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c#environment-variablescompile-time

Can I make a constant from a compile-time env variable in C#?

We use Hudson to build our projects, and Hudson conveniently defines environment variables like %BUILD_NUMBER% at compile time.

I'd like to use that variable in code, so we can do things like log what build this is at run time. However I cannot do System.Environment.GetEnvironmentVariable because that is accessing the run-time environment, what I want is something like:

#define BUILD_NUM = %BUILD_NUMBER%

Or:

const string BUILD_NUM = %BUILD_NUMBER%

Except I don't know the syntax. Can someone please point me in the right direction? Thanks!

Solution

  • Okay here's what I wound up doing. It's not very elegant, but it works. I created a pre-build step that looks like this:

    echo namespace Some.Namespace > "$(ProjectDir)\CiInfo.cs"
echo { >> "$(ProjectDir)\CiInfo.cs"
echo     ///^<summary^>Info about the continuous integration server build that produced this binary.^</summary^> >> "$(ProjectDir)\CiInfo.cs"
echo     public static class CiInfo >> "$(ProjectDir)\CiInfo.cs"
echo     { >> "$(ProjectDir)\CiInfo.cs"
echo         ///^<summary^>The current build number, such as "153"^</summary^> >> "$(ProjectDir)\CiInfo.cs"
echo         public const string BuildNumber = ("%BUILD_NUMBER%" == "" ? @"Unknown" : "%BUILD_NUMBER%"); >> "$(ProjectDir)\CiInfo.cs"
echo         ///^<summary^>String of the build number and build date/time, and other useful info.^</summary^> >> "$(ProjectDir)\CiInfo.cs"
echo         public const string BuildTag = ("%BUILD_TAG%" == "" ? @"nohudson" : "%BUILD_TAG%") + " built: %DATE%-%TIME%"; >> "$(ProjectDir)\CiInfo.cs"
echo     } >> "$(ProjectDir)\CiInfo.cs"
echo } >> "$(ProjectDir)\CiInfo.cs"

    Then I added "CiInfo.cs" to the project, but ignored it from version control. That way I never have to edit it or commit it, and the project always has a constant available that is the latest build number and time.