Coding on a Budget

48 Hours with Joel and Jeff..

Sun, 12 Apr 2009 08:47:23 -0500

Joel Spolsky of FogCreek Software and Jeff Atwood of nothing have joined forces to push out StackOverflow. To generate hype and the all important critical mass, they record a weekly podcast. There are now 48 one hour long podcasts in the wild and I've listened to all of them while driving to Sweet Peppers so I can work on RoR-izing FollowMeIP.

At some point a conversation was had about how cool it would be to have a website that would cater to the asking and answering of programming questions - Stackoverflow was born. Atwood is project manager over a couple of .net programmers and Joel simply tells his readers about how cool it is. It's a great situation really, Atwood does all the work, spends the money, takes the risks and Joel sits back and waits for success or failure. Either way, Joel will have tons of new material to write about.

Atwood seems to be in control of the technology stack and server infrastructure. It's rather amusing at times to listen to his rationale on why he did certain things. Stackoverflow is using ASP.NET MVC, microsoft's answer to ruby on rails. He opted to use this stack which was in beta over the actual RoR stack. He's definitely a microsoft centric developer and every time he denies it, take a drink. It's also amusing listening to hardware issues he's having trying to run his own server. In podcast 48, Atwood said software raid is better than hardware raid. Having dealt with both - extensively - software raid is one big slow steaming pile of crap. With drive sizes in the 2tb now, a nice hardware pci-e raid 1 solution is what you want. It's clear Atwood hasn't had much experience with hardware and really should move his project to some sort of cloud before he runs out of money playing with different raid settings.

After listening to 48 hours of rambling a few things become clear:

The only reason to listen is to hear what Joel says.

Atwood mostly just says "right" or "I agree" randomly.

Joel is not a Linux fan.

Atwood doesn't understand FOSS.

Atwood hasn't "been around" as much as he'd like to think he has.

Atwood should stick to writing.

The stackoverflow podcast is no longer about stackoverflow.

So how is stackoverflow doing? Fine I suppose. People seem to be using it, but it doesn't matter because Atwood made one fatal mistake - not open sourcing it. After the initial release, people started asking the same question: can I spawn a stackoverflow for xzy? Why not a stackoverflow for automotive questions? Atwood has repeatedly said the site just can't be switched from programming questions to some other type of question. That means poor design or lack of vision - most likely a little of both. If you've been in computers your entire life it's rather hard to see value in anything else. They missed the boat and the flood gates are about to be opened.

CNProg.com has replicated stackoverflow and released it under the apache license. The motivation was to enable Chinese programmers the ability to use a site like stackoverflow which doesn't support anything but English. Once again the podcast provided a smile on my face when Joel started talking about copyright violation. Sure, it's copyright infringement if China followed U.S. copyright laws - and they don't. When the Chinese government owns and operates a Disney Land clone, I seriously doubt they're going to mind a stackoverflow clone.

I'm reasonably sure CNProg didn't take nearly as long to write and I'm guessing a decent ruby on rails developer could rewrite stackoverflow within a week. Considering Atwood's poor choice in technology stacks, my prediction is someone will clone stackoverflow using ruby on rails and release it under an open source license. This will enable people to create their own niche sites without debating with Atwood about what's possible.

Git server setup using gitosis for Centos 5.2

Sun, 15 Mar 2009 08:46:10 -0500

This is a step by step HOWTO to host git repositories using gitosis on a Centos 5.2 box. I'm currently working on a ruby on rails project with Ryan. The need for a source management solution was apparent and I've been using subversion for while. Of course I could make a new subversion repo in no time, my server is already setup, backups being done, and it just works - but according to Linus I was ugly and stupid. Ryan wants me to use git and I really didn't want to be ugly and stupid.

I go about searching the web for a git server howto and found that git wasn't really meant to used in a server/client situation, but more of a peer to peer environment. Gitosis was written to emulate that server/client environment I'm after. I also didn't see anything useful on google that was CentOS specific with setting up gitosis.

Here's how I did it..

Step 1 - (On your server)

Install python-setuptools on your server, you'll need it to install gitosis.

As root:

yum -y install python-setuptools

Step 2 - (On your server)

Install git. You'll need the DAG RPM repository for this one.

As root:

- Red Hat Enterprise Linux 5 / i386:

rpm -Uhv http://apt.sw.be/redhat/el5/en/i386/rpmforge/RPMS/rpmforge-release-0.3.6-1.el5.rf.i386.rpm

- Red Hat Enterprise Linux 5 / x86_64:

rpm -Uhv http://apt.sw.be/redhat/el5/en/x86_64/rpmforge/RPMS//rpmforge-release-0.3.6-1.el5.rf.x86_64.rpm

yum -y install git

Step 3 - (On your server)

Install gitosis.

As root:

git clone git://eagain.net/gitosis.git

(it should download stuff and create a gitosis directory)

cd gitosis

python setup.py install

Step 4 - (On your server)

Make a user called git.

adduser git

Give your new user git a password.

passwd git

Step 5 - (On your client)

The whole point of gitosis is to transfer files via ssh using a shared key process (ie: no password required to login to user git on your server). Now before you go and start doing it the manual way - don't. Gitosis must create and maintain the authorized_keys file.

As your normal user on your client/development box:

ssh-keygen -t rsa (take the defaults)

There is now a new file called id_rsa.pub in ~/.ssh/

Copy the id_rsa.pub file to the server:

scp ~/.ssh/id_rsa.pub git@someServer.com:/home/git/

Step 6 - (On your server)

I'm assuming you're still root on the server.

Change to the git user.

su git

cd /home/git

gitosis-init < id_rsa.pub

It should reply with Initialized empty Git repository in ./ - twice..

We can now remove id_rsa.pub as we don't need it anymore.

rm id_rsa.pub

Now we must set some directory and file permissions to let sshd see the new authorized_keys file.

chmod 755 /home/git

chmod 700 /home/git/.ssh

chmod 644 /home/git/.ssh/authorized_keys

Step 7 - (On your client)

We're pretty much done server side. Now we're going to configure the server via the client.

Although I assume this is obvious, you need to install git on your client machine.

git clone git@someServer.com:gitosis-admin.git

cd gitosis-admin

You should see a gitosis.conf file and keydir directory. Here's the thing, anything you need to configure on the server, you actually configure here and commit the changes to the server. Open up gitosis.conf in your favorite text editor

Make a new group name for your project. It really doesn't matter what you name this group. Add users to the member section who will need push access.

[group myTeam]

members = (copy and paste the user from the members = line in the [group gitosis-admin] section)

writable = myNewProject

Save the file. Why did we use that members=user@someServer.com? If you look in the keydir directory, you'll see your public key with the filename user@someServer.com.pub. These are your users (minus the .pub).

Step 8 - (On your client)

You've just made a configuration change. You want the server to allow user@someServer.com to have write access to a project called myNewProject. You must commit this change to the server.

git commit -a -m "Allow the machine I am on right now write access to myNewProject"

git push

Now it's time to make the directory that will contain your project files. Move up out of the gitosis-admin directory.

cd ..

mkdir myNewProject

cd myNewProject

git init

git remote add origin git@someServer.com:myNewProject.git

Add your files, move some files, create some files. Put some files in the myNewProject directory.

Now we can commit the initial push to the server.

git add .

git commit -a -m "This is my initial commit for myNewProject"

git push origin master:refs/heads/master

Git will do some neat things and push things to the server. Now to delete the directory you just created.. Yeah, I said it.

cd ..

rm -fr myNewProject

And now to pull myNewProject from the server using clone..

git clone git@someServer.com:myNewProject

Now you have a version of your code you can actually use, make changes and commit to the server using normal git commands.

As of now, you have a fully functioning git server with a project and a client that can make changes. But what about other people?

Step 9 - (On your client)

So your friend Bob wants to help you out with myNewProject. Have Bob generate his own id_rsa.pub and send it you. When you have it:

cd gitosis-admin

Assuming Bob's id_rsa.pub is in your home directory, move it to the key directory renaming it at the same time:

mv ~/id_rsa.pub keydir/bob.pub

Tell git about the new file:

git add keydir/bob.pub

Edit your gitosis.conf file again. Look for the members line in myNewProject and add Bob to it:

members = user@someServer.com bob

Now you could add bob to be in the gitosis-admin group if you wanted him to be able to do what you're doing now. How much do you trust Bob?

Save the file and quit. It's time to tell your server about Bob and send Bob's public key.

git commit -a -m "Added commit rights to Bob on myNewProject"

git push

The server will automatically add Bob's public key to authorized_keys. Do not attempt to add him manually.

Step 10 -

Do a little dance, you're done.

SSH without password HOWTO for CentOS 5.2

Sun, 15 Mar 2009 05:22:39 -0500

This one is short and sweet and is for CentOS 5.2 installs.

On the client machine generate a public key. Do this command as the user you normally run under:

ssh-keygen -t rsa (take the defaults)

There is now a new file called id_rsa.pub in ~/.ssh/

Copy the id_rsa.pub file to the server:

scp ~/.ssh/id_rsa.pub someUser@someServer.com:/home/someUser/

Log into the server:

ssh someUser@someServer.com

Append your client public key to authorized_keys:

cat ~/id_rsa.pub >> ~/.ssh/authorized_keys

Remove the client public key on the server, you don't need it anymore:

rm ~/id_rsa.pub

Set permissions on the server so sshd can see authorized_keys:

chmod 755 /home/someUser

chmod 700 /home/someUser/.ssh

chmod 644 /home/someUser/.ssh/authorized_keys

That's it, the next time you login to the server via the client it shouldn't ask for a password.