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ramalhoramalho
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Merge pull request fluentpython#4 from eumiro/ch21
ch21 cleanup, f-strings, and pathlib
2 parents 5ce5f8a + 93dfeae commit 584a7f2

11 files changed

+70
-81
lines changed

‎21-futures/demo_executor_map.py

+1-1
Original file line numberDiff line numberDiff line change
@@ -24,7 +24,7 @@ def main():
2424
display('results:', results) # <6>
2525
display('Waiting for individual results:')
2626
for i, result in enumerate(results): # <7>
27-
display('result {}: {}'.format(i, result))
27+
display(f'result {i}: {result}')
2828

2929
if __name__ == '__main__':
3030
main()

‎21-futures/getflags/flags.py

+3-6
Original file line numberDiff line numberDiff line change
@@ -17,8 +17,8 @@
1717
"""
1818

1919
# tag::FLAGS_PY[]
20-
import os
2120
import time
21+
from pathlib import Path
2222
from typing import Callable
2323

2424
import requests # <1>
@@ -27,12 +27,10 @@
2727
'MX PH VN ET EG DE IR TR CD FR').split() # <2>
2828

2929
BASE_URL = 'http://fluentpython.com/data/flags' # <3>
30-
DEST_DIR = 'downloaded/' # <4>
30+
DEST_DIR = Path('downloaded') # <4>
3131

3232
def save_flag(img: bytes, filename: str) -> None: # <5>
33-
path = os.path.join(DEST_DIR, filename)
34-
with open(path, 'wb') as fp:
35-
fp.write(img)
33+
(DEST_DIR / filename).write_bytes(img)
3634

3735
def get_flag(cc: str) -> bytes: # <6>
3836
cc = cc.lower()
@@ -45,7 +43,6 @@ def download_many(cc_list: list[str]) -> int: # <7>
4543
image = get_flag(cc)
4644
print(cc, end=' ', flush=True) # <9>
4745
save_flag(image, cc.lower() + '.gif')
48-
4946
return len(cc_list)
5047

5148
def main(downloader: Callable[[list[str]], int]) -> None: # <10>

‎21-futures/getflags/flags2_asyncio.py

+3-3
Original file line numberDiff line numberDiff line change
@@ -28,7 +28,8 @@ def __init__(self, country_code):
2828

2929

3030
async def get_flag(session, base_url, cc): # <2>
31-
url = '{}/{cc}/{cc}.gif'.format(base_url, cc=cc.lower())
31+
cc = cc.lower()
32+
url = f'{base_url}/{cc}/{cc}.gif'
3233
async with session.get(url) as resp:
3334
if resp.status == 200:
3435
return await resp.read()
@@ -87,8 +88,7 @@ async def downloader_coro(cc_list: list[str],
8788
except IndexError:
8889
error_msg = exc.__cause__.__class__.__name__ # <11>
8990
if verbose and error_msg:
90-
msg = '*** Error for {}: {}'
91-
print(msg.format(country_code, error_msg))
91+
print(f'*** Error for {country_code}: {error_msg}')
9292
status = HTTPStatus.error
9393
else:
9494
status = res.status

‎21-futures/getflags/flags2_common.py

+45-45
Original file line numberDiff line numberDiff line change
@@ -1,14 +1,13 @@
11
"""Utilities for second set of flag examples.
22
"""
33

4-
import os
5-
import time
6-
import sys
7-
import string
84
import argparse
5+
import string
6+
import sys
7+
import time
98
from collections import namedtuple, Counter
109
from enum import Enum
11-
10+
from pathlib import Path
1211

1312
Result = namedtuple('Result', 'status data')
1413

@@ -28,14 +27,12 @@
2827
}
2928
DEFAULT_SERVER = 'LOCAL'
3029

31-
DEST_DIR = 'downloaded/'
32-
COUNTRY_CODES_FILE = 'country_codes.txt'
30+
DEST_DIR = Path('downloaded')
31+
COUNTRY_CODES_FILE = Path('country_codes.txt')
3332

3433

3534
def save_flag(img: bytes, filename: str) -> None:
36-
path = os.path.join(DEST_DIR, filename)
37-
with open(path, 'wb') as fp:
38-
fp.write(img)
35+
(DEST_DIR / filename).write_bytes(img)
3936

4037

4138
def initial_report(cc_list: list[str],
@@ -44,77 +41,79 @@ def initial_report(cc_list: list[str],
4441
if len(cc_list) <= 10:
4542
cc_msg = ', '.join(cc_list)
4643
else:
47-
cc_msg = 'from {} to {}'.format(cc_list[0], cc_list[-1])
48-
print('{} site: {}'.format(server_label, SERVERS[server_label]))
49-
msg = 'Searching for {} flag{}: {}'
44+
cc_msg = f'from {cc_list[0]} to {cc_list[-1]}'
45+
print(f'{server_label} site: {SERVERS[server_label]}')
5046
plural = 's' if len(cc_list) != 1 else ''
51-
print(msg.format(len(cc_list), plural, cc_msg))
47+
print(f'Searching for {len(cc_list)} flag{plural}: {cc_msg}')
5248
plural = 's' if actual_req != 1 else ''
53-
msg = '{} concurrent connection{} will be used.'
54-
print(msg.format(actual_req, plural))
49+
print(f'{actual_req} concurrent connection{plural} will be used.')
5550

5651

5752
def final_report(cc_list: list[str],
5853
counter: Counter[HTTPStatus],
5954
start_time: float) -> None:
60-
elapsed = time.time() - start_time
55+
elapsed = time.perf_counter() - start_time
6156
print('-' * 20)
62-
msg = '{} flag{} downloaded.'
6357
plural = 's' if counter[HTTPStatus.ok] != 1 else ''
64-
print(msg.format(counter[HTTPStatus.ok], plural))
58+
print(f'{counter[HTTPStatus.ok]} flag{plural} downloaded.')
6559
if counter[HTTPStatus.not_found]:
66-
print(counter[HTTPStatus.not_found], 'not found.')
60+
print(f'{counter[HTTPStatus.not_found]} not found.')
6761
if counter[HTTPStatus.error]:
6862
plural = 's' if counter[HTTPStatus.error] != 1 else ''
69-
print('{} error{}.'.format(counter[HTTPStatus.error], plural))
70-
print('Elapsed time: {:.2f}s'.format(elapsed))
63+
print(f'{counter[HTTPStatus.error]} error{plural}')
64+
print(f'Elapsed time: {elapsed:.2f}s')
7165

7266

7367
def expand_cc_args(every_cc: bool,
7468
all_cc: bool,
7569
cc_args: list[str],
7670
limit: int) -> list[str]:
7771
codes: set[str] = set()
78-
A_Z = string.ascii_uppercase
72+
A_Z = set(string.ascii_uppercase)
7973
if every_cc:
80-
codes.update(a+b for a in A_Z for b in A_Z)
74+
codes.update(f'{a}{b}' for a in A_Z for b in A_Z)
8175
elif all_cc:
82-
with open(COUNTRY_CODES_FILE) as fp:
83-
text = fp.read()
76+
text = COUNTRY_CODES_FILE.read_text()
8477
codes.update(text.split())
8578
else:
8679
for cc in (c.upper() for c in cc_args):
8780
if len(cc) == 1 and cc in A_Z:
88-
codes.update(cc+c for c in A_Z)
81+
codes.update(cc + c for c in A_Z)
8982
elif len(cc) == 2 and all(c in A_Z for c in cc):
9083
codes.add(cc)
9184
else:
92-
msg = 'each CC argument must be A to Z or AA to ZZ.'
93-
raise ValueError('*** Usage error: '+msg)
85+
raise ValueError('*** Usage error: each CC argument '
86+
'must be A to Z or AA to ZZ.')
9487
return sorted(codes)[:limit]
9588

9689

9790
def process_args(default_concur_req):
9891
server_options = ', '.join(sorted(SERVERS))
9992
parser = argparse.ArgumentParser(
10093
description='Download flags for country codes. '
101-
'Default: top 20 countries by population.')
102-
parser.add_argument('cc', metavar='CC', nargs='*',
94+
'Default: top 20 countries by population.')
95+
parser.add_argument(
96+
'cc', metavar='CC', nargs='*',
10397
help='country code or 1st letter (eg. B for BA...BZ)')
104-
parser.add_argument('-a', '--all', action='store_true',
98+
parser.add_argument(
99+
'-a', '--all', action='store_true',
105100
help='get all available flags (AD to ZW)')
106-
parser.add_argument('-e', '--every', action='store_true',
101+
parser.add_argument(
102+
'-e', '--every', action='store_true',
107103
help='get flags for every possible code (AA...ZZ)')
108-
parser.add_argument('-l', '--limit', metavar='N', type=int,
109-
help='limit to N first codes', default=sys.maxsize)
110-
parser.add_argument('-m', '--max_req', metavar='CONCURRENT', type=int,
104+
parser.add_argument(
105+
'-l', '--limit', metavar='N', type=int, help='limit to N first codes',
106+
default=sys.maxsize)
107+
parser.add_argument(
108+
'-m', '--max_req', metavar='CONCURRENT', type=int,
111109
default=default_concur_req,
112110
help=f'maximum concurrent requests (default={default_concur_req})')
113-
parser.add_argument('-s', '--server', metavar='LABEL',
114-
default=DEFAULT_SERVER,
115-
help=('Server to hit; one of ' +
116-
f'{server_options} (default={DEFAULT_SERVER})'))
117-
parser.add_argument('-v', '--verbose', action='store_true',
111+
parser.add_argument(
112+
'-s', '--server', metavar='LABEL', default=DEFAULT_SERVER,
113+
help=f'Server to hit; one of {server_options} '
114+
f'(default={DEFAULT_SERVER})')
115+
parser.add_argument(
116+
'-v', '--verbose', action='store_true',
118117
help='output detailed progress info')
119118
args = parser.parse_args()
120119
if args.max_req < 1:
@@ -127,8 +126,8 @@ def process_args(default_concur_req):
127126
sys.exit(1)
128127
args.server = args.server.upper()
129128
if args.server not in SERVERS:
130-
print('*** Usage error: --server LABEL must be one of',
131-
server_options)
129+
print(f'*** Usage error: --server LABEL '
130+
f'must be one of {server_options}')
132131
parser.print_usage()
133132
sys.exit(1)
134133
try:
@@ -148,8 +147,9 @@ def main(download_many, default_concur_req, max_concur_req):
148147
actual_req = min(args.max_req, max_concur_req, len(cc_list))
149148
initial_report(cc_list, actual_req, args.server)
150149
base_url = SERVERS[args.server]
151-
t0 = time.time()
150+
t0 = time.perf_counter()
152151
counter = download_many(cc_list, base_url, args.verbose, actual_req)
153-
assert sum(counter.values()) == len(cc_list), \
152+
assert sum(counter.values()) == len(cc_list), (
154153
'some downloads are unaccounted for'
154+
)
155155
final_report(cc_list, counter, t0)

‎21-futures/getflags/flags2_sequential.py

-1
Original file line numberDiff line numberDiff line change
@@ -24,7 +24,6 @@
2424

2525
from flags2_common import main, save_flag, HTTPStatus, Result
2626

27-
2827
DEFAULT_CONCUR_REQ = 1
2928
MAX_CONCUR_REQ = 1
3029

‎21-futures/getflags/flags2_threadpool.py

+3-3
Original file line numberDiff line numberDiff line change
@@ -50,8 +50,8 @@ def download_many(cc_list: list[str],
5050
try:
5151
res = future.result() # <14>
5252
except requests.exceptions.HTTPError as exc: # <15>
53-
error_msg = 'HTTP {res.status_code} - {res.reason}'
54-
error_msg = error_msg.format(res=exc.response)
53+
error_fmt = 'HTTP {res.status_code} - {res.reason}'
54+
error_msg = error_fmt.format(res=exc.response)
5555
except requests.exceptions.ConnectionError:
5656
error_msg = 'Connection error'
5757
else:
@@ -63,7 +63,7 @@ def download_many(cc_list: list[str],
6363
counter[status] += 1
6464
if verbose and error_msg:
6565
cc = to_do_map[future] # <16>
66-
print('*** Error for {}: {}'.format(cc, error_msg))
66+
print(f'*** Error for {cc}: {error_msg}')
6767

6868
return counter
6969

‎21-futures/getflags/flags_asyncio.py

+1-2
Original file line numberDiff line numberDiff line change
@@ -18,7 +18,7 @@
1818

1919
from flags import BASE_URL, save_flag, main # <2>
2020

21-
async def get_flag(session: ClientSession ,cc: str) -> bytes: # <3>
21+
async def get_flag(session: ClientSession, cc: str) -> bytes: # <3>
2222
cc = cc.lower()
2323
url = f'{BASE_URL}/{cc}/{cc}.gif'
2424
async with session.get(url) as resp: # <4>
@@ -36,7 +36,6 @@ async def supervisor(cc_list):
3636
to_do = [download_one(session, cc)
3737
for cc in sorted(cc_list)] # <8>
3838
res = await asyncio.gather(*to_do) # <9>
39-
4039
return len(res)
4140

4241
def download_many(cc_list):

‎21-futures/getflags/flags_threadpool.py

+1-1
Original file line numberDiff line numberDiff line change
@@ -31,4 +31,4 @@ def download_many(cc_list: list[str]) -> int:
3131

3232
if __name__ == '__main__':
3333
main(download_many) # <6>
34-
# end::FLAGS_THREADPOOL[]
34+
# end::FLAGS_THREADPOOL[]

‎21-futures/getflags/flags_threadpool_futures.py

+4-9
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@
66
"""
77
from concurrent import futures
88

9-
from flags import save_flag, main
9+
from flags import main
1010
from flags_threadpool import download_one
1111

1212

@@ -18,19 +18,14 @@ def download_many(cc_list: list[str]) -> int:
1818
for cc in sorted(cc_list): # <3>
1919
future = executor.submit(download_one, cc) # <4>
2020
to_do.append(future) # <5>
21-
msg = 'Scheduled for {}: {}'
22-
print(msg.format(cc, future)) # <6>
21+
print(f'Scheduled for {cc}: {future}') # <6>
2322

24-
count = 0
25-
for future in futures.as_completed(to_do): # <7>
23+
for count, future in enumerate(futures.as_completed(to_do)): # <7>
2624
res: str = future.result() # <8>
27-
msg = '{} result: {!r}'
28-
print(msg.format(future, res)) # <9>
29-
count += 1
25+
print(f'{future} result: {res!r}') # <9>
3026

3127
return count
3228
# end::FLAGS_THREADPOOL_AS_COMPLETED[]
3329

3430
if __name__ == '__main__':
3531
main(download_many)
36-

‎21-futures/getflags/slow_server.py

+5-6
Original file line numberDiff line numberDiff line change
@@ -8,14 +8,14 @@
88
the requests if given the --error_rate command-line argument.
99
"""
1010

11-
import time
11+
import contextlib
1212
import os
1313
import socket
14-
import contextlib
14+
import time
1515
from functools import partial
16-
from random import random
1716
from http import server, HTTPStatus
1817
from http.server import ThreadingHTTPServer, SimpleHTTPRequestHandler
18+
from random import random
1919

2020

2121
class SlowHTTPRequestHandler(SimpleHTTPRequestHandler):
@@ -52,7 +52,6 @@ def do_GET(self):
5252
# https://github.com/python/cpython/blob/master/Lib/http/server.py
5353

5454
if __name__ == '__main__':
55-
5655
import argparse
5756

5857
parser = argparse.ArgumentParser()
@@ -61,11 +60,11 @@ def do_GET(self):
6160
'[default: all interfaces]')
6261
parser.add_argument('--directory', '-d', default=os.getcwd(),
6362
help='Specify alternative directory '
64-
'[default:current directory]')
63+
'[default:current directory]')
6564
parser.add_argument('--error-rate', '-e', metavar='PROBABILITY',
6665
default=0.0, type=float,
6766
help='Error rate; e.g. use .25 for 25%% probability '
68-
'[default:0.0]')
67+
'[default:0.0]')
6968
parser.add_argument('port', action='store',
7069
default=8000, type=int,
7170
nargs='?',

‎21-futures/primes/proc_pool.py

+4-4
Original file line numberDiff line numberDiff line change
@@ -6,10 +6,10 @@
66
"""
77

88
# tag::PRIMES_POOL[]
9+
import sys
10+
from concurrent import futures # <1>
911
from time import perf_counter
1012
from typing import NamedTuple
11-
from concurrent import futures # <1>
12-
import sys
1313

1414
from primes import is_prime, NUMBERS
1515

@@ -43,8 +43,8 @@ def main() -> None:
4343
print(f'{n:16} {label} {elapsed:9.6f}s')
4444

4545
time = perf_counter() - t0
46-
print('Total time:', f'{time:0.2f}s')
46+
print(f'Total time: {time:.2f}s')
4747

4848
if __name__ == '__main__':
4949
main()
50-
# end::PRIMES_POOL[]
50+
# end::PRIMES_POOL[]

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