how to get started with a project - tcl

I have to write a program that tests products fully automatic.
I still don't have the finished prototype board but i have an development board for the I.MX6UL processor
see picture below
http://www.nxp.com/products/sensors/gyroscopes/i.mx6ultralite-evaluation-kit:MCIMX6UL-EVK?
My first task is to put an uboot and linux file system on the board trought TCL code => asked by customer.
This all have to be done trough a usb connection that is connected to the development kit board.
NXP provide some tools that is called MFGTOOL2 => with this i can install a fully working linux but ofcourse i need to do this with code scripting and not via a tool because it's for production testing.
All this has to be installed on an nand flash ?

Your question is very vague and likely to not be useful to others as so much of it looks specific to your development environment. This means that the first step is going to be for you to do some research so that you can learn how to split the project up into smaller tasks that are more easily achievable. One of the key things is likely to be identifying a mechanism — any mechanism — for achieving what you want in terms of communication (and enumerating exactly what are the things that will be communicating!) Once you know what program to run, API to call or message to send, you can then think “How do I do that in Tcl?” but until you are clear what you are trying to do, you won't get good answers from anyone else. Indeed, right now your question is so vague that we could answer “write some programs” and have that be a precisely correct (but unhelpful) reply to you.
You might want to start by identifying in your head whether the program will be running on the board, or on the system that is connected to the board, or on a system that is remote from both of those and that will be doing more complex management from afar.

Related

Mercurial MSSCCAPI Provider?

Does anyone know of an MSSCCAPI provider for Mercurial? I'd like to try out Kiln/Mercurial with PowerBuilder, but the PowerBuilder IDE only recognizes MSSCCAPI providers (which is not the same as MS SCC Package API) and the only one I can find is the original version of HgSccPackage.
I've contacted the developer and he has stated that he will not switch back from the Package to the regular API so that option leaves me with no upgrade path. This question was asked in July of 2010 with only the response that I have already mentioned. I'm hoping there's been something new since then. Thanks!
I don't have enough rep to post this as a comment to the question.
Maybe your PowerBuilder source control methodology is holding you back. Do you control the PB objects inside of the PBLs? Or do you control *.sr? (PB Export) files, maybe using PowerGen to synchronize them into the PBLs?
At work, a set of PBLs is published to programmers by the Build Manager at every build. This avoids having to pay one PowerGen license per programmer for them to sync up (which can take 5-40 minutes depending on the number of changes and the app size). You need just one license for the build server.
One caveat is that programmers need to understand the flow correctly so not to lose code or cause regressions, but a good inspection of the TortoiseHg diff window should allow to catch most problems before committing.

Moving on from Hello world style simple programs to big / real world projects : A guide to real world projects

Somebody please re-tag with appropriate tags
Hello,
This is my story but I guess it holds true for all programmers.
We begin programming with some simple Hello World program. We practice & add functions/classes to the program. But they still maintain the Hello World style. function calling some other functions standard library.
But when it comes to real world projects(I'm just familiar with OpenSource). Lot more other things come into picture. Then begins the hardships of this newbie programmer.
Project Flow:
Program is not running as expected. Make use of Debugger
Making use of third party libraries. Today, we have
library in every popular language for
almost everything we need.
Multiple persons working on same project. Using Version Control
Systems.
Project is growing big. Build Automation
Lot of people started using your application. You need to port it to
different platforms (operating
systems/architectures). Need for
Cross Compiliation
I don't know why but we need Unit Testing Framework and/or unit tests
What else???
The problem in this is the lack of knowledge of this newbie programmer about existence of these things.
What I mean is when I started looking into some real world projects(Opensource). I didn't know what is this? and why we need to do this?
$./configure
$make
$make install
Recently I became aware of the keyword "Build Automation". I was in need of some library which was available for linux but I needed it in windows. I didn't know that its called "Cross compilation" and tools like MinGW/MSYS exist for this purpose. I had to learn these things in the hard way. I wish some one has told me about existence of such things. That would have saved my lot of time.
Today I ran into performance problem and was feeling the need for something. I guess the thing I'm looking for is Profiler. Thanks to my involvement in opensource projects. Even though I didn't realized/felt the need for this, I'm aware of term Unit Testing.
Though this (hard)way of learning things has some big advantages like now, I'm able to figure out solution or some unknown thing very quickly & unlike my other friends I don't get struck at any point. But I hate the wastage of time involved. You do not believe how much I time I wasted in figuring out the Makefiles & Gnu Build System
So, what am I looking for this in this post?
Please complete the Project Flow. I want to see what all things are involved.
For each of the tasks in the Project Flow list. I want to see following information.
Most popular solutions/tools availabe.
Wikipedia list to all alternatives.
[optional] Suggest some good books/tutorials/guides for learning about this. Or link to relavent SO posts/tags.
I know somethings are language & OS specific. I would say we have only handful of major platforms Linux/Unix, Windows, Java, .NET and handful of major languages C, C++, Java, .NET, Python. Address these languages. Its more than sufficient.
Example:
Making use of libraries:
Libraries are distributed in any of the following forms
Source Distrubtion
Static Libraries(*.lib for windows / *.a for linux)
Dynamic Libraries (.dll for windows /.so for linux)
.NET assemblies
I don't know about java
Resources (Now, once I know the above info. I can search on my own for resources)
http://en.wikipedia.org/wiki/Library_(computing)
How To Write Shared Libraries
http://www.tenouk.com/ModuleBB.html
Note:
Please not that I'm not asking to suggest info on how to learn each of these things. I'm asking about what more such kind of things are involved and alternatives for each of them.
Your question seems to be too broad, but in comments you asked for examples of different methods. This would at least enable you to find some other pointers and make your own decisions.
Rational Unified Process (RUP)/Unified Process (UP)
eXtreme Programming (XP)
Scrum
Test Driven Development (TDD)/Behaviour Driven Development (BDD)
Lean Software development
Kanban
Feature Driven Development (FDD)
Those and many more are software development methods, which comprise of different principles, processes and roles. Most of them also come with some sets of practices for different purposes, e.g. ones you mention in your question. Those are quite widely used in real world, although many companies use different combinations and also some own processes and methods. What is not part of what is used so widely, but might give you some interesting views on development are formal methods, which are precise, but most of the time too unpractical.

Best Practices for Setup and Management of an Open Source Project

Later this year I want to release a PHP framework that I've been working on as open source. I do use source control (SVN), but it's on an extremely limited basis. I'm self-taught, I develop by myself and don't have the experience of working with large teams. I have some ideas about what can help make a project successful, but I'm fuzzy on some of the details. Since it's not yet released, I want to do everything I can to set up the right infrastructure from the beginning. What do I need to know in order to setup and manage a successful project?
Some ideas that I have to make it successful (beyond marketing it):
Good documentation and tutorials
Automated unit tests and builds to
push update to the website
A clear roadmap
Bug Tracking integrated with the
source control
A style guide to keep the code
consistent
A forum for the community to get
support, share ideas, etc.
A good example application built with
the framework
A blog to keep the community informed
Maintaining backwards compatibility
wherever possible
Some of my questions:
How do I setup and automate a one
step submit-test-commit-generate API
docs-push update to website process? Edit: Would Ant or Maven be good candidates for this? If so, do you know of any resources for setting up a PHP project using them?
How do I handle (technically)
submissions from other users? How can
I ensure that those submissions must
be approved before being integrated?
What are some of the pitfalls that
can be avoided in terms of the
project community? I'd prefer to have
it be as friendly and helpful as
possible without a lot of drama.
I'd love to learn from your experience on any of these points. If you think I'm missing anything big, please share that as well. Any resources (preferably geared toward a beginner) that you could point me towards would also be greatly appreciated.
I'm just getting started in community projects, but I'll give you some advice on what I know.
How do I setup and automate a one step submit-test-commit-generate API docs-push update to website process?
I've never implemented it as one process. You could just have a checklist, and possibly even create some scripts to do certain tasks. I've never worked with any source control that automates the uploading and such to be done by a script. Most of the time, there is some web interaction to be involved.
You don't want to push API changes until it's an official release.
EDIT: Working Environment
For PHP, most of the time, I either edit directly on the server and test it there, using a beta.example.com, or similar, before pushing to example.com. You could also set up an web environment on your home PC (using XAMPP for Windows, or the standard LAMP installation on Linux). You would probably just use a mirror of your repository here, so you'd do svn commit, or whichever is appropriate for the VCS or DVCS you choose.
The fun part is testing this with different PHP versions. I've not done this myself, but you could probably use a .htaccess file to run a different PHP binary in order to test it out. I'm not really sure what the best option is for this is.
I've not done much with API, as I've never created a library, but just doing a quick search I found http://www.phpdoc.org/. It looks like a mature project, so that might be a starting point.
As far as creating releases go, I generally create a script that only includes the files that are part of the distribution (it will filter out any VCS files, and anything that you don't want in the distributed file). You could write a script around find on linux (which is what I do most of the time), or there may be other better options.
How do I handle (technically) submissions from other users? How can I ensure that those submissions must be approved before being integrated?
This is mostly handled by the bug tracker, and limited access in the Version Control System. Usually, you, and the people you allow, can commit to the VCS. Other users can submit patches, but then you might have someone review the patch, test the patch, and commit. You could split these tasks up as a team, or assign a patch to one person and have them do it all.
What are some of the pitfalls that can be avoided in terms of the project community? I'd prefer to have it be as friendly and helpful as possible without a lot of drama.
I would just make sure to keep it as positive as possible with the project members and community. There's going to be some disagreements, and it will drive a few people away, but as long as you have a stable product that meets the needs of most people, I think that's all that anyone can expect.
One minor suggestion that's worked well for me: start using first-person plural pronouns, rather than singular ones. That is, talk about "we" and "us" rather than "I" and "me." It encourages other people to participate when they feel like part of team, rather than when they feel like they're contributing your own self-aggrandizement.
The most important thing you have to do is to attract users. Without users, you won't get any contributions and developers helping you out. Because developers are users first, and then they decide to extend/fix something they use and might become contributors.
So to get users, you should consider
describe what your framework does in one or two sentences at the top of your project page
mention how your framework can be used and for what, what situations it is most useful for
add a lot of examples on how to use it
mention whether your framework is stable, beta or alpha. That's important because user need to know that before they start using it
also mention whether you want to keep improving it and keep working on it - most users don't want to use a framework that's abandoned (also keep in mind that a lot of users check your commits to see whether you really are working on it - if your last commit to the repository was months ago then you're not really working on it, so cheating isn't possible)
If you got all this, and people start submitting patches, you can use a patch tool to apply those to your source. Depending on your version control system, you can either use the GNU patch, a diff/patch tool that comes with your version control or maybe even a GUI tool that helps you with this. SVN doesn't have a patch tool (yet), but 'svn diff' will create a patchfile which you can then apply with the GNU patch tool, or in case you're using TortoiseSVN, right-drag the patchfile to your working copy and have TortoiseMerge apply it for you.
And on how to best deal with the community:
answer questions in time, don't wait more than two or three days to answer questions
try to be nice, even with upset and angry people. Only if they keep bothering tell them to (still in a nice way if possible) go elsewhere
always keep discussions about the project on a mailing list. You don't want to repeat the same discussions over and over again - if you have a mailing list, just point users to the archives before the discussion starts all over again
And you should watch the talk "How Open Source Projects Survive Poisonous People (And You Can Too)" - it's really good and tells you a lot on how to deal not just with 'poisonous people' but also how to deal with all people involved in your project.
I'd like to add that you should make it as easy as possible for your users to get the whole thing running and modify the code - these 'power users' can be 'converted' into developers or at least people who send smaller patches.
Don't try to do it all yourself - for open source projects there are several hosting providers that solve most of the problems. I recommend codeplex or google code.
Setting up build scripts will depend a certain amount on what platform you set up, but in general it's easy to add any tool you want into the script once you start using any sort of build script.
If you really need the one step process you describe, you need a build server. I use TeamCity, which I have set up to watch for any changes in svn and trigger build/test whenever something is checked in. The build server will generally be able to perform any steps that you put into the build script.
Read up on Git as an alternative to SVN
free public repository/bug tracker/wiki/fork-enabled community in Github (which hosts symfony and PHPUnit amongst others)
"How do I handle (technically) submissions from other users? How can I ensure that those submissions must be approved before being integrated?" - with Git, pull what you/your closest team finds most interesting to the master branch
Consistent API
be inspired of other public API:s
only change in major versions
guessable
Interesting for both users & developers
clear goal (your roadmap - excellent)
useful, contra everything else available
easy to use, but still not easy-enough-to-write/maintain-yourself
You could check out either Ant or Phing to build your project. Include CodeSniffer in the build and you'll save time checking for basic formatting errors/differences.
These are all technical tips, about the soft part... treat humans with respect, a lot of interest and be overly excited about their contributions and make them feel that they're not wasting their time. That would appeal to me.
Take a look at Karl Fogel's book on Producing Open Source Software. It probably has everything that you asked.
You should also plan for engaging the community. I'd recommend reading Jono Bacon's The Art of Community [http://www.artofcommunityonline.org/].
You have a great set of ideas to start. You might have to start by trimming them down! Ask yourself what's necessary for a first release.
For automating the builds and tests, the scripting can be done with ant, maven or phing for PHP projects.
You'll probably need a host so you can demo the product. For PHP that is pretty easy to find.
You need an open source hosting provider-- especially github (but also google code, source forge, etc). Github provides bug tracking, default licenses, blog and great mechanisms for accepting changes from the community. Built on git, it facilitates distributed projects quite well.
Although it's good to have a one-step build and install in place, automating integration of others changes probably isn't important (or desirable) off the bat.
Good luck!

How did you get involved with your open source community? [closed]

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It seems that the normal progression to join projects is to contribute for a while, earn the trust, then get accepted as a member of the community (i.e. having commit access).
Now, I already apparently know "the best way" of how to get involed, in a manner of speaking; this is not my question; what I was hoping to attain is: How did everyone else get involed? Surely not everyone has gone down the "find a project and submit patches" route - or have they? I dont happen to know anybody in the open source community, so I'm just itching to know...
Perhaps you already knew someone in a community and just fell into it? Maybe you were getting frustrated with some bug and started contributing regulary as a result? Maybe you did just spot a project on SourceForge...
Update:
It seems that the most common reason is simply scratching an itch, to quote singpolyma: "Looking for a project to contribute to is often not the right way." Instead, you should join the open source community by contributing to a project that you already know and use.
Important:
Please, please, please: Tell me about your specific experience, no general answers please. Also, answer only if you are either a project member or a patch contributor. Please do not give advice on how to join a community, this isn't the kind of answer I'm looking for. If you would like to give advice on joing a community, please answer in this other thread.
Great Answers:
Mark Harrison talks about Tcl, cx_Oracle, kap and orapig
singpolyma talks about DiSo and Greasemonkey
Pax talks about contributing to GnuCash because of his wife
Related:
How to get involved in an open source project
How Open Source Projects Survive Poisonous People (And You Can Too)
My personal anecdotes:
I got involved with the Tcl community when it was first starting out in 1991 or so. The mailing list and later the usenet newsgroup were pretty important to connect with people. I specialized in user evangelism and teaching, and eventually ended up writing two books about the subject. One of them is still in print after ten years:
http://www.amazon.com/dp/0201634740
Now I use a lot of Python, and really like the cx_Oracle package. Again I was active in the mailing list, and contributed a few patches.
I've made a couple of software packages available that I had written for work. By making them open source, I was able to get some nice contributions back, and since they were not the "secret sauce" of my employers at the time, they didn't mind sharing the code. The two most popular packages were
http://sourceforge.net/projects/kap/ The Kinetic Application Processor -- this was built when I was working on the China Internet backbone.
http://code.google.com/p/orapig/ - OraPIG, the Oracle Python Interface Generator -- it generated Python code to call APIs defined in the database, and includes an XML-RPC database interface.
Advice:
Instead of looking for projects to join, try contributing to projects you already use.
It's often difficult to jump into the "core" development, because (a) on a big project, that might be a pretty big chunk of code to understand, and (b) there are probably a core group of people already working on it.
So, suppose you like a certain piece of software and want to start contributing, you can start working around the edges. Here's a couple of concrete tasks that will help you to become integrated with the group.
write some test cases for bugs to add to the regression test suite.
browse through the bug database and find a bug to work on. This might be the best way to get into the core development.
look at the feature request database and see if there's a small task you can work on.
look for "user doc" requests... a lot of them involve writing example code which you can provide.
Good luck!
The way people normally get involved is:
you use the FOSS product in your day to day work
you notice a problem or a missing feature
you mail the maintainer to ask if this bug/missing feature is real
the maintainer says yes, this is a bug/missing feature
you decide to try to fix/add the bug/feature
you code like mad
you submit a patch to the maintainer
the maintainer laughs in or face or says "thanks very much!
If you repeat the last few steps a few times, the maintainer will probably give you commit access to the project's RCS repository, and then you can really become dangerous. But the bottom line is that it is up to you to do something i.e. write some code - merely being "interested" in a project is not enough.
I joined DiSo and Greasemonkey.
The best way I've found to get involved is to get in early in the life of the project, or just be very interested. With DiSo or the various github projects I'm on, it was the former, with my Greasemonkey contributions, the latter.
Looking for a project to contribute to is often not the right way. Use stuff and find out what you want to build/fix, then do that.
I did a little bit of patch work on GnuCash since my wife restarted work part-time recently after our kids were a little more grown up.
I would've rather had my eyes ripped out with a hot poker than re-install Windows but GnuCash was missing something that [a certain other accounting package] had so I told her I'd get it added.
As it turns out, they took my patch and made it a lot better before putting it in (to the point where maybe 1% of the final patch was my stuff) but at least we can now use GnuCash instead of that proprietary stuff. They were also incredibly responsive - from patch submission to patch availability was only a week or so and it was in the product three weeks later.
I also once investigated getting a patch into the process accounting in the Linux kernel but the effort required far outweighed my needs :-)
I don't contribute on a regular basis, more as-needed (find your itch and scratch it). There are some who make a hobby of it but I'd rather be spending my spare time with the kids and, unfortunately, my employer won't pay me to contribute elsewhere.
That last bit particularly galled me since:
the Linux patch would have greatly assisted our product (and a lot of others).
it was change in behavior of another of our products that degraded the usefulness of our product.
the solution was fairly simple, conceptually (the effort required was testing since a problem would have been high-impact [task switching] and very pervasive [everyone using Linux]).
it would have been quicker to code up the patch than the workaround we eventually implemented.
the workaround is a kludge (p'tooee).
now, nobody in the world has the benefit of our patch (including us).
What I did was pretty simple; I opened one.
I have been joined by one permanent developer, and other two who donate code behind the scenes. The project is in very early stages, so not many users have downloaded it.
What really helps an open source project is having a plugin architecture.
It's much easier to contribute a simple plugin for eg. a file format than to try to add something to the Linux kernel. This makes it a lot quicker and easier to build a community.
TODO: Please supply an anecdote.

Nightly Builds: Why should I do it? [closed]

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Why should I do Nightly Builds?
You should do nightly builds to ensure that your codebase stays healthy.
A side effect of doing nightly builds is that it forces the team to create and maintain a fully automated build script. This helps to ensure that your build process is documented and repeatable.
Automated builds are good at finding the following problems:
Somebody checked in something that breaks stuff.
Somebody forgot to check in a necessary file or change.
Your build scripts no longer work.
Your build machine is broken.
Doing this nightly ensures that you catch such problems within 24 hours of when they occur. That is preferable to finding all the problems 24 hours before you are supposed to deliver the software.
You should also, of course, have automated unit tests that are run for each nightly build.
I've personally found continuous integration to be better than nightly builds:
http://en.wikipedia.org/wiki/Continuous_integration
I even use it on one man projects, it's amazing how fast you can expose issues and take care of them right there.
I've been doing build engineering (among other things) for 16 years. I am a strong believer in build-early, build-often, continuous integration. So the first thing I do with a project is establish how it will be built (Java: Ant or Maven; .NET: NAnt or MSBuild) and how it will be managed (Subversion or some other version control). Then I'll add Continuous Integration (CruiseControl or CruiseControl.NET) depending upon the platform, then let the other developers loose.
As the project grows, and the need for reports and documentation grows, eventually the builds will take longer to run. At that point I'll split the builds into continuous builds (run on checkin) that only compile and run unit tests and daily builds that build everything, run all the reports, and build any generated documentation. I may also add a delivery build that tags the repository and does any additional packaging for a customer delivery. I'll use fine-grained build targets to manage the details, so that any developer can build any part of the system -- the Continuous Integration server use the exact same build steps as any developer. Most importantly, we never deliver a build for testing or a customer that wasn't built using the build server.
That's what I do -- here's why I do it (and why you should too):
Suppose you have a typical application, with multiple projects and several developers. While the developers may start with a common, consistent development environment (same OS, same patches, same tools, same compilers), over the course of time their environments will diverge. Some developers will religiously apply all security patches and upgrades, others won't. Some developers will add new (maybe better) tools, others won't. Some will remember to update their complete workspace before building; others will only update the part of the project they're developing. Some developers will add source code and data files to the project, but forget to add them to source control. Others will write unit tests that depend upon specific quirks of their environment. As a consequence, you'll quickly see the ever-popular "Well, it builds/works on my machine" excuses.
By having a separate, stable, consistent, known-good server for building your application, you'll easily discover these sorts of problems, and by running builds from every commit, you'll be able to pinpoint when a problem crept into the system. Even more importantly, because you use a separate server for building and packaging your application, it will always package everything the same way, every time. There is nothing worse than having a developer ship a custom build to a customer, have it work, and then have no idea how to reproduce the customizations.
When I saw this question, first I searched for Joel Spolsky's answer. Bit disappointed, so I planned to add it here.
Hope everyone is aware of Joel Test on Careers.
From his blog on The Joel Test: 12 Steps to Better Code
3. Do you make daily builds?
When you're using source control, sometimes one programmer
accidentally checks in something that breaks the build. For example,
they've added a new source file, and everything compiles fine on their
machine, but they forgot to add the source file to the code
repository. So they lock their machine and go home, oblivious and
happy. But nobody else can work, so they have to go home too, unhappy.
Breaking the build is so bad (and so common) that it helps to make
daily builds, to insure that no breakage goes unnoticed. On large
teams, one good way to insure that breakages are fixed right away is
to do the daily build every afternoon at, say, lunchtime. Everyone
does as many checkins as possible before lunch. When they come back,
the build is done. If it worked, great! Everybody checks out the
latest version of the source and goes on working. If the build failed,
you fix it, but everybody can keep on working with the pre-build,
unbroken version of the source.
On the Excel team we had a rule that whoever broke the build, as their
"punishment", was responsible for babysitting the builds until someone
else broke it. This was a good incentive not to break the build, and a
good way to rotate everyone through the build process so that everyone
learned how it worked.
Though I haven't got an opportunity to make daily builds, I'm a great fan of it.
Still not convinced? Check out the brief here in Daily Builds Are Your Friend!!
You don't actually, what you should be wanting is Continuous Integration and automatic testing (which is a step further than nightly builds).
If you are in any doubt you should read this article by Martin Fowler about Continuous Integration.
To summarize, you want to build and test as early and often as possible to spot errors immediately so they can be fixed while what you were trying to achieve when you caused them is still fresh in your mind.
I'd actually recommend to do builds every time you check in. In other words, I'd recommend setting up a Continuous Integration system.
The advantages of such a system and other details can be found in Fowler's article and on the Wikipedia entry among other places.
In my personal experience, it's a matter of Quality Control: every time code (or tests, which can be seen as a form of requirements) are modified, bugs might be creeping in. To ensure quality you should make a fresh build of the product as it would be shipped and perform all the tests available. The more often this is done, the less likely bugs will be allowed to form a colony. Therefore, daily (nightly) or continuous cycles are preferred.
In addition, whether you restrict access o your project to developers or a larger group of users, a nightly build enables everyone to be on the 'latest version', minimizing the pain of merging their own contributions back into the code.
You want to do builds on a regular schedule in order to catch problems with integration of code between developers. The reason you want to do this nightly, as opposed to weekly or on some longer schedule, is that the longer you wait to discover these kinds of problems, the more difficult it will be to resolve them. The practice of doing a build on every check in (Continuous Integration) is just taking the nightly build process to a logical extreme.
The side benefit of having a repeatable build process is important in the long run as well. If you work on a team where there are multiple projects going on, then at some point you will need to be able to easily recreate an old build, perhaps for creating a patch. :(
The more you can automate the build process, the more time you will save for each subsequent build. It also takes the build process itself off of the critical path of delivering the final product, which should make your manager happy. :)
It also depends on the size and structure of the team(s) working on your project. If there are different teams relying on each others API, it may make a lot of sense to have nightly builds for frequent integration. If you're hacking away with only one or two team mates it may or may not be worth it.
Depending on the complexity of your product continuous integration may or may not be able run a full test suite.
Imagine Cisco testing a router with the literally 1000s of different setups to test. To run a full test suite on some products takes time. Sometimes weeks. So you need builds for different purposes. A nightly build can be the basis for a more thorough test suite.
I think they are very important especially on projects with more than 1 person. The team needs to know ASAP if someone:
checks in a bad file
doesn't check in a file
...
Any build automation is better than no build automation :-)
Personally, I prefer daily builds - that way if the build doesn't work then everyone is around to get it fixed.
In fact, if at all possible then Continuous Integration builds are the way to go (i.e. a build on every check-in) as that minimizes the amount of change between a build and so makes it easy to tell who broke the build and also easy to fix the build.
Well ... I guess it depends a lot on your project, of course. If it's just your hobby project, with no releases, no dependencies, and noone but you submitting code, it might be overkill.
If, on the other hand, there's a team of developers all submitting code, automatic nightly builds will help you ensure the quality of the code in the repository. If someone does something that "breaks the build" for all others, it will quickly be noticed. It is possible to break the build without noticing, for instance by forgetting to add a new file to the repository, and nightly builds in a centralized location will detect these quite quickly.
There are of course other possible benefits, I'm sure others will supply them. :)
Nightly builds are only necessary for significantly large projects (when it takes too long to build it often throughout the day). If you have a small project that does not take long to build you can build it as you get functional pieces of code done so that you know that you did not mess anything up in the procees. However, with larger projects this is not possible so it is important to build the project just so that you know that everything is still in working order
There are several reasons, some will be more applicable than others
If your project is being worked on by two or more people
It's a good way to grab the latest version of code that you aren't working on
A nightly build provides a slice in time of the current state of the code
A nightly build will give you a stable build if you need to send code to people
Nightly builds aren't always necessary - I think they're only really useful on big projects. But if you're on a big project, a nightly build is a good way of checking that everything is working - you can run all your tests (unit tests, integration tests), build all your code - in short, verify that nothing is broken in your project.
If you've got a smaller project your build and test times will be shorter so you can probably afford to do more regular builds.
Nightly builds are ideal for performing static code analysis (see qalab and the projects it collects stats from if you are in java world). Unfortunately, this is something that's rarely done.