VSO(TFS) - get current date time as variable - deployment

Question

How can I get a current date-time and pass it as a variable to some Deployment task?

Answer 1

You can define a variable with any value, and then modify the variable as current date. Detail steps as below:
Define a variable in release
Assume the variable name is time, and we set the value as none. If you need to use the variable for a environment, you can define it in environment variables. Else you should define it in variables Tab.
Add a power shell task at the begin of deploy tasks:
Type: Inline Script.
Inline script:
$date=$(Get-Date -Format g);
Write-Host "##vso[task.setvariable variable=time]$date"
Note:
I use the date format as MM/DD/YYYY HH:MM AM/PM here. You can use other date formats.
For the subsequent deploy task, if you want to use current date time, you can direct use $(time).
Update
Documentation for Defining Variables: Set Variables Using Expressions has a nugget of gold for the answer to this question in the example for creating a counter value that is reset daily.
a: $[counter(format('{0:yyyyMMdd}', pipeline.startTime), 100)]
The pipeline.startTime variable used here is subtle and not mentioned anywhere in the Pipeline Predefined Variables documentation, even when being careful to land on the correct documentation based on the pipeline method being used. As is suggested HERE and in some of the answers on this thread, certain variables may have different values or not exist at all depending on where you are while trying to access them.

Answer 2

There is now a variable specific to a release stage named "Release.Deployment.StartTime" or if you use it in powershell the environment variable is "Release_Deployment_StartTime".
It's in UTC and the format is "yyyy-MM-dd HH:mm:ssZ"
ex: "2018-11-09 21:23:27Z"
NOTE: This variable is set at the time the deployment stage is started, so if you have pre-deployment approvals the time will be set before any approvals are completed. From my testing if you have multiple stages that execute at the same time it will be the same between them, even if one stage waits for the other due to limited agent availability.
I'm using Azure DevOps online, unsure if local TFS installations will have this.

Answer 3

For those who use Linux on tfs:
Define variable
Make sure it has "Settable at queue time set"
Create a script in root of your repository
set-build.date.sh:
#!/usr/bin/env bash
DATE=$(date '+%d/%m/%Y %H:%M:%S')
echo "##vso[task.setvariable variable=BUILD_DATE;]$DATE"
Other options are listed here.
Add shell script right after get sources
Type bash to find this task.
Done, you can use BUILD_DATE variable in later tasks :)

Answer 4

An easier way is
$(Date:MMddyy)
Some options are only available in the Build Definition options section. The date formatting is one of them. However, if you were to go into the options section, set the build number format as $(Date:yyyyMMdd-HHmmss), you could then use the $(Build.BuildNumber) variable in your tasks.
More info here - https://learn.microsoft.com/en-us/vsts/build-release/concepts/definitions/build/variables?tabs=batch

Answer 5

Based on answer of Marina Liu (here) for quick copy and paste.
Define variable on top:
variables:
buildTimeStamp: # will be set by script
# ...
Add this as first task (and change format as needed):
- task: PowerShell#2
displayName: set variable buildTimeStamp
inputs:
targetType: 'inline'
script: |
$date=$(Get-Date -Format yyyy-MM-dd_HH.mm);
Write-Host "##vso[task.setvariable variable=buildTimeStamp]$date"
Now you can use variable $(buildTimeStamp) in your code below.