fix symlink broken in container log filepath

CHANGELOG.md

@@ -43,4 +43,5 @@ your changes, such as:
 - [public] [both] [added] add new plugin: input_command
 - [public] [both] [added] add new plugin: processor_log_to_sls_metric
 - [public] [both] [fixed] fix service_go_profile nil panic
-- [public] [both] [fixed] service_prometheus support scale in kubernetes
+- [public] [both] [fixed] fix broken container log path link
+- [public] [both] [fixed] service_prometheus support scale in kubernetes

pkg/go.mod

@@ -136,7 +136,7 @@ require (
 )
 
 replace (
- github.com/VictoriaMetrics/VictoriaMetrics => github.com/iLogtail/VictoriaMetrics v1.83.3-ilogtail
+ github.com/VictoriaMetrics/VictoriaMetrics => github.com/iLogtail/VictoriaMetrics v1.83.4-ilogtail
  github.com/VictoriaMetrics/metrics => github.com/iLogtail/metrics v1.23.0-ilogtail
  github.com/aliyun/alibaba-cloud-sdk-go/services/sls_inner => ../external/github.com/aliyun/alibaba-cloud-sdk-go/services/sls_inner
  github.com/elastic/beats/v7 => ../external/github.com/elastic/beats/v7

pkg/helper/mount_others.go

@@ -18,7 +18,9 @@
 package helper
 
 import (
+ "io/fs"
  "os"
+ "strings"
 )
 
 var DefaultLogtailMountPath string
@@ -31,6 +33,43 @@ func GetMountedFilePathWithBasePath(basePath, logPath string) string {
  return basePath + logPath
 }
 
+func TryGetRealPath(path string) (string, fs.FileInfo) {
+ sepLen := len(string(os.PathSeparator))
+ index := 0 // assume path is absolute
+ for i := 0; i < 10; i++ {
+ if f, err := os.Stat(path); err == nil {
+ return path, f
+ }
+ for {
+ j := strings.IndexRune(path[index+sepLen:], os.PathSeparator)
+ if j == -1 {
+ index = len(path)
+ } else {
+ index += j + sepLen
+ }
+
+ f, err := os.Lstat(path[:index])
+ if err != nil {
+ return "", nil
+ }
+ if f.Mode()&os.ModeSymlink != 0 {
+ // path[:index] is a symlink
+ target, _ := os.Readlink(path[:index])
+ partialPath := GetMountedFilePath(target)
+ path = partialPath + path[index:]
+ if _, err := os.Stat(partialPath); err != nil {
+ // path referenced by partialPath does not exist or has symlink
+ index = 0
+ } else {
+ index = len(partialPath)
+ }
+ break
+ }
+ }
+ }
+ return "", nil
+}
+
 func init() {
  defaultPath := "/logtail_host"
  _, err := os.Stat(defaultPath)

pkg/helper/mount_windows.go

@@ -17,6 +17,7 @@ package helper
 import (
  "flag"
  "fmt"
+ "io/fs"
  "os"
  "strings"
 
@@ -118,3 +119,10 @@ func GetMountedFilePathWithBasePath(basePath, filePath string) string {
  }
  return basePath + filePath[colonPos+1:]
 }
+
+func TryGetRealPath(path string) (string, fs.FileInfo) {
+ if f, err := os.Stat(path); err == nil {
+ return path, f
+ }
+ return "", nil
+}

plugins/input/docker/stdout/input_docker_stdout.go

@@ -16,7 +16,6 @@ package stdout
 
 import (
  "fmt"
- "os"
  "regexp"
  "sync"
  "time"
@@ -85,9 +84,9 @@ func NewDockerFileSyner(sds *ServiceDockerStdout,
  }
 
  // first watch this container
- stat, err := os.Stat(checkpoint.Path)
- if err != nil {
- logger.Warning(sds.context.GetRuntimeContext(), "DOCKER_STDOUT_STAT_ALARM", "stat log file error, path", checkpoint.Path, "error", err.Error())
+ realPath, stat := helper.TryGetRealPath(checkpoint.Path)
+ if realPath == "" {
+ logger.Warning(sds.context.GetRuntimeContext(), "DOCKER_STDOUT_STAT_ALARM", "stat log file error, path", checkpoint.Path, "error", "path not found")
  } else {
  checkpoint.Offset = stat.Size()
  if checkpoint.Offset > sds.StartLogMaxOffset {