feat: allow to read version from .ruby-version or .tool-versions file

fixes #23

Author: p0deje

.github/workflows/ci.yml

@@ -53,32 +53,15 @@ jobs:
           # TruffleRuby doesn't work on Windows.
           - os: windows
             ruby: truffleruby-23.1.1
-          # https://github.com/bazel-contrib/rules_ruby/issues/23
-          - mode: bzlmod
-            ruby: system
-          - mode: bzlmod
-            ruby: 3.0.6
-          - mode: bzlmod
-            ruby: 3.1.4
-          - mode: bzlmod
-            ruby: 3.2.2
-          - mode: bzlmod
-            ruby: 3.3.0-preview3
-          - mode: bzlmod
-            ruby: 3.0.6
-          - mode: bzlmod
-            ruby: truffleruby-23.1.1
     defaults:
       run:
         working-directory: examples/gem
     steps:
       - uses: actions/checkout@v4
       - uses: p0deje/setup-bazel@0.3.2
         with:
-          bazelrc: |
-            common --announce_rc --color=yes
-            ${{ matrix.mode == 'bzlmod' && 'common --enable_bzlmod' || '' }}
-      - run: echo 'RUBY_VERSION = "${{ matrix.ruby }}"' > ruby_version.bzl
+          bazelrc: common --announce_rc --color=yes ${{ matrix.mode == 'bzlmod' && '--enable_bzlmod' || '' }}
+      - run: echo ${{ matrix.ruby }} > .ruby-version
       - if: matrix.ruby == 'system'
         uses: ruby/setup-ruby@v1
         with:

README.md

@@ -21,7 +21,9 @@ The ruleset is known to work with:
 load("@rules_ruby//ruby:deps.bzl", "rb_register_toolchains")
 
 rb_register_toolchains(
-    version = "3.0.6"
+    version = "3.0.6",
+    # alternatively, load version from .ruby-version file
+    # version_file = "//:.ruby-version",
 )
 ```
 
@@ -50,7 +52,9 @@ rb_bundle(
 ruby = use_extension("@rules_ruby//ruby:extensions.bzl", "ruby")
 ruby.toolchain(
     name = "rules_ruby",
-    version = "3.0.6"
+    version = "3.0.6",
+    # alternatively, load version from .ruby-version file
+    # version_file = "//:.ruby-version",
 )
 use_repo(ruby, "rules_ruby_dist")
 ```
@@ -92,7 +96,7 @@ The following toolchains are known to work and tested on CI.
 
 | Ruby              | Linux | macOS | Windows |
 |-------------------|-------|-------|---------|
-| MRI 3.3 (preview) | 🟩    | 🟩    | 🟩      |
+| MRI 3.3 (preview) | 🟩    | 🟩    | 🟥      |
 | MRI 3.2           | 🟩    | 🟩    | 🟩      |
 | MRI 3.1           | 🟩    | 🟩    | 🟩      |
 | MRI 3.0           | 🟩    | 🟩    | 🟩      |

docs/repository_rules.md

@@ -0,0 +1 @@
+3.0.6

examples/gem/.ruby-version

@@ -10,7 +10,7 @@ local_path_override(
 ruby = use_extension("@rules_ruby//ruby:extensions.bzl", "ruby")
 ruby.toolchain(
     name = "rules_ruby",
-    version = "jruby-9.4.5.0",
+    version_file = "//:.ruby-version",
 )
 use_repo(ruby, "rules_ruby_dist")
 ruby.bundle(

examples/gem/MODULE.bazel

@@ -14,10 +14,9 @@ http_archive(
 )
 
 load("@rules_ruby//ruby:deps.bzl", "rb_bundle", "rb_register_toolchains")
-load("ruby_version.bzl", "RUBY_VERSION")
 
 rb_register_toolchains(
-    version = RUBY_VERSION,
+    version_file = "//:.ruby-version",
 )
 
 rb_bundle(

examples/gem/WORKSPACE

@@ -14,6 +14,7 @@ ruby_bundle = tag_class(attrs = {
 ruby_toolchain = tag_class(attrs = {
     "name": attr.string(doc = "Base name for generated repositories, allowing multiple to be registered."),
     "version": attr.string(doc = "Explicit version of ruby."),
+    "version_file": attr.label(doc = "File to read Ruby version from."),
 })
 
 def _ruby_module_extension(module_ctx):
@@ -40,15 +41,17 @@ def _ruby_module_extension(module_ctx):
                 fail("Multiple conflicting toolchains declared for name {} ({} and {}".format(
                     toolchain.name,
                     toolchain.version,
+                    toolchain.version_file,
                     registrations[toolchain.name],
                 ))
             else:
-                registrations[toolchain.name] = toolchain.version
+                registrations[toolchain.name] = (toolchain.version, toolchain.version_file)
 
-    for name, version in registrations.items():
+    for name, (version, version_file) in registrations.items():
         rb_register_toolchains(
             name = name,
             version = version,
+            version_file = version_file,
             register = False,
         )
 

examples/gem/ruby_version.bzl

@@ -1,19 +1,29 @@
 "Repository rule for fetching Ruby interpreters"
+
 _JRUBY_BINARY_URL = "https://repo1.maven.org/maven2/org/jruby/jruby-dist/{version}/jruby-dist-{version}-bin.tar.gz"
 _RUBY_BUILD_URL = "https://github.com/rbenv/ruby-build/archive/refs/tags/v{version}.tar.gz"
 _RUBY_INSTALLER_URL = "https://github.com/oneclick/rubyinstaller2/releases/download/RubyInstaller-{version}-1/rubyinstaller-devkit-{version}-1-x64.exe"
 
 def _rb_download_impl(repository_ctx):
-    if repository_ctx.attr.version.startswith("jruby"):
-        _install_jruby(repository_ctx)
-    elif repository_ctx.attr.version == "system":
+    if repository_ctx.attr.version and not repository_ctx.attr.version_file:
+        version = repository_ctx.attr.version
+    elif repository_ctx.attr.version_file and not repository_ctx.attr.version:
+        version = _read_version_from_file(repository_ctx)
+    elif repository_ctx.attr.version_file and repository_ctx.attr.version:
+        fail("only one of mandatory attributes 'version' or 'version_file' is allowed")
+    else:
+        fail("missing value for one of mandatory attributes 'version' or 'version_file'")
+
+    if version.startswith("jruby"):
+        _install_jruby(repository_ctx, version)
+    elif version == "system":
         _symlink_system_ruby(repository_ctx)
     elif repository_ctx.os.name.startswith("windows"):
-        _install_via_rubyinstaller(repository_ctx)
+        _install_via_rubyinstaller(repository_ctx, version)
     else:
-        _install_via_ruby_build(repository_ctx)
+        _install_via_ruby_build(repository_ctx, version)
 
-    if repository_ctx.attr.version.startswith("jruby"):
+    if version.startswith("jruby"):
         ruby_binary_name = "jruby"
         gem_binary_name = "jgem"
     else:
@@ -26,14 +36,28 @@ def _rb_download_impl(repository_ctx):
         executable = False,
         substitutions = {
             "{bindir}": repr(repository_ctx.path("dist/bin")),
-            "{version}": repository_ctx.attr.version,
+            "{version}": version,
             "{ruby_binary_name}": ruby_binary_name,
             "{gem_binary_name}": gem_binary_name,
         },
     )
 
-def _install_jruby(repository_ctx):
-    version = repository_ctx.attr.version.removeprefix("jruby-")
+def _read_version_from_file(repository_ctx):
+    version = repository_ctx.read(repository_ctx.attr.version_file).strip("\r\n")
+    if repository_ctx.attr.version_file.name == ".tool-versions":
+        return _parse_version_from_tool_versions(version)
+    else:
+        return version
+
+def _parse_version_from_tool_versions(file):
+    for line in file.splitlines():
+        if line.startswith("ruby"):
+            version = line.partition(" ")[-1]
+            return version
+    return None
+
+def _install_jruby(repository_ctx, version):
+    version = version.removeprefix("jruby-")
     repository_ctx.report_progress("Downloading JRuby %s" % version)
     repository_ctx.download_and_extract(
         url = _JRUBY_BINARY_URL.format(version = version),
@@ -45,14 +69,14 @@ def _install_jruby(repository_ctx):
         repository_ctx.symlink("dist/bin/bundle.bat", "dist/bin/bundle.cmd")
 
 # https://github.com/oneclick/rubyinstaller2/wiki/FAQ#q-how-do-i-perform-a-silentunattended-install-with-the-rubyinstaller
-def _install_via_rubyinstaller(repository_ctx):
+def _install_via_rubyinstaller(repository_ctx, version):
     repository_ctx.report_progress("Downloading RubyInstaller")
     repository_ctx.download(
-        url = _RUBY_INSTALLER_URL.format(version = repository_ctx.attr.version),
+        url = _RUBY_INSTALLER_URL.format(version = version),
         output = "ruby-installer.exe",
     )
 
-    repository_ctx.report_progress("Installing Ruby %s" % repository_ctx.attr.version)
+    repository_ctx.report_progress("Installing Ruby %s" % version)
     result = repository_ctx.execute([
         "./ruby-installer.exe",
         "/components=ruby,msys2",
@@ -76,17 +100,17 @@ def _install_via_rubyinstaller(repository_ctx):
             "{}/bundle.cmd".format(binpath),
         )
 
-def _install_via_ruby_build(repository_ctx):
+def _install_via_ruby_build(repository_ctx, version):
     repository_ctx.report_progress("Downloading ruby-build %s" % repository_ctx.attr.ruby_build_version)
     repository_ctx.download_and_extract(
         url = _RUBY_BUILD_URL.format(version = repository_ctx.attr.ruby_build_version),
         output = "ruby-build",
         stripPrefix = "ruby-build-%s" % repository_ctx.attr.ruby_build_version,
     )
 
-    repository_ctx.report_progress("Installing Ruby %s" % repository_ctx.attr.version)
+    repository_ctx.report_progress("Installing Ruby %s" % version)
     result = repository_ctx.execute(
-        ["ruby-build/bin/ruby-build", "--verbose", repository_ctx.attr.version, "dist"],
+        ["ruby-build/bin/ruby-build", "--verbose", version, "dist"],
         timeout = 1200,
         quiet = not repository_ctx.os.environ.get("RUBY_RULES_DEBUG", default = False),
     )
@@ -106,10 +130,11 @@ rb_download = repository_rule(
     implementation = _rb_download_impl,
     attrs = {
         "version": attr.string(
-            mandatory = True,
-            doc = """
-Ruby version to install.
-            """,
+            doc = "Ruby version to install.",
+        ),
+        "version_file": attr.label(
+            allow_single_file = [".ruby-version"],
+            doc = "File to read Ruby version from.",
         ),
         "ruby_build_version": attr.string(
             default = "20231114",

ruby/extensions.bzl

@@ -5,7 +5,7 @@ load("//ruby/private/toolchain:repository_proxy.bzl", _rb_toolchain_repository_p
 
 DEFAULT_RUBY_REPOSITORY = "rules_ruby"
 
-def rb_register_toolchains(name = DEFAULT_RUBY_REPOSITORY, version = None, register = True, **kwargs):
+def rb_register_toolchains(name = DEFAULT_RUBY_REPOSITORY, version = None, version_file = None, register = True, **kwargs):
     """
     Register a Ruby toolchain and lazily download the Ruby Interpreter.
 
@@ -20,13 +20,14 @@ def rb_register_toolchains(name = DEFAULT_RUBY_REPOSITORY, version = None, regis
     load("@rules_ruby//ruby:deps.bzl", "rb_register_toolchains")
 
     rb_register_toolchains(
-        version = "2.7.5"
+        version = "3.0.6"
     )
     ```
 
     Args:
         name: base name of resulting repositories, by default "rules_ruby"
-        version: a semver version of Matz Ruby Interpreter, or a string like [interpreter type]-[version], or "system"
+        version: a semver version of MRI, or a string like [interpreter type]-[version], or "system"
+        version_file: .ruby-version or .tool-versions file to read version from
         register: whether to register the resulting toolchains, should be False under bzlmod
         **kwargs: additional parameters to the downloader for this interpreter type
     """
@@ -36,6 +37,7 @@ def rb_register_toolchains(name = DEFAULT_RUBY_REPOSITORY, version = None, regis
         _rb_download(
             name = repo_name,
             version = version,
+            version_file = version_file,
             **kwargs
         )
         _rb_toolchain_repository_proxy(