from xml.etree.ElementTree import ElementTree as ET
from xml.etree.ElementTree import tostring, fromstring

def xml2file (a_xml, a_root, xslHeader=None):
    file_object = open("target.xml" , "wb")
    pam = tostring(a_root, 'utf-8', method="xml")
    file_object.write(pam)
    file_object.close()
    if xslHeader != None:
        file_object = open("target.xml" , "r+", encoding='utf-8')
        linie = file_object.readlines()
        file_object.seek(0, 0)
        with open(xslHeader, "r", encoding='utf-8') as header:
            xls = [header.readline(), header.readline()]
        for linia in xls:
            file_object.write(linia)
        for linia in linie:
            file_object.write(linia)
        file_object.close()



def modify_core_site(namenode_hostname):
    tree = ET()
    tree.parse("test.xml")
    root = tree.getroot()
    for p in root.iter("property"):
        name = p.find("name").text
        if name == "fs.default.name":
            text = "hdfs://%s:9000" % namenode_hostname
            p.find("value").text = text
    xml2file(tree, root, xslHeader="test.xml")
    #tree.write("result.xml", encoding="utf-8", xml_declaration=True)

modify_core_site("c80")