feat: init go project

internal/app/app.go

@@ -0,0 +1,39 @@
+package app
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+)
+
+type Options struct {
+	ConfigPath string
+	Stdout     io.Writer
+}
+
+func Run(ctx context.Context, opts Options) error {
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+
+	if opts.ConfigPath == "" {
+		return errors.New("config path is required")
+	}
+
+	if opts.Stdout == nil {
+		opts.Stdout = io.Discard
+	}
+
+	if _, err := os.Stat(opts.ConfigPath); err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return fmt.Errorf("config file %q does not exist; copy config.example.yaml to config.yaml and fill credentials", opts.ConfigPath)
+		}
+
+		return fmt.Errorf("check config file %q: %w", opts.ConfigPath, err)
+	}
+
+	fmt.Fprintf(opts.Stdout, "overnight trading bot initialized with config %q\n", opts.ConfigPath)
+	return nil
+}