Add envfile.Generate

envfile/envfile.go

@@ -6,7 +6,42 @@
 // files.
 package envfile
 
+import (
+	"github.com/go-pogo/errors"
+	"path"
+	"path/filepath"
+	"runtime"
+)
+
 const (
 	panicNilFile = "envfile: file must not be nil"
 	panicNilFsys = "envfile: fs.FS must not be nil"
 )
+
+// Generate encodes and writes an env file in dir based on the provided src.
+// It is meant to be used with go generate to create .env files based on the
+// project's config(s).
+func Generate(dir, filename string, src any) error {
+	if dir == "" {
+		_, dir, _, _ = runtime.Caller(1)
+		dir = filepath.Dir(dir)
+	}
+
+	if !path.IsAbs(filename) {
+		filename = filepath.Join(dir, ".env")
+	}
+
+	enc, err := Create(filename)
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	enc.TakeValues = true
+	defer errors.AppendFunc(&err, enc.Close)
+
+	if err = enc.Encode(src); err != nil {
+		err = errors.WithStack(err)
+		return err
+	}
+	return nil
+}