如何在使用subprocess.call之后打印变量

Question

在我的程序中，我使用subprocess.call自动运行apache drill。之后，我进行了一些查询，并希望打印结果。在对代码进行编程以自动运行apachedrill之前，我是手动执行的，我可以打印结果，但现在我无法执行。我最后一次尝试是在文件中写入，但行为是一样的，没有写入任何内容。我的密码如下。

import subprocess
from pydrill.client import PyDrill
import sys
writer = open('resultado.txt', 'w')
cmdmsg = subprocess.check_output("cd C:\Users\Tito\Downloads\apache-drill-1.14.0\bin & sqlline -u "jdbc:drill:zk=local"", shell = True)
writer.write("teste de msg: " + str(cmdmsg))
drill = PyDrill(host='localhost', port=8047)
if drill.is_active:
result = drill.query('''SELECT * FROM cp.`employee.json` LIMIT 3''')
result2 = drill.query('''SELECT * FROM dfs.`/Users/Tito/Desktop/banco_gal.csv` LIMIT 5''')
for tuple in result2:
writer.write(tuple)
writer.close

Answer 1

我可以解决这个问题。本主题有三件事很重要。a( 我们应该在打开apachedrill之后杀死java虚拟机和shell。b( windows缓冲区非常短，因此尚未打印结果。c( popen方法比调用这个任务要好。

import os
import re
import subprocess
import traceback
from os import path
from pydrill.client import PyDrill
DRILL_HOST = 'localhost'
DRILL_PORT = 8047
JAVA_HOME = ''
JAVA_HOME = JAVA_HOME or ("JAVA_HOME" in os.environ and os.environ["JAVA_HOME"])

JPS_EXE_PATH = path.join(JAVA_HOME, 'bin', 'jps.exe')
KILL_DRILL_JVM = True
def getJvmPID(className):
pid = None
print('Running JPS cmd: %s' % JPS_EXE_PATH)
jpsOutput = subprocess.check_output(JPS_EXE_PATH)
jpsOutput = str(jpsOutput)
se = re.search(r'([0-9]*s*)' + className, jpsOutput)
if se:
pid = se.group(1)
return pid
def killProcessByPID(pid):
killCmd = ['taskkill', '/f', '/pid', str(pid)]
print('Running taskkill cmd: %s' % killCmd)
killCmdOuput = subprocess.check_output(killCmd, stderr=subprocess.STDOUT)
print(str(killCmdOuput))
def killJvm(className):
pid = getJvmPID(className)
killProcessByPID(pid)

drillBinDir    = 'C:/Users/Tito/Downloads/apache-drill-1.14.0/bin'
sqlinePath   = path.join(drillBinDir, 'sqlline.bat')
drillCmdList = [sqlinePath , '-u', '"jdbc:drill:zk=local"']
drillCmdStr = " ".join(drillCmdList)
drillConAttempts = 2
while drillConAttempts > 0:
drillConAttempts -= 1
print("Connecting to drill on %s:%d..." % (DRILL_HOST, DRILL_PORT))
try:
drill = PyDrill(host=DRILL_HOST, port=DRILL_PORT)
except:
print("Exception when creating object")
traceback.print_exc()
print("Checking Drill conection...")
try:
if drill.is_active():
print("Connected.")
break
elif drillConAttempts > 0:
print("Could not connect to Drill. Trying to start Drill...")
print("Running cmd '%s > %s'" % (drillCmdStr, os.devnull) )
devNull = open(os.devnull,"w")
cmdProc = subprocess.Popen(drillCmdStr, cwd=drillBinDir, stdout=devNull, stderr=subprocess.STDOUT, shell=True)
print("Started CMD process with PID %d" %(cmdProc.pid))
except:
print("Exception when checking connection")
traceback.print_exc()

if drill.is_active():
result = drill.query('''SELECT * FROM cp.`employee.json` LIMIT 3''')
for resultTuple in result:
print(resultTuple)
if KILL_DRILL_JVM:
print('Killing Drill process...')
killJvm('SqlLine')