mirror of
https://github.com/luckfox-eng29/kvm.git
synced 2026-01-18 03:28:19 +01:00
chore(usbgadget): update usbgadget config only when needed (#474)
This commit is contained in:
Aveline
GitHub
432
internal/usbgadget/changeset.go
Normal file
432
internal/usbgadget/changeset.go
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@@ -0,0 +1,432 @@
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package usbgadget
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import (
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"bytes"
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"fmt"
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"os"
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"path/filepath"
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"reflect"
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"time"
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"github.com/prometheus/procfs"
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"github.com/sourcegraph/tf-dag/dag"
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)
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// it's a minimalistic implementation of ansible's file module with some modifications
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// to make it more suitable for our use case
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// https://docs.ansible.com/ansible/latest/modules/file_module.html
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// we use this to check if the files in the gadget config are in the expected state
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// and to update them if they are not in the expected state
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type FileState uint8
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type ChangeState uint8
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type FileChangeResolvedAction uint8
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type ApplyFunc func(c *ChangeSet, changes []*FileChange) error
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const (
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FileStateUnknown FileState = iota
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FileStateAbsent
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FileStateDirectory
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FileStateFile
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FileStateFileContentMatch
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FileStateFileWrite // update file content without checking
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FileStateMounted
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FileStateMountedConfigFS
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FileStateSymlink
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FileStateSymlinkInOrderConfigFS // configfs is a shithole, so we need to check if the symlinks are created in the correct order
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FileStateSymlinkNotInOrderConfigFS
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FileStateTouch
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)
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var FileStateString = map[FileState]string{
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FileStateUnknown: "UNKNOWN",
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FileStateAbsent: "ABSENT",
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FileStateDirectory: "DIRECTORY",
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FileStateFile: "FILE",
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FileStateFileContentMatch: "FILE_CONTENT_MATCH",
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FileStateFileWrite: "FILE_WRITE",
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FileStateMounted: "MOUNTED",
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FileStateMountedConfigFS: "CONFIGFS_MOUNT",
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FileStateSymlink: "SYMLINK",
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FileStateSymlinkInOrderConfigFS: "SYMLINK_IN_ORDER_CONFIGFS",
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FileStateTouch: "TOUCH",
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}
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const (
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ChangeStateUnknown ChangeState = iota
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ChangeStateRequired
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ChangeStateNotChanged
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ChangeStateChanged
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ChangeStateError
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)
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const (
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FileChangeResolvedActionUnknown FileChangeResolvedAction = iota
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FileChangeResolvedActionDoNothing
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FileChangeResolvedActionRemove
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FileChangeResolvedActionCreateFile
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FileChangeResolvedActionWriteFile
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FileChangeResolvedActionUpdateFile
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FileChangeResolvedActionAppendFile
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FileChangeResolvedActionCreateSymlink
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FileChangeResolvedActionRecreateSymlink
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FileChangeResolvedActionCreateDirectoryAndSymlinks
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FileChangeResolvedActionReorderSymlinks
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FileChangeResolvedActionCreateDirectory
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FileChangeResolvedActionRemoveDirectory
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FileChangeResolvedActionTouch
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FileChangeResolvedActionMountConfigFS
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)
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var FileChangeResolvedActionString = map[FileChangeResolvedAction]string{
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FileChangeResolvedActionUnknown: "UNKNOWN",
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FileChangeResolvedActionDoNothing: "DO_NOTHING",
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FileChangeResolvedActionRemove: "REMOVE",
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FileChangeResolvedActionCreateFile: "FILE_CREATE",
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FileChangeResolvedActionWriteFile: "FILE_WRITE",
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FileChangeResolvedActionUpdateFile: "FILE_UPDATE",
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FileChangeResolvedActionAppendFile: "FILE_APPEND",
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FileChangeResolvedActionCreateSymlink: "SYMLINK_CREATE",
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FileChangeResolvedActionRecreateSymlink: "SYMLINK_RECREATE",
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FileChangeResolvedActionCreateDirectoryAndSymlinks: "DIR_CREATE_AND_SYMLINKS",
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FileChangeResolvedActionReorderSymlinks: "SYMLINK_REORDER",
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FileChangeResolvedActionCreateDirectory: "DIR_CREATE",
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FileChangeResolvedActionRemoveDirectory: "DIR_REMOVE",
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FileChangeResolvedActionTouch: "TOUCH",
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FileChangeResolvedActionMountConfigFS: "CONFIGFS_MOUNT",
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}
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type ChangeSet struct {
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Changes []FileChange
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}
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type RequestedFileChange struct {
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Component string
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Key string
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Path string // will be used as Key if Key is empty
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ParamSymlinks []symlink
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ExpectedState FileState
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ExpectedContent []byte
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DependsOn []string
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BeforeChange []string // if the file is going to be changed, apply the change first
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Description string
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IgnoreErrors bool
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When string // only apply the change if when meets the condition
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}
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type FileChange struct {
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RequestedFileChange
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ActualState FileState
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ActualContent []byte
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resolvedDeps []string
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checked bool
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changed ChangeState
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action FileChangeResolvedAction
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}
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func (f *RequestedFileChange) String() string {
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var s string
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switch f.ExpectedState {
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case FileStateDirectory:
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s = fmt.Sprintf("dir: %s", f.Path)
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case FileStateFile:
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s = fmt.Sprintf("file: %s", f.Path)
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case FileStateSymlink:
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s = fmt.Sprintf("symlink: %s -> %s", f.Path, f.ExpectedContent)
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case FileStateSymlinkInOrderConfigFS:
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s = fmt.Sprintf("symlink_in_order_configfs: %s -> %s", f.Path, f.ExpectedContent)
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case FileStateSymlinkNotInOrderConfigFS:
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s = fmt.Sprintf("symlink_not_in_order_configfs: %s -> %s", f.Path, f.ExpectedContent)
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case FileStateAbsent:
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s = fmt.Sprintf("absent: %s", f.Path)
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case FileStateFileContentMatch:
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s = fmt.Sprintf("file: %s with content [%s]", f.Path, f.ExpectedContent)
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case FileStateFileWrite:
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s = fmt.Sprintf("write: %s with content [%s]", f.Path, f.ExpectedContent)
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case FileStateMountedConfigFS:
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s = fmt.Sprintf("configfs: %s", f.Path)
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case FileStateTouch:
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s = fmt.Sprintf("touch: %s", f.Path)
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case FileStateUnknown:
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s = fmt.Sprintf("unknown change for %s", f.Path)
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default:
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s = fmt.Sprintf("unknown expected state %d for %s", f.ExpectedState, f.Path)
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}
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return s
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}
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func (f *RequestedFileChange) IsSame(other *RequestedFileChange) bool {
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return f.Path == other.Path &&
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f.ExpectedState == other.ExpectedState &&
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reflect.DeepEqual(f.ExpectedContent, other.ExpectedContent) &&
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reflect.DeepEqual(f.DependsOn, other.DependsOn) &&
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f.IgnoreErrors == other.IgnoreErrors
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}
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func (fc *FileChange) checkIfDirIsMountPoint() error {
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// check if the file is a mount point
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mounts, err := procfs.GetMounts()
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if err != nil {
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return fmt.Errorf("failed to get mounts")
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}
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for _, mount := range mounts {
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if mount.MountPoint == fc.Path {
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fc.ActualState = FileStateMounted
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fc.ActualContent = []byte(mount.Source)
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if mount.FSType == "configfs" {
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fc.ActualState = FileStateMountedConfigFS
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}
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return nil
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}
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}
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return nil
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}
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// GetActualState returns the actual state of the file at the given path.
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func (fc *FileChange) getActualState() error {
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l := defaultLogger.With().Str("path", fc.Path).Logger()
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fi, err := os.Lstat(fc.Path)
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if err != nil {
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if os.IsNotExist(err) {
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fc.ActualState = FileStateAbsent
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} else {
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l.Warn().Err(err).Msg("failed to stat file")
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fc.ActualState = FileStateUnknown
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}
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return nil
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}
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// check if the file is a symlink
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if fi.Mode()&os.ModeSymlink == os.ModeSymlink {
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fc.ActualState = FileStateSymlink
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// get the target of the symlink
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target, err := os.Readlink(fc.Path)
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if err != nil {
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l.Warn().Err(err).Msg("failed to read symlink")
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return fmt.Errorf("failed to read symlink")
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}
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// check if the target is a relative path
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if !filepath.IsAbs(target) {
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// make it absolute
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target, err = filepath.Abs(filepath.Join(filepath.Dir(fc.Path), target))
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if err != nil {
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l.Warn().Err(err).Msg("failed to make symlink target absolute")
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return fmt.Errorf("failed to make symlink target absolute")
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}
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}
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fc.ActualContent = []byte(target)
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return nil
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}
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if fi.IsDir() {
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fc.ActualState = FileStateDirectory
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switch fc.ExpectedState {
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case FileStateMountedConfigFS:
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err := fc.checkIfDirIsMountPoint()
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if err != nil {
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l.Warn().Err(err).Msg("failed to check if dir is mount point")
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return err
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}
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case FileStateSymlinkInOrderConfigFS:
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state, err := checkIfSymlinksInOrder(fc, &l)
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if err != nil {
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l.Warn().Err(err).Msg("failed to check if symlinks are in order")
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return err
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}
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fc.ActualState = state
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}
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return nil
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}
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if fi.Mode()&os.ModeDevice == os.ModeDevice {
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l.Info().Msg("file is a device")
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return nil
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}
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// check if the file is a regular file
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if fi.Mode().IsRegular() {
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fc.ActualState = FileStateFile
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// get the content of the file
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content, err := os.ReadFile(fc.Path)
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if err != nil {
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l.Warn().Err(err).Msg("failed to read file")
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return fmt.Errorf("failed to read file")
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}
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fc.ActualContent = content
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return nil
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}
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l.Warn().Interface("file_info", fi.Mode()).Bool("is_dir", fi.IsDir()).Msg("unknown file type")
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return fmt.Errorf("unknown file type")
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}
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func (fc *FileChange) ResetActionResolution() {
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fc.checked = false
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fc.action = FileChangeResolvedActionUnknown
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fc.changed = ChangeStateUnknown
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}
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func (fc *FileChange) Action() FileChangeResolvedAction {
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if !fc.checked {
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fc.action = fc.getFileChangeResolvedAction()
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fc.checked = true
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}
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return fc.action
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}
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func (fc *FileChange) getFileChangeResolvedAction() FileChangeResolvedAction {
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l := defaultLogger.With().Str("path", fc.Path).Logger()
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// some actions are not needed to be checked
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switch fc.ExpectedState {
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case FileStateFileWrite:
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return FileChangeResolvedActionWriteFile
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case FileStateTouch:
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return FileChangeResolvedActionTouch
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}
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// get the actual state of the file
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err := fc.getActualState()
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if err != nil {
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return FileChangeResolvedActionDoNothing
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}
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baseName := filepath.Base(fc.Path)
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switch fc.ExpectedState {
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case FileStateDirectory:
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// if the file is already a directory, do nothing
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if fc.ActualState == FileStateDirectory {
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return FileChangeResolvedActionDoNothing
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}
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return FileChangeResolvedActionCreateDirectory
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case FileStateFile:
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// if the file is already a file, do nothing
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if fc.ActualState == FileStateFile {
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return FileChangeResolvedActionDoNothing
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}
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return FileChangeResolvedActionCreateFile
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case FileStateFileContentMatch:
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// if the file is already a file with the expected content, do nothing
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if fc.ActualState == FileStateFile {
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looserMatch := baseName == "inquiry_string"
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if compareFileContent(fc.ActualContent, fc.ExpectedContent, looserMatch) {
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return FileChangeResolvedActionDoNothing
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}
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// TODO: move this to somewhere else
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// this is a workaround for the fact that the file is not updated if it has no content
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if baseName == "file" &&
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bytes.Equal(fc.ActualContent, []byte{}) &&
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bytes.Equal(fc.ExpectedContent, []byte{0x0a}) {
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return FileChangeResolvedActionDoNothing
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}
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return FileChangeResolvedActionUpdateFile
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}
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return FileChangeResolvedActionCreateFile
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case FileStateSymlink:
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// if the file is already a symlink, check if the target is the same
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if fc.ActualState == FileStateSymlink {
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if reflect.DeepEqual(fc.ActualContent, fc.ExpectedContent) {
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return FileChangeResolvedActionDoNothing
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}
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return FileChangeResolvedActionRecreateSymlink
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}
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return FileChangeResolvedActionCreateSymlink
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case FileStateSymlinkInOrderConfigFS:
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// if the file is already a symlink, check if the target is the same
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if fc.ActualState == FileStateSymlinkInOrderConfigFS {
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return FileChangeResolvedActionDoNothing
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}
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return FileChangeResolvedActionReorderSymlinks
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case FileStateAbsent:
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if fc.ActualState == FileStateAbsent {
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return FileChangeResolvedActionDoNothing
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}
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return FileChangeResolvedActionRemove
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case FileStateMountedConfigFS:
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if fc.ActualState == FileStateMountedConfigFS {
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return FileChangeResolvedActionDoNothing
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}
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return FileChangeResolvedActionMountConfigFS
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default:
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l.Warn().Interface("file_change", FileStateString[fc.ExpectedState]).Msg("unknown expected state")
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return FileChangeResolvedActionDoNothing
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}
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}
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func (c *ChangeSet) AddFileChangeStruct(r RequestedFileChange) {
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fc := FileChange{
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RequestedFileChange: r,
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}
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c.Changes = append(c.Changes, fc)
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}
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func (c *ChangeSet) AddFileChange(component string, path string, expectedState FileState, expectedContent []byte, dependsOn []string, description string) {
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c.AddFileChangeStruct(RequestedFileChange{
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Component: component,
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Path: path,
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ExpectedState: expectedState,
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ExpectedContent: expectedContent,
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DependsOn: dependsOn,
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Description: description,
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})
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}
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func (c *ChangeSet) ApplyChanges() error {
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r := ChangeSetResolver{
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changeset: c,
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g: &dag.AcyclicGraph{},
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l: defaultLogger,
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}
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return r.Apply()
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}
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func (c *ChangeSet) applyChange(change *FileChange) error {
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switch change.Action() {
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case FileChangeResolvedActionWriteFile:
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return os.WriteFile(change.Path, change.ExpectedContent, 0644)
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case FileChangeResolvedActionUpdateFile:
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return os.WriteFile(change.Path, change.ExpectedContent, 0644)
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case FileChangeResolvedActionCreateFile:
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return os.WriteFile(change.Path, change.ExpectedContent, 0644)
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case FileChangeResolvedActionCreateSymlink:
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return os.Symlink(string(change.ExpectedContent), change.Path)
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case FileChangeResolvedActionRecreateSymlink:
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if err := os.Remove(change.Path); err != nil {
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return fmt.Errorf("failed to remove symlink: %w", err)
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}
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return os.Symlink(string(change.ExpectedContent), change.Path)
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case FileChangeResolvedActionReorderSymlinks:
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return recreateSymlinks(change, nil)
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case FileChangeResolvedActionCreateDirectory:
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return os.MkdirAll(change.Path, 0755)
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case FileChangeResolvedActionRemove:
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return os.Remove(change.Path)
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case FileChangeResolvedActionRemoveDirectory:
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return os.RemoveAll(change.Path)
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case FileChangeResolvedActionTouch:
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return os.Chtimes(change.Path, time.Now(), time.Now())
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case FileChangeResolvedActionMountConfigFS:
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return mountConfigFS(change.Path)
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case FileChangeResolvedActionDoNothing:
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return nil
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default:
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return fmt.Errorf("unknown action: %d", change.Action())
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}
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}
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func (c *ChangeSet) Apply() error {
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return c.ApplyChanges()
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}
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Reference in New Issue
Block a user