How to synchronized two folders with a Python script

That's what I wanted to do. So, I wrote my first Python (3) script. Don't hesitate to use or modified this code. It can synchronized two folders in two-way directions. It never deletes files or folders in its strategy. It only replicates older or missing files and folders from the two folders to synchronized.

Enjoy!

PS : Be cool with me, this is my first steps with Python


__author__ = 'Alexandre de Pellegrin'
import os
import shutil

srcDir = '/home/user/folder1'
dstDir = '/home/user/folder2'

def main():
    try:
        print("Begin sync")
        checkIfRootDirsExist(srcDir, dstDir)
        syncDirs(srcDir, dstDir)
        syncFiles(srcDir, dstDir)
        print("End sync with success")
    except Exception as e:
        print(e)
        print("End sync with failure!")




def checkIfRootDirsExist(rootDir1, rootDir2) :
    if (not os.path.exists(rootDir1) and not os.path.isdir(rootDir1)) :
        raise Exception(rootDir1 + " doesn't exist")
    if (not os.path.exists(rootDir2) and not os.path.isdir(rootDir2)) :
        raise Exception(rootDir2 + " doesn't exist")




def syncDirs(rootDir1, rootDir2):
    for root1, dirs1, files1 in os.walk(rootDir1):
        for relativePath1 in dirs1 :
            fullPath1 = os.path.join(root1, relativePath1)
            fullPath2 = fullPath1.replace(rootDir1, rootDir2)
            if os.path.exists(fullPath2) and os.path.isdir(fullPath2) :
                continue
            if os.path.exists(fullPath2) and os.path.isfile(fullPath2) :
                raise Exception("Cannot perform dir sync." + str(fullPath2) + " should be a dir, not a file!")
            # Case 1 : dest dir does not exit
            shutil.copytree(fullPath1, fullPath2)
            print("Directory " + str(fullPath2) + " copied from " + str(fullPath1))
            continue
    for root2, dirs2, files2 in os.walk(rootDir2):
        for relativePath2 in dirs2:
            fullPath2 = os.path.join(root2, relativePath2)
            fullPath1 = fullPath2.replace(rootDir2, rootDir1)
            if os.path.exists(fullPath1) and os.path.isdir(fullPath1) :
                continue
            if os.path.exists(fullPath1) and os.path.isfile(fullPath1) :
                raise Exception("Cannot perform dir sync." + str(fullPath1) + " should be a dir, not a file!")
            # Case 3 : dest dir exists but not src dir, so we need to copy it
            shutil.copytree(fullPath2, fullPath1)
            print("Directory " + str(fullPath1) + " copied from" + str(fullPath2))
            continue





def syncFiles(rootDir1, rootDir2):
    for root1, dirs1, files1 in os.walk(rootDir1):
        for file1 in files1:
            fullPath1 = os.path.join(root1, file1)
            fullPath2 = fullPath1.replace(rootDir1, rootDir2)
            # Case 1 : the file does not exist in dest dir
            if (not os.path.exists(fullPath2)) :
                shutil.copy2(fullPath1, fullPath2)
                print("File " + str(fullPath2) + " copied from " + str(fullPath1))
                continue
            # Case 2 : src file is more recent than dest file
            file1LastModificationTime = round(os.path.getmtime(fullPath1))
            file2LastModificationTime = round(os.path.getmtime(fullPath2))
            if (file1LastModificationTime > file2LastModificationTime):
                os.remove(fullPath2)
                shutil.copy2(fullPath1, fullPath2)
                print("File " + str(fullPath2) + " synchronized from " + str(fullPath1))
                continue
            # Case 3 : dest file is more recent than src file
            if (file1LastModificationTime < file2LastModificationTime):
                os.remove(fullPath1)
                shutil.copy2(fullPath2, fullPath1)
                print("File " + str(fullPath1) + " synchronized from " + str(fullPath2))
                continue
    # Case 4 : file only exists in dest dir but not in src
    # So, we copy it back to src dir
    for root2, dirs2, files2 in os.walk(rootDir2):
        for file2 in files2:
            fullPath2 = os.path.join(root2, file2);
            fullPath1 = fullPath2.replace(rootDir2, rootDir1);
            if (os.path.exists(fullPath1)):
                continue
            shutil.copy2(fullPath2, fullPath1)
            print("File " + str(fullPath1) + " copied from " + str(fullPath2))


if __name__ == '__main__':
    main()