The repair checker and repair worker both need to determine which pieces
are healthy, which are retrievable, and which should be replaced, but
they have been doing it in different ways in different code, which has
been the cause of bugs. The same term could have very similar but subtly
different meanings between the two, causing much confusion.
With this change, the piece- and node-classification logic is
consolidated into one place within the satellite/repair package, so that
both subsystems can use it. This ought to make decision-making code more
concise and more readable.
The consolidated classification logic has been expanded to create more
sets, so that the decision-making code does not need to do as much
precalculation. It should now be clearer in comments and code that a
piece can belong to multiple sets arbitrarily (except where the
definition of the sets makes this logically impossible), and what the
precise meaning of each set is. These sets include Missing, Suspended,
Clumped, OutOfPlacement, InExcludedCountry, ForcingRepair,
UnhealthyRetrievable, Unhealthy, Retrievable, and Healthy.
Some other side effects of this change:
* CreatePutRepairOrderLimits no longer needs to special-case excluded
countries; it can just create as many order limits as requested (by
way of len(newNodes)).
* The repair checker will now queue a segment for repair when there are
any pieces out of placement. The code calls this "forcing a repair".
* The checker.ReliabilityCache is now accessed by way of a GetNodes()
function similar to the one on the overlay. The classification methods
like MissingPieces(), OutOfPlacementPieces(), and
PiecesNodesLastNetsInOrder() are removed in favor of the
classification logic in satellite/repair/classification.go. This
means the reliability cache no longer needs access to the placement
rules or excluded countries list.
Change-Id: I105109fb94ee126952f07d747c6e11131164fadb
