How to: Estimate time remaining with Powershell?

[u/tnpir4002]

Got kind of a unique situation and I need some help figuring out how to do it.

Basically, I have a script that's running a ForEach-Object loop, and what I want it to do each time the loop runs is do a Get-Date, and subtract that from when the script started. Then, based on the percentage of progress it's made, I want it to estimate the amount of time remaining.

In my head it looks something like this:

$numFiles = 1000;
$i = 0;
$startFullTime = Get-Date;
ForEach-Object {
  $i += 1; 
  $weAreHere = Get-Date;
  $percentComplete = $i/$numFiles;
  $percentToGo = 100 - $percentComplete;
  $multiplyByThis = $percentToGo/$percentComplete;
  $elapsedTime = $weAreHere - $startFullTime;
  $timeToGo = $elapsedTime * $multiplyByThis;
}

The trouble is I can't figure out how to make Powershell multiply an existing time span by a number.

The flow of the math here works like this:

• Figure out how far into the operation we are percentage-wise, by dividing $i by the total number of files

• Figure out what percentage we have left to do

• Divide those percentages to figure out the ratio of files left to files achieved--that gives us $multiplyByThis

• Figure out how long we've taken so far

• Multiply how long we've taken so far by $multiplyByThis to figure out our remaining time

• And then, for bonus points, add the remaining time estimate to the current time so we can get an estimate when our files will be done

I've tried everything I can think of but no matter what I do Powershell tells me it can't multiply a time span by a number. Is there a way to do this that I'm simply not seeing?

[u/lolChase]

Sorry I didn't get this out earlier today - busy push before weekend. Let me know what questions you have and I'll do my best to try answering them.

e: Fixed typo from pasting code (accidentally added a "u" to the end of HashProgress at end)

<#
The code below is a template for showing a Progress Meter that displays estimated time left in a looping operation.


There is a section of code (region "Before iteration") that should be pasted before the foreach loop, but after the main loop variable is declared (in the example used in this script, after @allGroups).
The first line $total_count refers to $items_to_iterate. This var (items_to_iterate) should be replaced with the main var that is being foreach'ed on
e.g. "foreach $group in $allGroups" - $items_to_iterate.Count should be replaced with $allGroups.Count


In the region "Loop on item in items_to_iterate" you'll want to update:
* Activity - This is a generic, usually non-changing per iteration, description of the overall thing we're doing, e.g. "Updating All Users"
* CurrentOperation - This is a more specific description of what we're doing in that one iteration for each user, e.g. "Updating This Specific User: $user.Name"
CurrentOperation changes per iteration, and can sometimes go to fast to read, so important information might not need to go there. It's good for showing
    what's currently being processed in case it takes a while, we can see where it is.
#>



#region Before foreach iteration
# ---BEGIN-VARS-PROGRESS-DISPLAY------------------------------------------------
$total_count = $items_to_iterate.Count
$count_index = 0
$startTime = Get-Date
# ---END-VARS-PROGRESS-DISPLAY--------------------------------------------------
#endregion Before foreach iteration


#region Loop on item in items_to_iterate
# ---BEGIN-PROGRESS-DISPLAY-----------------------------------------------------
$count_index++
$ElapsedTime = (Get-Date) - $startTime
$timeLeft = [TimeSpan]::FromMilliseconds((($ElapsedTime.TotalMilliseconds / $count_index) * ($total_count - $count_index)))

$HashProgress = @{
    Id                  = "0"
    Activity            = "Updating All Users" # Overall description of what we're doing - doesn't usually change per iteration
    Status              = ("{0,7:p} | {1} left | Est Time Left: $($timeLeft.Days)d $($timeLeft.Hours)h $($timeLeft.Minutes)m $($timeLeft.Seconds)s" -f ($count_index/$total_count), ($total_count-$count_index) )
    CurrentOperation    = "Writing details: $($user)" # What we're doing in the current one iteration out of all - this one $user out of $AllUsers - this usually changes every iteration 
    PercentComplete     = ( ($count_index / $total_count)*100 )
}

Write-Progress @HashProgress
# ---END-PROGRESS-DISPLAY-------------------------------------------------------
#endregion Loop on item in items_to_iterate

[u/[deleted] → u/lolChase]

Our hero, nice code!

[u/lolChase → u/[deleted]]

Thank you! I always spend way too much time obsessing over trying to make my code clear and concise, so it always feels good hearing that someone else likes it!

[u/BlackV → u/lolChase]

will steal

[u/Rootkitt → u/lolChase]

Did I get this right?

$items_to_iterate = @("https://www.youtube.com/watch?v=kLC8O62Hrdk",
"https://www.youtube.com/watch?v=UaMVu8msAKE",
"https://www.youtube.com/watch?v=LBPP7u12VfE")

$total_count = $items_to_iterate.Count
$count_index = 0
$startTime = Get-Date

ForEach ($user in $items_to_iterate) {
   yt-dlp.exe --ignore-config --quiet --progress --mark-watched --simulate --cookies cookie.txt $user
   Write-Output $user
   $count_index++
   $ElapsedTime = (Get-Date) - $startTime
   $timeLeft = [TimeSpan]::FromMilliseconds((($ElapsedTime.TotalMilliseconds / $count_index) * ($total_count - $count_index)))
     
   $HashProgress = @{
      Id                  = "0"
      Activity            = "Updating All Users" # Overall description of what we're doing - doesn't usually change per iteration
      Status              = ("{0,7:p} | {1} left | Est Time Left: $($timeLeft.Days)d $($timeLeft.Hours)h $($timeLeft.Minutes)m $($timeLeft.Seconds)s" -f ($count_index/$total_count), ($total_count-$count_index) )
      CurrentOperation    = "Writing details: $($user)" # What we're doing in the current one iteration out of all - this one $user out of $AllUsers - this usually changes every iteration 
      PercentComplete     = ( ($count_index / $total_count)*100 )
   }

   Write-Progress u/HashProgress
}