Resolve "Requesting information from the Controller via NBI takes very long"

Description

Related Issue

#230 (closed)

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

controller/config/gnmiSubscriptionConfig.go

+package config
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+const (
+	defaultGnmiSubscriptionFilePath = "controller/configs/gNMISubscriptions.txt"
+)
+
+var gnmiSubscriptionPaths [][]string
+
+// ReadGnmiSubscriptionPaths reads the paths the watcher should subscribe to provided in a file.
+func ReadGnmiSubscriptionPaths() error {
+	currentDir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+
+	filePath := filepath.Join(currentDir, defaultGnmiSubscriptionFilePath)
+
+	f, err := os.Open(filePath)
+	if err != nil {
+		return err
+	}
+
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+
+	for scanner.Scan() {
+		path := strings.Split(scanner.Text(), "/")
+		gnmiSubscriptionPaths = append(gnmiSubscriptionPaths, path)
+	}
+
+	fmt.Println(gnmiSubscriptionPaths)
+
+	return nil
+}
+
+// GetGnmiSubscriptionPaths returns the paths the watcher should subscribe to.
+func GetGnmiSubscriptionPaths() [][]string {
+	return gnmiSubscriptionPaths
+}