#435: ability to set number of concurrent schedules

docs/Tutorials/Schedules.md

@@ -1,6 +1,6 @@
 # Schedules
 
-A Schedule in Pode is a long-running async task, and unlike timers, when they trigger they are run in their own separate runspace - so they don't affect each other if they take a while to process.
+A Schedule in Pode is a long-running async task, and unlike timers, when they trigger they are run in their own separate runspace - so they don't affect each other if they take a while to process. By default up to a maximum of 10 schedules can run concurrently, this can be changed by using the [`Set-PodeScheduleConcurrency`](../../Functions/Core/Set-PodeScheduleConcurrency) function.
 
 Schedule triggers are defined using [`cron expressions`](../Misc/CronExpressions), basic syntax is supported as well as some predefined expressions. Schedules can start immediately, have a delayed start time, and also have a defined end time.
 

examples/schedules-long-running.ps1

@@ -0,0 +1,26 @@
+$path = Split-Path -Parent -Path (Split-Path -Parent -Path $MyInvocation.MyCommand.Path)
+Import-Module "$($path)/src/Pode.psm1" -Force -ErrorAction Stop
+
+# or just:
+# Import-Module Pode
+
+# create a server, and start listening on port 8085
+Start-PodeServer {
+
+    # listen on localhost:8085
+    Add-PodeEndpoint -Address * -Port 8085 -Protocol Http
+
+    # add lots of schedules that each sleep for a while
+    1..30 | ForEach-Object {
+        Add-PodeSchedule -Name "Schedule_$($_)" -Cron '@minutely' -ArgumentList @{ ID = $_ } -ScriptBlock {
+            param($ID)
+
+            $seconds = (Get-Random -Minimum 5 -Maximum 40)
+            Start-Sleep -Seconds $seconds
+            "ID: $($ID) [$($seconds)]" | Out-PodeHost
+        }
+    }
+
+    Set-PodeScheduleConcurrency -Maximum 30
+
+}

src/Pode.psd1

@@ -125,6 +125,7 @@
         'Clear-PodeSchedule',
         'Invoke-PodeSchedule',
         'Edit-PodeSchedule',
+        'Set-PodeScheduleConcurrency',
 
         # timers
         'Add-PodeTimer',

src/Private/Context.ps1

@@ -265,7 +265,7 @@ function New-PodeRunspacePools
     $PodeContext.RunspacePools.Signals.Open()
 
     # setup schedule runspace pool
-    $PodeContext.RunspacePools.Schedules = [runspacefactory]::CreateRunspacePool(1, 2, $PodeContext.RunspaceState, $Host)
+    $PodeContext.RunspacePools.Schedules = [runspacefactory]::CreateRunspacePool(1, 10, $PodeContext.RunspaceState, $Host)
     $PodeContext.RunspacePools.Schedules.Open()
 
     # setup gui runspace pool (only for non-ps-core)

src/Private/Server.ps1

@@ -16,6 +16,9 @@ function Start-PodeInternalServer
         # create the shared runspace state
         New-PodeRunspaceState
 
+        # start the runspace pools for web, schedules, etc
+        New-PodeRunspacePools
+
         # get the server's script and invoke it - to set up routes, timers, middleware, etc
         $_script = $PodeContext.Server.Logic
         if (Test-PodePath -Path $PodeContext.Server.LogicPath -NoStatus) {
@@ -24,9 +27,6 @@ function Start-PodeInternalServer
 
         Invoke-PodeScriptBlock -ScriptBlock $_script -NoNewClosure
 
-        # start the runspace pools for web, schedules, etc
-        New-PodeRunspacePools
-
         # create timer/schedules for auto-restarting
         New-PodeAutoRestartServer
 

src/Public/Core.ps1

@@ -1068,6 +1068,43 @@ function Add-PodeSchedule
     }
 }
 
+<#
+.SYNOPSIS
+Set the maximum number of concurrent schedules.
+
+.DESCRIPTION
+Set the maximum number of concurrent schedules.
+
+.PARAMETER Maximum
+The Maximum number of schdules to run.
+
+.EXAMPLE
+Set-PodeScheduleConcurrency -Maximum 25
+#>
+function Set-PodeScheduleConcurrency
+{
+    [CmdletBinding()]
+    param(
+        [Parameter(Mandatory=$true)]
+        [int]
+        $Maximum
+    )
+
+    # error if <=0
+    if ($Maximum -le 0) {
+        throw "Maximum concurrent schedules must be >=0 but got: $($Maximum)"
+    }
+
+    # ensure max > min
+    $_min = $PodeContext.RunspacePools.Schedules.GetMinRunspaces()
+    if ($_min -gt $Maximum) {
+        throw "Maximum concurrent schedules cannot be less than the minimum of $($_min) but got: $($Maximum)"
+    }
+
+    # set the max schedules
+    $PodeContext.RunspacePools.Schedules.SetMaxRunspaces($Maximum)
+}
+
 <#
 .SYNOPSIS
 Adhoc invoke a Schedule's logic.