C# Rules for Bazel

• Buildkite:

  

• Azure pipelines

  

Contents

• Documentation
• Overview
• Caveats
• Setup
• Examples

Documentation

• Runtime considerations
• Multiple framework versions
• Nuget usage
• Core API
  • dotnet_library, core_library, net_library
  • dotnet_binary, net_binary, core_binary
  • dotnet_resx, net_resx, core_resx
  • dotnet_nunit_test, net_nunit_test, net_nunit3_test, core_xunit_test, net_xunit_test, dotnet_xunit_test
  • dotnet_resx, net_resx, core_resx
  • dotnet_import_library, core_import_library, net_import_library, dotnet_import_binary, core_import_binary, net_import_binary
  • dotnet_stdlib, core_stdlib, net_stdlib
• Workspace rules
• Toolchains
• Tests

Overview

This is a minimal viable set of C# bindings for building C# code with Core, Net and Mono. It's still pretty rough but it works.

Warning: on Windows requires minimum 1.1.0 version of bazel (due to improper symbolic link targets handling in previous versions).

Caveats

These rules are not compatible with sandboxing. Particularly, running dotnet rules on Linux or OSX requires passing --spawn_strategy=standalone.

Bazel creates long paths. Therefore it is recommended to increase the length limit using newer version of Windows. Please see here.

However, some Windows programs do not handle long path names. Most notably - Microsoft C compiler (cl.exe). Therefore TMP env variable should be set to something short (like X:\ or c:\TEMP).

Bazel and dotnet_rules rely on symbolic linking. On Windows it, typically, requires elevated permissions. However, newer versions of Windows have a workaround.

NUnit v2 runner used in some tests requires .NET Framework 3.5 installation.

If you intend to use Mono or .Net Framework then they have to be installed locally on the machine. The producers of these frameworks do not provide downloadable "run-in-place" (without installation) versions. The developer versions of these frameworks have to be used.

Setup

• Add the following to your WORKSPACE file to add the external repositories:

  # A newer version should be fine
  load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
  git_repository(
      name = "io_bazel_rules_dotnet",
      remote = "https://github.com/bazelbuild/rules_dotnet",
      tag = "0.0.3",
  )
  
  load("@io_bazel_rules_dotnet//dotnet:defs.bzl", "core_register_sdk", "net_register_sdk", "mono_register_sdk",
      "dotnet_register_toolchains", "dotnet_repositories", "nuget_package")
  
  dotnet_register_toolchains()
  dotnet_repositories()
  # For .NET Core:
  core_register_sdk("v2.1.502", name = "core_sdk")
  # For .NET Framework:
  net_register_sdk("net471", name = "net_sdk")
  # For Mono:
  mono_register_sdk()

  The dotnet_repositories rule fetches external dependencies, namely the nuget binary. The dotnet_register_toolchains configures toolchains. The mono_register_sdk, core_register_sdk, net_register_sdk "glue" toolchains with appropriate SDKs.

• Add a file named BUILD.bazel in the root directory of your project. In general, you need one of these files in every directory with dotnet code. At the top of the file used rules should be imported:

  load("@io_bazel_rules_dotnet//dotnet:defs.bzl", "dotnet_library", "dotnet_binary")

• If you intend to use CoreCLR make sure to install libunwind-devel if it is not present on your system (applies to Linux).

Examples

• dotnet_library

  dotnet_library(
    name = "foo_bar.dll",
    srcs = [
        "foo.cs",
        "bar.cs",
    ],
    deps = [
        "//examples/example_lib:MyClass",
        "@npgsql//:npgsqllib",
    ],
  )

  Note: The defined library must have extension .dll. Otherwise launchers used by rules_dotnet are not able to correctly locate necessary files.

• dotnet_binary

  dotnet_binary(
    name = "foo_bar.exe",
    srcs = [
        "foo.cs",
        "bar.cs",
    ],
    deps = [
        "//examples/example_lib:MyClass",
        "@npgsql//:npgsqllib",
    ],
    visibility = ["//visibility:public"],
  )

  Note: The defined library must have extension .exe. Otherwise launchers used by rules_dotnet are not able to correctly locate necessary files.

• dotnet_nunit_test

  dotnet_nunit_test(
      name = "MyTest.dll",
      srcs = [
          "MyTest.cs",
      ],
      deps = [
          "//examples/example_lib:MyClass",
          "//dotnet/externals/nunit2:nunit.framework",
      ],
  )

  Note: The defined library must have extension .dll. Otherwise launchers used by rules_dotnet are not able to correctly locate necessary files.

• dotnet_resx

  dotnet_resx(
      name = "Transform",
      src = "//dotnet/externals/nunit2/nunitv2:src/ClientUtilities/util/Transform.resx",
  )

• nuget_package

  In the WORKSPACE file for your project record a nuget dependency like so. This is a repository rule so it will not work unless it is in a workspace file.

  nuget_package(
      name = "newtonsoft.json",
      package = "newtonsoft.json",
      version = "11.0.2",
      sha256 = "679e438d5eb7d7e5599aa71b65fd23ee50dabf57579607873b87d34aec11ca1e",
      core_lib = "lib/netstandard2.0/Newtonsoft.Json.dll",
      net_lib = "lib/net45/Newtonsoft.Json.dll",
      mono_lib = "lib/net45/Newtonsoft.Json.dll",
      core_deps = [
      ],
      net_deps = [
      ],
      mono_deps = [
      ],
      core_files = [
          "lib/netstandard2.0/Newtonsoft.Json.dll",
          "lib/netstandard2.0/Newtonsoft.Json.xml",
      ],
      net_files = [
          "lib/net45/Newtonsoft.Json.dll",
          "lib/net45/Newtonsoft.Json.xml",
      ],
      mono_files = [
          "lib/net45/Newtonsoft.Json.dll",
          "lib/net45/Newtonsoft.Json.xml",
      ],
  )

  Now, in a BUILD file, you can add the package to your deps

  dotnet_binary(
      name = "foo_bar.exe",
      srcs = [
          "foo.cs",
          "bar.cs",
      ],
      deps = [
          "//examples/example_lib:MyClass",
          "@newtonsoft.json//:dotnet",
      ],
      visibility = ["//visibility:public"],
  )

• dotnet_nuget_new

  In the WORKSPACE file for your project record a nuget dependency like so. This is a repository rule so it will not work unless it is in a workspace file.

  dotnet_nuget_new(
          name = "npgsql",
          package="Npgsql",
          version="3.2.7",
          sha256="fa3e0cfbb2caa9946d2ce3d8174031a06320aad2c9e69a60f7739b9ddf19f172",
          build_file_content = """
      package(default_visibility = [ "//visibility:public" ])
      load("@io_bazel_rules_dotnet//dotnet:defs.bzl", "dotnet_import_library")
  
      dotnet_import_library(
          name = "npgsqllib",
          src = "lib/net451/Npgsql.dll"
      )
          """
  )

  Now, in a BUILD file, you can add the package to your deps:

  dotnet_binary(
      name = "foo_bar.exe",
      srcs = [
          "foo.cs",
          "bar.cs",
      ],
      deps = [
          "//examples/example_lib:MyClass",
          "@npgsql//:npgsqllib",
      ],
      visibility = ["//visibility:public"],
  )