Add some logging for missing helm exe during acquisition

Fixes: OctopusDeploy/Issues#5057

Author: zentron

source/Calamari.Shared/Integration/Packages/Download/Scripts/HelmFetch.ps1

@@ -1,6 +1,12 @@
 #Ideally this single line would replace everything below ... But there appears to be a bug somewhere
 #helm fetch --repo $Url --username $Username --password $Password --version $version --destination $TempStaging $package
 
+if (!$(Get-Command helm -errorAction SilentlyContinue))
+{
+    Write-Error "The helm client tool does not appear to be available on the current path.`nSee http://g.octopushq.com/HelmLimitations for more details."
+    Exit 1
+}
+
 $TempHelmHome = $((Resolve-Path .\).Path) +"\helm"
 $TempStaging = $((Resolve-Path .\).Path) +"\staging"
 
@@ -30,7 +36,4 @@ if(!$?) {
 
 Write-Host "Fetching Chart"
 Write-Verbose "helm fetch --home $TempHelmHome --version $Version --destination $TempStaging $TempRepoName/$Package"
-helm fetch --home $TempHelmHome --version $Version --destination $TempStaging $TempRepoName/$Package
-
-#$files=(Get-ChildItem "$TempStaging/*");
-#Set-OctopusVariable -name "PackageFile" -value $files[0].FullName;
+helm fetch --home $TempHelmHome --version $Version --destination $TempStaging $TempRepoName/$Package

source/Calamari.Shared/Integration/Packages/Download/Scripts/helmFetch.sh

@@ -1,4 +1,9 @@
-
+command -v "helm" &>/dev/null
+if [[ $? != 0 ]]; then
+    echo >&2 "The helm client tool does not appear to be available on the current path. See http://g.octopushq.com/HelmLimitations for more details."
+    deps=1;
+fi
+
 username=$(get_octopusvariable "Username")
 password=$(get_octopusvariable "Password")
 url=$(get_octopusvariable "Url")