NiFi site to site ClassCastException when using SSL and HDF 3.0.0.0 due to HTTPCLIENT-1836

In case someone else finds when using HDF 3.0.0.0 they get a ClassCastException from o.apache.nifi.controller.FlowController

2017-07-19 13:48:57,498 WARN [Timer-Driven Process Thread-26] o.apache.nifi.controller.FlowController 
java.lang.ClassCastException: [B cannot be cast to java.lang.String
        at org.apache.http.conn.ssl.DefaultHostnameVerifier.getSubjectAltNames(DefaultHostnameVerifier.java:309)
        at org.apache.http.conn.ssl.DefaultHostnameVerifier.verify(DefaultHostnameVerifier.java:112)
        at org.apache.http.conn.ssl.DefaultHostnameVerifier.verify(DefaultHostnameVerifier.java:99)
        at org.apache.http.conn.ssl.SSLConnectionSocketFactory.verifyHostname(SSLConnectionSocketFactory.java:463)
        at org.apache.http.conn.ssl.SSLConnectionSocketFactory.createLayeredSocket(SSLConnectionSocketFactory.java:397)

We found that it was due to HTTPCLIENT-1836 , and we are experimenting with downgrading the httpclient library jar file from 4.5.3 to 4.5.2

To replace the library in the NAR files, we wrote this:

#!/usr/bin/python

import argparse
import cStringIO
import datetime
import hashlib
import os.path
import requests
import sys
import syslog
import urlparse
import zipfile

def log(msg):
    syslog.syslog(msg)
    print msg

parser = argparse.ArgumentParser(description='Remove file from nar and insert new one')
parser.add_argument('--new-jar-url', metavar='URL', required=True,
                    help='URL to the new JAR file')
parser.add_argument('--new-jar-sha512', metavar='SHA512', required=True,
                    help='Checksum of the new Jar file to verify the download')
parser.add_argument('--old-jar-name', metavar='FILENAME', required=True,
                    help='Filename of the JAR file to remove')
parser.add_argument('--path-to-nars', dest='path', required=True,
                    help='Path to the NAR files to rewrite')

args = parser.parse_args()

log('Rewriting NAR files to remove {} and add {}'.format(args.old_jar_name,
                                                                   args.new_jar_url))

if args.new_jar_url.startswith("file://"):
    new_jar_body = open(args.new_jar_url[len("file://"):], 'rb').read()
else:
    new_jar_body = requests.get(args.new_jar_url).content

m = hashlib.sha512()
m.update(new_jar_body)
new_jar_hash = m.hexdigest()
log('{} downloaded and hashed to {}'.format(args.new_jar_url, new_jar_hash))
if new_jar_hash != args.new_jar_sha512:
    log("hash of {} doesn't match (download={}, wanted={}), aborting".format(args.new_jar_url,
                                                                                    new_jar_hash,
                                                                                    args.new_jar_sha512))
    sys.exit(2)

for nar in os.listdir(args.path):
    if not nar.endswith('.nar'):
        continue
    changed_content = False
    fullpath = os.path.join(args.path, nar)
    m = hashlib.sha512()
    m.update(open(fullpath,'rb').read())
    log('Possibly rewriting {}, current sha512={}'.format(fullpath, m.hexdigest()))

    zin = zipfile.ZipFile (fullpath, 'r')
    buffer = cStringIO.StringIO()
    zout = zipfile.ZipFile (buffer, 'w')
    for item in zin.infolist():
        log('{} contained {}'.format(fullpath, item.filename))
        if os.path.basename(item.filename) == args.old_jar_name:
            new_jar_filename = urlparse.urlsplit(args.new_jar_url).path.split('/')[-1]
            new_full_filename = "{}/{}".format(os.path.dirname(item.filename),
                                               new_jar_filename)
            log('Replacing {} with {}'.format(item.filename, new_full_filename))
            zout.writestr(new_full_filename, new_jar_body, zipfile.ZIP_DEFLATED)
            changed_content = True            
        else:
            zout.writestr(item, zin.read(item.filename))
    zout.close()
    zin.close()
    if changed_content:
        tempfullpath = "{}_".format(fullpath)
        log('Now writing to {}'.format(tempfullpath))
        open(tempfullpath, 'wb').write(buffer.getvalue())
        log('Renaming {} to {}'.format(tempfullpath, fullpath))
        os.rename(tempfullpath, fullpath)
        log('Renamed over {}'.format(fullpath))
        m = hashlib.sha512()
        m.update(open(fullpath,'rb').read())
        log('Rewritten {}, new sha512={}'.format(fullpath, m.hexdigest()))