Conditionally run a target for publish profile

In the last post we have seen how to write custom actions for BeforePublish and AfterPublish events. In this post we will take one more step towards customizing the action execution. Occasionally we need to perform custom actions like copying files to output folder but with some condition, like if a particular directory not already exists in the output or could be any other condition etc.

In this post we are not the exploring capability of actions you can perform with target tag but will see how you can add conditions with Target tag. So I will simply write custom messages to the console with different conditions.

The following Target tag outputs the text message to console based on the condition specified in Condition attribute. Here we are checking if the $(MSBuildProjectDirectory)\MyData folder exists, if so, then it will output a text message to the console otherwise it will do nothing.

<Target Name="CustomActionsAfterPublish" AfterTargets="AfterPublish" Condition="Exists('$(MSBuildProjectDirectory)\MyData')">
   <Message Text="Some text to the console" Importance="high" />
</Target>

Here we have used MSBuild reserved property MSBuildProjectDirectory which represents the absolute path of the directory where the project file is located, and then we are checking if a folder named MyData exists in that location.

Obviously you are not going to check for this condition in real project but this is just to demonstrate that you can use the Exists operrator in Condition attribute to check for a folder exists. You can reverse the same condition by using the ! operator to check if folder not exists.

<Target Name="CustomActionsAfterPublish" AfterTargets="AfterPublish" Condition="!Exists('$(MSBuildProjectDirectory)\MyData')">
   <Message Text="Some text to the console" Importance="high" />
</Target>

Another operator you can use in Condition attribute is == operator. For exmaple may want to check if the current publish profile's configuration is DEBUG then you want to run the target action. You can write this condition as follows:

<Target Name="CustomActionsAfterPublish" AfterTargets="AfterPublish" Condition="'$(Configuration)'=='DEBUG'">
   <Message Text="Some text to the console" Importance="high" />
</Target>

Here we have used MSBuild project property Configuration which contains the configuration value you specified in your publish profile.

Similary you can use != operator to check for inequality.

<Target Name="CustomActionsAfterPublish" AfterTargets="AfterPublish" Condition="'$(Configuration)'!='DEBUG'">
   <Message Text="Some text to the console" Importance="high" />
</Target>

This will run the target action if current configuration is not equal to DEBUG.

Some of the commonly used project propeties are:

• MSBuildProjectName: Represents the filename of the project without extension.
• MSBuildProjectFile: Represents the full filename of the project with extension.
• Platform: The operating system you are building for. e.g "Any CPU", "x86", and "x64".
• MSBuildProjectDirectory: Absolute path of the directory where the project file is located.

You may find more details about project properties on Microsoft Docs:

• MSBuild reserved and well-known properties
• Common MSBuild project properties
• MSBuild well-known item metadata

Run a target action before or after publishing

Target tag allow us to execute custom actions on particular events. We can also specify the order of target actions in a particular sequence we need. We have different target attributes for publish profiles, but in this post I will demonstrate BeforeTargets and AfterTargets for publish event.

Microsoft Docs:

BeforeTargets and AfterTargets. These Target attributes specify that this target should run before or after the specified targets (MSBuild 4.0).

We can use these built-in BeforePublish and AfterPublish targets to execute an action before or after the publish. For exmaple, following tag logs the console messages before and after publishing.

<Target Name="MyCustomActionBeforePublish" BeforeTargets="BeforePublish">
    <Message Text="Logging Message BeforePublish" Importance="high" />
  </Target>
  <Target Name="MyCustomActionAfterPublish" AfterTargets="AfterPublish">
    <Message Text="Logging Message AfterPublish" Importance="high" />
</Target>

Just logging a console message is not very helpful. You can perform a variety of options, one could be to copy files from a particular source directory. Following example allows the publishing profile to copy files from the path specified in Include attribute of MySourceFiles to the destination path specified in DestinationFolder attribute of Copy tag. Since we are using the event name AfterPublish, the source content will be copied after it completes the publishing.

<Target Name="MyCustomActionAfterPublish" AfterTargets="AfterPublish">
    <ItemGroup>
      <MySourceFiles Include="C:\Test\ExternalContent\*.*"/>
    </ItemGroup>
    <Copy SourceFiles="@(MySourceFiles)" DestinationFolder="bin\Debug\netcoreapp2.2\publish\TestTarget\"/>
  </Target>

In this exmaple, we are using absolute path in MySourceFiles tag, you can also use relative path as illustrated in DestinationFolder attribute of Copy tag.

References:

• Microsoft Docs - Visual Studio publish profiles for ASP.NET Core app deployment

How to include external files/folders in Publish Profile

Often we need to include external files/folders in publish profile to deploy on published site. We have two ways to achieve this:

General file inclusion

In this method we use the DotNetPublishFiles tag, which is provided by a publish targets file in the Web SDK.

The following example's demonstrates how to copy a folder located outside of the project directory to the published site.

<ItemGroup>
    <MyCustomFiles Include="$(MSBuildProjectDirectory)/../ExternalContent/**/*" />
    <DotNetPublishFiles Include="@(MyCustomFiles)">
      <DestinationRelativePath>wwwroot/ExternalContent/%(RecursiveDir)%(Filename)%(Extension)</DestinationRelativePath>
    </DotNetPublishFiles>
  </ItemGroup>

• Declares a MyCustomFiles(it can be any custom name) tag to cover files matching the globbing pattern specified in Include attribute. The ExternalContent folder referenced in the pattern is located outside of the project directory. We are using a reserved property $(MSBuildProjectDirectory), which resolves the project file's absolute path.

• In DotNetPublishFiles tag, we provide our custom tag name MyCustomFiles in the Include attribute, whih serves as a source path for files/folders. In DestinationRelativePath tag, we specified the target path(with respect to published folder) where we want to copy the files. In this example, we are copying ExternalContent folder's content to wwwroot/ExternalContent folder. We have also used item metadata such as %(RecursiveDir), %(Filename), %(Extension). This represents the wwwroot/ExternalContent folder of the published site.

If you don't want to specify source path relative to the project file's absolute path, you can also specific local absolute path, like:

  <ItemGroup>
    <MyCustomFiles Include="C:\Test\ExternalContent\*" />
    <DotNetPublishFiles Include="@(MyCustomFiles)">
      <DestinationRelativePath>wwwroot/ExternalContent/%(RecursiveDir)%(Filename)%(Extension)</DestinationRelativePath>
    </DotNetPublishFiles>
  </ItemGroup>

Here we have changed the source relative path from $(MSBuildProjectDirectory)/../ExternalContent/**/* to C:\Test\ExternalContent\*.

Selective file inclusion

In this method we will use the ResolvedFileToPublish tag, which is provided by a publish targets file in the .NET Core SDK. Because the Web SDK depends on the .NET Core SDK, either item can be used in an ASP.NET Core project.

The following exmaple demonstrates how to copy a file located outside of the project into the published site's wwwroot folder. The file name of externalfile.txt is maintained.

  <ItemGroup>
    <ResolvedFileToPublish Include="..\externalfile.txt">
      <RelativePath>wwwroot\externalfile.txt</RelativePath>
    </ResolvedFileToPublish>
  </ItemGroup>

• In ResolvedFileToPublish tag, we are using Include attribute to specify the file we want to copy. This file resides in the parent directory of the project file's container directory.

• RelativePath represent the relative path for the published directory.

The default behavior of ResolvedFileToPublish is to always copy the files provided in the Include attribute to the published site. We can override this default behavior by including a CopyToPublishDirectory child tag with inner text of either Never or PreserveNewest. For example:

 <ResolvedFileToPublish Include="..\externalfile.txt">
   <RelativePath>wwwroot\externalfile.txt</RelativePath>
   <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
 </ResolvedFileToPublish>

Again, if you don't want to specify source path relative to the project file's absolute path, you can also specific local absolute path, like:

  <ItemGroup>
    <ResolvedFileToPublish Include="C:\Test\externalfile.txt">
      <RelativePath>wwwroot\externalfile.txt</RelativePath>
      <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
    </ResolvedFileToPublish>
  </ItemGroup>

References:

• Microsoft Docs - Visual Studio publish profiles for ASP.NET Core app deployment

How to exclude files from Publish Profile

When publishing ASP.NET Core web apps, it will publish/deploy the:

• Build artifacts
• files with .config extension
• files with .json extension
• everything inside wwwroot folder

At certain times you may need to exclude some specific file or folder from deployment content.

There are two ways you can exclude files from publishing.

Content Tag

If you need to prevent multiple files from being copied to deployed folder, you can use globbing patterns to cover a range of matching files.

Content tag will be used to specify the action on the file. For example, the following Content element will exclude all (.txt) files in the wwwroot\content folder and its subfolders.

<ItemGroup>
  <Content Update="wwwroot/content/**/*.txt" CopyToPublishDirectory="Never" />
</ItemGroup>

Note that it will delete all (.txt) files that are already exists at the deployed site within specified folder path.

You can specify different globbing patterns as per your requirement. Another version of pattern coud be like this:

<ItemGroup>
  <Content Update="wwwroot/content/Site*.css" CopyToPublishDirectory="Never" />
</ItemGroup>

This will match all css files in wwwroot/content folder with file name starts with Site e.g. SiteAdmin.css, SiteCustomer.css, etc...

You can add this markup to a publish profile (.pubxml file) or the .csproj file. Since .csproj file operates at the global level, if you add this tag to the .csproj file, the rule will be applied to all publish profiles in the project.

MsDeploySkipRules Tag

Another way to exclude file or folder is to use MsDeploySkipRules tag.

The following tag excludes all files/folders from the wwwroot\content folder:

<ItemGroup>
  <MsDeploySkipRules Include="CustomSkipFolder">
    <ObjectName>dirPath</ObjectName>
    <AbsolutePath>wwwroot\\content</AbsolutePath>
  </MsDeploySkipRules>
</ItemGroup>

Note that unlike Content tag, this will not delete the targeted file or folder if that are already exists on the deployed site.

Similarly you can specify a single file in AbsolutePath tag, but you need to change the ObjectName tag to filePath rather than dirPath, and also change the value of Include attribute from CustomSkipFolder to CustomSkipFile.

<ItemGroup>
  <MsDeploySkipRules Include="CustomSkipFile">
    <ObjectName>filePath</ObjectName>
    <AbsolutePath>wwwroot\\content\\Site.css</AbsolutePath>
  </MsDeploySkipRules>
</ItemGroup>

References:

• Microsoft Docs - Visual Studio publish profiles for ASP.NET Core app deployment

Fixing the error "Web Deploy cannot modify the file on the destination because it is locked by an external process."

When you publish your web application from Visual Studio, you many encounter file lock error:

Web Deploy cannot modify the file 'MyApi.dll' on the destination because it is locked by an external process.
In order to allow the publish operation to succeed, you may need to either restart your application to release the lock, 
or use the AppOffline rule handler for .Net applications on your next publish attempt.  
Learn more at: http://go.microsoft.com/fwlink/?LinkId=221672#ERROR_FILE_IN_USE.

When you publish web application in Visual Studio, it will not force the remote app to be stopped/restarted. The Web Deploy team has introduced an AppOffline rule which provides a solution for this problem.

There could be many reasons you may want to take your app offline while publishing. For example you app has files locked which need to be updated (the reason behind above error), or you need to clear an in-memory cache for changes to take effect (like ASP.Net Core app pool will keep configuration values from appsettings.json file in memory, and you have to restart the apppool to make changes take effect, if it is not configured with auto-load option).

We can define publish profiles in Visual Studio, which are simple xml files with .pubxml extension stored under Properties\PublishProfiles.

These publish profiles contain the settings for a particular profile. You can customize these files to modify the publish process. To enable this find the .pubxml file corresponding to the publish profile you want to update. Then add the following element in the PropertyGroup element.

 <EnableMSDeployAppOffline>true</EnableMSDeployAppOffline>

The resulting publish profile will look similar to this.

<?xml version="1.0" encoding="utf-8"?>
<!--
This file is used by the publish/package process of your Web project. You can customize the behavior of this process
by editing this MSBuild file. In order to learn more about this please visit https://go.microsoft.com/fwlink/?LinkID=208121. 
-->
<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
    <EnableMSDeployAppOffline>true</EnableMSDeployAppOffline>
    <WebPublishMethod>MSDeploy</WebPublishMethod>
    <LastUsedBuildConfiguration>Release</LastUsedBuildConfiguration>
    <LastUsedPlatform>Any CPU</LastUsedPlatform>
    <SiteUrlToLaunchAfterPublish />
    <LaunchSiteAfterPublish>True</LaunchSiteAfterPublish>
    <ExcludeApp_Data>False</ExcludeApp_Data>
    <TargetFramework>netcoreapp2.2</TargetFramework>
    <ProjectGuid>51c6d4da-2c14-4beb-8113-2bea0cfa3000</ProjectGuid>
    <SelfContained>false</SelfContained>
    <_IsPortable>true</_IsPortable>
    <MSDeployServiceURL>localhost</MSDeployServiceURL>
    <DeployIisAppPath>Default Web Site/MyApi</DeployIisAppPath>
    <RemoteSitePhysicalPath />
    <SkipExtraFilesOnServer>True</SkipExtraFilesOnServer>
    <MSDeployPublishMethod>InProc</MSDeployPublishMethod>
    <EnableMSDeployBackup>False</EnableMSDeployBackup>
    <UserName />
    <_SavePWD>False</_SavePWD>
  </PropertyGroup>
</Project>

Once you save these changes, when you publish using that profile your app will be taken offline during publishing, and you will not receive above error message for file lock.

Edit .csproj file

Another way to set this property is from .csproj file, which will effect every profile in a given project.

You can place the following PropertyGroup in your project file.

<PropertyGroup>
  
  <!--... other properties-->
  
  <EnableMSDeployAppOffline>true</EnableMSDeployAppOffline>
</PropertyGroup>