knotserver,hook: setup default post-receive hook on startup

this also populates the script with the correct executable path for
the `knot` command.

Signed-off-by: oppiliappan <[e-mail]>

cmd/knot/main.go

···
 
 	"github.com/urfave/cli/v3"
 	"tangled.sh/tangled.sh/core/guard"
+	"tangled.sh/tangled.sh/core/hook"
 	"tangled.sh/tangled.sh/core/keyfetch"
 	"tangled.sh/tangled.sh/core/knotserver"
 	"tangled.sh/tangled.sh/core/log"
···
 			guard.Command(),
 			knotserver.Command(),
 			keyfetch.Command(),
+			hook.Command(),
 		},
 	}
 

hook/hook.go

···
 
 	client := &http.Client{}
 
-	req, err := http.NewRequest("POST", endpoint+"/hooks/post-receive", strings.NewReader(payload))
+	req, err := http.NewRequest("POST", "http://"+endpoint+"/hooks/post-receive", strings.NewReader(payload))
 	if err != nil {
 		return fmt.Errorf("failed to create request: %w", err)
 	}

hook/setup.go

···
+// heavily inspired by gitea's model
+
+package hook
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/go-git/go-git/v5"
+)
+
+var ErrNoGitRepo = errors.New("not a git repo")
+var ErrCreatingHookDir = errors.New("failed to create hooks directory")
+var ErrCreatingHook = errors.New("failed to create hook")
+var ErrCreatingDelegate = errors.New("failed to create delegate hook")
+
+type config struct {
+	scanPath    string
+	internalApi string
+}
+
+type setupOpt func(*config)
+
+func WithScanPath(scanPath string) setupOpt {
+	return func(c *config) {
+		c.scanPath = scanPath
+	}
+}
+
+func WithInternalApi(api string) setupOpt {
+	return func(c *config) {
+		c.internalApi = api
+	}
+}
+
+// setup hooks for all users
+//
+// directory structure is typically like so:
+//
+//	did:plc:foobar/repo1
+//	did:plc:foobar/repo2
+//	did:web:barbaz/repo1
+func Setup(opts ...setupOpt) error {
+	config := config{}
+	for _, o := range opts {
+		o(&config)
+	}
+	// iterate over all directories in current directory:
+	userDirs, err := os.ReadDir(config.scanPath)
+	if err != nil {
+		return err
+	}
+
+	for _, user := range userDirs {
+		if !user.IsDir() {
+			continue
+		}
+
+		did := user.Name()
+		if !strings.HasPrefix(did, "did:") {
+			continue
+		}
+
+		userPath := filepath.Join(config.scanPath, did)
+		if err := setupUser(&config, userPath); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// setup hooks in /scanpath/did:plc:user
+func setupUser(config *config, userPath string) error {
+	repos, err := os.ReadDir(userPath)
+	if err != nil {
+		return err
+	}
+
+	for _, repo := range repos {
+		if !repo.IsDir() {
+			continue
+		}
+
+		path := filepath.Join(userPath, repo.Name())
+		if err := setup(config, path); err != nil {
+			if errors.Is(err, ErrNoGitRepo) {
+				continue
+			}
+			return err
+		}
+	}
+
+	return nil
+}
+
+// setup hook in /scanpath/did:plc:user/repo
+func setup(config *config, path string) error {
+	if _, err := git.PlainOpen(path); err != nil {
+		return fmt.Errorf("%s: %w", path, ErrNoGitRepo)
+	}
+
+	preReceiveD := filepath.Join(path, "hooks", "pre-receive.d")
+	if err := os.MkdirAll(preReceiveD, 0755); err != nil {
+		return fmt.Errorf("%s: %w", preReceiveD, ErrCreatingHookDir)
+	}
+
+	notify := filepath.Join(preReceiveD, "40-notify.sh")
+	if err := mkHook(config, notify); err != nil {
+		return fmt.Errorf("%s: %w", notify, ErrCreatingHook)
+	}
+
+	delegate := filepath.Join(path, "hooks", "pre-receive")
+	if err := mkDelegate(delegate); err != nil {
+		return fmt.Errorf("%s: %w", delegate, ErrCreatingDelegate)
+	}
+
+	return nil
+}
+
+func mkHook(config *config, hookPath string) error {
+	executablePath, err := os.Executable()
+	if err != nil {
+		return err
+	}
+
+	hookContent := fmt.Sprintf(`#!/usr/bin/env bash
+# AUTO GENERATED BY KNOT, DO NOT MODIFY
+%s hook -git-dir "$GIT_DIR" -user-did "$GIT_USER_DID" -user-handle "$GIT_USER_HANDLE" -internal-api "%s" post-recieve
+	`, executablePath, config.internalApi)
+
+	return os.WriteFile(hookPath, []byte(hookContent), 0755)
+}
+
+func mkDelegate(path string) error {
+	content := fmt.Sprintf(`#!/usr/bin/env bash
+# AUTO GENERATED BY KNOT, DO NOT MODIFY
+data=$(cat)
+exitcodes=""
+hookname=$(basename $0)
+GIT_DIR=${GIT_DIR:-$(dirname $0)/..}
+
+for hook in ${GIT_DIR}/hooks/${hookname}.d/*; do
+  test -x "${hook}" && test -f "${hook}" || continue
+  echo "${data}" | "${hook}"
+  exitcodes="${exitcodes} $?"
+done
+
+for i in ${exitcodes}; do
+  [ ${i} -eq 0 ] || exit ${i}
+done
+	`)
+
+	return os.WriteFile(path, []byte(content), 0755)
+}

knotserver/server.go

···
 
 	"github.com/urfave/cli/v3"
 	"tangled.sh/tangled.sh/core/api/tangled"
+	"tangled.sh/tangled.sh/core/hook"
 	"tangled.sh/tangled.sh/core/jetstream"
 	"tangled.sh/tangled.sh/core/knotserver/config"
 	"tangled.sh/tangled.sh/core/knotserver/db"
···
 	if err != nil {
 		return fmt.Errorf("failed to load config: %w", err)
 	}
+
+	err = hook.Setup(
+		hook.WithScanPath(c.Repo.ScanPath),
+		hook.WithInternalApi(c.Server.InternalListenAddr),
+	)
+	if err != nil {
+		return fmt.Errorf("failed to setup hooks: %w", err)
+	}
+	l.Info("successfully finished setting up hooks")
 
 	if c.Server.Dev {
 		l.Info("running in dev mode, signature verification is disabled")