Project harness for Ruby (#335)

## What was changed
Adds `ruby/harness/` package, effectively a port of the same Python
harness (`python/harness`).

`ruby/harness is a standalone Ruby package that supports the same
harness semantics, structure, and API as the existing Python harness.
The test suite (`ruby/harness/tests`) similarly mimics the existing
Python harness test suite.

Notable, a significant portion of the change comes from making the
harness a standalone Ruby package with linting support (RBS, Steepfile,
etc.).

## Why?
- load testing ergonomics / DX
- Language parity

Author: THardy98

.gitignore

@@ -24,6 +24,7 @@ workers/python/**/__pycache__/
 workers/typescript/harness/dist/
 workers/typescript/harness/dist-test/
 workers/typescript/harness/src/generated/
+workers/**/.rubocop_cache/
 workers/*/omes-temp-*/
 workers/*/prepared/
 workers/**/project-build-*/

cmd/dev/install.go

@@ -224,6 +224,13 @@ func installRuby(ctx context.Context) error {
 		return err
 	}
 	fmt.Println("✅ Ruby worker dependencies installed successfully!")
+
+	harnessDir := targetDir + "/harness"
+	fmt.Println("Installing Ruby harness dependencies...")
+	if err := runCommandInDir(ctx, harnessDir, "bundle", "install"); err != nil {
+		return err
+	}
+	fmt.Println("✅ Ruby harness dependencies installed successfully!")
 	return nil
 }
 

cmd/dev/lint_and_format.go

@@ -228,6 +228,23 @@ func lintAndFormatRubyWorker(ctx context.Context, workerDir string) error {
 		return err
 	}
 
+	harnessDir := workerDir + "/harness"
+
+	fmt.Println("Formatting Ruby harness...")
+	if err := runCommandInDir(ctx, harnessDir, "bundle", "exec", "rubocop", "-A"); err != nil {
+		return err
+	}
+
+	fmt.Println("Linting Ruby harness...")
+	if err := runCommandInDir(ctx, harnessDir, "bundle", "exec", "rubocop"); err != nil {
+		return err
+	}
+
+	fmt.Println("Type checking Ruby harness...")
+	if err := runCommandInDir(ctx, harnessDir, "bundle", "exec", "steep", "check"); err != nil {
+		return err
+	}
+
 	fmt.Println("✅ Ruby lint-and-format completed successfully!")
 	return nil
 }

cmd/dev/test.go

@@ -92,6 +92,11 @@ func runTestWorker(ctx context.Context, language string) error {
 			return err
 		}
 	}
+	if language == "ruby" {
+		if err := runRubyHarnessTests(ctx, repoDir); err != nil {
+			return err
+		}
+	}
 	return testWorkerLocally(ctx, repoDir, language, sdkVersion)
 }
 
@@ -125,6 +130,34 @@ func runTypeScriptHarnessTests(ctx context.Context, repoDir string) error {
 	return nil
 }
 
+func runRubyHarnessTests(ctx context.Context, repoDir string) error {
+	harnessDir := filepath.Join(repoDir, "workers", "ruby", "harness")
+	rubyVersion, err := getVersion("ruby")
+	if err != nil {
+		return err
+	}
+	if err := checkMise(); err != nil {
+		return err
+	}
+	fmt.Println("Running Ruby harness tests...")
+	if err := runCommandInDir(
+		ctx,
+		harnessDir,
+		"mise",
+		"exec",
+		"ruby@"+rubyVersion,
+		"--",
+		"bundle",
+		"exec",
+		"rake",
+		"test",
+	); err != nil {
+		return fmt.Errorf("failed Ruby harness tests: %w", err)
+	}
+	fmt.Println("✅ Ruby harness tests completed successfully!")
+	return nil
+}
+
 func testWorkerLocally(ctx context.Context, repoDir, language, sdkVersion string) error {
 	args := []string{
 		"go", "run", "./cmd", "run-scenario-with-worker",

go.mod

@@ -12,7 +12,7 @@ require (
 	github.com/spf13/cobra v1.7.0
 	github.com/spf13/pflag v1.0.5
 	github.com/stretchr/testify v1.11.1
-	github.com/temporalio/features v0.0.0-20260331150122-757294c2a9e9
+	github.com/temporalio/features v0.0.0-20260427223549-86e4c0deedd7
 	github.com/temporalio/omes/workers/go/harness/api v0.0.0-00010101000000-000000000000
 	go.temporal.io/api v1.62.7
 	go.temporal.io/sdk v1.42.0

go.sum

@@ -97,8 +97,8 @@ github.com/stretchr/objx v0.5.2/go.mod h1:FRsXN1f5AsAjCGJKqEizvkpNtU+EGNCLh3NxZ/
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
 github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
-github.com/temporalio/features v0.0.0-20260331150122-757294c2a9e9 h1:9ifP6KcfPhf22qFb4t7L8M11nkWGD8cyAFQ3fUrLqFw=
-github.com/temporalio/features v0.0.0-20260331150122-757294c2a9e9/go.mod h1:LsZUh/AkCjnOKrEpnEklGmsJ3g758Hyq2X+hzMofMjw=
+github.com/temporalio/features v0.0.0-20260427223549-86e4c0deedd7 h1:gBLwgyi8xw0oqZgxMwxTRGIfP8RxtI7r1igm3G6aXGY=
+github.com/temporalio/features v0.0.0-20260427223549-86e4c0deedd7/go.mod h1:BUWwBMK+Ga5h9xPTS7+kmutSIfY4K1gfSH8eG7fSbU0=
 github.com/tklauser/go-sysconf v0.3.15 h1:VE89k0criAymJ/Os65CSn1IXaol+1wrsFHEB8Ol49K4=
 github.com/tklauser/go-sysconf v0.3.15/go.mod h1:Dmjwr6tYFIseJw7a3dRLJfsHAMXZ3nEnL/aZY+0IuI4=
 github.com/tklauser/numcpus v0.10.0 h1:18njr6LDBk1zuna922MgdjQuJFjrdppsZG60sHGfjso=

workers/build.go

@@ -285,37 +285,22 @@ func (b *Builder) buildDotNet(ctx context.Context, baseDir string) (sdkbuild.Pro
 }
 
 func (b *Builder) buildRuby(ctx context.Context, baseDir string) (sdkbuild.Program, error) {
-	// If version not provided, read the version constraint from the gemspec.
-	version := b.SdkOptions.Version
-	if version == "" {
-		gemspecBytes, err := os.ReadFile(filepath.Join(baseDir, "omes.gemspec"))
-		if err != nil {
-			return nil, fmt.Errorf("failed reading omes.gemspec: %w", err)
-		}
-		for _, line := range strings.Split(string(gemspecBytes), "\n") {
-			line = strings.TrimSpace(line)
-			if strings.Contains(line, "'temporalio'") || strings.Contains(line, `"temporalio"`) {
-				parts := strings.Split(line, ",")
-				if len(parts) >= 2 {
-					version = strings.TrimSpace(parts[1])
-					version = strings.Trim(version, `"'`)
-				}
-				break
-			}
-		}
-		if version == "" {
-			return nil, fmt.Errorf("version not found in omes.gemspec")
-		}
-	}
-
-	prog, err := sdkbuild.BuildRubyProgram(ctx, sdkbuild.BuildRubyProgramOptions{
+	options := sdkbuild.BuildRubyProgramOptions{
 		BaseDir:   baseDir,
 		SourceDir: baseDir,
 		DirName:   b.DirName,
-		Version:   version,
+		Version:   b.SdkOptions.Version,
 		Stdout:    b.stdout,
 		Stderr:    b.stderr,
-	})
+	}
+	if b.ProjectName == "" {
+		options.MoreDependencies = []sdkbuild.RubyDependency{{
+			Name: "harness",
+			Path: filepath.Join(baseDir, "harness"),
+		}}
+	}
+
+	prog, err := sdkbuild.BuildRubyProgram(ctx, options)
 	if err != nil {
 		return nil, fmt.Errorf("failed preparing: %w", err)
 	}

workers/go/go.sum

@@ -88,8 +88,8 @@ github.com/stretchr/objx v0.5.2/go.mod h1:FRsXN1f5AsAjCGJKqEizvkpNtU+EGNCLh3NxZ/
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
 github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
-github.com/temporalio/features v0.0.0-20260331150122-757294c2a9e9 h1:9ifP6KcfPhf22qFb4t7L8M11nkWGD8cyAFQ3fUrLqFw=
-github.com/temporalio/features v0.0.0-20260331150122-757294c2a9e9/go.mod h1:LsZUh/AkCjnOKrEpnEklGmsJ3g758Hyq2X+hzMofMjw=
+github.com/temporalio/features v0.0.0-20260427223549-86e4c0deedd7 h1:gBLwgyi8xw0oqZgxMwxTRGIfP8RxtI7r1igm3G6aXGY=
+github.com/temporalio/features v0.0.0-20260427223549-86e4c0deedd7/go.mod h1:BUWwBMK+Ga5h9xPTS7+kmutSIfY4K1gfSH8eG7fSbU0=
 github.com/tklauser/go-sysconf v0.3.15 h1:VE89k0criAymJ/Os65CSn1IXaol+1wrsFHEB8Ol49K4=
 github.com/tklauser/go-sysconf v0.3.15/go.mod h1:Dmjwr6tYFIseJw7a3dRLJfsHAMXZ3nEnL/aZY+0IuI4=
 github.com/tklauser/numcpus v0.10.0 h1:18njr6LDBk1zuna922MgdjQuJFjrdppsZG60sHGfjso=

workers/ruby/.rubocop.yml

@@ -1,7 +1,9 @@
 AllCops:
   TargetRubyVersion: 3.3
   NewCops: enable
+  SuggestExtensions: false
   Exclude:
+    - "harness/**/*"
     - "protos/**/*"
     - "vendor/**/*"
     - "omes-temp-*/**/*"
@@ -44,3 +46,6 @@ Metrics/PerceivedComplexity:
 
 Metrics/AbcSize:
   Max: 25
+
+Metrics/ParameterLists:
+  CountKeywordArgs: false

workers/ruby/Gemfile

@@ -1,7 +1,10 @@
 source 'https://rubygems.org'
 
 gemspec
+gem 'harness', path: 'harness'
 
 group :development do
+  gem 'rbs', '~> 3.10'
   gem 'rubocop', '~> 1.0'
+  gem 'steep', '~> 1.10'
 end