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#!/usr/bin/env python
'''
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
'''
import json
import logging
import os
import subprocess
import pprint
import threading
from threading import Thread
import time
from BackgroundCommandExecutionHandle import BackgroundCommandExecutionHandle
from Grep import Grep
import shell, sys
logger = logging.getLogger()
class PythonExecutor:
"""
Performs functionality for executing python scripts.
Warning: class maintains internal state. As a result, instances should not be
used as a singleton for a concurrent execution of python scripts
"""
NO_ERROR = "none"
grep = Grep()
event = threading.Event()
python_process_has_been_killed = False
def __init__(self, tmpDir, config):
self.tmpDir = tmpDir
self.config = config
pass
def open_subporcess_files(self, tmpoutfile, tmperrfile, override_output_files):
if override_output_files: # Recreate files
tmpout = open(tmpoutfile, 'w')
tmperr = open(tmperrfile, 'w')
else: # Append to files
tmpout = open(tmpoutfile, 'a')
tmperr = open(tmperrfile, 'a')
return tmpout, tmperr
def run_file(self, script, script_params, tmp_dir, tmpoutfile, tmperrfile,
timeout, tmpstructedoutfile, logger_level, callback, task_id,
override_output_files = True, handle = None):
"""
Executes the specified python file in a separate subprocess.
Method returns only when the subprocess is finished.
Params arg is a list of script parameters
Timeout meaning: how many seconds should pass before script execution
is forcibly terminated
override_output_files option defines whether stdout/stderr files will be
recreated or appended
"""
# need to remove this file for the following case:
# status call 1 does not write to file; call 2 writes to file;
# call 3 does not write to file, so contents are still call 2's result
try:
os.unlink(tmpstructedoutfile)
except OSError:
pass # no error
script_params += [tmpstructedoutfile, logger_level, tmp_dir]
pythonCommand = self.python_command(script, script_params)
logger.info("Running command " + pprint.pformat(pythonCommand))
if(handle == None) :
tmpout, tmperr = self.open_subporcess_files(tmpoutfile, tmperrfile, override_output_files)
process = self.launch_python_subprocess(pythonCommand, tmpout, tmperr)
# map task_id to pid
callback(task_id, process.pid)
logger.debug("Launching watchdog thread")
self.event.clear()
self.python_process_has_been_killed = False
thread = Thread(target = self.python_watchdog_func, args = (process, timeout))
thread.start()
# Waiting for the process to be either finished or killed
process.communicate()
self.event.set()
thread.join()
return self.prepare_process_result(process, tmpoutfile, tmperrfile, tmpstructedoutfile, timeout=timeout)
else:
holder = Holder(pythonCommand, tmpoutfile, tmperrfile, tmpstructedoutfile, handle)
background = BackgroundThread(holder, self)
background.start()
return {"exitcode": 777}
def prepare_process_result (self, process, tmpoutfile, tmperrfile, tmpstructedoutfile, timeout=None):
out, error, structured_out = self.read_result_from_files(tmpoutfile, tmperrfile, tmpstructedoutfile)
# Building results
returncode = process.returncode
if self.python_process_has_been_killed:
error = str(error) + "\n Python script has been killed due to timeout" + \
(" after waiting %s secs" % str(timeout) if timeout else "")
returncode = 999
result = self.condenseOutput(out, error, returncode, structured_out)
logger.info("Result: %s" % result)
return result
def read_result_from_files(self, out_path, err_path, structured_out_path):
out = open(out_path, 'r').read()
error = open(err_path, 'r').read()
try:
with open(structured_out_path, 'r') as fp:
structured_out = json.load(fp)
except Exception:
if os.path.exists(structured_out_path):
errMsg = 'Unable to read structured output from ' + structured_out_path
structured_out = {
'msg' : errMsg
}
logger.warn(structured_out)
else:
structured_out = {}
return out, error, structured_out
def launch_python_subprocess(self, command, tmpout, tmperr):
"""
Creates subprocess with given parameters. This functionality was moved to separate method
to make possible unit testing
"""
return subprocess.Popen(command,
stdout=tmpout,
stderr=tmperr, close_fds=True)
def isSuccessfull(self, returncode):
return not self.python_process_has_been_killed and returncode == 0
def python_command(self, script, script_params):
python_binary = sys.executable
python_command = [python_binary, script] + script_params
return python_command
def condenseOutput(self, stdout, stderr, retcode, structured_out):
log_lines_count = self.config.get('heartbeat', 'log_lines_count')
grep = self.grep
result = {
"exitcode": retcode,
"stdout": grep.tail(stdout, log_lines_count) if log_lines_count else stdout,
"stderr": grep.tail(stderr, log_lines_count) if log_lines_count else stderr,
"structuredOut" : structured_out
}
return result
def python_watchdog_func(self, python, timeout):
self.event.wait(timeout)
if python.returncode is None:
logger.error("Subprocess timed out and will be killed")
shell.kill_process_with_children(python.pid)
self.python_process_has_been_killed = True
pass
class Holder:
def __init__(self, command, out_file, err_file, structured_out_file, handle):
self.command = command
self.out_file = out_file
self.err_file = err_file
self.structured_out_file = structured_out_file
self.handle = handle
class BackgroundThread(threading.Thread):
def __init__(self, holder, pythonExecutor):
threading.Thread.__init__(self)
self.holder = holder
self.pythonExecutor = pythonExecutor
def run(self):
process_out, process_err = self.pythonExecutor.open_subporcess_files(self.holder.out_file, self.holder.err_file, True)
logger.info("Starting process command %s" % self.holder.command)
process = self.pythonExecutor.launch_python_subprocess(self.holder.command, process_out, process_err)
logger.info("Process has been started. Pid = %s" % process.pid)
self.holder.handle.pid = process.pid
self.holder.handle.status = BackgroundCommandExecutionHandle.RUNNING_STATUS
self.holder.handle.on_background_command_started(self.holder.handle.command['taskId'], process.pid)
process.communicate()
self.holder.handle.exitCode = process.returncode
process_condenced_result = self.pythonExecutor.prepare_process_result(process, self.holder.out_file, self.holder.err_file, self.holder.structured_out_file)
logger.info("Calling callback with args %s" % process_condenced_result)
self.holder.handle.on_background_command_complete_callback(process_condenced_result, self.holder.handle)
logger.info("Exiting from thread for holder pid %s" % self.holder.handle.pid)
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