从子进程调用的外部 python 脚本打印 tqdm 进度条
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【中文标题】从子进程调用的外部 python 脚本打印 tqdm 进度条【英文标题】:Print tqdm progress bar from external python script called by subprocess 【发布时间】:2021-04-09 08:31:06 【问题描述】:我的主要目标是通过subprocess
在另一个python 脚本(调用者脚本)中运行一个外部python 脚本(客户端脚本)。调用者脚本的控制台显示来自客户端脚本的所有输出除了 tqdm 输出 - 所以这不是subprocess
显示输出的一般问题,而是与subprocess
交互相关的特定问题tqdm
。
我的次要目标是我想了解它:)。非常感谢您提供如此周到的解释。
客户端脚本 (train.py) 包含多个 tqdm 调用。到目前为止,我还没有看到各种 tqdm 参数配置之间的输出有太大差异,所以让我们使用最简单的。
在train.py
:
...
from tqdm import tqdm
with tqdm(total = 10, ncols = 80,
file=sys.stdout, position = 0, leave = True,
desc='f5b: pbar.set_postfix') as pbar:
for i in range(10):
pbar.update(1)
postfix = 'loss': '0:.4f'.format(1+i)
pbar.set_postfix(**postfix)
sleep(0.1)
调用者脚本experiment.py
执行函数execute_experiment
,该函数通过参数train.py
调用command_list
:
def execute_experiment(command_list):
tic = time.time()
try:
process = subprocess.Popen(
command_list, shell=False,
encoding='utf-8',
bufsize=0,
stdin=subprocess.DEVNULL,
universal_newlines=True,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE
)
# Poll process for new output until finished
# Source: https://***.com/q/37401654/7769076
while process.poll() is None:
nextline = process.stdout.readline()
sys.stdout.write(nextline)
sys.stdout.flush()
except CalledProcessError as err:
print("CalledProcessError: 0".format(err))
sys.exit(1)
except OSError as err:
print("OS error: 0".format(err))
sys.exit(1)
except:
print("Unexpected error:", sys.exc_info()[0])
raise
if (process.returncode == 0):
toc = time.time()
time1 = str(round(toc - tic))
return time1
else:
return 1
此脚本调用上述从 train.py 截取的代码确实返回输出,但 tqdm 输出在 0 秒后停止,如下所示:
f5b: pbar.set_postfix: 0%| | 0/10 [00:00<?, ?it/s]
f5b: pbar.set_postfix: 10%|█▊ | 1/10 [00:00<00:00, 22310.13it/s]
脚本调用train.py原代码返回所有输出除了tqdm输出:
Training default configuration
train.py data --use-cuda ...
device: cuda
...
评论:
shell = False
:因为python脚本调用python脚本。 shell=True
时,根本不调用客户端脚本
bufsize=0
: 防止缓冲
train.py
调用前面带有sys.executable
,以确保在本地计算机上调用相应 conda 环境的 python 解释器。
问题:
tqdm.set_postfix
是否会阻止将进度条输出传递到上游?我知道在调用 tqdm.set_description
时会发生这种情况,例如作者:
pbar.set_description('已处理:%d' %(1 + i))
这段代码包含它:
def train(self, dataloader, max_batches=500, verbose=True, **kwargs):
with tqdm(total=max_batches, disable=not verbose, **kwargs) as pbar:
for results in self.train_iter(dataloader, max_batches=max_batches):
pbar.update(1)
postfix = 'loss': '0:.4f'.format(results['mean_outer_loss'])
if 'accuracies_after' in results:
postfix['accuracy'] = '0:.4f'.format(
np.mean(results['accuracies_after']))
pbar.set_postfix(**postfix)
# for logging
return results
-
是嵌套函数调用导致进度条不显示的原因吗?
调用顺序为experiment.py
> train.py
> nested.py
。
train.py
通过以下方式调用nested.py
中的train 函数:
对于范围内的纪元(args.num_epochs):
results_metatraining = metalearner.train(meta_train_dataloader,
max_batches=args.num_batches,
verbose=args.verbose,
desc='Training',
# leave=False
leave=True
)
尝试了替代方案但没有成功:
### try2
process = subprocess.Popen(command_list, shell=False, encoding='utf-8',
stdin=DEVNULL, stdout=subprocess.PIPE)
while True:
output = process.stdout.readline().strip()
print('output: ' + output)
if output == '' and process.poll() is not None: # end of output
break
if output: # print output in realtime
print(output)
else:
output = process.communicate()
process.wait()
### try6
process = subprocess.Popen(command_list, shell=False,
stdout=subprocess.PIPE, universal_newlines=True)
for stdout_line in iter(process.stdout.readline, ""):
yield stdout_line
process.stdout.close()
return_code = process.wait()
print('return_code' + str(return_code))
if return_code:
raise subprocess.CalledProcessError(return_code, command_list)
### try7
with subprocess.Popen(command_list, stdout=subprocess.PIPE,
bufsize=1, universal_newlines=True) as p:
while True:
line = p.stdout.readline()
if not line:
break
print(line)
exit_code = p.poll()
【问题讨论】:
【参考方案1】:我认为 readline 正在等待'\n',而 tqdm 没有创建新行,也许这会有所帮助(我没有尝试):
import io
def execute_experiment(command_list):
tic = time.time()
try:
process = subprocess.Popen(
command_list, shell=False,
encoding='utf-8',
bufsize=1,
stdin=subprocess.DEVNULL,
universal_newlines=True,
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT
)
# Poll process for new output until finished
# Source: https://***.com/q/37401654/7769076
reader = io.TextIOWrapper(process.stdout, encoding='utf8')
while process.poll() is None:
char = reader.read(1)
sys.stdout.write(char)
sys.stdout.flush()
except CalledProcessError as err:
print("CalledProcessError: 0".format(err))
sys.exit(1)
except OSError as err:
print("OS error: 0".format(err))
sys.exit(1)
except:
print("Unexpected error:", sys.exc_info()[0])
raise
if (process.returncode == 0):
toc = time.time()
time1 = str(round(toc - tic))
return time1
else:
return 1
【讨论】:
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