Source code for biothings.utils.hub

# from http://asyncssh.readthedocs.io/en/latest/#id13

# To run this program, the file ``ssh_host_key`` must exist with an SSH
# private key in it to use as a server host key.

import sys
import os
import re
import datetime
import json
import pydoc
import copy
import asyncio
import io
import time
from functools import partial
from pprint import pformat
from collections import OrderedDict

from IPython import InteractiveShell

from biothings.utils.dataload import to_boolean
from biothings.utils.common import timesofar
import biothings.utils.aws as aws
from biothings.utils.hub_db import get_cmd, get_last_command, backup, restore
from biothings.utils.loggers import ShellLogger
from biothings.utils.web.es import flatten_doc
from biothings import config
if hasattr(config, 'logger'):
    logging = config.logger
else:
    import logging

# useful variables to bring into hub namespace
pending = "pending"

HUB_ENV = hasattr(config, "HUB_ENV") and config.HUB_ENV or ""    # default: prod (or "normal")
VERSIONS = HUB_ENV and "%s-versions" % HUB_ENV or "versions"
LATEST = HUB_ENV and "%s-latest" % HUB_ENV or "latest"


def jsonreadify(cmd):
    newcmd = copy.copy(cmd)
    newcmd.pop("jobs")
    return newcmd

##############
# HUB SERVER #
##############

[docs]class AlreadyRunningException(Exception): pass
[docs]class CommandError(Exception): pass
[docs]class NoSuchCommand(Exception): pass
[docs]class CommandNotAllowed(Exception): pass
[docs]class CommandInformation(dict): pass
[docs]class CommandDefinition(dict): pass
[docs]class HubShell(InteractiveShell): launched_commands = {} pending_outputs = {} cmd_cnt = None cmd = None # "cmd" collection def __init__(self, job_manager): self.job_manager = job_manager self.commands = OrderedDict() self.managers = {} self.extra_ns = OrderedDict() self.tracked = {} # command calls kept in history or not self.hidden = {} # not returned by help() self.origout = sys.stdout self.buf = io.StringIO() self.shellog = ShellLogger(name="shell") # there should be only one shell instance (todo: singleton) self.__class__.cmd = get_cmd() self.__class__.set_command_counter() super(HubShell, self).__init__(user_ns=self.extra_ns) @classmethod def set_command_counter(cls): assert cls.cmd, "No cmd collection set" try: res = get_last_command() if res: logging.debug("Last launched command ID: %s", res["_id"]) cls.cmd_cnt = int(res["_id"]) + 1 else: logging.info("No previously stored command found, set counter to 1") cls.cmd_cnt = 1 except StopIteration: logging.info("Can't find highest command number, assuming starting from scratch") cls.cmd_cnt = 1 def set_commands(self, basic_commands, *extra_ns): def register(commands, hidden=False): for name, cmd in commands.items(): if name in self.commands: raise CommandError("Command defined multiple time: %s" % name) # if type(cmd) == CommandDefinition: # TODO: remove this line if isinstance(cmd, CommandDefinition): try: self.commands[name] = cmd["command"] self.tracked[name] = cmd.get("tracked", True) self.hidden[name] = cmd.get("hidden", False) or hidden except KeyError as e: raise CommandError("Could not register command because missing '%s' in definition: %s" % (e, cmd)) else: self.commands[name] = cmd self.hidden[name] = hidden # update original passed commands to caller knows what's been done there if name not in basic_commands: basic_commands[name] = cmd # update with ssh server default commands register(basic_commands) # don't track this calls register({"restart": CommandDefinition(command=self.restart, track=True)}) register({"stop": CommandDefinition(command=self.stop, track=True)}) register({"backup": CommandDefinition(command=backup, track=True)}) register({"restore": CommandDefinition(command=restore, track=True)}) register({"help": CommandDefinition(command=self.help, track=False)}) register({"commands": CommandDefinition(command=self.command_info, tracked=False)}) register({"command": CommandDefinition( command=lambda id, *args, **kwargs: self.command_info(id=id, *args, **kwargs), tracked=False )}) for extra in extra_ns: # don't expose extra commands, they're kind of private/advanced register(extra, hidden=True) #self.extra_ns["cancel"] = self.__class__.cancel # for boolean calls self.extra_ns["_and"] = _and self.extra_ns["partial"] = partial self.extra_ns["hub"] = self # merge official/public commands with hidden/private to # make the whole available in shell's namespace self.extra_ns.update(self.commands) # Note: there's no need to update shell namespace as self.extra_ns # has been passed by ref in __init__() so things get updated automagically # (self.user_ns.update(...) can be used otherwise, self.user_ns is IPython # internal namespace dict def stop(self, force=False): return self.restart(force=force, stop=True) def restart(self, force=False, stop=False): @asyncio.coroutine def do(): try: if stop: event = "hub_stop" msg = "Hub is stopping" else: event = "hub_restart" msg = "Hub is restarting" logging.critical( json.dumps({ "type": "alert", "msg": msg, "event": event }), extra={"event": True} ) logging.info("Stopping job manager...") j = self.job_manager.stop(force=force) def ok(f): f.result() # consume logging.error("Job manager stopped") j.add_done_callback(ok) yield from j except Exception as e: logging.error("Error while recycling the process queue: %s", e) raise def start(f): f.result() # consume future's result to potentially raise exception logging.debug("%s %s", [sys.executable], sys.argv) import subprocess subprocess.Popen([sys.executable] + sys.argv) self.job_manager.hub_process.kill() sys.exit(0) def autokill(f): f.result() self.job_manager.hub_process.kill() fut = asyncio.ensure_future(do()) if stop: logging.warning("Stopping hub") fut.add_done_callback(autokill) else: logging.warning("Restarting hub") fut.add_done_callback(start) return fut
[docs] def help(self, func=None): """ Display help on given function/object or list all available commands """ if not func: cmds = "\nAvailable commands:\n\n" for k in self.commands: if self.hidden[k]: continue cmds += "\t%s\n" % k cmds += "\nType: 'help(command)' for more\n" return cmds elif isinstance(func, partial): docstr = "\n" + pydoc.render_doc(func.func, title="Hub documentation: %s") docstr += "\nDefined et as a partial, with:\nargs:%s\nkwargs:%s\n" % (repr(func.args), repr(func.keywords)) return docstr elif isinstance(func, CompositeCommand): docstr = "\nComposite command:\n\n%s\n" % func return docstr else: try: return "\n" + pydoc.render_doc(func, title="Hub documentation: %s") except ImportError: return "\nHelp not available for this command\n"
[docs] def launch(self, pfunc): """ Helper to run a command and register it pfunc is partial taking no argument. Command name is generated from partial's func and arguments """ res = pfunc() # rebuild a command as string strcmd = pfunc.func.__name__ strcmd += "(" strargs = [] if pfunc.args: strargs.append(",".join([repr(a) for a in pfunc.args])) if pfunc.keywords: strargs.append(",".join(["%s=%s" % (k, repr(v)) for (k, v) in pfunc.keywords.items()])) strcmd += ",".join(strargs) strcmd += ")" # we use force here because, very likely, the command from strcmd we generated # isn't part of shell's known commands (and there's a check about that when force=False) self.register_command(strcmd, res, force=True) return pfunc
def extract_command_name(self, cmd): try: # extract before () (non-callable are never tracked) grps = re.fullmatch("([\w\.]+)(\(.*\))", cmd.strip()).groups() return grps[0] except AttributeError: raise CommandError("Can't extract command name from '%s'" % repr(cmd)) @classmethod def save_cmd(cls, _id, cmd): newcmd = jsonreadify(cmd) cls.cmd.replace_one({"_id": _id}, newcmd, upsert=True) def register_managers(self, managers): self.managers = managers
[docs] def register_command(self, cmd, result, force=False): """ Register a command 'cmd' inside the shell (so we can keep track of it). 'result' is the original value that was returned when cmd was submitted. Depending on the type, returns a cmd number (ie. result was an asyncio task and we need to wait before getting the result) or directly the result of 'cmd' execution, returning, in that case, the output. """ # see if command should actually be registered try: cmdname = self.extract_command_name(cmd) except CommandError: # if can't extract command name, then don't even try to register # (could be, for instance, "pure" python code typed from the console) logging.debug("Can't extract command from %s, can't register", cmd) return result # also, never register non-callable command if not force and (not callable(self.extra_ns.get(cmdname)) or \ self.tracked.get(cmdname, True) == False): return result cmdnum = self.__class__.cmd_cnt cmdinfo = CommandInformation(cmd=cmd, jobs=result, started_at=time.time(), id=cmdnum, is_done=False) assert cmdnum not in self.__class__.launched_commands # register self.__class__.launched_commands[cmdnum] = cmdinfo self.__class__.save_cmd(cmdnum, cmdinfo) self.__class__.cmd_cnt += 1 # TODO: clean up the following if statement, confirm with Sebastien if type(result) == asyncio.tasks.Task or type(result) == asyncio.tasks._GatheringFuture or \ type(result) == asyncio.Future or \ type(result) == list and len(result) > 0 and type(result[0]) == asyncio.tasks.Task: # it's asyncio related result = type(result) != list and [result] or result # TODO: cleanup and confirm this line cmdinfo["jobs"] = result return cmdinfo else: # ... and it's not asyncio related, we can display it directly cmdinfo["is_done"] = True cmdinfo["failed"] = False cmdinfo["started_at"] = time.time() cmdinfo["finished_at"] = time.time() cmdinfo["duration"] = "0s" return result
def eval(self, line, return_cmdinfo=False, secure=False): line = line.strip() self.shellog.input(line) origline = line # keep what's been originally entered # poor man's singleton... if line in [j["cmd"] for j in self.__class__.launched_commands.values() if not j.get("is_done")]: raise AlreadyRunningException("Command '%s' is already running\n" % repr(line)) # is it a hub command, in which case, intercept and run the actual declared cmd # IMPORTANT !!! this is where we allow the command or not when secure=True IMPORTANT !!! # the logic is following: # - what's before parenthesis must exactly match a command # - parenthesis are mandatory # - no '&&' operator allowed if secure: # command must be alpha only, argument with "," and "=", or no arg at all pat = r'^([A-Za-z_]+)\(["\'\w\s=,.-]*\)$' else: pat = r'(.*)\(.*\)' # more permissive m = re.match(pat, line) if m: cmd = m.groups()[0].strip() if secure and cmd not in self.commands: # match regex rule but not a valid/existing command, discard it raise NoSuchCommand(cmd) if cmd in self.commands and \ isinstance(self.commands[cmd], CompositeCommand): line = self.commands[cmd] elif line != "" and secure: # we have something entered, it doesn't match our regex rule, discard it raise CommandNotAllowed(line) # cmdline is the actual command sent to shell, line is the one displayed # they can be different if there's a preprocessing cmdline = line # && cmds ? ie. chained cmds if "&&" in line: chained_cmds = [cmd for cmd in map(str.strip, line.split("&&")) if cmd] if len(chained_cmds) > 1: # need to build a command with _and and using partial, meaning passing original func param # to the partials strcmds = [] for one_cmd in chained_cmds: func, args = re.match("(.*)\((.*)\)", one_cmd).groups() if args: strcmds.append("partial(%s,%s)" % (func, args)) else: strcmds.append("partial(%s)" % func) cmdline = "_and(%s)" % ",".join(strcmds) else: raise CommandError("Using '&&' operator required two operands\n") r = self.run_cell(cmdline, store_history=True) outputs = [] if not r.success: raise CommandError("%s\n" % repr(r.error_in_exec)) else: # command was a success, now get the results: if r.result is None: # -> nothing special was returned, grab the stdout self.buf.seek(0) # from print stdout ? b = self.buf.read() outputs.append(b) # clear buffer self.buf.seek(0) self.buf.truncate() else: # -> we have something returned... res = self.register_command(cmd=origline, result=r.result) # if type(res) != CommandInformation: # TODO: remove this line if not isinstance(res, CommandInformation): # if type(res) != str: # TODO: remove this line if not isinstance(res, str): outputs.append(pformat(res)) else: outputs.append(res) else: if return_cmdinfo: return res # Note: this will cause all outputs to go to one SSH session, ie. if multiple users # are logged, only one will the results if self.__class__.pending_outputs: outputs.extend(self.__class__.pending_outputs.values()) self.__class__.pending_outputs = {} return outputs #@classmethod #def cancel(klass,jobnum): # return klass.launched_commands.get(jobnum) @classmethod def refresh_commands(cls): for num, info in sorted(cls.launched_commands.items()): # already process, this current command is now history # Note: if we have millions of commands there, it could last quite a while, # but IRL we only have a few if info.get("is_done") == True: continue # is_done = set([j.done() for j in info["jobs"]]) == set([True]) # TODO: remove this line is_done = {j.done() for j in info["jobs"]} == {True} has_err = is_done and [True for j in info["jobs"] if j.exception()] or None localoutputs = is_done and ([str(j.exception()) for j in info["jobs"] if j.exception()] or \ [j.result() for j in info["jobs"]]) or None if is_done: cls.launched_commands[num]["is_done"] = True cls.launched_commands[num]["failed"] = has_err and has_err[0] or False cls.launched_commands[num]["results"] = localoutputs cls.launched_commands[num]["finished_at"] = time.time() cls.launched_commands[num]["duration"] = timesofar(t0=cls.launched_commands[num]["started_at"], t1=cls.launched_commands[num]["finished_at"]) cls.save_cmd(num, cls.launched_commands[num]) if not has_err and localoutputs and set(map(type, localoutputs)) == {str}: localoutputs = "\n" + "".join(localoutputs) cls.pending_outputs[num] = "[%s] %s {%s} %s: finished %s " % \ (num, has_err and "ERR" or "OK", timesofar(info["started_at"]), info["cmd"], localoutputs) else: cls.pending_outputs[num] = "[%s] RUN {%s} %s" % (num, timesofar(info["started_at"]), info["cmd"]) @classmethod def command_info(cls, id=None, running=None, failed=None): cmds = {} if id is not None: try: id = int(id) return jsonreadify(cls.launched_commands[id]) except KeyError: raise CommandError("No such command with ID %s" % repr(id)) except ValueError: raise CommandError("Invalid ID %s" % repr(id)) if running is not None: is_done = not to_boolean(running) else: is_done = None if failed is not None: failed = to_boolean(failed) for _id, cmd in cls.launched_commands.items(): if is_done is not None: # running or done commands (not both) if cmd.get("is_done") == is_done: # done + failed (a failed command is always done btw) if failed is not None and cmd.get("is_done") == True: if cmd.get("failed") == failed: cmds[_id] = jsonreadify(cmd) else: # don't care if failed or not cmds[_id] = jsonreadify(cmd) else: # If asked is_done=true, it means command _id has is_done=false # if we get there. So the command is sill running, so we don't # know if it failed or not, so no need to check failed there, # it's been handled above. # If asksed is_done=false, we don't need to check failed, # same logic applies continue else: # either running or done commands (both) if failed is not None and cmd.get("is_done") == True: if cmd.get("failed") == failed: cmds[_id] = jsonreadify(cmd) else: # don't care if failed or not cmds[_id] = jsonreadify(cmd) return cmds
#################### # DEFAULT HUB CMDS # #################### # these can be used in client code to define # commands. partial should be used to pass the # required arguments, eg.: # {"schedule" ; partial(schedule,loop)} def stats(src_dump): pass
[docs]def template_out(field, confdict): """ Return field as a templated-out filed, substituting some "%(...)s" part with confdict, Fields can follow dotfield notation. Fields like "$(...)" are replaced with a timestamp following specified format (see time.strftime) Example:: confdict = {"a":"one"} field = "%(a)s_two_three_$(%Y%m)" => "one_two_three_201908" # assuming we're in August 2019 """ # first deal with timestamp pat = re.compile(".*(\$\((.*?)\)).*") try: m = pat.match(field) except TypeError: # not string/byte-like just skip the process return field if m: tosub, fmt = m.groups() ts = datetime.datetime.now().strftime("%%%s" % fmt) field = field.replace(tosub, ts) flatdict = flatten_doc(confdict) # then use dict to sub keys field = field % flatdict return field
[docs]def publish_data_version(s3_bucket, s3_folder, version_info, update_latest=True, aws_key=None, aws_secret=None): """ Update remote files: - versions.json: add version_info to the JSON list or replace if arg version_info is a list - latest.json: update redirect so it points to latest version url "versions" is dict such as:: {"build_version":"...", # version name for this release/build "require_version":"...", # version required for incremental update "target_version": "...", # version reached once update is applied "type" : "incremental|full" # release type "release_date" : "...", # ISO 8601 timestamp, release date/time "url": "http...."} # url pointing to release metadata """ # register version versionskey = os.path.join(s3_folder, "%s.json" % VERSIONS) try: versions = aws.get_s3_file(versionskey, return_what="content", aws_key=aws_key, aws_secret=aws_secret, s3_bucket=s3_bucket) versions = json.loads(versions.decode()) # S3 returns bytes except (FileNotFoundError, json.JSONDecodeError): versions = {"format": "1.0", "versions": []} # if type(version_info) == list: # remove this line if isinstance(version_info, list): versions["versions"] = version_info else: # used to check duplicates tmp = {} # [tmp.setdefault(e["build_version"], e) for e in versions["versions"]] # TODO: remove this line for e in versions["versions"]: tmp.setdefault(e["build_version"], e) tmp[version_info["build_version"]] = version_info # order by build_version versions["versions"] = sorted(tmp.values(), key=lambda e: e["build_version"]) aws.send_s3_file(None, versionskey, content=json.dumps(versions, indent=True), aws_key=aws_key, aws_secret=aws_secret, s3_bucket=s3_bucket, content_type="application/json", overwrite=True) # update latest # if type(version_info) != list and update_latest: # TODO: remove this line if not isinstance(version_info, list) and update_latest: latestkey = os.path.join(s3_folder, "%s.json" % LATEST) key = None try: key = aws.get_s3_file( latestkey, return_what="key", aws_key=aws_key, aws_secret=aws_secret, s3_bucket=s3_bucket ) except FileNotFoundError: pass aws.send_s3_file( None, latestkey, content=json.dumps(version_info["build_version"], indent=True), content_type="application/json", aws_key=aws_key, aws_secret=aws_secret, s3_bucket=s3_bucket, overwrite=True ) if not key: key = aws.get_s3_file( latestkey, return_what="key", aws_key=aws_key, aws_secret=aws_secret, s3_bucket=s3_bucket ) newredir = os.path.join("/", s3_folder, "{}.json".format(version_info["build_version"])) key.set_redirect(newredir)
def _and(*funcs): """ Calls passed functions, one by one. If one fails, then it stops. Function should return a asyncio Task. List of one Task only are also permitted. Partial can be used to pass arguments to functions. Ex: _and(f1,f2,partial(f3,arg1,kw=arg2)) """ all_res = [] func1 = funcs[0] func2 = None fut1 = func1() # if type(fut1) == list: # TODO: remove this line if isinstance(fut1, list): assert len(fut1) == 1, "Can't deal with list of more than 1 task: %s" % fut1 fut1 = fut1.pop() if not isinstance(fut1, asyncio.Future): raise CommandError("First command didn't return a future, can't chain commands") all_res.append(fut1) # err = None def do(f, cb): f.result() # consume exception if any if cb: all_res.extend(_and(cb, *funcs)) if len(funcs) > 1: func2 = funcs[1] if len(funcs) > 2: funcs = funcs[2:] else: funcs = [] fut1.add_done_callback(partial(do, cb=func2)) return all_res
[docs]class CompositeCommand(str): """ Defines a composite hub commands, that is, a new command made of other commands. Useful to define shortcuts when typing commands in hub console. """ def __init__(self, cmd): self.cmd = cmd def __str__(self): return "<CompositeCommand: '%s'>" % self.cmd
############ # RELOADER # ############ def exclude_from_reloader(path): # exlucde cached, git and hidden files return path.endswith("__pycache__") or \ ".git" in path or \ os.path.basename(path).startswith(".")
[docs]class BaseHubReloader(object): """ Monitor sources' code and reload hub accordingly to update running code """ def __init__(self, paths, reload_func, wait=5.0): """ Monitor given paths for directory deletion/creation and for file deletion/creation. Poll for events every 'wait' seconds. """ raise NotImplementedError("Implement me in a sub-class")
[docs] def poll(self): """Start monitoring changes on files and/directories""" raise NotImplementedError("Implement me in a sub-class")
[docs] def watched_files(self): """Return a list of files/directories being watched""" raise NotImplementedError("Implement me in a sub-class")
[docs]class PyInotifyHubReloader(BaseHubReloader): """Based on pyinotify events""" # inner class to hide pyinotify in case not available import pyinotify
[docs] class ReloadListener(pyinotify.ProcessEvent):
[docs] def my_init(self, watcher_manager, reload_func): self.reload_func = reload_func self.watcher_manager = watcher_manager
[docs] def process_default(self, event): pyinotify = sys.modules["pyinotify"] if exclude_from_reloader(event.pathname): return if event.dir: if event.mask & pyinotify.IN_CREATE: # add to watcher. no need to check if already watched, manager knows # how to deal with that logging.info("Add '%s' to watcher", event.pathname) self.watcher_manager.add_watch(event.pathname, self.notifier.mask, rec=1) elif event.mask & pyinotify.IN_DELETE: logging.info("Remove '%s' from watcher", event.pathname) # watcher knows when directory is deleted (file descriptor become invalid), # so no need to do it manually logging.error("Need to reload manager because of %s", event) self.reload_func()
def __init__(self, paths, reload_func, wait=5, mask=None): pyinotify = sys.modules["pyinotify"] # get it from sys.modules or we'd need another "import" # just sure why... if isinstance(paths, str): paths = [paths] paths = set(paths) # get rid of duplicated, just in case self.mask = mask or pyinotify.IN_CREATE|pyinotify.IN_DELETE|pyinotify.IN_CLOSE_WRITE self.reload_func = reload_func # only listen to these events. Note: directory detection is done via a flag so # no need to use IS_DIR self.watcher_manager = pyinotify.WatchManager(exclude_filter=exclude_from_reloader) self.paths = [] # cleaned for path in paths: if not os.path.isabs(path): path = os.path.abspath(path) self.paths.append(path) self.watcher_manager.add_watch(path, self.mask, rec=True, exclude_filter=exclude_from_reloader) # recursive self.listener = self.__class__.ReloadListener( watcher_manager=self.watcher_manager, reload_func=self.reload_func) self.notifier = pyinotify.Notifier( self.watcher_manager, default_proc_fun=self.listener ) # propagate notifier so notifer itself can be reloaded (when new directory/source) self.listener.notifier = self self.wait = wait self.do_monitor = False def monitor(self): @asyncio.coroutine def do(): logging.info( "Monitoring source code in, %s:\n%s", repr(self.paths), pformat(self.watched_files()) ) while self.do_monitor: try: yield from asyncio.sleep(self.wait) # this reads events from OS if self.notifier.check_events(0.1): self.notifier.read_events() # Listener gets called there if event avail self.notifier.process_events() except KeyboardInterrupt: logging.warning("Stop monitoring code") break self.do_monitor = True return asyncio.ensure_future(do())
[docs] def watched_files(self): return [v.path for v in self.watcher_manager.watches.values()]
[docs]class TornadoAutoReloadHubReloader(BaseHubReloader): """Reloader based on tornado.autoreload module""" def __init__(self, paths, reload_func, wait=5): self.mod = sys.modules["tornado.autoreload"] if isinstance(paths, str): paths = [paths] paths = set(paths) # get rid of duplicated, just in case self.reload_func = reload_func self.mod.add_reload_hook(self.reload_func) # only listen to these events. Note: directory detection is done via a flag so # no need to use IS_DIR self.paths = [] # cleaned for path in paths: if not os.path.isabs(path): path = os.path.abspath(path) self.paths.append(path) self.mod.watch(path) for dirpath, dirnames, filenames in os.walk(path): if exclude_from_reloader(dirpath): continue if not dirnames: # reaching files (leaves) for fn in filenames: f_path = os.path.join(dirpath, fn) if exclude_from_reloader(f_path): continue self.mod.watch(f_path) self.wait = wait self.do_monitor = False def monitor(self): logging.info( "Monitoring source code in, %s:\n%s", repr(self.paths), pformat(self.watched_files()) ) self.mod.start(self.wait*1000) # millis
[docs] def watched_files(self): return self.mod._watched_files
#return [d for d in self.mod._watched_files if os.path.isdir(d)]
[docs]def get_hub_reloader(*args, **kwargs): """ Select proper reloader depending on whether pyinotify is available (1st choice) or not (tornado.autoreload otherwise) """ if getattr(config, "USE_RELOADER", False) and config.USE_RELOADER: try: import pyinotify logging.info("Using Hub reloader based on pyinotify") return PyInotifyHubReloader(*args,**kwargs) except ImportError: import tornado.autoreload logging.info("Using Hub reloader based on tornado.autoreload") return TornadoAutoReloadHubReloader(*args,**kwargs) else: logging.info("USE_RELOADER not set (or False), won't monitor for changes") return None