Merge branch '74-go-go-go-go-go' into 'master'

Feature flag for go/ruby gitlab-shell implementations

Closes #74

See merge request gitlab-org/gitlab-shell!233

1 files changed, 56 insertions, 0 deletions

diff --git a/go/cmd/gitlab-shell/main.go b/go/cmd/gitlab-shell/main.go
new file mode 100644
index 0000000..ae54151
--- /dev/null
+++ b/go/cmd/gitlab-shell/main.go
@@ -0,0 +1,56 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"syscall"
+
+	"gitlab.com/gitlab-org/gitlab-shell/go/internal/config"
+)
+
+var (
+	binDir  string
+	rootDir string
+)
+
+func init() {
+	binDir = filepath.Dir(os.Args[0])
+	rootDir = filepath.Dir(binDir)
+}
+
+func migrate(*config.Config) (int, bool) {
+	// TODO: Dispatch appropriate requests to Go handlers and return
+	// <exitstatus, true> depending on how they fare
+	return 0, false
+}
+
+// rubyExec will never return. It either replaces the current process with a
+// Ruby interpreter, or outputs an error and kills the process.
+func execRuby() {
+	rubyCmd := filepath.Join(binDir, "gitlab-shell-ruby")
+
+	execErr := syscall.Exec(rubyCmd, os.Args, os.Environ())
+	if execErr != nil {
+		fmt.Fprintf(os.Stderr, "Failed to exec(%q): %v\n", rubyCmd, execErr)
+		os.Exit(1)
+	}
+}
+
+func main() {
+	// Fall back to Ruby in case of problems reading the config, but issue a
+	// warning as this isn't something we can sustain indefinitely
+	config, err := config.NewFromDir(rootDir)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "Failed to read config, falling back to gitlab-shell-ruby")
+		execRuby()
+	}
+
+	// Try to handle the command with the Go implementation
+	if exitCode, done := migrate(config); done {
+		os.Exit(exitCode)
+	}
+
+	// Since a migration has not handled the command, fall back to Ruby to do so
+	execRuby()
+}