feat: cmd alias config file support special (#232)

cmd/kubevpn/cmds/alias.go

@@ -15,6 +15,7 @@ import (
 	yaml "sigs.k8s.io/yaml/goyaml.v3"
 
 	"github.com/wencaiwulue/kubevpn/v2/pkg/daemon"
+	"github.com/wencaiwulue/kubevpn/v2/pkg/util"
 )
 
 // CmdAlias
@@ -36,6 +37,7 @@ Flags:
   - --extra-hosts xxx.com
 */
 func CmdAlias(f cmdutil.Factory) *cobra.Command {
+	var localFile, remoteAddr string
 	cmd := &cobra.Command{
 		Use:   "alias",
 		Short: "Config file alias to execute command simply",
@@ -68,29 +70,43 @@ Config file support three field: Name,Needs,Flags
 		kubevpn alias jumper
 `)),
 		PreRunE: func(cmd *cobra.Command, args []string) (err error) {
-			_, err = os.Stat(daemon.GetConfigFilePath())
+			if localFile != "" {
+				_, err = os.Stat(localFile)
+			}
 			return err
 		},
 		Args: cobra.MatchAll(cobra.ExactArgs(1)),
 		RunE: func(cmd *cobra.Command, args []string) error {
-			file, err := os.ReadFile(daemon.GetConfigFilePath())
+			var content []byte
+			var err error
+			var path string
+			if localFile != "" {
+				path = localFile
+				content, err = os.ReadFile(path)
+			} else if remoteAddr != "" {
+				path = remoteAddr
+				content, err = util.DownloadFileStream(path)
+			} else {
+				path = daemon.GetConfigFilePath()
+				content, err = os.ReadFile(path)
+			}
 			if err != nil {
 				return err
 			}
-			configList, err := ParseConfig(file)
+			configList, err := ParseConfig(content)
 			if err != nil {
 				return err
 			}
 			configs, err := GetConfigs(configList, args[0])
 			if len(configs) == 0 {
-				return fmt.Errorf("can not found any alias for name %s, please check your config file %s", args[0], daemon.GetConfigFilePath())
+				return fmt.Errorf("can not found any alias for name %s, please check your config file %s", args[0], path)
 			}
-			path, err := os.Executable()
+			name, err := os.Executable()
 			if err != nil {
 				return err
 			}
 			for _, config := range configs {
-				c := exec.Command(path, strings.Split(strings.Join(config.Flags, " "), " ")...)
+				c := exec.Command(name, strings.Split(strings.Join(config.Flags, " "), " ")...)
 				c.Stdout = os.Stdout
 				c.Stdin = os.Stdin
 				c.Stderr = os.Stderr
@@ -103,6 +119,8 @@ Config file support three field: Name,Needs,Flags
 			return nil
 		},
 	}
+	cmd.Flags().StringVarP(&localFile, "file", "f", daemon.GetConfigFilePath(), "Config file location")
+	cmd.Flags().StringVarP(&remoteAddr, "remote", "r", "", "Remote config file, eg: https://raw.githubusercontent.com/kubenetworks/kubevpn/master/pkg/config/config.yaml")
 	return cmd
 }
 

pkg/util/file.go

@@ -0,0 +1,106 @@
+package util
+
+import (
+	"fmt"
+	"io"
+	"math"
+	"net/http"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/sirupsen/logrus"
+)
+
+func DownloadFileWithName(uri, name string) (string, error) {
+	resp, err := getWithRetry(uri)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("downloading file %s failed. status code: %d, expected: %d", uri, resp.StatusCode, http.StatusOK)
+	}
+
+	dir, err := os.MkdirTemp("", "")
+	if err != nil {
+		return "", err
+	}
+
+	file := filepath.Join(dir, name)
+	out, err := os.Create(file)
+	if err != nil {
+		return "", err
+	}
+	defer out.Close()
+
+	_, err = io.Copy(out, resp.Body)
+	if err != nil {
+		return "", fmt.Errorf("failed to save file %s. error: %v", file, err)
+	}
+
+	logrus.Infof("downloaded file %s", file)
+	return file, nil
+}
+
+func DownloadFileStream(uri string) ([]byte, error) {
+	resp, err := getWithRetry(uri)
+	if err != nil {
+		return nil, err
+	}
+
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("downloading file %s failed. status code: %d, expected: %d", uri, resp.StatusCode, http.StatusOK)
+	}
+	return io.ReadAll(resp.Body)
+}
+
+func DownloadFile(uri string) (string, error) {
+	return DownloadFileWithName(uri, fmt.Sprintf("%d", time.Now().Unix()))
+}
+
+const (
+	maxRetries   = 4
+	retryWaitMin = 2 * time.Second
+	retryWaitMax = 10 * time.Second
+)
+
+func getWithRetry(uri string) (*http.Response, error) {
+	var resp *http.Response
+	var err error
+
+	for i := 0; i < maxRetries; i++ {
+		resp, err = http.Get(uri)
+		shouldRetry := checkRetry(resp, err)
+		if !shouldRetry {
+			break
+		}
+
+		drainBody(resp.Body)
+		wait := backoff(retryWaitMin, retryWaitMax, i)
+		<-time.After(wait)
+	}
+
+	return resp, err
+}
+
+func checkRetry(resp *http.Response, err error) bool {
+	return resp != nil && resp.StatusCode == http.StatusNotFound
+}
+
+func drainBody(b io.ReadCloser) {
+	defer b.Close()
+	io.Copy(io.Discard, io.LimitReader(b, int64(4096)))
+}
+
+func backoff(min, max time.Duration, attemptNum int) time.Duration {
+	mult := math.Pow(2, float64(attemptNum)) * float64(min)
+	sleep := time.Duration(mult)
+	if float64(sleep) != mult || sleep > max {
+		sleep = max
+	}
+	return sleep
+}