Use a pool of detectors.

When more than a single request was coming in at a time, the server
would crash when trying to write the output file. Each worker had a
single detector with one DN network, so if more than <WORKER#> requests
came in at once, one network would be used multiple times--and it's not
threadsafe.

I've added a queue of nets to pull from, so each request has exclusive
access to a specific network.
This commit is contained in:
niten 2023-03-15 12:31:01 -07:00
parent d4de83bf4b
commit ed962240b3
4 changed files with 111 additions and 49 deletions

View File

@ -36,6 +36,18 @@ in {
default = [ "127.0.0.1" ];
};
pool-size = mkOption {
type = int;
description = "Number of nets to initialize.";
default = 5;
};
detection-timeout = mkOption {
type = int;
description = "Time in seconds to allow for detection to start.";
default = 5;
};
cleanup = {
max_file_age = mkOption {
type = int;
@ -63,6 +75,8 @@ in {
OBJECTIFIER_BUFFER_SIZE = "524288";
OBJECTIFIER_CLEANUP_MAX_AGE = toString cfg.cleanup.max_file_age;
OBJECTIFIER_CLEANUP_DELAY = toString cfg.cleanup.delay;
OBJECTIFIER_TIMEOUT = toString cfg.detection-timeout;
OBJECTIFIER_POOL_SIZE = toString cfg.pool-size;
};
serviceConfig = {
PrivateUsers = true;

View File

@ -6,9 +6,11 @@ import sys
import shutil
from os import path
import hashlib
from contextlib import contextmanager
import tempfile
from pathlib import Path
from queue import Queue, Empty, Full
class Detection:
"""Represents an object dectected in an image."""
@ -25,14 +27,52 @@ class AnalyzedImage:
self.detections = detections
self.outfile = outfile
class ResourcePoolError(Exception):
"""Base class for Pool errors."""
class ResourcePoolTimeout(Exception):
"""Timed out while waiting to resource to become available."""
class ResourcePoolFull(Exception):
"""Pool is full."""
class ResourcePool:
"""A pool to store shared resources."""
def __init__(self, pool_size, factory):
self._pool = Queue(pool_size)
for _ in range(pool_size):
self.__put(factory())
def __get(self, timeout):
try:
return self._pool.get(timeout=timeout)
except Empty:
raise ResourcePoolTimeout()
def __put(self, resource):
try:
return self._pool.put_nowait(resource)
except Full:
raise ResourcePoolFull()
@contextmanager
def reserve(self, timeout):
resource = self.__get(timeout)
try:
yield resource
finally:
self.__put(resource)
def build_net(weights, cfg):
return cv.dnn.readNet(weights, cfg)
class Detector:
"""Detects objects in images, returning an AnalyzedImage."""
def __init__(self, weights, cfg, classes, tempdir, confidence=0.6):
self.net = cv.dnn.readNet(weights, cfg)
def __init__(self, weights, cfg, classes, tempdir, pool_size, confidence=0.7):
self.nets = ResourcePool(pool_size, lambda: build_net(weights, cfg))
self.classes = classes
self.layer_names = self.net.getLayerNames()
self.output_layer = [self.layer_names[i - 1] for i in self.net.getUnconnectedOutLayers()]
self.tmpdir = tempdir
self.minimum_confidence = confidence
@ -40,48 +80,51 @@ class Detector:
simple_name = path.splitext(path.basename(filename))[0]
return str(self.tmpdir / (simple_name + ".png"))
def detect_objects(self, filename, output_filename=None):
def detect_objects(self, filename, timeout=5, output_filename=None):
img = cv.imread(str(filename))
height, width, channel = img.shape
blob = cv.dnn.blobFromImage(img, 0.00392, (416, 416), (0,0,0), True, crop=False)
self.net.setInput(blob)
outs = self.net.forward(self.output_layer)
with self.nets.reserve(timeout) as net:
layer_names = net.getLayerNames()
output_layer = [layer_names[i - 1] for i in net.getUnconnectedOutLayers()]
net.setInput(blob)
outs = net.forward(output_layer)
class_ids = []
confidences = []
boxes = []
detections = []
class_ids = []
confidences = []
boxes = []
detections = []
for out in outs:
for detection in out:
scores = detection[5:]
class_id = np.argmax(scores)
confidence = scores[class_id]
if confidence > self.minimum_confidence:
center_x = int(detection[0] * width)
center_y = int(detection[1] * height)
w = int(detection[2] * width)
h = int(detection[3] * height)
x = int(center_x - w/2)
y = int(center_y - h/2)
boxes.append([x, y, w, h])
confidences.append(float(confidence))
class_ids.append(class_id)
for out in outs:
for detection in out:
scores = detection[5:]
class_id = np.argmax(scores)
confidence = scores[class_id]
if confidence > self.minimum_confidence:
center_x = int(detection[0] * width)
center_y = int(detection[1] * height)
w = int(detection[2] * width)
h = int(detection[3] * height)
x = int(center_x - w/2)
y = int(center_y - h/2)
boxes.append([x, y, w, h])
confidences.append(float(confidence))
class_ids.append(class_id)
indexes = cv.dnn.NMSBoxes(boxes, confidences, 0.5, 0.4)
indexes = cv.dnn.NMSBoxes(boxes, confidences, 0.5, 0.4)
for i in indexes:
label = str(self.classes[class_ids[i]])
box = [int(n) for n in boxes[i]]
detections.append(Detection(label, confidences[i], box))
for i in indexes:
label = str(self.classes[class_ids[i]])
box = [int(n) for n in boxes[i]]
detections.append(Detection(label, confidences[i], box))
font = cv.FONT_HERSHEY_PLAIN
marked = cv.imread(str(filename))
for detection in detections:
x, y, w, h = detection.box
cv.rectangle(marked, (x,y), (x + w, y + h), (255,255,255,0), 2)
cv.putText(marked, detection.label, (x,y+30), font, 3, (255,255,255,0), 1)
font = cv.FONT_HERSHEY_PLAIN
marked = cv.imread(str(filename))
for detection in detections:
x, y, w, h = detection.box
cv.rectangle(marked, (x,y), (x + w, y + h), (255,255,255,0), 2)
cv.putText(marked, detection.label, (x,y+30), font, 3, (255,255,255,0), 1)
out_file = output_filename if output_filename else self.output_filename(filename)
cv.imwrite(out_file, marked)
return AnalyzedImage(filename, detections, str(out_file))
out_file = output_filename if output_filename else self.output_filename(filename)
cv.imwrite(out_file, marked)
return AnalyzedImage(filename, detections, str(out_file))

View File

@ -36,6 +36,8 @@ yolo_labels_file = get_envvar_or_fail('OBJECTIFIER_YOLOV3_LABELS')
buffer_size = to_int(get_envvar('OBJECTIFIER_BUFFER_SIZE')) or 524288
max_file_age = to_int(get_envvar('OBJECTIFIER_CLEANUP_MAX_AGE'))
file_cleanup_delay = to_int(get_envvar('OBJECTIFIER_CLEANUP_DELAY'))
detection_timeout = to_int(get_envvar('OBJECTIFIER_TIMEOUT')) or 5
pool_size = to_int(get_envvar('OBJECTIFIER_POOL_SIZE')) or 10
yolo_labels = []
with open(yolo_labels_file, "r") as f:
@ -45,10 +47,11 @@ incoming_dir = Path(get_envvar_or_fail('CACHE_DIRECTORY'))
outgoing_dir = Path(get_envvar_or_fail('STATE_DIRECTORY'))
detector = Detector(
yolo_weights,
yolo_config,
yolo_labels,
outgoing_dir)
weights=yolo_weights,
cfg=yolo_config,
classes=yolo_labels,
tempdir=outgoing_dir,
pool_size=pool_size)
app = FastAPI()
@ -108,7 +111,8 @@ def analyze_image(request: Request, image: UploadFile):
chunk = image.file.read(buffer_size)
result = detector.detect_objects(
infile,
str(outgoing_dir / (file_hash.hexdigest() + ".png")))
str(outgoing_dir / (file_hash.hexdigest() + ".png")),
detection_timeout)
remove(infile)
return result_to_dict(result, base_url)

View File

@ -27,10 +27,11 @@ with open(args.yolo_labels) as f:
classes = [line.strip() for line in f.readlines()]
detector = Detector(
args.yolo_weights,
args.yolo_config,
classes,
outgoing_dir)
weights=args.yolo_weights,
cfg=args.yolo_config,
classes=classes,
tempdir=outgoing_dir,
pool_size=1)
for filename in args.files:
print(filename + ":")