71 lines
2.7 KiB
Python
71 lines
2.7 KiB
Python
# Copyright (c) 2024 Airbyte, Inc., all rights reserved.
|
|
|
|
import sys
|
|
import time
|
|
from io import StringIO
|
|
from threading import RLock
|
|
from types import TracebackType
|
|
from typing import Optional
|
|
|
|
|
|
class PrintBuffer:
|
|
"""
|
|
A class to buffer print statements and flush them at a specified interval.
|
|
|
|
The PrintBuffer class is designed to capture and buffer output that would
|
|
normally be printed to the standard output (stdout). This can be useful for
|
|
scenarios where you want to minimize the number of I/O operations by grouping
|
|
multiple print statements together and flushing them as a single operation.
|
|
|
|
Attributes:
|
|
buffer (StringIO): A buffer to store the messages before flushing.
|
|
flush_interval (float): The time interval (in seconds) after which the buffer is flushed.
|
|
last_flush_time (float): The last time the buffer was flushed.
|
|
lock (RLock): A reentrant lock to ensure thread-safe operations.
|
|
|
|
Methods:
|
|
write(message: str) -> None:
|
|
Writes a message to the buffer and flushes if the interval has passed.
|
|
|
|
flush() -> None:
|
|
Flushes the buffer content to the standard output.
|
|
|
|
__enter__() -> "PrintBuffer":
|
|
Enters the runtime context related to this object, redirecting stdout and stderr.
|
|
|
|
__exit__(exc_type, exc_val, exc_tb) -> None:
|
|
Exits the runtime context and restores the original stdout and stderr.
|
|
"""
|
|
|
|
def __init__(self, flush_interval: float = 0.1):
|
|
self.buffer = StringIO()
|
|
self.flush_interval = flush_interval
|
|
self.last_flush_time = time.monotonic()
|
|
self.lock = RLock()
|
|
|
|
def write(self, message: str) -> None:
|
|
with self.lock:
|
|
self.buffer.write(message)
|
|
current_time = time.monotonic()
|
|
if (current_time - self.last_flush_time) >= self.flush_interval:
|
|
self.flush()
|
|
self.last_flush_time = current_time
|
|
|
|
def flush(self) -> None:
|
|
with self.lock:
|
|
combined_message = self.buffer.getvalue()
|
|
sys.__stdout__.write(combined_message) # type: ignore[union-attr]
|
|
self.buffer = StringIO()
|
|
|
|
def __enter__(self) -> "PrintBuffer":
|
|
self.old_stdout, self.old_stderr = sys.stdout, sys.stderr
|
|
# Used to disable buffering during the pytest session, because it is not compatible with capsys
|
|
if "pytest" not in str(type(sys.stdout)).lower():
|
|
sys.stdout = self
|
|
sys.stderr = self
|
|
return self
|
|
|
|
def __exit__(self, exc_type: Optional[BaseException], exc_val: Optional[BaseException], exc_tb: Optional[TracebackType]) -> None:
|
|
self.flush()
|
|
sys.stdout, sys.stderr = self.old_stdout, self.old_stderr
|