Friday, March 20, 2015

Quick notes on using git (gitolite) + NetBeans + ssh keys

Most of my posts (hopefully) talk about something that might be useful/helpful to others. Others are to help me not repeat a mistake. This is one of the latter ones; don't expect it to be very impressive. Really. Just look the other way, or at least have the decency of waiting until to laugh at my expense. Deal?

If you remember, I setup a git server using gitolite and docker not long ago. And then I found out one of the future users wanted to access it using NetBeans in Windows. As I have never used that IDE before, I looked in its website and found some info on how to make it talk to github. Well that sounded promising. First place I got stuck was creating the ssh key pair. You see, I know how to use ssh-keygen in Linux/Unix/OSX, but did not know how to do that in Windows. I could install cygwin and do it command line, and that would be great for me but not as nice for a typical Windows user. And, I would be installing a lot of crap this user did not need.

Searching around the net, I found a quick article about how to generate a ssh key on windows using putty (that is exactly how it is called). Now we are making progress; we just need to go and get puttygen, whcih can be obtained by itself, and create the keys. Following the last link, I created a key pair -- 4092 SSH2 RSA without passphrase since this is a test -- as shown in the picture on the left (you can click on it to make it bigger or something). Note the field I highlighted; I will refer to it later. For now, let's ignore that.

Here is the second place I screwed up. At first I thought the buttons to export the public and private keys were what I needed. So, I clicked on them and saved the files. The fact it wanted to give the private key the extension .ppk should have woken me up, but I dozed through that. Completely.

But, as I completely ignored that warning sign, I went back to the NetBeans Instructions and put the private key where it should be. And then I put the public key in my gitolite server. And then tried.

And it did not work.

So I decided to take a look at the keys. Here is the private one (trimmed out a bit to show the format while keeping this article small):

PuTTY-User-Key-File-2: ssh-rsa
Encryption: none
Comment: rsa-key-20150320
Public-Lines: 12
Private-Lines: 28
Private-MAC: 56aa3a9bcb05a65a89110a5de990d5021cfb9273

It sure does not look like the ones I created using ssh-keygen. The public key also looked a bit different. Then it hit me: because gitolite uses openssh, it expects the key to be puttygen is exporting the keys in a different format. So, how do we make this work? Well, do you remember the field I highlighted in the first picture? That is the public key already in the ssh format; that is what gitolite needs. So, cut-n-paste that to, say, inside the keydir directory in the gitolite config file.

Next is to export the private key in the right format. That is done by clickign on Conversions->Exporting OpenSSH key, naming it as something helpful; I named mine smurf_rsa to remind me I happened to have created a RSA key.

Time to go back to Netbeans. The picture on the left shows the setup I used. I was in a hurry so I used the testing repo, which is a bit of a village bicycle in my server: everyone who can connect to localgit can access, read, and write to and in general monkey with it. The key was fed and then I told it to finish. This time it worked or seemed to: proceeded to want me to create a project (with all the little files and directories the IDE creates). I let it do the deed and later on was able to check out what was created.

The moral of this tale is make sure you use the right key format or things will get very interesting. Either that or only drink warm beer if the fridge was built by Lucas, the Prince of Darkness. Or something like that. On the bright side, you managed to reach the end of this tale! You now may put your seat and tray in the upright position and start to laugh.

I did.

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