Código de Python - Clase para configurar el archivo dhcpd.conf de nuestro servidor

#!/usr/bin/env python

# -*- coding: utf-8 -*-

"""

Class for read or modify dhcpd server config file

Last versión:

http://lwp-l.com/s5385

readFile() -> read dhcpd file received in constructor and put data in two lists

getValue() -> return value from key received

    sample:

        key: "option domain-name-servers"

        return: "option domain-name-servers ns1.example.org, ns2.example.org;"

setValue() -> update the value if exist or add new value if not exists

removeValue() -> remove values

clearSubnet() -> remove the subnets created or readed from file

newSubnet() -> create a new subnet

getSubnetNumber() -> return the number of subnets

getSubnetValue() -> return value of indicated subnet

setSubnetValue() -> add or update values of the subnet

save() -> save any changes to the file

config file is similar to:

    option domain-name "example.org";                               getValue(), setValue()

    option domain-name-servers ns1.example.org, ns2.example.org;    getValue(), setValue()

    default-lease-time 600;                                         getValue(), setValue()

    max-lease-time 7200;                                            getValue(), setValue()

    subnet 10.5.5.0 netmask 255.255.255.224 {                       getSubnetNumber(), newSubnet(), clearSubnet(), getSubnetValue()

        range 10.5.5.26 10.5.5.30;                                  setSubnetValue(), getSubnetValue()

        option domain-name-servers ns1.internal.example.org;        setSubnetValue(), getSubnetValue()

        option domain-name "internal.example.org";                  setSubnetValue(), getSubnetValue()

        option routers 10.5.5.1;                                    setSubnetValue(), getSubnetValue()

        option broadcast-address 10.5.5.31;                         setSubnetValue(), getSubnetValue()

        default-lease-time 600;                                     setSubnetValue(), getSubnetValue()

        max-lease-time 7200;                                        setSubnetValue(), getSubnetValue()

    }

    subnet 10.10.10.0 netmask 255.255.255.0 {                       getSubnetNumber(), newSubnet(), clearSubnet(), getSubnetValue()

        range 10.10.10.200 10.10.10.230;                            setSubnetValue(), getSubnetValue()

        option domain-name-servers 8.8.8.8;                         setSubnetValue(), getSubnetValue()

        option domain-name "internal.example.org";                  setSubnetValue(), getSubnetValue()

        option routers 10.10.10.1;                                  setSubnetValue(), getSubnetValue()

        option broadcast-address 10.10.10.255;                      setSubnetValue(), getSubnetValue()

    }

"""

import os, sys

from subprocess import Popen, PIPE

import glob

import re

__ver__="0.2"

class Dhcpd():

    """ Contain a file name and path to dhcpd server """

    file=""

    """ variables that contain the vaues and subnets """

    valuesData=[]

    subnetData=[]

    def __init__(self, file):

        """

        Parameters:

            file string - path and file name

        """

        self.file=file

    def readFile(self):

        """

        This function read dhcpd file an set data into vars

        Return

            boolean - False if not possible read the file

        """

        self.valuesData=[]

        self.subnetData=[]

        if not self.file or not os.path.exists(self.file):

            return False

        inSubnet=False

        subnet=-1

        with open(self.file,"r") as f:

            for line in f:

                line=line.strip()

                if line and line[0]!="#":

                    if len(line)>=7 and line[:7]=="subnet ":

                        inSubnet=True

                        subnet+=1

                        self.subnetData.append([])

                    if inSubnet:

                        self.subnetData[subnet].append(line)

                    else:

                        self.valuesData.append(line)

                    if inSubnet and line and line[0]=="}":

                        inSubnet=False

        return True

    def getValue(self, key):

        """

        Function that return a line for a value in dhcpd config file

        Find the text that start line to len the value is same

        Parameteres:

            key string

        Return:

            string 

        """

        for line in self.valuesData:

            if len(line)>=len(key) and line[0:len(key)]==key:

                return line

        return ""

    def setValue(self, key, value):

        """

        Function to update value if exist or add new value if not exists

        Parameters:

            key string

            value string

        return:

            integer - [1 updated, 2 insert]

        """

        for i in range(len(self.valuesData)):

            line=self.valuesData[i]

            if len(line)>=len(key) and line[0:len(key)]==key:

                self.valuesData[i]=key+" "+value.strip()

                return 1

        self.valuesData.append(key+" "+value)

        return 2

    def removeValue(self, key):

        """

        Function to remove values

        Parameters:

            key string

        return:

            boolean

        """

        for line in self.valuesData:

            if len(line)>=len(key) and line[0:len(key)]==key:

                self.valuesData.remove(line)

                return True

        return False

    def clearSubnet(self):

        """

        function that remove the subnets created or readed from file

        """

        self.subnetData=[]

        return self

    def newSubnet(self, ip, netmask):

        """

        This function create a new subnet

        Parameters:

            ip string

            netmask string

        Return:

            int - index of new subnet

        """

        newIndex=len(self.subnetData)

        self.subnetData.append([])

        self.subnetData[newIndex].append("subnet {} netmask {}".format(ip, netmask))

        self.subnetData[newIndex].append("{")

        self.subnetData[newIndex].append("}")

        return newIndex

    def getSubnetNumber(self):

        """

        Function that return the number of subnets

        Return:

            int

        """

        return len(self.subnetData)

    def getSubnetValue(self, index, key):

        """

        Function that return value for subnet

        Parameteres:

            index int - index of subnet

            key string

        Return:

            string

        """

        if len(self.subnetData)==0 or index<0 or index>len(self.subnetData)-1:

            return ""

        for line in self.subnetData[index]:

            if len(line)>=len(key) and line[0:len(key)]==key:

                return line

        return ""

    def setSubnetValue(self, index, key, value):

        """

        Function to add or update values of the subnet

        Parameters:

            index int - define the subnet index

            key string - key to update or insert

            value string

        Return:

            integer - [1 updated, 2 insert]

        """

        if len(self.subnetData)==0 or index<0 or index>len(self.subnetData)-1:

            return self

        for i in range(len(self.subnetData[index])):

            line=self.subnetData[index][i]

            if len(line)>=len(key) and line[0:len(key)]==key:

                self.subnetData[index][i]=key+" "+value.strip()

                return 1

        self.subnetData[index][-1]=key+" "+value

        self.subnetData[index].append("}")

        return 2

    def save(self):

        """

        This function save the file with the changes

        Return:

            int - number of lines saved in a file | -1 not writable file

        """

        if not os.access(self.file, os.W_OK):

            return -1

        linesSaved=0

        with open(self.file, "w") as f:

            f.write("# file created from class dhcpd.py\n")

            f.write("# http://lwp-l.com/s5385\n\n")

            for line in self.valuesData:

                linesSaved+=1

                f.write(line+"\n")

            for subnets in self.subnetData:

                for line in subnets:

                    linesSaved+=1

                    f.write(line+"\n")

        return linesSaved