MSBuild 验证属性

Question

我正在开发一个可重用的 MSBuild 目标，该目标将被其他几个任务使用。这个目标需要定义几个属性。验证属性是否已定义的最佳方法是什么，如果未定义则抛出错误？

我几乎喜欢的两次尝试：

<?xml version="1.0" encoding="utf-8" ?>
  <Project ToolsVersion="3.5" DefaultTarget="Release" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">

  <Target Name="Release">
    <Error
      Text="Property PropA required"
      Condition="'$(PropA)' == ''"/>
    <Error
      Text="Property PropB required"
      Condition="'$(PropB)' == ''"/>

    <!-- The body of the task -->

  </Target>
</Project>

这是批处理的尝试。由于额外的“名称”参数，它很难看。是否可以改用 Include 属性？

<?xml version="1.0" encoding="utf-8" ?>
<Project ToolsVersion="3.5" DefaultTarget="Release" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Target Name="Release">
    <!-- MSBuild BuildInParallel="true" Projects="@(ProjectsToBuild)"/ -->
    <ItemGroup>
      <RequiredProperty Include="PropA"><Name>PropA</Name></RequiredProperty>
      <RequiredProperty Include="PropB"><Name>PropB</Name></RequiredProperty>
      <RequiredProperty Include="PropC"><Name>PropC</Name></RequiredProperty>
    </ItemGroup>

    <Error
      Text="Property %(RequiredProperty.Name) required"
      Condition="'$(%(RequiredProperty.Name))' == ''" />

  </Target>

</Project>

Answer 1

好问题！我已经在我的book 和一篇博文Elements of Reusable MSBuild Scripts: Validation 中深入探讨了这一点。我的方法将涵盖属性和项目。

这里是失败的地方。在共享的 .targets 文件中创建一个验证目标，这应该是文件中声明的第一个目标，以便用户可以轻松找到它。

属性

在验证目标中定义您的属性，如下所示：

<_RequiredProperties Include="Root">
  <Value>$(Root)</Value>
</_RequiredProperties>

我将属性的名称放在 include 中，并将其值放在 Value 元数据中。这样做的原因是我可以检测到 Value 何时为空白，然后我使用包含值将丢失的属性的名称报告给用户。

项目

在目标内放置所需的项目，如：

<_RequiredItems Include="AllConfigurations">
  <RequiredValue>@(AllConfigurations)</RequiredValue>
</_RequiredItems>

与属性类似，在 include 中放置项目的名称，然后在 RequiredValue 元数据中放置要检查的值。在此示例中，它只是检查以确保 AllConfiguraitons 项目不为空。如果您想确保在所有项目上指定给定的元数据值，请执行以下操作：

<_RequiredItems Include = "AllConfigurations.Configuration">
  <RequiredValue>%(AllConfigurations.Configuration </RequiredValue>
</_RequiredItems>

如果要确保文件存在，请添加额外的元数据，RequiredFilePath。

<_RequiredItems Include ="ProjectsToBuild">
  <RequiredValue>%(ProjectsToBuild.Identity)</RequiredValue>
  <RequiredFilePath>%(ProjectsToBuild.Identity)</RequiredFilePath>
</_RequiredItems>

验证

这是您执行验证所需的内容

完整示例

这是完整的例子

<Target Name="ValidateBuildSettings">
  <ItemGroup>
    <_RequiredProperties Include="Root">
      <Value>$(Root)</Value>
    </_RequiredProperties>

    <_RequiredProperties Include="BuildInstallRoot">
      <Value>$(BuildInstallRoot)</Value>
    </_RequiredProperties>

    <_RequiredProperties Include="SourceRoot">
      <Value>$(SourceRoot)</Value>
    </_RequiredProperties>
    <!-- 
    _RequiredItems is the item where required items should be placed. 
    The following metadata is significant: 
      REQUIRED METADATA: 
      Identity          = This will basically be used to identify the specific required item 
      RequiredValue     = This is the specific value that will be validated to exist 

      OPTIONAL METADATA 
      RequiredFilePath  = Populate this with a path that should exists, if it is not empty 
                            then it will be checked to exist on disk. 
    -->

    <_RequiredItems Include="AllConfigurations">
      <RequiredValue>@(AllConfigurations)</RequiredValue>
    </_RequiredItems>
    <_RequiredItems Include = "AllConfigurations.Configuration">
      <RequiredValue>%(AllConfigurations.Configuration </RequiredValue>
    </_RequiredItems>
    <_RequiredItems Include ="ProjectsToBuild">
      <RequiredValue>%(ProjectsToBuild.Identity)</RequiredValue>
      <RequiredFilePath>%(ProjectsToBuild.Identity)</RequiredFilePath>
    </_RequiredItems>
  </ItemGroup>
  <!-- Raise an error if any value in _RequiredProperties is missing -->

  <Error Condition =" '%(_RequiredProperties.Value)'=='' "
          Text=" Missing required property [%(_RequiredProperties.Identity)]" />

  <!-- Raise an error if any value in _RequiredItems is empty -->
  <Error Condition = " '%(_RequiredItems.RequiredValue)'=='' "
          Text = " Missing required item value [%(_RequiredItems.Identity)] " />

  <!-- Validate any file/directory that should exist -->
  <Error Condition = " '%(_RequiredItems.RequiredFilePath)' != '' and !Exists('%(_RequiredItems.RequiredFilePath)') "
          Text = " Unable to find expeceted path [%(_RequiredItems.RequiredFilePath)] on item [%(_RequiredItems.Identity)] " />
</Target>