feat(01-01): generate and build hello app from manifest

- Add summer build with validated summer.yaml codegen - Generate stable main.go and plugins.gen.go then go build - Smoke-test the built hello binary greeter:hello command
2026-09-16 13:01:24 +02:00
parent 96a8d38be2
commit 2078f91a2b
5 changed files with 557 additions and 0 deletions
--- a/internal/build/build.go
+++ b/internal/build/build.go
@@ -0,0 +1,308 @@
+package build
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"go/format"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+	"unicode"
+
+	"github.com/knadh/koanf/parsers/yaml"
+)
+
+const manifestName = "summer.yaml"
+
+// Manifest is the ordered app plugin list used to generate imports.
+type Manifest struct {
+	Module  string
+	Binary  string
+	Plugins []Plugin
+}
+
+// Plugin is one compiled plugin module in manifest order.
+type Plugin struct {
+	ID     string
+	Module string
+}
+
+// LoadManifest reads and validates summer.yaml at path.
+func LoadManifest(path string) (Manifest, error) {
+	raw, err := os.ReadFile(path)
+	if err != nil {
+		return Manifest{}, fmt.Errorf("build: read %s: %w", path, err)
+	}
+	tree, err := yaml.Parser().Unmarshal(raw)
+	if err != nil {
+		return Manifest{}, fmt.Errorf("build: parse %s: %w", path, err)
+	}
+	m := Manifest{
+		Module: strings.TrimSpace(asString(tree["module"])),
+		Binary: strings.TrimSpace(asString(tree["binary"])),
+	}
+	if err := validateModulePath(m.Module); err != nil {
+		return Manifest{}, fmt.Errorf("build: module: %w", err)
+	}
+	if err := validateBinary(m.Binary); err != nil {
+		return Manifest{}, fmt.Errorf("build: binary: %w", err)
+	}
+
+	seenID := make(map[string]struct{})
+	seenMod := make(map[string]struct{})
+	for i, item := range asSlice(tree["plugins"]) {
+		entry := asMap(item)
+		if entry == nil {
+			return Manifest{}, fmt.Errorf("build: plugins[%d] must be a mapping with id and module", i)
+		}
+		p := Plugin{
+			ID:     strings.TrimSpace(asString(entry["id"])),
+			Module: strings.TrimSpace(asString(entry["module"])),
+		}
+		if p.ID == "" {
+			return Manifest{}, fmt.Errorf("build: plugins[%d] is missing id", i)
+		}
+		if strings.ContainsAny(p.ID, " \t\r\n\"'`") {
+			return Manifest{}, fmt.Errorf("build: plugins[%d] has invalid id %q", i, p.ID)
+		}
+		if _, dup := seenID[p.ID]; dup {
+			return Manifest{}, fmt.Errorf("build: duplicate plugin id %q", p.ID)
+		}
+		if err := validateModulePath(p.Module); err != nil {
+			return Manifest{}, fmt.Errorf("build: plugins[%d] module: %w", i, err)
+		}
+		if _, dup := seenMod[p.Module]; dup {
+			return Manifest{}, fmt.Errorf("build: duplicate plugin module %q", p.Module)
+		}
+		seenID[p.ID] = struct{}{}
+		seenMod[p.Module] = struct{}{}
+		m.Plugins = append(m.Plugins, p)
+	}
+	return m, nil
+}
+
+// App generates app sources from summer.yaml and runs go build in appDir.
+func App(ctx context.Context, appDir string, out io.Writer) error {
+	if appDir == "" {
+		return fmt.Errorf("build: app directory is empty")
+	}
+	if !filepath.IsAbs(appDir) {
+		abs, err := filepath.Abs(appDir)
+		if err != nil {
+			return fmt.Errorf("build: resolve app directory: %w", err)
+		}
+		appDir = abs
+	}
+	if out == nil {
+		out = os.Stdout
+	}
+	m, err := LoadManifest(filepath.Join(appDir, manifestName))
+	if err != nil {
+		return err
+	}
+	if err := generate(appDir, m); err != nil {
+		return err
+	}
+
+	binRel := filepath.Join("bin", m.Binary)
+	if err := os.MkdirAll(filepath.Join(appDir, "bin"), 0o755); err != nil {
+		return fmt.Errorf("build: create bin dir: %w", err)
+	}
+
+	cmd := exec.CommandContext(ctx, "go", "build", "-o", binRel, ".")
+	cmd.Dir = appDir
+	cmd.Stdout = out
+	cmd.Stderr = out
+	start := time.Now()
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("build: go build: %w", err)
+	}
+	fmt.Fprintf(out, "built %s in %s\n", m.Binary, time.Since(start).Round(time.Millisecond))
+	return nil
+}
+
+func generate(appDir string, m Manifest) error {
+	mainSrc, err := generateMain(m)
+	if err != nil {
+		return err
+	}
+	pluginsSrc, err := generatePluginsGen(m)
+	if err != nil {
+		return err
+	}
+	if err := writeIfChanged(filepath.Join(appDir, "main.go"), mainSrc); err != nil {
+		return err
+	}
+	if err := writeIfChanged(filepath.Join(appDir, "plugins.gen.go"), pluginsSrc); err != nil {
+		return err
+	}
+	return nil
+}
+
+func generateMain(m Manifest) ([]byte, error) {
+	var b strings.Builder
+	b.WriteString("// Code generated by summer build. DO NOT EDIT.\n\n")
+	b.WriteString("package main\n\n")
+	b.WriteString("import (\n")
+	b.WriteString("\t\"fmt\"\n")
+	b.WriteString("\t\"io\"\n")
+	b.WriteString("\t\"os\"\n\n")
+	b.WriteString("\t\"git.golem15.com/golem15/summercms/backpack\"\n")
+	b.WriteString("\t\"git.golem15.com/golem15/summercms/bonfire\"\n")
+	b.WriteString("\t\"git.golem15.com/golem15/summercms/compass\"\n")
+	b.WriteString("\t\"git.golem15.com/golem15/summercms/pact\"\n")
+	b.WriteString("\t\"git.golem15.com/golem15/summercms/party\"\n")
+	b.WriteString(")\n\n")
+	b.WriteString("func main() {\n")
+	b.WriteString("\tif err := run(os.Args[1:], os.Stdout); err != nil {\n")
+	b.WriteString("\t\tfmt.Fprintln(os.Stderr, err)\n")
+	b.WriteString("\t\tos.Exit(1)\n")
+	b.WriteString("\t}\n")
+	b.WriteString("}\n\n")
+	b.WriteString("func run(args []string, out io.Writer) error {\n")
+	b.WriteString("\tcfg, err := compass.Load(\"config\")\n")
+	b.WriteString("\tif err != nil {\n")
+	b.WriteString("\t\treturn err\n")
+	b.WriteString("\t}\n")
+	b.WriteString("\tapp := backpack.New(cfg)\n")
+	b.WriteString("\tplugins, err := party.Activate(app, PluginIDs)\n")
+	b.WriteString("\tif err != nil {\n")
+	b.WriteString("\t\treturn err\n")
+	b.WriteString("\t}\n")
+	b.WriteString("\tvar commands []bonfire.Command\n")
+	b.WriteString("\tfor _, plugin := range plugins {\n")
+	b.WriteString("\t\tif hasCommands, ok := plugin.(pact.HasCommands); ok {\n")
+	b.WriteString("\t\t\tcommands = append(commands, hasCommands.Commands()...)\n")
+	b.WriteString("\t\t}\n")
+	b.WriteString("\t}\n")
+	fmt.Fprintf(&b, "\troot := bonfire.NewRoot(%s, commands, out)\n", strconv.Quote(m.Binary))
+	b.WriteString("\troot.SetArgs(args)\n")
+	b.WriteString("\treturn root.Execute()\n")
+	b.WriteString("}\n")
+	return formatSource([]byte(b.String()))
+}
+
+func generatePluginsGen(m Manifest) ([]byte, error) {
+	var b strings.Builder
+	b.WriteString("// Code generated by summer build. DO NOT EDIT.\n\n")
+	b.WriteString("package main\n\n")
+	if len(m.Plugins) > 0 {
+		b.WriteString("import (\n")
+		for _, p := range m.Plugins {
+			fmt.Fprintf(&b, "\t_ %s\n", strconv.Quote(p.Module))
+		}
+		b.WriteString(")\n\n")
+	}
+	b.WriteString("// PluginIDs is the ordered plugin list from summer.yaml.\n")
+	b.WriteString("var PluginIDs = []string{\n")
+	for _, p := range m.Plugins {
+		fmt.Fprintf(&b, "\t%s,\n", strconv.Quote(p.ID))
+	}
+	b.WriteString("}\n")
+	return formatSource([]byte(b.String()))
+}
+
+func formatSource(src []byte) ([]byte, error) {
+	formatted, err := format.Source(src)
+	if err != nil {
+		return nil, fmt.Errorf("build: format generated go: %w", err)
+	}
+	return formatted, nil
+}
+
+func writeIfChanged(path string, content []byte) error {
+	existing, err := os.ReadFile(path)
+	if err == nil && bytes.Equal(existing, content) {
+		return nil
+	}
+	if err != nil && !errors.Is(err, os.ErrNotExist) {
+		return fmt.Errorf("build: read %s: %w", path, err)
+	}
+	if err := os.WriteFile(path, content, 0o644); err != nil {
+		return fmt.Errorf("build: write %s: %w", path, err)
+	}
+	return nil
+}
+
+func validateBinary(name string) error {
+	if name == "" {
+		return fmt.Errorf("is empty")
+	}
+	if name != filepath.Base(name) || strings.ContainsRune(name, os.PathSeparator) {
+		return fmt.Errorf("%q must be a bare file name", name)
+	}
+	if name == "." || name == ".." {
+		return fmt.Errorf("%q is not a valid binary name", name)
+	}
+	for _, r := range name {
+		if r > unicode.MaxASCII || !(unicode.IsLetter(r) || unicode.IsDigit(r) || r == '.' || r == '_' || r == '-') {
+			return fmt.Errorf("%q contains invalid characters", name)
+		}
+	}
+	return nil
+}
+
+func validateModulePath(path string) error {
+	if path == "" {
+		return fmt.Errorf("is empty")
+	}
+	if strings.HasPrefix(path, "-") {
+		return fmt.Errorf("%q must not start with -", path)
+	}
+	if strings.ContainsAny(path, " \t\r\n\\\"'`$;&|*?<>()[]{}") {
+		return fmt.Errorf("%q contains invalid characters", path)
+	}
+	if filepath.IsAbs(path) || strings.Contains(path, `\`) {
+		return fmt.Errorf("%q is not a valid module path", path)
+	}
+	for _, seg := range strings.Split(path, "/") {
+		if seg == "" || seg == "." || seg == ".." {
+			return fmt.Errorf("%q has an invalid path segment", path)
+		}
+		if strings.Contains(seg, "@") {
+			return fmt.Errorf("%q must not contain a version suffix", path)
+		}
+	}
+	return nil
+}
+
+func asString(v any) string {
+	s, _ := v.(string)
+	return s
+}
+
+func asSlice(v any) []any {
+	switch s := v.(type) {
+	case []any:
+		return s
+	case nil:
+		return nil
+	default:
+		return nil
+	}
+}
+
+func asMap(v any) map[string]any {
+	switch m := v.(type) {
+	case map[string]any:
+		return m
+	case map[any]any:
+		out := make(map[string]any, len(m))
+		for k, val := range m {
+			ks, ok := k.(string)
+			if !ok {
+				continue
+			}
+			out[ks] = val
+		}
+		return out
+	default:
+		return nil
+	}
+}
--- a/internal/build/build_test.go
+++ b/internal/build/build_test.go
@@ -0,0 +1,129 @@
+package build
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestLoadHelloManifest(t *testing.T) {
+	m, err := LoadManifest(filepath.Join("..", "..", "examples", "hello", "summer.yaml"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if m.Binary != "hello" {
+		t.Fatalf("binary = %q", m.Binary)
+	}
+	if len(m.Plugins) != 2 || m.Plugins[0].ID != "golem15.hello" || m.Plugins[1].ID != "golem15.greeter" {
+		t.Fatalf("plugins = %+v", m.Plugins)
+	}
+}
+
+func TestParseManifestRejectsDuplicatesAndInvalidPaths(t *testing.T) {
+	dir := t.TempDir()
+
+	t.Run("duplicate id", func(t *testing.T) {
+		path := filepath.Join(dir, "dup.yaml")
+		write(t, path, "module: example.com/app\nbinary: app\nplugins:\n  - id: a.b\n    module: example.com/one\n  - id: a.b\n    module: example.com/two\n")
+		if _, err := LoadManifest(path); err == nil || !strings.Contains(err.Error(), "a.b") {
+			t.Fatalf("want duplicate id error, got %v", err)
+		}
+	})
+
+	t.Run("invalid module", func(t *testing.T) {
+		path := filepath.Join(dir, "bad.yaml")
+		write(t, path, "module: example.com/app\nbinary: app\nplugins:\n  - id: a.b\n    module: \"example.com/one; rm -rf /\"\n")
+		if _, err := LoadManifest(path); err == nil {
+			t.Fatal("want invalid module error")
+		}
+	})
+
+	t.Run("path traversal module", func(t *testing.T) {
+		path := filepath.Join(dir, "dotdot.yaml")
+		write(t, path, "module: example.com/app\nbinary: app\nplugins:\n  - id: a.b\n    module: example.com/../evil\n")
+		if _, err := LoadManifest(path); err == nil {
+			t.Fatal("want invalid module error")
+		}
+	})
+}
+
+func TestGenerateStableQuotedImportsInManifestOrder(t *testing.T) {
+	m := Manifest{
+		Module: "example.com/app",
+		Binary: "hello",
+		Plugins: []Plugin{
+			{ID: "golem15.hello", Module: "example.com/app/plugins/base"},
+			{ID: "golem15.greeter", Module: "example.com/app/plugins/greeter"},
+		},
+	}
+	first, err := generatePluginsGen(m)
+	if err != nil {
+		t.Fatal(err)
+	}
+	second, err := generatePluginsGen(m)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(first, second) {
+		t.Fatal("generated plugins.gen.go is not byte-stable")
+	}
+	src := string(first)
+	baseAt := strings.Index(src, `example.com/app/plugins/base`)
+	greeterAt := strings.Index(src, `example.com/app/plugins/greeter`)
+	if baseAt < 0 || greeterAt < 0 || baseAt > greeterAt {
+		t.Fatalf("imports not in manifest order:\n%s", src)
+	}
+	if !strings.Contains(src, "\t_ \"example.com/app/plugins/base\"") {
+		t.Fatalf("import is not Go-quoted:\n%s", src)
+	}
+
+	mainSrc, err := generateMain(m)
+	if err != nil {
+		t.Fatal(err)
+	}
+	again, err := generateMain(m)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(mainSrc, again) {
+		t.Fatal("generated main.go is not byte-stable")
+	}
+	if !bytes.Contains(mainSrc, []byte(`bonfire.NewRoot("hello"`)) {
+		t.Fatalf("main does not use manifest binary:\n%s", mainSrc)
+	}
+	if bytes.Contains(mainSrc, []byte("examples/hello")) {
+		t.Fatal("generated main hard-codes examples/hello")
+	}
+}
+
+func TestWriteIfChangedSkipsIdenticalBytes(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "out.go")
+	content := []byte("package main\n")
+	if err := writeIfChanged(path, content); err != nil {
+		t.Fatal(err)
+	}
+	info, err := os.Stat(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := writeIfChanged(path, content); err != nil {
+		t.Fatal(err)
+	}
+	again, err := os.Stat(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !info.ModTime().Equal(again.ModTime()) {
+		t.Fatal("identical content rewrote the file")
+	}
+}
+
+func write(t *testing.T, path, body string) {
+	t.Helper()
+	if err := os.WriteFile(path, []byte(body), 0o644); err != nil {
+		t.Fatal(err)
+	}
+}