basic common app packages

dotenv/read.go

@@ -0,0 +1,101 @@
+package dotenv
+
+import (
+	"bytes"
+	"io"
+	"log/slog"
+	"maps"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+//
+// ported from https://github.com/joho/godotenv/blob/main/godotenv.go
+//
+
+// Read all env (with same file loading semantics as Load) but return values as
+// a map rather than automatically writing values into env
+func Read(dir string, filenames ...string) (envMap map[string]string, err error) {
+	filenames = filenamesOrDefault(filenames)
+	envMap = make(map[string]string)
+
+	for _, filename := range filenames {
+		slog.Info("read .env", slog.String("file", filepath.Join(dir, filename)))
+		individualEnvMap, individualErr := readFile(filepath.Join(dir, filename))
+
+		if individualErr != nil {
+			err = individualErr
+			return
+		}
+
+		maps.Copy(envMap, individualEnvMap)
+	}
+
+	return
+}
+
+// LoadFile env file value to app env
+//
+// overload = true will replace env value even if they already there in process env
+func LoadFile(filename string, overload bool) error {
+	envMap, err := readFile(filename)
+	if err != nil {
+		if os.IsNotExist(err) {
+			slog.Info(".env not found", slog.String("file", filename))
+			return nil
+		}
+		return err
+	}
+
+	currentEnv := map[string]bool{}
+	rawEnv := os.Environ()
+	for _, rawEnvLine := range rawEnv {
+		key := strings.Split(rawEnvLine, "=")[0]
+		currentEnv[key] = true
+	}
+
+	for key, value := range envMap {
+		if !currentEnv[key] || overload {
+			_ = os.Setenv(key, value)
+		}
+	}
+
+	return nil
+}
+
+func filenamesOrDefault(filenames []string) []string {
+	if len(filenames) == 0 {
+		return []string{".env"}
+	}
+	return filenames
+}
+
+func readFile(filename string) (envMap map[string]string, err error) {
+	file, err := os.Open(filename)
+	if err != nil {
+		return
+	}
+	defer file.Close()
+
+	return parse(file)
+}
+
+// parse reads an env file from io.Reader, returning a map of keys and values.
+func parse(r io.Reader) (map[string]string, error) {
+	var buf bytes.Buffer
+	_, err := io.Copy(&buf, r)
+	if err != nil {
+		return nil, err
+	}
+
+	return unmarshal(buf.Bytes())
+}
+
+// unmarshal parses env file from byte slice of chars, returning a map of keys and values.
+func unmarshal(src []byte) (map[string]string, error) {
+	out := make(map[string]string)
+	err := parseBytes(src, out)
+
+	return out, err
+}