Add polyglot hook integration tests

.buildkite/Dockerfile-compile

@@ -1,3 +1,6 @@
 FROM golang:1.20.3@sha256:403f48633fb5ebd49f9a2b6ad6719f912df23dae44974a0c9445be331e72ff5e
 COPY build/ssh.conf /etc/ssh/ssh_config.d/
 RUN go install github.com/google/go-licenses@latest
+
+# Ruby used for polyglot hook integration tests
+RUN apt update && apt install -y ruby

bootstrap/integration/hooks_integration_test.go

@@ -3,6 +3,7 @@ package integration
 import (
 	"fmt"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"runtime"
 	"strings"
@@ -489,3 +490,85 @@ func TestPreExitHooksFireAfterCancel(t *testing.T) {
 
 	tester.CheckMocks(t)
 }
+
+func TestPolyglotScriptHooksCanBeRun(t *testing.T) {
+	if !which("ruby") {
+		t.Fatal("ruby not found in $PATH. This test requires ruby to be installed on the host")
+	}
+
+	defer experiments.WithUndo(experiments.PolyglotHooks)()
+
+	tester, err := NewBootstrapTester()
+	if err != nil {
+		t.Fatalf("NewBootstrapTester() error = %v", err)
+	}
+	defer tester.Close()
+
+	filename := "environment"
+	script := []string{
+		"#!/usr/bin/env ruby",
+		`puts "ohai, it's ruby!"`,
+	}
+
+	if err := os.WriteFile(filepath.Join(tester.HooksDir, filename), []byte(strings.Join(script, "\n")), 0755); err != nil {
+		t.Fatalf("os.WriteFile(%q, script, 0755 = %v", filename, err)
+	}
+
+	tester.RunAndCheck(t)
+
+	if !strings.Contains(tester.Output, "ohai, it's ruby!") {
+		t.Fatalf("tester.Output %s does not contain expected output: %q", tester.Output, "ohai, it's ruby!")
+	}
+}
+
+func TestPolyglotBinaryHooksCanBeRun(t *testing.T) {
+	defer experiments.WithUndo(experiments.PolyglotHooks)()
+	defer experiments.WithUndo(experiments.JobAPI)()
+
+	tester, err := NewBootstrapTester()
+	if err != nil {
+		t.Fatalf("NewBootstrapTester() error = %v", err)
+	}
+	defer tester.Close()
+
+	// We build a binary as part of this test so that we can produce a binary hook
+	// Forgive me for my sins, RSC, but it's better than the alternatives.
+	// The code that we're building is in ./test-binary-hook/main.go, it's pretty straightforward.
+
+	fmt.Println("Building test-binary-hook")
+	hookPath := filepath.Join(tester.HooksDir, "environment")
+	output, err := exec.Command("go", "build", "-o", hookPath, "./test-binary-hook").CombinedOutput()
+	if err != nil {
+		t.Fatalf("Failed to build test-binary-hook: %v, output: %s", err, string(output))
+	}
+
+	tester.ExpectGlobalHook("post-command").Once().AndExitWith(0).AndCallFunc(func(c *bintest.Call) {
+		// Set via ./test-binary-hook/main.go
+		if c.GetEnv("OCEAN") != "Pacífico" {
+			fmt.Fprintf(c.Stderr, "Expected OCEAN to be Pacífico, got %q", c.GetEnv("OCEAN"))
+			c.Exit(1)
+		} else {
+			c.Exit(0)
+		}
+	})
+
+	tester.RunAndCheck(t)
+
+	if !strings.Contains(tester.Output, "hi there from golang 🌊") {
+		t.Fatalf("tester.Output %s does not contain expected output: %q", tester.Output, "hi there from golang 🌊")
+	}
+}
+
+func which(prog string) bool {
+	paths := strings.Split(os.Getenv("PATH"), string(os.PathListSeparator))
+
+	for _, path := range paths {
+		if fi, err := os.Stat(filepath.Join(path, prog)); err == nil {
+			if !fi.IsDir() && fi.Mode()&0o111 != 0 {
+				return true
+			}
+		}
+	}
+
+	return false
+}

bootstrap/integration/test-binary-hook/main.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+
+	"github.com/buildkite/agent/v3/jobapi"
+)
+
+// This file gets built and commited to this repo, then used as part of the hooks integration test to ensure that the
+// bootstrap can run binary hooks
+func main() {
+	c, err := jobapi.NewDefaultClient()
+	if err != nil {
+		log.Fatalf("error: %v", fmt.Errorf("creating job api client: %w", err))
+	}
+
+	_, err = c.EnvUpdate(context.TODO(), &jobapi.EnvUpdateRequest{
+		Env: map[string]string{
+			"OCEAN":    "Pacífico",
+			"MOUNTAIN": "chimborazo",
+		},
+	})
+
+	if err != nil {
+		log.Fatalf("error: %v", fmt.Errorf("updating env: %w", err))
+	}
+
+	fmt.Println("hi there from golang 🌊")
+}