refactor(cli): rename operator command to tht

tools/tht/internal/compose/runner.go

@@ -0,0 +1,56 @@
+// Package compose executes Docker Compose through a fixed executable and argument arrays.
+package compose
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+)
+
+// Result is the captured output and process exit code for one Docker invocation.
+type Result struct {
+	Stdout   string
+	Stderr   string
+	ExitCode int
+}
+
+// Runner executes the Docker CLI. It never invokes a shell.
+type Runner struct {
+	binary string
+}
+
+// NewRunner returns a runner for binary. An empty binary selects docker from PATH.
+func NewRunner(binary string) Runner {
+	if binary == "" {
+		binary = "docker"
+	}
+	return Runner{binary: binary}
+}
+
+// Run invokes Docker with the supplied argument array and optional standard input.
+func (r Runner) Run(ctx context.Context, args []string, stdin io.Reader) (Result, error) {
+	command := exec.CommandContext(ctx, r.binary, args...)
+	command.Stdin = stdin
+	var stdout, stderr bytes.Buffer
+	command.Stdout = &stdout
+	command.Stderr = &stderr
+	err := command.Run()
+	result := Result{Stdout: stdout.String(), Stderr: stderr.String()}
+	if err == nil {
+		return result, nil
+	}
+	var exitError *exec.ExitError
+	if errors.As(err, &exitError) {
+		result.ExitCode = exitError.ExitCode()
+		return result, err
+	}
+	if errors.Is(err, exec.ErrNotFound) || errors.Is(err, os.ErrNotExist) {
+		result.ExitCode = 127
+		return result, fmt.Errorf("%w: %w", exec.ErrNotFound, err)
+	}
+	return result, err
+}