[tor-bugs] #27308 [Core Tor/Tor]: add completion milestones to bootstrap

[Tor Bug Tracker & Wiki]

#27308: add completion milestones to bootstrap
-------------------------+-------------------------------------------------
     Reporter:           |      Owner:  catalyst
  catalyst               |
         Type:  defect   |     Status:  assigned
     Priority:  Medium   |  Milestone:  Tor: 0.3.5.x-final
    Component:  Core     |    Version:
  Tor/Tor                |   Keywords:  usability, ux, ux-team, bootstrap,
     Severity:  Normal   |  035-roadmap-subtask, 035-triaged-in-20180711,
                         |  s8-bootstrap
Actual Points:           |  Parent ID:  #22266
       Points:           |   Reviewer:
      Sponsor:           |
  Sponsor8               |
-------------------------+-------------------------------------------------
 Right now many bootstrap events get reported when the preceding task has
 completed.  This makes it somewhat harder to tell what has gone wrong if
 bootstrap progress stalls.

 We should add completion milestones to bootstrap reporting.  This makes
 bootstrap reporting more future-proof.  If in the future we add a time-
 consuming task with (no bootstrap reporting) between two existing
 bootstrap tasks, it will be a little more obvious what's going on.

 For example, say we have task X followed by task Z, but then we add a
 lengthy task Y without adding bootstrap reporting to it.  In the old
 scheme without completion milestones, if Y stalls, the user sees:
 * starting X
 * starting Z
 * [hang]
 The user thinks Z has already started when no such thing has happened
 because Y is still in progress.  If we add completion milestones, the user
 will see:
 * starting X
 * finished X
 * starting Z
 * finishing Z
 in a normal bootstrap.  If something gets stuck in task Y, the user will
 see:
 * starting X
 * finished X
 * [hang]
 This will make it more clear that something got stuck in between tasks.

 In a one-line display like Tor Launcher, the completion milestones will
 normally flash by quickly and not be very visible to users.  Completion
 milestones might make the NOTICE logs a bit more verbose.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/27308>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online