make min_bw configurable in bwauths

[teor]

In a testing network, there isn't much traffic. So skipping nodes with an observed bandwidth less than 1 MByte/second means that it's easy to skip a large fraction of the network.

It would be helpful if min_bw were a configurable option in bwauthority.cfg. If it is an option, we could consider making the unmeasured node scanner measure all nodes, regardless of bandwidth.

[teor]

Workaround for small networks

[tom]

This doesn't look like something we would want to apply to the main repo. Where would you want it to live? In a separate branch? I'm doubtful it would be helpful to re-architect things sufficiently that this was easily parameterized...

[teor]

Replying to tom:

This doesn't look like something we would want to apply to the main repo. Where would you want it to live? In a separate branch? I'm doubtful it would be helpful to re-architect things sufficiently that this was easily parameterized...

I'm not sure - this is an architectural question:

Core tor has an option that sets a whole lot of parameters useful for test networks.
Perhaps we could do the same with the bandwidth scanner. But that means the resulting changes are scattered throughout the code.

Maybe a separate branch is better, but then it easily gets outdated.

Ideally, we could make these parameters configurable, and distribute a testing config (or a set of testing defaults).

Perhaps documenting this issue and providing a patch is the best strategy?

[teor]

Priorities and Severities in torflow are meaningless, setting them all to Medium/Normal.

[teor]

aagbsn was the default owner, unassigning

[Sebastian]

I applied the patch but that wasn't enough for bwauth to work in a small test netork. It seemed to go OK at first, but then scanner.1 went into logspam mode with these lines:

./bwauthority.py:71: SyntaxWarning: name 'p' is assigned to before global declaration
  global p
NOTICE[Sat Nov 11 16:13:10 2017]:TorFlow Version: master 75abb44bf73b3a061063145ebdb97029afe91fb7
NOTICE[Sat Nov 11 16:13:10 2017]:TorCtl Version: detached c8fcb25b079d52a20cafc7f7adf178e90ab76338
NOTICE[Sat Nov 11 16:13:10 2017]:Child Process Spawned...
NOTICE[Sat Nov 11 16:14:13 2017]:Starting slice for percentiles 0-100
NOTICE[Sat Nov 11 16:14:15 2017]:Ran out of choices in ExactUniformGenerator. Incrementing nodes
NOTICE[Sat Nov 11 16:14:15 2017]:Ran out of routers during buildpath..
NOTICE[Sat Nov 11 16:14:15 2017]:Ran out of choices in ExactUniformGenerator. Incrementing nodes
NOTICE[Sat Nov 11 16:14:15 2017]:Ran out of routers during buildpath..

[teor]

Would you mind opening a separate ticket with these log lines?
And describing the size of your network (authorities, relays, exits)?
I'll see if I have any local patches that might help.
If we ever want to be able to run bwauthority in chutney, we'll need to fix issues like this.

[teor]

Logging issue split off into #24248

[teor]

Mark all tickets that are assigned to nobody as "new".