writeback

Documentation

Overview

Package writeback keeps track of the files which need to be written back to storage

Index

• Variables
• type Handle
• type PutFn
• type QueueInfo
• type WriteBack
  • func New(ctx context.Context, opt *vfscommon.Options) *WriteBack
  • func (wb *WriteBack) Add(id Handle, name string, size int64, modified bool, putFn PutFn) Handle
  • func (wb *WriteBack) Queue() []QueueInfo
  • func (wb *WriteBack) Remove(id Handle) (found bool)
  • func (wb *WriteBack) Rename(id Handle, name string)
  • func (wb *WriteBack) SetExpiry(id Handle, expiry time.Time) error
  • func (wb *WriteBack) SetID(pid *Handle)
  • func (wb *WriteBack) Stats() (uploadsInProgress, uploadsQueued int)

Variables

var ErrorIDNotFound = errors.New("id not found in queue")

ErrorIDNotFound is returned from SetExpiry when the item is not found

Types

type Handle

type Handle uint64

Handle is returned for callers to keep track of writeback items

type PutFn

type PutFn func(context.Context) error

PutFn is the interface that item provides to store the data

type QueueInfo

type QueueInfo struct {
	Name      string  `json:"name"`      // name (full path) of the file,
	ID        Handle  `json:"id"`        // id of queue item
	Size      int64   `json:"size"`      // integer size of the file in bytes
	Expiry    float64 `json:"expiry"`    // seconds from now which the file is eligible for transfer, oldest goes first
	Tries     int     `json:"tries"`     // number of times we have tried to upload
	Delay     float64 `json:"delay"`     // delay between upload attempts (s)
	Uploading bool    `json:"uploading"` // true if item is being uploaded
}

QueueInfo is information about an item queued for upload, returned by Queue

type WriteBack

type WriteBack struct {
	// contains filtered or unexported fields
}

WriteBack keeps track of the items which need to be written back to the disk at some point

func New

func New(ctx context.Context, opt *vfscommon.Options) *WriteBack

New make a new WriteBack

cancel the context to stop the background processing

func (*WriteBack) Add

func (wb *WriteBack) Add(id Handle, name string, size int64, modified bool, putFn PutFn) Handle

Add adds an item to the writeback queue or resets its timer if it is already there.

If id is 0 then a new item will always be created and the new Handle will be returned.

Use SetID to create Handles in advance of calling Add.

If modified is false then it it doesn't cancel a pending upload if there is one as there is no need.

func (*WriteBack) Queue

func (wb *WriteBack) Queue() []QueueInfo

Queue return info about the current upload queue

func (*WriteBack) Remove

func (wb *WriteBack) Remove(id Handle) (found bool)

Remove should be called when a file should be removed from the writeback queue. This cancels a writeback if there is one and doesn't return the item to the queue.

func (*WriteBack) Rename

func (wb *WriteBack) Rename(id Handle, name string)

Rename should be called when a file might be uploading and it gains a new name. This will cancel the upload and put it back in the queue.

func (*WriteBack) SetExpiry

func (wb *WriteBack) SetExpiry(id Handle, expiry time.Time) error

SetExpiry sets the expiry time for an item in the writeback queue.

id should be as returned from the Queue call

If the item isn't found then it will return ErrorIDNotFound

func (*WriteBack) SetID

func (wb *WriteBack) SetID(pid *Handle)

SetID sets the Handle pointed to if it is non zero to the next handle.

func (*WriteBack) Stats

func (wb *WriteBack) Stats() (uploadsInProgress, uploadsQueued int)

Stats return the number of uploads in progress and queued