Using GitHub Two Factor Authentication (2FA) with TeamCity

If you have two factor authentication (2FA) set up in GitHub and you also want to use TeamCity, the easiest way to set this up is to set up SSH keys to access the GitHub repository.

The first step is to follow this guide to creating SSH keys for GitHub. Remember the passphrase you use when creating the key, you’ll need it later.

Once you have created your keys and applied it to your GitHub account you can then follow this guide for managing SSH keys in TeamCity.

Finally, when setting up your VCS Root in Team City you set the Fetch URL to the SSH variant. You can find this on your project page on Github towards the bottom of the right sidebar.

You may need to click the “SSH” link below the URL if it does not already show the SSH URL.

Back in Team City you can paste this URL in the Fetch URL box in the general settings. Further down the form in the Authentication Settings section you can specify the SSH key you uploaded earlier.

By specifying “Uploaded Key” the boxes below will change. Select the key you uploaded earlier, the user name is “git”, and enter the passphase you used when you created the SSH key.

You should now be able to test the connection to see if all is well.

Two Factor Authentication with GitHub and Visual Studio 2013

New job, new tools, new processes. In my new job we’re using GitHub for source control, and because the data is sensitive we’re also using two factor authentication. Because I develop with Visual Studio that presents and interesting issue if you are using Visual Studio 2013’s build in Git Source Control provider.

After turning on Two Factor Authentication, the next time you have to communicate with GitHub (e.g. pull/push/sync’ing, etc.) it will pop up a dialog asking for your credentials, even if you already entered them previously before turning on 2FA.

You get an error message that looks like this:

An error occurred. Detailed message: An error was raised by libgit2. Category = Net (Error).
Response status code does not indicate success: 401 (Authorization Required).

Entering your credentials won’t do you any good. It won’t work. It will just request them again, ad infinitum.

There is no where to enterthe 2FA code, so you can’t authenticate yourself here.

However, you can go to GitHub and create a personal access token in order that Visual Studio 2013 can access your repositories.

You can either drop down the menu on your avatar and go to “Settings”, then go to “Personal Access Tokens” (link in the side bar) or you can just go hereĀ https://github.com/settings/tokens.

Then click on “Generate New Token”. You’ll be asked for your credentials again just to be sure you are still you.

Once you’ve done that you’ll be taken to the page to create your credentials

For what Visual Studio wants the default permissions are fine. Also, give the token an appropriate name so it can be identified easily.

Then press “Generate token”.

You will then be taken back to the “Personal access tokens” page. This time there is a new token which you can use in Visual Studio. Be careful here, this is the one and only time you will be able to access this token so copy it and keep it safe.

Back in Visual Studio try and sync the commits to GitHub. It will pop up the credentials dialog again. This time you are going to enter the token in the username box and leave the password box blank.

Then press OK.

Finally, your changes will sync with GitHub and you’ll get a success message.