feat: add update rules file command

cmd/update.go

@@ -0,0 +1,28 @@
+package cmd
+
+import (
+	"log"
+
+	"github.com/doron-cohen/antidot/internal/utils"
+	"github.com/spf13/cobra"
+)
+
+func init() {
+	rootCmd.AddCommand(updateCmd)
+}
+
+var rulesSource = "https://raw.githubusercontent.com/doron-cohen/antidot/master/rules.yaml"
+
+var updateCmd = &cobra.Command{
+	Use:   "update",
+	Short: "Update rules file",
+	Run: func(cmd *cobra.Command, args []string) {
+		log.Printf("Updating rules...")
+		err := utils.Download(rulesSource, rulesFilePath)
+		if err != nil {
+			log.Fatalf("Failed to update rules: %v", err)
+		}
+
+		log.Printf("Rules updated")
+	},
+}

internal/utils/fetch.go

@@ -0,0 +1,36 @@
+package utils
+
+import (
+	"io"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+)
+
+func Download(src, dest string) error {
+	resp, err := http.Get(src)
+	if err != nil {
+		return err
+	}
+	// TODO: check for close() errors (across the code)
+	defer resp.Body.Close()
+
+	tempFile, err := ioutil.TempFile("", "rules.*.yaml")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer os.Remove(tempFile.Name())
+
+	_, err = io.Copy(tempFile, resp.Body)
+	if err != nil {
+		return err
+	}
+
+	err = MoveFile(tempFile.Name(), dest)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

internal/utils/files.go

@@ -1,6 +1,10 @@
 package utils
 
-import "os"
+import (
+	"fmt"
+	"io"
+	"os"
+)
 
 func FileExists(filename string) bool {
 	_, err := os.Stat(filename)
@@ -9,3 +13,29 @@ func FileExists(filename string) bool {
 	}
 	return true
 }
+
+func MoveFile(sourcePath, destPath string) error {
+	inputFile, err := os.Open(sourcePath)
+	if err != nil {
+		return fmt.Errorf("Couldn't open source file: %s", err)
+	}
+
+	outputFile, err := os.Create(destPath)
+	if err != nil {
+		inputFile.Close()
+		return fmt.Errorf("Couldn't open dest file: %s", err)
+	}
+	defer outputFile.Close()
+
+	_, err = io.Copy(outputFile, inputFile)
+	inputFile.Close()
+	if err != nil {
+		return fmt.Errorf("Writing to output file failed: %s", err)
+	}
+
+	err = os.Remove(sourcePath)
+	if err != nil {
+		return fmt.Errorf("Failed removing original file: %s", err)
+	}
+	return nil
+}