Production deployment with your build script – Part 2

In the first post I gave a quick overview of what our deployment script does and why you’d want one. This post will go over some of the pre-deployment steps we take. Most all of this code will probably be pretty self explanatory, but I know just having something to work off of is a huge boost to starting your own, so here ya go.

function modify_web_config_for_production($webConfig)
{
	echo "Modifying $webConfig for production deployment."
 
	$xml = [xml](Get-Content $webConfig)
	$root = $xml.get_DocumentElement();
 
	$root."system.web".compilation.debug = "false"
 
	$xml.Save($webConfig)
}

Given the path to a web.config file, this function switches off the debug flag (and any other changes you’d need). Being a dynamic language, you can access XML keys quite easily. You’ll need the quotes around system.web since there’s the dot in the name though. Also, if you need access to any of the app.settings keys, you can use something like: $xml.selectSingleNode('//appSettings/add[@key="WhateverYourKeyIs"]').value = "false".

function precompile_site($siteToPreCompile, $compiledSite)
{
	echo "Precompiling $siteToPreCompile."
 
	$virtual_directory = "/"
 
	exec { & $tools_aspnetCompiler -nologo -errorstack -fixednames -d -u -v $virtual_directory -p "$siteToPreCompile" $compiledSite }
}

This little beauty precompiles the site (located in the $siteToPreCompile directory, with the results output to the $compiledSite directory) using the ASP.NET compiler. I prefer to copy the actual compiler executable into the project folder even though it’s installed with the Framework. Not sure why. Anyway, $tools_aspnetCompiler can either point locally, or to C:\Windows\Microsoft.NET\Framework\vwhatever\aspnet_compiler.exe. You can also configure the options being passed into the compiler to suit your needs.

function execute_with_secure_share($share, [scriptblock]$command)
{
	try
	{
		echo "Mapping share $share"
		exec { & net use $share /user:$security_full_user $security_password }
 
		& $command
	}
	finally
	{
		echo "Unmapping share $share"
		exec { & net use $share /delete }
	}
}

This is more of a helper method that executes a given script block (think of it as an Action or anonymous code block in C#) while the given share is mapped with some known username and password. This is used to copy out the site, create backups, etc. I’ll leave the $security_full_user & $security_password variable declarations out, if you don’t mind! We just put them in plain text in the build script (I know, *gasp!*).

properties {
	$share_web = "wwwroot"
	$servers_production = @("server1", "server2")
	$live_backup_share = "\\server\LiveSiteBackups"
 
	$number_of_live_backups_to_keep = 10
}
 
function archive_current_live_site
{
	$current_datetime = Get-Date -Format MM_dd_yyyy-hh_mm_tt
	$one_of_the_production_servers = $servers_production[0]
 
	$web_share_path = "\\$one_of_the_production_servers\$share_web"
 
	echo "Archiving $web_share_path"
 
	$full_backup_path = "$web_share_path\*"
	$full_archive_file = "$live_backup_share\$current_datetime.zip"
 
	execute_with_secure_share $web_share_path {
		execute_with_secure_share $live_backup_share {
			exec { & $tools_7zip a $full_archive_file $full_backup_path } 
		}
	}
}
 
function delete_extra_live_site_backups
{
	execute_with_secure_share $live_backup_share {
		$current_backups = Get-ChildItem $live_backup_share -Filter "*.zip" | sort -Property LastWriteTime
		$current_backups_count = $current_backups.Count
 
		echo "Found $current_backups_count live backups out there, and we're aiming to keep only $number_of_live_backups_to_keep."
 
		$number_of_backups_to_kill = ($current_backups_count - $number_of_live_backups_to_keep);
 
		for ($i = 0; $i -lt $number_of_backups_to_kill; $i++)
		{
			$file_to_delete = $current_backups[$i]
			$extra_backup = "$live_backup_share\$file_to_delete"
 
			echo "Removing old backup file: $extra_backup"
			delete_file $extra_backup
		}
	}
}

These pair of methods create a backup of the current live site and make sure we’re only keeping a set number of those backups from previous runs, to keep storage and maintenance in check. Nothing too complicated. To create the backup, we just farm out to 7-Zip to compress the directory, which is ran withing nested execute_with_secure_share calls from above, which map the web server file share and backup file share. Likewise, the second method just gets a count of zip files in the storage directory and deletes the oldest ones in there until the total count gets to a specified count.

Conclusion

That’s the basics for what we do pre-deployment. Again, not really that complicated, but it can give you a starting point for your script. I’ll go over our actual deployment steps in the next post, then follow that up with some post-deployment goodness. I know, you can’t wait.

One Response

  1. Taller Code » Blog Archive » Production deployment with your build script - Part 3 Says:

    […] I gave a quick overview of what our deployment script does and why you’d want one, then the second post went over pre-deployment steps. This post will go over the actual deployment steps we take to […]

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