Azure Pipelines, iterate through files - azure

Question

In azure build pipeline, I'm trying to iterate through all the files that have extension .hex. The aim is to use every file the same way, but not knowing how many are there.
I receive an error from Azure :
Encountered error(s) while parsing pipeline YAML:
/azure-pipelines.yml (Line: 11, Col: 3): Unexpected symbol: '*'. Located at position 26 within expression: $(Build.SourcesDirectory)*.hex.
The Pipeline has been reduced to the minimum possible :
trigger: none
pool:
name: "LabelManagementPool"
steps:
- ${{ each filename in $(Build.SourcesDirectory)\*.hex}}:
- script: echo ${{ filename }}
What am I missing here ? Is what I want to achieve possible ?

Answer 1

Unfortunately it is not possible to do it this way as when the pipeline kicks of it will compile into a structure with all stages, jobs, etc defined. Since this path doesn't exist yet it can't be compiled.
The workaround would be to use another programming language, such as python or powershell, to obtain the list of files that match the decription. And then use it to loop over each file and perform whatever action you want it to run.
As an example, you could use the following in PowerShell to find all hex files and then would need to write additional code for looping over it and performing your desired task.
# Obtain list of all files that are hex
$files = Get-ChildItem "C:\repos\python" -Filter *.hex -Recurse | % { $_.FullName }
# Loop over every file
Foreach ($file in $files)
{echo $file}
The yaml would be this
- task: PowerShell#2
inputs:
targetType: 'inline'
script: |
# Obtain list of all files that are hex
$files = Get-ChildItem "$(Build.SourcesDirectory)" -Filter *.hex -Recurse | % { $_.FullName }
# Loop over every file
Foreach ($file in $files)
{echo $file}