Backing up your TFVC and Git Source from VSTS

calendarApr 20, 2018 · 3 min read · VSTS VSTS  ·
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The Issue

Azure is a highly resilient service, and VSTS has excellent SLAs. However, a question that is often asked is ‘How do I backup my VSTS instance?’. The simple answer is you don’t. Microsoft handle keeping the instance up, patched and serviceable. Hence, there is no built in means for you to get a local copy of all your source code, work items or CI/CD definitions. Though there have been requests for such a service. This can be an issue for some organisations, particularly for source control, where there can be a need to have a way to keep a private copy of source code for escrow, DR or similar purposes.

A Solution

To address this issue I decided to write a PowerShell script to download all the GIT and TFVC source in a VSTS instance. The following tactics were used

  • Using the REST API to download each project’s TFVC code as a ZIP file. The use of a ZIP file avoids any long file path issues, a common problem with larger Visual Studio solutions with complex names
  • Clone each Git repo. I could download single Git branches as ZIP files via the API as per TFVC, but this seemed a poorer solution given how important branches are in Git.

So that the process was run on regular basis I designed it to be run within a VSTS build. Again here I had choices:

  • To pass in a Personal Access Token (PAT) to provide access rights to read the required source to be backed up. This has the advantage the script can be run inside or outside of a VSTS build. It also means that a single VSTS build can backup other VSTS instances as long as it has a suitable PAT for access
  • To use the System Token already available to the build agent. This makes the script very neat, and PATs won’t expire, but means it only works within a VSTS build, and can only backup the VSTS instance the build is running on.

I chose the former, so a single scheduled build could backup all my VSTS instances by running the script a number of time with different parameters

To use this script you just pass in

  • The name of the instance to backup

  • A valid PAT for the named instance

  • The path to backup too, which can be a UNC share assuming the build agent has rights to the location

What’s Next

The obvious next step is to convert the PowerShell script to be a VSTS Extension, at this point it would make sense to make it optional to use a provided PAT or the System Access Token. Also I could add code to allow a number of multiple cycling backups to be taken e.g. keep the last 3 backups These are maybe something for the future, but they don’t really seems a good return in investment at this time to package up a working script as an extensions just for a single VSTS instance.