Helcaraxan/gomod

package util

import (
    "fmt"
    "os"
    "path/filepath"

    "go.uber.org/zap"

    "github.com/Helcaraxan/gomod/internal/logger"
)

// PrepareOutputPath ensures that the directory containing the specified path exist. It also checks
// that the full path does not refer to an existing file or directory. If such a path already exists
// an error is returned.
func PrepareOutputPath(log *logger.Logger, outputPath string) (*os.File, error) {
    l := log.With(zap.String("output-path", outputPath))
    log.Debug("Preparing output path.")

    // Perform target file sanity checks.
    var sanityCheckErr error
    if _, err := os.Stat(outputPath); err == nil {
        l.Error("The specified output path already exists.")
        sanityCheckErr = fmt.Errorf("target file %q already exists", outputPath)
    } else if !os.IsNotExist(err) {
        l.Error("Failed to check if output path already exists.", zap.Error(err))
        sanityCheckErr = fmt.Errorf("could not stat about %q", outputPath)
    }
    if sanityCheckErr != nil {
        return nil, sanityCheckErr
    }

    l.Debug("Ensuring output path folder exists.")
    if err := os.MkdirAll(filepath.Dir(outputPath), 0755); err != nil {
        l.Error("Failed to create output directory.", zap.Error(err))
        return nil, fmt.Errorf("could not create %q", filepath.Dir(outputPath))
    }
    out, err := os.OpenFile(outputPath, os.O_CREATE|os.O_WRONLY, 0644)
    if err != nil {
        l.Error("Could not create output file.", zap.Error(err))
        return nil, err
    }
    return out, nil
}