[tahoe-lafs-trac-stream] [Tahoe-LAFS] #1587: I want an indicator of progress on a backup

[Tahoe-LAFS]

#1587: I want an indicator of progress on a backup
-----------------------------+-------------------------------------------
     Reporter:  zooko        |      Owner:  somebody
         Type:  enhancement  |     Status:  new
     Priority:  major        |  Milestone:  undecided
    Component:  code         |    Version:  1.9.0b1
   Resolution:               |   Keywords:  backup usability transparency
Launchpad Bug:               |
-----------------------------+-------------------------------------------

Comment (by exarkun):

 One minor improvement that could be made relatively easily here is just to
 report progress by file count.  This isn't the most accurate kind of
 progress report.  However, it would be an incremental step towards
 something based on actual size of data transfer required.  The current
 implementation doesn't know how many files it is working on, it discovers
 them as it goes.  Reporting on file-count-based progress would require
 looking at all files in advance - which will also be required for a data-
 size-based progress report.

 I suggest that, to replace the current behavior of no-output, we have
 something like:

 {{{
 $ tahoe backup src dst
  Found 123 files to back up.
  Backing up 1/123...  0:00:0 elapsed...
  Backing up 2/123...  0:00:7 elapsed...
  .
  .
  .
  123 files uploaded (0 reused), 0 files skipped, 2 directories created (0
 reused), 0
 directories skipped
  backup done, elapsed time: 0:00:41
 }}}

 This serves three purposes.  First, it gives the user some feedback some
 _very_ rough feedback on the size of the job they've just initiated.
 Second, it gives them some _very_ rough indication of what kind of
 progress has been made through the job (and that _some_ progress is still
 being made).  Third, it gives them a running report of how much time has
 been spent on this job up to the current point.

 A variation on this could be that the `Backing up ...` line is updated
 rather than being re-written for each line.  I'm not sure what assumptions
 the Tahoe-LAFS CLI is happy making about its output destination though.
 Are basic control bytes are acceptable?  If so, an updating status line
 with \b is easy enough.

 I imagine in the future this could be improved to something like:

 {{{
 $ tahoe backup src dst
  Found 456 bytes in 123 files to back up.
  Backing up file 1/123, 20/456 bytes...  0:00:0 elapsed... estimated
 completion 1:23:45
  .
  .
  .
  123 files uploaded (0 reused), 0 files skipped, 2 directories created (0
 reused), 0
 directories skipped
  backup done, elapsed time: 0:00:41
 }}}

 Perhaps also including a b/s transfer rate.  And the "Backing up ..." line
 could again either be updating or repeating (if updating, some basic
 tabular formatting might be nice).

 Thoughts?

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Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/1587#comment:2>
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