This required a fsp task spawning logic rework which ended up being
cleaner just spawning tasks in a loop sequentially instead of trying
a 2-phase spawn-then-initialize approach.
This also includes changes from the symbol search branch hacked in.
Mostly it includes isolating the main chart startup-sequence to a
function that can be run in a new task every time a new symbol is
requested by the selector/searcher. The actual search functionality
obviously isn't in here yet but minor changes are included as part of
pulling out the `tractor` stream api patch from the symbol search dev
branch.
Avoid bothering with a trio event and expect the caller to do manual shm
registering with the write loop. Provide OHLC sample period indexing
through a re-branded pub-sub func ``iter_ohlc_periods()``.
Move all feed/stream agnostic logic and shared mem writing into a new
set of routines inside the ``data`` sub-package. This lets us move
toward a more standard API for broker and data backends to provide
cache-able persistent streams to client apps.
The data layer now takes care of
- starting a single background brokerd task to start a stream for as
symbol if none yet exists and register that stream for later lookups
- the existing broker backend actor is now always re-used if possible
if it can be found in a service tree
- synchronization with the brokerd stream's startup sequence is now
oriented around fast startup concurrency such that client code gets
a handle to historical data and quote schema as fast as possible
- historical data loading is delegated to the backend more formally by
starting a ``backfill_bars()`` task
- write shared mem in the brokerd task and only destruct it once requested
either from the parent actor or further clients
- fully de-duplicate stream data by using a dynamic pub-sub strategy
where new clients register for copies of the same quote set per symbol
This new API is entirely working with the IB backend; others will need
to be ported. That's to come shortly.
Tyler Goodlet
goodboy