Files
SIA/sia/entry/background_entry.py
2024-11-23 21:36:50 +01:00

162 lines
5.0 KiB
Python

import subprocess
import xml.etree.ElementTree as ET
from typing import Optional
from . import Entry
class BackgroundEntry(Entry):
"""
Entry type for long-running background processes.
Attributes:
script: The script/command to execute
stdout: Captured standard output
stderr: Captured standard error
process: The running subprocess.Popen instance
exit_code: Exit code when process completes
"""
def __init__(
self,
id: str,
script: str,
):
"""
Initialize a new background entry.
Args:
id: Unique identifier for this entry
script: The script/command to execute
"""
super().__init__(id)
self.script = script
self._process: Optional[subprocess.Popen] = None
self.stdout = ""
self.stderr = ""
self.exit_code = None
@property
def pid(self) -> Optional[int]:
"""Get the process ID (None if not running)."""
return self._process.pid if self._process is not None else None
def cleanup(self) -> None:
"""
Clean up the background process if it's still running.
Ensures process is terminated and file handles are closed.
"""
if self._process is not None:
try:
if self._process.stdout:
self._process.stdout.close()
if self._process.stderr:
self._process.stderr.close()
if self._process.poll() is None:
self._process.terminate()
try:
self._process.wait(timeout=1.0)
except subprocess.TimeoutExpired:
self._process.kill()
self._process.wait()
except:
pass # Ignore cleanup errors
finally:
self._process = None
def reset(self) -> None:
"""
Cleans up existing process and resets output buffers.
"""
self.cleanup()
self.stdout = ""
self.stderr = ""
self.exit_code = None
self.notify_change()
def update(self) -> None:
"""
Start the process if not running and collect any new output.
Updates stdout and stderr with any new output.
"""
if self._process is None and self.exit_code is None:
self._process = subprocess.Popen(
self.script,
shell=True,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
text=True,
bufsize=1 # Line buffered
)
self.notify_change()
return
if self._process is None:
return
exit_code = self._process.poll()
if exit_code is not None:
try:
remaining_out, remaining_err = self._process.communicate(timeout=0.1)
self.stdout += remaining_out
self.stderr += remaining_err
except subprocess.TimeoutExpired:
pass # Process didn't finish communicating, try again next update
self.exit_code = exit_code
self.cleanup()
self.notify_change()
return
if self._process.stdout:
while True:
try:
line = self._process.stdout.readline()
if not line:
break
self.stdout += line
except:
break
if self._process.stderr:
while True:
try:
line = self._process.stderr.readline()
if not line:
break
self.stderr += line
except:
break
self.notify_change()
def generate_context(self) -> ET.Element:
"""
Generate an XML Element representing this background entry.
Returns:
ET.Element: XML element containing the entry's data
"""
element = ET.Element("background", {"id": self.id})
if self._process is not None:
element.set("pid", str(self._process.pid))
elif self.exit_code is not None:
element.set("exit_code", str(self.exit_code))
element.text = self.script
stdout_elem = ET.SubElement(element, "stdout")
stdout_elem.text = self.stdout
stderr_elem = ET.SubElement(element, "stderr")
stderr_elem.text = self.stderr
return element
def serialize(self):
"""
Collect all public attributes of the entry into a dictionary.
"""
return {
"type": "background",
"id": self.id,
"script": self.script,
"stdout": self.stdout,
"stderr": self.stderr,
"exit_code": self.exit_code,
}