The blogs of Black Marble staff

Fix for my Docker image create dates being 8 hours in the past

I have been having a look at Docker for Windows recently. I have been experiencing a problem that when I create a new image the created date/time (as shown with docker images) is 8 hours in the past.


Turns out the problem seems to be due to putting my Windows 10 laptop into sleep mode. So the process to see the problem is

  1. Create a new Docker image – the create date is correct, the current time
  2. Sleep the PC
  3. Wake up the PC
  4. Check the create date, it is now 8 hours off in the past

Now the create date is not an issue in itself, but the fact that the time within the Docker images is also off by 8 hours can be, especially when trying to connect to cloud based services. I needed to sort it out

Turns out the fix is simple, you need to stop and restart the Docker process (or restarting the PC has the same effect as this restarts the Docker process). Why the Docker process ends up 8 hours off, irrespective of the time the PC is slept, I don’t know. Just happy to have a quick fix.

I am speaking at Microsoft UK TechDays Online event on Azure DevTest Labs

The registration link for Microsoft UK TechDays Online is now live. This is a 5 day event live broadcast from the Microsoft Campus in Reading. You will be able to view the sessions live at

The themes for each day are:

  • Monday, 12 September: Explore the world of Data Platform and BOTs
  • Tuesday, 13 September: DevOps in practice
  • Wednesday, 14 September: A day at the Office!
  • Thursday, 15 September: The inside track on Azure and UK Datacenter
  • Friday, 16 September: Find out more about Artificial Intelligence

I am doing a session on the Thursday on Azure DevTest Labs.

Hope you find time to watch some or all of the events. For more details see the registration link

Why have I got a ‘.NETCore50’ and a ‘netcore50’ folder in my nuget package?

I recently posted on how we were versioning our Nuget packages as part of a release pipeline. In test we noticed that the packages being produced by this process has an extra folder inside them.


We expected there to be a netcore50 folder, but not a .NETCore50 folder. Strangely if we build the package locally we only saw the expect netcore50 folder. The addition of this folder did not appear to be causing any problem, but I did want to find out why it had appeared and remove it as it was not needed.

Turns out the issue was the version of Nuget.exe, the automatically installed version on the on-prem TFS build agent was 3.2, my local copy 3.4. As soon as I upgraded the build box’s nuget.exe version to 3.4 the problem went away

Experiences versioning related sets of NuGet packages within a VSTS build


We are currently packaging up a set of UX libraries as NuGet packages to go on our internal NuGet server. The assemblies that make up the core of this framework are all in a single Visual Studio solution, however it makes sense to distribute them as a set of NuGet packages as you might not need all the parts in a given project. Hence we have a package structure as follows…

  • BM.UX.Common
  • BM.UX.Controls
  • BM.UX.Behaviours
  • etc…

There has been much thought on the versioning strategy of these packages. We did consider independent versioning of each of these fundamental packages, but decided it was worth the effort, keeping their versions in sync was reasonable  i.e. the packages have the same version number and are released as a set.

Now this might not be the case for future ‘extension’ packages, but it is an OK assumption for now, especially as it makes the development cycle quicker/easier. This framework is young and rapidly changing, there are often changes in a control that needs associated changes in the common assembly; it is hence good that a developers does not have to check-in a change on the common package before they can make an associated changed to the control package whist debugging a control prior to it being released.

However, this all meant it was important to make sure the package dependencies and versions are set correctly.


We are using Git for this project (though this process is just as relevant for TFVC) with a development branch and a master branch. Each branch has its own CI triggered build

  • Development branch build …
    • Builds the solution
    • Runs Unit tests
    • Does SonarQube analysis
    • DOES NOT store any built artifacts
    • [Is used to validate Pull requests]
  • Master branch build …
    • Versions the code
    • Builds the solution
    • Runs Unit tests
    • Creates the NuGet Packages
    • Stores the created packages (to be picked up by a Release pipeline for publishing to our internal NuGet server)


So within the Master build we need to do some versioning, this needs to be done to different files to make sure the assemblies and the NuGet packages are ‘stamped’ with the build version.

We get this version for the build number variable, $(Build.BuildNumber), we use the format $(Major).$(Minor).$(Year:yy)$(DayOfYear).$(rev:r)  e.g. 1.2.16123.3


  • $(Major) and $(Minor) build variables we manage (actually our release pipeline updates the $(Minor) on every successful release to production using a VSTS task)
  • $(Year:yy)$(DayOfYear) gives a date in the form 16123
  • and $(rev:r) is a count of builds on a given day

We have chosen to use this number format to version both the assemblies and Nuget packages, if you have different plans, such as semantic versioning , you will need to modify this process a bit.


The assemblies themselves are easy to version, we just need to set the correct value in their assemblyinfo.cs or assemblyinfo.vb files. I used my Assembly versioning VSTS task to do this

NuGet Packages

The packages turn out to be a bit more complex. Using the standard NuGet Packager task there is a checkbox to say to use the build number as the version. This works just fine versioning the actual package, adding the –Version flag to the package command to override the value in the project .nuspec file. However it does not help with managing the versions of any dependant packages in the solution, and here is why. In our build …

  1. AssemblyInfo files updated
  2. The solution is built, so we have version stamped DLLs
  3. We package the first ‘common’ Nuget package (which has no dependencies on other projects in the solution) and it is versioned using the –version setting, not the value in it’s nuspec file.
  4. We package the ‘next’ Nuget package, the package picks up the version from the –version flag (as needed), but it also needs to add a dependency to a specific version of the ‘common’ package. We pass the –IncludeReferencedProjects  argument to make sure this occurs. However, Nuget.exe gets this version number from  the ‘common’ packages .nuspec file NOT the package actually built in the previous step. So we end up with a mismatch.

The bottom line is we need to manage the version number in the .nuspec file of each package. So more custom VSTS extensions are needed.

Initially I reused my Update XML file task, passing in some XPath to select the node to update, and this is a very valid approach if using semantic versioning as it is a very flexible way yo build the version number. However, in the end I added an extra task to my versioning VSTS extension for Nuget to make my build neater and consistent with my other versions steps.

Once all the versioning was done I could create the packages. I ended up with a build process as shown below


A few notes about the NuGet packaging

  • Each project I wish to create a Nuget package for has a nuspec file of the same ‘root’ name in the same folder as the csproj eg. mypackage.csproj and mypackage.nuspec. This file contains all descriptions, copyright details etc.
  • I am building each package explicitly, I could use wildcards in the ‘Path/Pattern to nuspec files’ property, I choose not to at this time. This is down to the fact I don’t want to build all the solution’s package at this point in time.
  • IMPORTANT I am passing in the .csproj file names, not the .nuspec file names to the ‘Path/Pattern to nuspec files’ property. I found I had to do this else the   –IncludeReferencedProjects  was ignored. The Nuget documentation seems to suggest as long as the .csproj and .nuspec files have the same ‘root’ name then you could reference the .nuspec file but this was not my experience
  • I still set the flag to use the build version to version the package – this is not actually needed as the .nuspec file has already been update
  • I pass in the  –IncludeReferencedProjects  argument via the advanced parameters, to pick up the project dependancies.


So now I have a reliable way to make sure my NuGet packages have consistent version numbers 

Tidy up those VSTS release pipelines with meta-tasks

Do you have repeating blocks in your VSTS release pipelines?

I certainly do. A common one is to run a set of functional test, so I need to repeatedly …

  1. Deploy some test files to a VM
  2. Deploy a test agent to the VM – IMPORTANT I had not realised you can only run one test run against this deployed agent. You need to redeploy it for the next run
  3. Run my tests
  4. … and repeat for next test type/configuration/test plan/DLL etc.


In the past this lead to a lot of repeat tasks in my release pipeline, all very messy.

Now in VSTS we have the option of  Meta-tasks, these allow tasks to be grouped into in-effect functions with their own properties.



In the above screen shot below you can see I use a meta-task ‘Run Tests’ that wrappers the four tasks shown below.


Much neater, but as you might expect with something new I have come across a few minor gotchas

  • You cannot order the list of properties for the meta-task
  • This is a problem as the first one is used to generate the instance name in the pipeline. No a major problem you can always edit it.
  • Meta-tasks properties are auto-detected from any variables used with in the meta-task tasks, the auto-detection mechanism is case sensitive, unless the rest of VSTS variable handling. So be careful to not end up with duplicates.

That all said, I think this is big step forward in readability and reuse for release management

New version of my generate release notes task–now with authentication options

I have just released 1.4.7 of the release notes VSTS extension. This provides a new advanced options that allows you to switch the authentication model.

The default remains the same i.e. use a personal access token provided by the server, but you have the option to enable use of the 'defaultcredentials' (via the advanced properties). If this is done the account the build agent is running as is used. Hopefully this should fix the 401 issues some people have been seeing when using the task with on-prem TFS.

For most people the default PAT model should be fine

Windows 10 Anniversary (Build 1607) messed up my virtual NAT Switch – a fix

I use a virtual NAT Switch to allow my VMs to talk to the outside world. The way I do this is documented in this post, based on the work of  Thomas Maurer. The upgrade to Windows 10 Anniversary messed this up, just seemed to loose the virtual network completely, VMs failed to start with invalid configurations and would not even start.

I had to recreate my NATSwitch using Thomas’s revised instructions, but I did have an problem. The final ‘New-NetNat’ command failed with  a ‘The parameter is incorrect.’ error. I think the issue was that there was debris left from the old setup (seems Microsoft removed the NatSwitch interface type). I could find no way to remove the old NATSwitch as it did not appear in the list in PowerShell and there is no UI remove option. So I just ended up disabling it via the UI and this seemed to do the trick


My VMs seem happy again talking to the outside world

Out with the Band in with the Garmin

I have been using the Microsoft Band (both version Band1 and Band2) since they came out, and been reasonably happy. However, a year or so on my issues with it have remained the same

  • Poor battery life, I can live with charging it each day, but even with GPS Power-saver mode on I can’t go for any exercise over about 4 hours (bit of an issue for longer bike rides)
  • It is not waterproof, so no swimming (and worried doing the washing up)

Also there seem to be some build issues with the robustness of the Band2. I had to get mine replaced due to it not accepting recharging and the forums seems to report people suffering problems with the wrist strap splitting. That said, the warrantee service seems excellent, no complaints there, mine was swapped without any issue in a couple of days

In the end however, I decided it was time to to check out alternatives and picked the Garmin Vivoactive HR; basically the Garmin equivalent to the Band in feature set and price (it is a little more expensive in the UK)




I have to say a couple of weeks in I am very pleased. It fixes those two major issues for me. Most importantly I seem to need charging it only about every 5 days or so, that is with with an hour or two of full activity tracking each day. The specs claim 10 hour+ for full activity tracking on a charge. Also it is waterproof and allows activity tracking for pool based swimming (swim mode is lap based and has no GPS enabled so less use for open water).

That all said there are still issues

  • The Bluetooth link to my Windows Phone 10 is a little temperamental for things like notifications and sync -  a restart usually fixes everything (but hey it fully supports Windows Phone 10 not just Android and iPhone!)
  • Shame they disable heart rate monitor for swimming (signal not reliable enough, unless you pair with a chest strap it seems)
  • Lack of open water swimming tracking (see above – but of you want full multisport tracking look at the Garmin 920XT, their top of the range watch it does it all)

But I think these are all minor issues for me, and the third party apps store for the device help such as adding triathlon support which attempts HR monitoring for swimming, without needing to upgrade to the 920XT.

So a good alternative to theBand2?

For me yes, it addresses my key issues. Band2 is a good fitness tracker with unique styling, but if swimming or longer activities are your thing I think the Garmin Vivoactive HR has it.