initial import

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

file.go

@@ -0,0 +1,76 @@
+package file
+
+import (
+	"context"
+	"errors"
+	"io"
+	"io/ioutil"
+	"os"
+
+	"github.com/unistack-org/micro/v3/codec"
+	"github.com/unistack-org/micro/v3/config"
+)
+
+var (
+	DefaultStructTag = "file"
+	ErrInvalidStruct = errors.New("invalid struct specified")
+	ErrPathNotExist  = errors.New("path is not exist")
+)
+
+type fileConfig struct {
+	opts config.Options
+	path string
+}
+
+func (c *fileConfig) Options() config.Options {
+	return c.opts
+}
+
+func (c *fileConfig) Init(opts ...config.Option) error {
+	for _, o := range opts {
+		o(&c.opts)
+	}
+
+	path := ""
+
+	if c.opts.Context != nil {
+		if v, ok := c.opts.Context.Value(pathKey{}).(string); ok {
+			path = v
+		}
+	}
+
+	c.path = path
+
+	return nil
+}
+
+func (c *fileConfig) Load(ctx context.Context) error {
+	fp, err := os.OpenFile(c.path, os.O_RDONLY, os.FileMode(0400))
+	if err != nil {
+		return ErrPathNotExist
+	}
+	defer fp.Close()
+
+	buf, err := ioutil.ReadAll(io.LimitReader(fp, int64(codec.DefaultMaxMsgSize)))
+	if err != nil {
+		return err
+	}
+
+	return c.opts.Codec.Unmarshal(buf, c.opts.Struct)
+}
+
+func (c *fileConfig) Save(ctx context.Context) error {
+	return nil
+}
+
+func (c *fileConfig) String() string {
+	return "file"
+}
+
+func NewConfig(opts ...config.Option) config.Config {
+	options := config.NewOptions(opts...)
+	if len(options.StructTag) == 0 {
+		options.StructTag = DefaultStructTag
+	}
+	return &fileConfig{opts: options}
+}