files to import data into system.
Add our own calculated fields.
Ability to run custom scripts on forms during various events.
Identify our own custom fields.
If you clients are larger companies, you're almost going to need your own SDK, API's, etc.