Runtime layer builds into a single .psm1 file

[austoonz]

Description of changes:

Updated the pwsh-runtime layer build process, such that all .ps1 script files are built into the pwsh-runtime.psm1 module file. This speeds up the time taken to load the module as there is no evaluation of the file system or dot-sourcing of script files. This change reduces AWS Lambda init times.

When tested with a small sample size of cold start executions (ten execution before and after), with a Lambda Function configured with 1024MB of memory, this change improves Init Duration by ~200ms on average.

Testing

The data shows the Init Duration decreases when using a combined pwsh-runtime.psm1 file. The data shows a faster minimum, a faster maximum and a lower average Init Duration.

PS> $output = foreach ($group in ($data | Group-Object -Property Psm1Format)) {
  $measured = $group.Group.InitDuration | Measure-Object -Average -Maximum -Minimum
  [PSCustomObject]@{
    Name = $group.Name
    Maximum = $measured.Maximum
    Minimum = $measured.Minimum
    Average = $measured.Average
  }
}
$output | Format-Table

Name      Maximum  Minimum  Average
----      -------  -------  -------
Combined 1312.510  998.160 1139.207
Separate 1496.960 1176.150 1334.301

The raw init duration data in CSV format:

PS> $data | ConvertTo-Csv -NoTypeInformation

"Timestamp","Psm1Format","InitDuration"
"6:58:22 PM","Separate","1300.3"
"6:58:16 PM","Separate","1176.15"
"6:58:10 PM","Separate","1372.58"
"6:58:04 PM","Separate","1388.13"
"6:57:58 PM","Separate","1293.61"
"6:57:51 PM","Separate","1330.09"
"6:57:45 PM","Separate","1301.94"
"6:57:38 PM","Separate","1382.89"
"6:57:31 PM","Separate","1300.36"
"6:57:24 PM","Separate","1496.96"
"6:52:41 PM","Combined","1312.51"
"6:52:34 PM","Combined","1054.31"
"6:52:28 PM","Combined","1014.99"
"6:52:21 PM","Combined","1147.13"
"6:52:15 PM","Combined","1044.26"
"6:52:09 PM","Combined","1142.47"
"6:52:02 PM","Combined","998.16"
"6:51:56 PM","Combined","1194.04"
"6:51:49 PM","Combined","1235.42"
"6:51:41 PM","Combined","1248.78"

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