Move core tasks to separate module

Begin abstracting out broker backends by moving core data query tasks
into a module which requires and calls a broker backend API.

piker/brokers/_util.py

@@ -0,0 +1,34 @@
+"""
+Handy utils.
+"""
+import json
+import asks
+import logging
+
+from ..log import colorize_json
+
+
+class BrokerError(Exception):
+    "Generic broker issue"
+
+
+def resproc(
+    resp: asks.response_objects.Response,
+    log: logging.Logger,
+    return_json: bool = True
+) -> asks.response_objects.Response:
+    """Process response and return its json content.
+
+    Raise the appropriate error on non-200 OK responses.
+    """
+    if not resp.status_code == 200:
+        raise BrokerError(resp.body)
+    try:
+        data = resp.json()
+    except json.decoder.JSONDecodeError:
+        log.exception(f"Failed to process {resp}:\n{resp.text}")
+        raise BrokerError(resp.text)
+    else:
+        log.trace(f"Received json contents:\n{colorize_json(data)}")
+
+    return data if return_json else resp

piker/brokers/core.py

@@ -0,0 +1,104 @@
+"""
+Core broker-daemon tasks and API.
+"""
+import time
+import inspect
+from types import ModuleType
+
+import trio
+
+from .questrade import QuestradeError
+from ..log import get_logger
+log = get_logger('broker.core')
+
+
+async def api(brokermod: ModuleType, methname: str, **kwargs) -> dict:
+    """Make (proxy through) an api call by name and return its result.
+    """
+    async with brokermod.get_client() as client:
+        meth = getattr(client.api, methname, None)
+        if meth is None:
+            log.error(f"No api method `{methname}` could be found?")
+            return
+        elif not kwargs:
+            # verify kwargs requirements are met
+            sig = inspect.signature(meth)
+            if sig.parameters:
+                log.error(
+                    f"Argument(s) are required by the `{methname}` method: "
+                    f"{tuple(sig.parameters.keys())}")
+                return
+
+        return await meth(**kwargs)
+
+
+async def quote(brokermod: ModuleType, tickers: [str]) -> dict:
+    """Return quotes dict for ``tickers``.
+    """
+    async with brokermod.get_client() as client:
+        return await client.quote(tickers)
+
+
+async def poll_tickers(
+    client: 'Client',
+    tickers: [str],
+    q: trio.Queue,
+    rate: int = 3,  # delay between quote requests
+    diff_cached: bool = True,  # only deliver "new" quotes to the queue
+) -> None:
+    """Stream quotes for a sequence of tickers at the given ``rate``
+    per second.
+    """
+    t2ids = await client.tickers2ids(tickers)
+    ids = ','.join(map(str, t2ids.values()))
+    sleeptime = round(1. / rate, 3)
+    _cache = {}
+
+    while True:  # use an event here to trigger exit?
+        prequote_start = time.time()
+        try:
+            quotes_resp = await client.api.quotes(ids=ids)
+        except QuestradeError as qterr:
+            if "Access token is invalid" in str(qterr.args[0]):
+                # out-of-process piker may have renewed already
+                client._reload_config()
+                quotes_resp = await client.api.quotes(ids=ids)
+            else:
+                raise
+
+        postquote_start = time.time()
+        quotes = quotes_resp['quotes']
+        payload = []
+        for quote in quotes:
+
+            if quote['delay'] > 0:
+                log.warning(f"Delayed quote:\n{quote}")
+
+            if diff_cached:
+                # if cache is enabled then only deliver "new" changes
+                symbol = quote['symbol']
+                last = _cache.setdefault(symbol, {})
+                new = set(quote.items()) - set(last.items())
+                if new:
+                    log.info(
+                        f"New quote {quote['symbol']}:\n{new}")
+                    _cache[symbol] = quote
+                    payload.append(quote)
+            else:
+                payload.append(quote)
+
+        if payload:
+            q.put_nowait(payload)
+
+        req_time = round(postquote_start - prequote_start, 3)
+        proc_time = round(time.time() - postquote_start, 3)
+        tot = req_time + proc_time
+        log.debug(f"Request + processing took {req_time + proc_time}")
+        delay = sleeptime - (req_time + proc_time)
+        if delay <= 0:
+            log.warn(
+                f"Took {req_time} (request) + {proc_time} (processing) = {tot}"
+                f" secs (> {sleeptime}) for processing quotes?")
+        else:
+            log.debug(f"Sleeping for {delay}")
+            await trio.sleep(delay)

piker/brokers/questrade.py

@@ -1,8 +1,6 @@
 """
 Questrade API backend.
 """
-import inspect
-import json
 import time
 import datetime
 
@@ -10,6 +8,7 @@ import trio
 from async_generator import asynccontextmanager
 
 from . import config
+from ._util import resproc, BrokerError
 from ..log import get_logger, colorize_json
 
 # TODO: move to urllib3/requests once supported
@@ -26,28 +25,6 @@ class QuestradeError(Exception):
     "Non-200 OK response code"
 
 
-def resproc(
-    resp: asks.response_objects.Response,
-    return_json: bool = True
-) -> asks.response_objects.Response:
-    """Process response and return its json content.
-
-    Raise the appropriate error on non-200 OK responses.
-    """
-    if not resp.status_code == 200:
-        raise QuestradeError(resp.body)
-
-    try:
-        data = resp.json()
-    except json.decoder.JSONDecodeError:
-        log.exception(f"Failed to process {resp}:\n{resp.text}")
-        raise QuestradeError(resp.text)
-    else:
-        log.trace(f"Received json contents:\n{colorize_json(data)}")
-
-    return data if return_json else resp
-
-
 class Client:
     """API client suitable for use as a long running broker daemon or
     single api requests.
@@ -80,7 +57,7 @@ class Client:
             params={'grant_type': 'refresh_token',
                     'refresh_token': self.access_data['refresh_token']}
         )
-        data = resproc(resp)
+        data = resproc(resp, log)
         self.access_data.update(data)
 
         return data
@@ -121,11 +98,12 @@ class Client:
         expires_stamp = datetime.datetime.fromtimestamp(
             expires).strftime('%Y-%m-%d %H:%M:%S')
         if not access_token or (expires < time.time()) or force_refresh:
-            log.info(f"Refreshing access token {access_token} which expired at"
+            log.debug(
+                f"Refreshing access token {access_token} which expired at"
                 f" {expires_stamp}")
             try:
                 data = await self._new_auth_token()
-            except QuestradeError as qterr:
+            except BrokerError as qterr:
                 if "We're making some changes" in str(qterr.args[0]):
                     # API service is down
                     raise QuestradeError("API is down for maintenance")
@@ -135,13 +113,13 @@ class Client:
                     self._reload_config()
                     try:
                         data = await self._new_auth_token()
-                    except QuestradeError as qterr:
+                    except BrokerError as qterr:
                         if qterr.args[0].decode() == 'Bad Request':
                             # actually expired; get new from user
                             self._reload_config(force_from_user=True)
                             data = await self._new_auth_token()
                         else:
-                            raise qterr
+                            raise QuestradeError(qterr)
                 else:
                     raise qterr
 
@@ -151,7 +129,7 @@ class Client:
             # write to config on disk
             write_conf(self)
         else:
-            log.info(f"\nCurrent access token {access_token} expires at"
+            log.debug(f"\nCurrent access token {access_token} expires at"
                       f" {expires_stamp}\n")
 
         self._prep_sess()
@@ -168,12 +146,13 @@ class Client:
 
         return symbols2ids
 
-    async def quote(self, tickers):
+    async def quote(self, tickers: [str]):
         """Return quotes for each ticker in ``tickers``.
         """
         t2ids = await self.tickers2ids(tickers)
         ids = ','.join(map(str, t2ids.values()))
-        return (await self.api.quotes(ids=ids))['quotes']
+        results = (await self.api.quotes(ids=ids))['quotes']
+        return {sym: quote for sym, quote in zip(tickers, results)}
 
     async def symbols(self, tickers):
         """Return quotes for each ticker in ``tickers``.
@@ -196,7 +175,7 @@ class _API:
 
     async def _request(self, path: str, params=None) -> dict:
         resp = await self._sess.get(path=f'/{path}', params=params)
-        return resproc(resp)
+        return resproc(resp, log)
 
     async def accounts(self) -> dict:
         return await self._request('accounts')
@@ -268,6 +247,8 @@ def write_conf(client):
 @asynccontextmanager
 async def get_client() -> Client:
     """Spawn a broker client.
+
+    A client must adhere to the method calls in ``piker.broker.core``.
     """
     conf = get_config()
     log.debug(f"Loaded config:\n{colorize_json(dict(conf['questrade']))}")
@@ -290,110 +271,3 @@ async def get_client() -> Client:
         yield client
     finally:
         write_conf(client)
-
-
-async def serve_forever(tasks) -> None:
-    """Start up a client and serve until terminated.
-    """
-    async with get_client() as client:
-        # pretty sure this doesn't work
-        # await client._revoke_auth_token()
-
-        async with trio.open_nursery() as nursery:
-            # launch token manager
-            nursery.start_soon(token_refresher, client)
-
-            # launch children
-            for task in tasks:
-                nursery.start_soon(task, client)
-
-
-async def poll_tickers(
-    client: Client, tickers: [str],
-    q: trio.Queue,
-    rate: int = 3,  # delay between quote requests
-    diff_cached: bool = True,  # only deliver "new" quotes to the queue
-) -> None:
-    """Stream quotes for a sequence of tickers at the given ``rate``
-    per second.
-    """
-    t2ids = await client.tickers2ids(tickers)
-    ids = ','.join(map(str, t2ids.values()))
-    sleeptime = round(1. / rate, 3)
-    _cache = {}
-
-    while True:  # use an event here to trigger exit?
-        prequote_start = time.time()
-        try:
-            quotes_resp = await client.api.quotes(ids=ids)
-        except QuestradeError as qterr:
-            if "Access token is invalid" in str(qterr.args[0]):
-                # out-of-process piker may have renewed already
-                client._reload_config()
-                quotes_resp = await client.api.quotes(ids=ids)
-            else:
-                raise
-
-        postquote_start = time.time()
-        quotes = quotes_resp['quotes']
-        payload = []
-        for quote in quotes:
-
-            if quote['delay'] > 0:
-                log.warning(f"Delayed quote:\n{quote}")
-
-            if diff_cached:
-                # if cache is enabled then only deliver "new" changes
-                symbol = quote['symbol']
-                last = _cache.setdefault(symbol, {})
-                new = set(quote.items()) - set(last.items())
-                if new:
-                    log.info(
-                        f"New quote {quote['symbol']}:\n{new}")
-                    _cache[symbol] = quote
-                    payload.append(quote)
-            else:
-                payload.append(quote)
-
-        if payload:
-            q.put_nowait(payload)
-
-        req_time = round(postquote_start - prequote_start, 3)
-        proc_time = round(time.time() - postquote_start, 3)
-        tot = req_time + proc_time
-        log.debug(f"Request + processing took {req_time + proc_time}")
-        delay = sleeptime - (req_time + proc_time)
-        if delay <= 0:
-            log.warn(
-                f"Took {req_time} (request) + {proc_time} (processing) = {tot}"
-                f" secs (> {sleeptime}) for processing quotes?")
-        else:
-            log.debug(f"Sleeping for {delay}")
-            await trio.sleep(delay)
-
-
-async def api(methname: str, **kwargs) -> dict:
-    """Make (proxy through) an api call by name and return its result.
-    """
-    async with get_client() as client:
-        meth = getattr(client.api, methname, None)
-        if meth is None:
-            log.error(f"No api method `{methname}` could be found?")
-            return
-        elif not kwargs:
-            # verify kwargs requirements are met
-            sig = inspect.signature(meth)
-            if sig.parameters:
-                log.error(
-                    f"Argument(s) are required by the `{methname}` method: "
-                    f"{tuple(sig.parameters.keys())}")
-                return
-
-        return await meth(**kwargs)
-
-
-async def quote(tickers: [str]) -> dict:
-    """Return quotes dict for ``tickers``.
-    """
-    async with get_client() as client:
-        return await client.quote(tickers)