If I want to enable a new piece of functionality to a subset of known users first, is there any automated system of framework that exists to do this?
Perhaps not directly with version control - you might be interested to read how flickr goes about selectively deploying functionality: http://code.flickr.com/blog/page/2/
And this guy talks about implementing something similar in a rails app: http://www.alandelevie.com/2010/05/19/feature-flippers-with-rails/
Most programming languages have if statements.
I don't know what "switching between them at runtime" means. You usually don't check executable code into an SCM system. There's a separate process to check out, build, package, and deploy. That's the province of continuous integration and automated builds in agile techniques.
SCM systems like Subversion allow you to have tags and branches for parallel development. You're always free to build, package, and deploy those as you see fit.
As far as I know no...
If you wanted a revision control system that had multiple versions that you could switch between. Find a SCM you like and lookup branching.
But, it sounds like you want it to me able to switch versions in the SCM programmatically during runtime. The problem with that is, for a revision control system to be able to do that it would have to be aware of the language and how it's implemented.
It would have to know how load and run the next version. For example, if it was C code it would have to dynamically compile and run it on the fly. If it was PHP it would have to magically load the script in a sandbox http server that has PHP support. Etc... In which case, it isn't possible.
You can write an app to change the version in the scm by using the command line.
To do it during runtime, that functionality has to be part of the application itself.
The best (only) way I can think of doing it is to have one common piece of code that acts like a 'bootloader', which uses a system call to checkout the correct branch based on whatever your requirements are. It then (if necessary) compiles that code, and runs it.
It's not technically 'at runtime', but it appears that way if it works.
Your first other option is something that dynamically loads code, but that's very language-dependent, and you'd need to specify.
The other is to permanently have both in the working codebase (which doubles your size if it's a full duplication), and switch at runtime. You can save a good bit of space by using objects that are shared between both branches, and things like conditional compilation to use the same source files for both targets.
Related
I'm currently working on a project that's been going on for several years straight. The development-team is small (less than 5 programmers), and source-control is virtually non-existent, and the deployment-process as is is just based on manually moving files from one server to another. The project is in classic ASP, so building isn't an issue, as both deployment and testing is just about getting the files to where they need to be and directing the browser at the correct location. Currently all development is done on a network-drive which is also the test-server. The test-server is only available when inside the the local network (can be accessed trough vpn), and is available on the address 'site.test' in the browser (requires editing to the hosts-file on all the clients, but since there are so few of us that hasn't proven to be any problem at all). All development is done in visual studio. Whenever a file is change the developer that changed the file is required to write the file he changed into a word-document and include a small description as of what was changed and why. Then, whenever there's supposed to be a version-bump (deployment), our lead-developer goes trough the word-document and copies every file (file by file) that has changed over to the production-server. Now, I don't think I need to tell you that this method is very error prone (a developer might for instance forget to add that he changed some dependency, and that might cause problems when deployed), and there's a lot of work involved with deploying.
And here comes the main question. I've been asked by the lead developer to use some time and see if I can come up with a simple solution that can simplify and automate the "version-control" and the deployment. Now, the important thing is that it's as easy as posible to use for the developers. Two of the existing developers have worked with computers for a long time, and are pretty stuck up in their routines, so for instance changing it into something like git bash wouldn't work at all. Don't get me wrong, I love git, but the first time one of them got a merge-conflict they wouldn't know what to do at all. Also, it would be ideal to change to a more distributed development-process where the developers wouldn't need to be logged into vpn (or need internet at all) to develop, and the changes they made offline could be synced up when they were done with them. Now, I've looked at Teem Development Server from Microsoft because of it's strong integration with Visual Studio. As far as I've tested it seems possible to make Visual Studio prompt the user if they want to check in changes whenever the user closes Visual Studio. Now, using TFS for source-control would probably eliminate most of the problems with the development, but how about deployment? Not to mention versioning? As far as I've understood (I've only looked briefly at TFS), TFS has a running number for every check-in, but is it possible to tell TFS that this check-in should be version 2.0.1 of the system (for example), and then have it deploy it to the web-server? And another problem, the whole solution consists of about 10 directories with hundreds of files in, though the system itself (without images and such) is only 5 directories, and only these 5 should be deployed to the server, is this possible to automate?
I know there's a lot of questions here, but what is most important is that I want to automate the development process (not the coding, but the managing of the code), and the deployment process, and I want to make it as simple as possible to use. I don't care if the setup is a bit of work, cause I got enough time at hand to setup whatever system that fits our needs, but the other devs should not have to do a lot of setup. If all of the machines that should use the system needs to be setup once, that's no problem at all, cause I can do that, but there shouldn't bee any need to do config and setups as we go.
Now, do any of you have any suggestions to what systems to use/how to use them, in order to simplify the described processes above? I've worked with several types of scm-systems before (GIT, HG and SubVersion), but I don't have any experience with build-systems at all (if that is needed). Articles, and discussion on how to efficiently setup systems like this would be greatly appreciated. In advance, thanks.
This is pretty subjective territory, but I think you need to get some easy wins first. The developers who are "stuck up in there ways" are the main roadblock here. They are going to see change as disruptive and not worth it. You need to slowly and carefully go for the easy wins.
First, TFS is probably not going to be a good choice. It's expensive, heavy, and the source control in TFS is pretty lousy. Go for Subversion: it's easy to setup and easy to use, and it's free. Get that in place first, and get the devs using it. Much easier said than done.
Later (possibly much later), once the devs are using it and couldn't imagine life without a VCS, then you could switch to Hg or Git if you need first class branching and all those other nice features.
Once you have Subversion in place, you can use something like JetBrains TeamCity or Jenkins, both of which are free and easy to use. However, I'm just assuming you don't have a lot of tests and build scripts that the CI server is really going to be running, so it's far more important that you get VCS first. In all things: keep it as simple as possible. Baby steps. Get some wins, build trust, repeat.
I can't even begin to think where to begin with this! Intending no offense directed at you, apart from the mention of git and HG, this post could have been written 10 years ago.
1) Source control - How can a team of developers possibly work effectively without some form of source control? Hell, even if it's Visual Source Safe (* shudder *) at least it would be something. You have to insist that the team implement source control. You know what's available so I won't get into preaching about that. (However, Subversion with TortoiseSVN has worked quite well for me.)
2)
"write the file he changed into a
word-document and include a small
description as of what was changed and
why"
You have got to be kidding... What happens if two developers change the same file? Does the lead then have to manually merge two changes that s/he extracts from the word doc? Please see #1 and explain to them how commit comments work.
Since your don't really need to "build" (i.e. compiled, etc.) anything, you should be able to solve most of your problems with some simple tools. First and foremost you need to use a source control solution. Yes, the developers would have to learn how to use another tool (EEEK!). You could do the initial leg work of getting the code into the repository. If you have file access to the other developers machines, you could even copy a checked-out working copy to their machines so they wouldn't have to do the checkout themselves (not really that hard). You could then use all the creamy goodness of version control to create version branches when each deployment needs to be done. You could write simple scripts using the command line SVN tools to check out said branches and automatically copy the files to the target server(s). Using a tool like BeyondCompare, the copy process could be restricted to only the files that are different (plus BC can handle an FTP target if that is an issue). By enforcing commit comments on the SVN repo, you'll guarantee that the developers provide comments, and for each set of changes between releases you could very easily generate a list of all those comments using the CSM log retrieval features.
I am using Eclipse with the "statet plugin for R".
I am looking for a way to do collaborative development (like in google docs: allow people to modify code at the same time). Any preferred plugin for that? I have seen eXtreme Collaborative Development Environment but I don't know if it is good?
I wouldn't use a shared drive, I'd set up a source code respository using Mercurial or Git and use that. I'm sure there's plugins for those for Eclipse.
How would you stop it being a free-for-all? In my experience, when developing code you want to control change, not have it forced upon you when you aren't ready for it.
Consider this scenario. You have a hard to explain defect in your code. You are steadily debugging it, throwing different data at it, looking at intermediate values etc. You are just about to trap it when BOOM, somebody else changes some other code and your results change because of that.
Spacedman is right, use a revision control system of your choice and keep in control of change.
If you want to do something like pair programming, but remotely, then use a remote screen, e.g. VNC, with Skype so that you can explain to the other what you are trying to achieve.
I've used egit to add git functionality to Eclipse with StatEt and it works well. Allows others to edit code in whatever way works best for them (one repository, several individual repositories with frequent merges etc)
There are plugins out there that will facilitate realtime code sharing. They commonly work by having all individual devs have their own copy of the files and synching changes back-n-forth on the fly. If conflicts are found you get to decide how to resolve them explicitly.
Here is one such plugin from ECF project:
http://wiki.eclipse.org/DocShare_Plugin
I would recommend a source control system for day-to-day development. Real-time code sharing works best for holding short-term collaborative editing or debugging sessions, doing code reviews, etc.
I'm developing a web app.
If I include a jQuery plugin (or the jQuery file itself), this has to be put under my static directory, which is under SCM, to be served correctly.
Should I gitignore it, or add it, even if I don't plan on modifying anything from it?
And what about binary files (graphic resources) that might come with it?
Thanks in advance for any advice!
My view is that everything you need for your application to run correctly needs to be managed. This includes third-party code.
If you don't put it under SCM, how is it going to get deployed correctly on your production systems? If you have other ways of ensuring that, that's fine, but otherwise you run the risk that successful deployment is a matter of people remembering to do all the right things, rather than some automated low-risk "push the button" procedure.
If you don't manage it under SCM or something similar, how do you ensure that the versions you develop against and test against are the same? And that they're the same as production? Debugging an issue caused by a version difference you don't notice can be horrible.
I generally add external resources to my project directly. Doing so facilitates deployment and ensures that if someone changes the version of this file in your project, you have a clear audit history of what happened in case it causes issues in the code that you've written. Developers should know not to modify these external resources.
You could use something like git submodules, I suppose, but I haven't felt that this is worth the hassle in the past.
Binary files from external sources can be checked in to the project as well, although if they're extremely large you may want to consider a different approach.
There aren't a lot of reasons not to put external resources like jQuery into your repo:
If you pull it down from jQuery every time you check out or deploy, you have less control over which version you're using. This holds true for most third-party libraries; you probably don't want to upgrade your libraries without testing with your code to see if it breaks something.
You'll always have a complete copy of your site when you check out your repository and you won't need to go seeking resources that may have become unavailable.
For small (in terms of filesize) things like jQuery and images, I'd just add them unless you're really, really concerned about space.
It depends.
These arguments relate to having a copy of the library on your system and not pulling it from it's original location.
Arguments in favour:
It will ensure that everything needed for your project can be found in one place when someone else joins your development team. I've lost count of the number of times I've had to scramble around looking for the right versions of libraries in order to be able to get something working.
If you make any modifications to the library you can make these changes to the source controlled version so when a new version comes out you use the source control's merging tools to ensure your edits don't go missing.
Arguments against:
It could mean everyone has a copy of the library locally - unless you map the 3rd party tools to a central server.
Deploying could be problematical - again unless you map the 3rd party tools to a central server and don't include them in the deploy script.
Almost any IDE creates lots of files that have nothing to do with the application being developed, they are generated and mantained by the IDE so he knows how to build the application, where the version control repository is and so on.
Should those files be kept under version control along with the files that really have something to do with the aplication (source code, application's configuration files, ...)?
The things is: on some IDEs if you create a new project and then import it into the version-control repository using the version-control client/commands embedded in the IDE, then all those files are sent to the respitory. And I'm not sure that's right: what is two different developers working on the same project want to use two different IDEs?
I want to keep this question agnostic avoiding references to any particular IDE, programming language or version control system. So this question is not exactly the same as these:
SVN and binaries - but this talks about binaries and SVN
Do you keep your build tools in version control? - but this talks about build tools (e.g. putting the jdk under version control)
What project files shouldn’t be checked into SVN - but this talks about SVN and dll's
Do you keep your project files under version control? - very similar (haven't found it before), thanks VonC
Rules of thumb:
Include everything which has an influence on the build result (compiler options, file encodings, ASCII/binary settings, etc.)
Include everything to make it possible to open the project from a clean checkout and being able to compile/run/test/debug/deploy it without any further manual intervention
Don't include files which contain absolute paths
Avoid including personal preferences (tab size, colors, window positions)
Follow the rules in this order.
[Update] There is always the question what should happen with generated code. As a rule of thumb, I always put those under version control. As always, take this rule with a grain of salt.
My reasons:
Versioning generated code seems like a waste of time. It's generated right? I can get it back at a push of a button!
Really?
If you had to bite the bullet and generate the exact same version of some previous release without fail, how much effort would it be? When generating code, you not only have to get all the input files right, you also have to turn back time for the code generator itself. Can you do that? Always? As easy as it would be to check out a certain version of the generated code if you had put it under version control?
And even if you could, could you ever be sure that didn't miss something?
So on one hand, putting generated code under version control make sense since it makes it dead easy to do what VCS are meant for: Go back in time.
Also it makes it easy to see the differences. Code generators are buggy, too. If I fix a bug and have 150'000 files generated, it helps a lot when I can compare them to the previous version to see that a) the bug is gone and b) nothing else changed unexpectedly. It's the unexpected part which you should worry about. If you don't, let me know and I'll make sure you never work for my company ever :-)
The major pain point of code generators is stability. It doesn't do when your code generator just spits out a random mess of bytes every time you run (well, unless you don't care about quality). Code generators need to be stable and deterministic. You run them twice with the same input and the output must be identical down to least significant bit.
So if you can't check in generated code because every run of the generator creates differences that aren't there, then your code generator has a bug. Fix it. Sort the code when you have to. Use hash maps that preserve order. Do everything necessary to make the output non-random. Just like you do everywhere else in your code.
Generated code that I might not put under version control would be documentation. Documentation is somewhat of a soft target. It doesn't matter as much when I regenerate the wrong version of the docs (say, it has a few typos more or less). But for releases, I might do that anyway so I can see the differences between releases. Might be useful, for example, to make sure the release notes are complete.
I also don't check in JAR files. As I do have full control over the whole build and full confidence that I can get back any version of the sources in a minute plus I know that I have everything necessary to build it without any further manual intervention, why would I need the executables for? Again, it might make sense to put them into a special release repo but then, better keep a copy of the last three years on your company's web server to download. Think: Comparing binaries is hard and doesn't tell you much.
I think it's best to put anything under version control that helps developers to get started quickly, ignoring anything that may be auto-generated by an IDE or build tools (e.g. Maven's eclipse plugin generates .project and .classpath - no need to check these in). Especially avoid files that change often, that contain nothing but user preferences, or that conflict between IDEs (e.g. another IDE that uses .project just like eclipse does).
For eclipse users, I find it especially handy to add code style (.settings/org.eclipse.jdt.core.prefs - auto formatting on save turned on) to get consistently formatted code.
Everything that can be automatically generated from the source+configuration files should not be under the version control! It only causes problems and limitations (like the one you stated - using 2 different project files by different programmers).
Its true not only for IDE "junk files" but also for intermediate files (like .pyc in python, .o in c etc).
This is where build automation and build files come in.
For example, you can still build the project (the two developers will need the same build software obviously) but they then could in turn use two different IDE's.
As for the 'junk' that gets generated, I tend to ignore most if it. I know this is meant to be language agnostic but consider Visual Studio. It generates user files (user settings etc..) this should not be under source control.
On the other hand, project files (used by the build process) most certainly should. I should add that if you are on a team and have all agreed on an IDE, then checking in IDE specific files is fine providing they are global and not user specific and/or not needed.
Those other questions do a good job of explaining what should and shouldn't be checked into source control so I wont repeat them.
In my opinion it depends on the project and environment. In a company environment where everybody is using the same IDE it can make sense to add the IDE files to the repository. While this depends a bit on the IDE, as some include absolute paths to things.
For a project which is developed in different environments it doesn't make sense and will be pain in the long run as the project files aren't maintained by all developers and make it harder to find "relevant" things.
Anything that would be devastating if it were lost, should be under version control.
In my opinion, anything needed to build the project (code, make files, media, databases with required program info, etc) should be in repositories. I realise that especially for media/database files this is contriversial, but to me if you can't branch and then hit build the source control's not doing it's job. This goes double for distributed systems with cheap branch creation/merging.
Anything else? Store it somewhere different. Developers should choose their own working environment as much as possible.
From what I have been looking at with version control, it seems that most things should go into it - e.g. source code and so on. However, the problem that many VCS's run into is when trying to handle large files, typically binaries, and at times things like audio and graphic files. Therefore, my personal way to do it is to put the source code under version control, along with general small sized graphics, and leave any binaries to other systems of management. If it is a binary that I created myself using the build system of the IDE, then that can definitily be ignored, because it is going to be regenerated every build. For dependancy libraries, well this is where dependancy package managers come in.
As for IDE generated files (I am assuming these are ones that aren't generated during the build process, such as the solution files for Visual Studio) - well, I think it would depend on whether or not you are working alone. If you are working alone, then go ahead and add them - they will allow you to revert settings in the solution or whatever you make. Same goes for other non-solution like files as well. However, if you are collaborating, then my recomendation is no - most IDE generated files tend to be, well, user specific - aka they work on your machine, but not neccesarily on others. Hence, you may be better of not including IDE generated files in that case.
tl;dr you should put most things that relate to your program into version control, excluding dependencies (things like libraries, graphics and audio should be handled by some other dependancy management system). As for things directly generated by the IDE - well, it would depend on if you are working alone or with other people.
We need to regularly synchronize many dozens of binary files (project executables and DLLs) between many developers at several different locations, so that every developer has an up to date environment to build and test at. Due to nature of the project, updates must be done often and on-demand (overnight updates are not sufficient). This is not pretty, but we are stuck with it for a time.
We settled on using a regular version (source) control system: put everything into it as binary files, get-latest before testing and check-in updated DLL after testing.
It works fine, but a version control client has a lot of features which don't make sense for us and people occasionally get confused.
Are there any tools better suited for the task? Or may be a completely different approach?
Update:
I need to clarify that it's not a tightly integrated project - more like extensible system with a heap of "plugins", including thrid-party ones. We need to make sure those modules-plugins works nicely with recent versions of each other and the core. Centralised build as was suggested was considered initially, but it's not an option.
I'd probably take a look at rsync.
Just create a .CMD file that contains the call to rsync with all the correct parameters and let people call that. rsync is very smart in deciding what part of files need to be transferred, so it'll be very fast even when large files are involved.
What rsync doesn't do though is conflict resolution (or even detection), but in the scenario you described it's more like reading from a central place which is what rsync is designed to handle.
Another option is unison
You should look into continuous integration and having some kind of centralised build process. I can only imagine the kind of hell you're going through with your current approach.
Obviously that doesn't help with the keeping your local files in sync, but I think you have bigger problems with your process.
Building the project should be a centralized process in order to allow for better control soon your solution will be caos in the long run. Anyway here is what I'd do.
Create the usual repositories for
source files, resources,
documentation, etc for each project.
Create a repository for resources.
There will be the latest binary
versions for each project as well as
any required resources, files, etc.
Keep a good folder structure for
each project so developers can
"reference" the files directly.
Create a repository for final buidls
which will hold the actual stable
release. This will get the stable
files, done in an automatic way (if
possible) from the checked in
sources. This will hold the real
product, the real version for
integration testing and so on.
While far from being perfect you'll be able to define well established protocols. Check in your latest dll here, generate the "real" versión from latest source here.
What about embedding a 'what' string in the executables and libraries. Then you can synchronise the desired list of versions with a manifest.
We tend to use CVS id strings as a part of the what string.
const char cvsid[] = "#(#)INETOPS_filter_ip_$Revision: 1.9 $";
Entering the command
what filter_ip | grep INETOPS
returns
INETOPS_filter_ip_$Revision: 1.9 $
We do this for all deliverables so we can see if the versions in a bundle of libraries and executables match the list in a associated manifest.
HTH.
cheers,
Rob
Subversion handles binary files really well, is pretty fast, and scriptable. VisualSVN and TortoiseSVN make dealing with Subversion very easy too.
You could set up a folder that's checked out from Subversion with all your binary files (that all developers can push and update to) then just type "svn update" at the command line, or use TortoiseSVN: right click on the folder, click "SVN Update" and it'll update all the files and tell you what's changed.