* feat(storage): first array cursor
* feat: add first and last to rpc messages
* test(launcher): push down group first and group last
* feat(storage): window first array cursor
* test(launcher): push down bare first and bare last
* feat(storage): add capabilities for group first and group last
* refactor: rename first to limit
* refactor: make zero value for every period meaningful
* refactor: standardize launcher pushdown tests
I did this with a dumb editor macro, so some comments changed too.
Also rename root package from platform to influxdb.
In interest of minimizing risk, anyone importing the root package has
now aliased it to "platform" so that no changes beyond imports were
necessary in those files.
Lastly, replace the old platform module to local path /dev/null so that
nobody can accidentally reintroduce a platform dependency while
migrating platform code to influxdb.
This pulls in the code that allows doing reads with flux into the
platform repo, and removes extra.go.
The reusable portion is under storage/reads, where the concrete
implementation for one of the platform's engines is in
storage/readservice.
In order to make this more reusable, the cursors had to move into
their own package, decoupling it from all of the other code in the
tsdb package. tsdb/cursors is this new package, and type/function
aliases have been added to the tsdb package to point at it.
The models package already is very light on transitive dependencies
and so it was allowed to be depended on in a concrete way in the
cursors package.
Finally, the protobuf definitions for issuing GRPC reads has been
moved into its own package for two reasons:
1. It's a clean separation, and helps keep it that way.
2. Many/most consumers will not be using GRPC. We just
use the datatypes to express the API which helps making
a GRPC server easier.
It is left up to future refactorings (specifically ones that involve
GPRC) to determine if these types should remain, or if there is a
cleaner way.
There's still some dependencies on both github.com/influxdata/influxql
and github.com/influxdata/influxdb/logger that we can hopefully remove
in future refactorings.
Stuart Carnie
Edd Robinson
Christopher M. Wolff
jlapacik
Yiqun (Ethan) Zhang
Jonathan A. Sternberg
Jacob Marble
Mark Rushakoff
Jeff Wendling