35 lines
1.2 KiB
Python
35 lines
1.2 KiB
Python
# Copyright (c) Facebook, Inc. and its affiliates.
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# All rights reserved.
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#
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# This source code is licensed under the BSD-style license found in the
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# LICENSE file in the root directory of this source tree.
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from contextlib import contextmanager
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import os
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import subprocess
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import signal
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@contextmanager
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def magic_trace(output='trace.fxt', magic_trace_cache='/tmp/magic-trace'):
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pid = os.getpid()
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if not os.path.exists(magic_trace_cache):
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print(f"Downloading magic_trace to: {magic_trace_cache}")
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subprocess.run(['wget', '-O', magic_trace_cache, '-q',
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'https://github.com/janestreet/magic-trace/releases/download/v1.0.2/magic-trace'])
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subprocess.run(['chmod', '+x', magic_trace_cache])
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args = [magic_trace_cache, 'attach', '-pid', str(pid), '-o', output]
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p = subprocess.Popen(args, stderr=subprocess.PIPE, encoding='utf-8')
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while True:
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x = p.stderr.readline()
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print(x)
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if 'Attached' in x:
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break
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try:
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yield
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finally:
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p.send_signal(signal.SIGINT)
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r = p.wait()
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print(p.stderr.read())
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p.stderr.close()
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if r != 0:
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raise ValueError(f'magic_trace exited abnormally: {r}')
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