Add support for Python 3

- Import print_function from __future__ and change all print statements to function calls.
- Handle different import paths to urllib.urlretrieve/urllib.request.urlretrieve in setup.py

Author: Jeppe Toustrup

Diff for: samples/amazon_kclpy_helper.py

@@ -13,6 +13,7 @@
 express or implied. See the License for the specific language governing
 permissions and limitations under the License.
 '''
+from __future__ import print_function
 from amazon_kclpy import kcl
 from glob import glob
 import os, argparse, sys, samples
@@ -140,11 +141,11 @@ def get_kcl_app_command(java, multi_lang_daemon_class, properties, paths=[]):
 
     # Print what the asked for
     if args.print_classpath:
-        print get_kcl_classpath(args.properties, args.paths)
+        print(get_kcl_classpath(args.properties, args.paths))
     elif args.print_command:
         if args.java and args.properties:
             multi_lang_daemon_class = 'com.amazonaws.services.kinesis.multilang.MultiLangDaemon'
-            print get_kcl_app_command(args.java, multi_lang_daemon_class, args.properties, paths=args.paths)
+            print(get_kcl_app_command(args.java, multi_lang_daemon_class, args.properties, paths=args.paths))
         else:
             sys.stderr.write("Must provide arguments: --java and --properties\n")
             parser.print_usage()

Diff for: samples/sample_kclpy_app.py

@@ -13,6 +13,7 @@
 express or implied. See the License for the specific language governing
 permissions and limitations under the License.
 '''
+from __future__ import print_function
 import sys, time, json, base64
 from amazon_kclpy import kcl
 
@@ -59,7 +60,7 @@ def checkpoint(self, checkpointer, sequence_number=None):
                     A ShutdownException indicates that this record processor should be shutdown. This is due to
                     some failover event, e.g. another MultiLangDaemon has taken the lease for this shard.
                     '''
-                    print 'Encountered shutdown execption, skipping checkpoint'
+                    print('Encountered shutdown execption, skipping checkpoint')
                     return
                 elif 'ThrottlingException' == e.value:
                     '''
@@ -70,7 +71,7 @@ def checkpoint(self, checkpointer, sequence_number=None):
                         sys.stderr.write('Failed to checkpoint after {n} attempts, giving up.\n'.format(n=n))
                         return
                     else:
-                        print 'Was throttled while checkpointing, will attempt again in {s} seconds'.format(s=self.SLEEP_SECONDS)
+                        print('Was throttled while checkpointing, will attempt again in {s} seconds'.format(s=self.SLEEP_SECONDS))
                 elif 'InvalidStateException' == e.value:
                     sys.stderr.write('MultiLangDaemon reported an invalid state while checkpointing.\n')
                 else: # Some other error
@@ -146,10 +147,10 @@ def shutdown(self, checkpointer, reason):
                 # Checkpointing with no parameter will checkpoint at the
                 # largest sequence number reached by this processor on this
                 # shard id
-                print 'Was told to terminate, will attempt to checkpoint.'
+                print('Was told to terminate, will attempt to checkpoint.')
                 self.checkpoint(checkpointer, None)
             else: # reason == 'ZOMBIE'
-                print 'Shutting down due to failover. Will not checkpoint.'
+                print('Shutting down due to failover. Will not checkpoint.')
         except:
             pass
 

Diff for: samples/sample_kinesis_wordputter.py

@@ -13,6 +13,7 @@
 express or implied. See the License for the specific language governing
 permissions and limitations under the License.
 '''
+from __future__ import print_function
 import sys, random, time, argparse
 from boto import kinesis
 
@@ -46,10 +47,10 @@ def wait_for_stream(conn, stream_name):
     SLEEP_TIME_SECONDS = 3
     status = get_stream_status(conn, stream_name)
     while status != 'ACTIVE':
-        print '{stream_name} has status: {status}, sleeping for {secs} seconds'.format(
+        print('{stream_name} has status: {status}, sleeping for {secs} seconds'.format(
                 stream_name = stream_name,
                 status      = status,
-                secs        = SLEEP_TIME_SECONDS)
+                secs        = SLEEP_TIME_SECONDS))
         time.sleep(SLEEP_TIME_SECONDS) # sleep for 3 seconds
         status = get_stream_status(conn, stream_name)
 
@@ -69,7 +70,7 @@ def put_words_in_stream(conn, stream_name, words):
     for w in words:
         try:
             conn.put_record(stream_name, w, w)
-            print "Put word: " + w + " into stream: " + stream_name
+            print("Put word: " + w + " into stream: " + stream_name)
         except Exception as e:
             sys.stderr.write("Encountered an exception while trying to put a word: "
                              + w + " into stream: " + stream_name + " exception was: " + str(e))
@@ -93,7 +94,7 @@ def put_words_in_stream_periodically(conn, stream_name, words, period_seconds):
     '''
     while True:
         put_words_in_stream(conn, stream_name, words)
-        print "Sleeping for {period_seconds} seconds".format(period_seconds=period_seconds)
+        print("Sleeping for {period_seconds} seconds".format(period_seconds=period_seconds))
         time.sleep(period_seconds)
 
 if __name__ == '__main__':
@@ -123,12 +124,12 @@ def put_words_in_stream_periodically(conn, stream_name, words, period_seconds):
     Getting a connection to Amazon Kinesis will require that you have your credentials available to
     one of the standard credentials providers.
     '''
-    print "Connecting to stream: {s} in {r}".format(s=stream_name, r=args.region)
+    print("Connecting to stream: {s} in {r}".format(s=stream_name, r=args.region))
     conn = kinesis.connect_to_region(region_name = args.region)
     try:
         status = get_stream_status(conn, stream_name)
         if 'DELETING' == status:
-            print 'The stream: {s} is being deleted, please rerun the script.'.format(s=stream_name)
+            print('The stream: {s} is being deleted, please rerun the script.'.format(s=stream_name))
             sys.exit(1)
         elif 'ACTIVE' != status:
             wait_for_stream(conn, stream_name)
@@ -138,7 +139,7 @@ def put_words_in_stream_periodically(conn, stream_name, words, period_seconds):
         wait_for_stream(conn, stream_name)
     # Now the stream should exist
     if len(args.words) == 0:
-        print 'No -w options provided. Waiting on input from STDIN'
+        print('No -w options provided. Waiting on input from STDIN')
         words = [l.strip() for l in sys.stdin.readlines() if l.strip() != '']
     else:
         words = args.words

Diff for: setup.py

@@ -12,11 +12,19 @@
 express or implied. See the License for the specific language governing
 permissions and limitations under the License.
 """
+from __future__ import print_function
 from setuptools import setup
 import os, urllib, sys, glob
 from setuptools import Command
 from setuptools.command.install import install
 
+try:
+    # Python 3
+    from urllib.request import urlretrieve
+except ImportError:
+    # Python 2
+    from urllib import urlretrieve
+
 '''
 This script modifies the basic setuptools by adding some functionality to the standard
 "install" command and by adding an additional command "download_jars" which
@@ -88,19 +96,19 @@ def download_file(self, url, dest):
         '''
         Downloads a file at the url to the destination.
         '''
-        print 'Attempting to retrieve remote jar {url}'.format(url=url)
+        print('Attempting to retrieve remote jar {url}'.format(url=url))
         try:
-            urllib.urlretrieve(url, dest)
-            print 'Saving {url} -> {dest}'.format(url=url, dest=dest)
+            urlretrieve(url, dest)
+            print('Saving {url} -> {dest}'.format(url=url, dest=dest))
         except:
-            print 'Failed to retrieve {url}'.format(url=url)
+            print('Failed to retrieve {url}'.format(url=url))
             return
 
     def download_files(self):
         for package in self.packages:
             dest = os.path.join(self.destdir, self.package_destination(package[1], package[2]))
             if os.path.isfile(dest):
-                print 'Skipping download of {dest}'.format(dest=dest)
+                print('Skipping download of {dest}'.format(dest=dest))
             else:
                 url = self.package_url(package[0], package[1], package[2])
                 self.download_file(url, dest)
@@ -122,13 +130,13 @@ def run(self):
         '''
         downloader = MavenJarDownloader()
         downloader.download_files()
-        print '''
+        print('''
 Now you should run:
 
     python setup.py install
 
 Which will finish the installation.
-'''
+''')
 
 class InstallThenCheckForJars(install):
 
@@ -175,7 +183,7 @@ def run(self):
             install.run(self)
         missing_jars = downloader.missing_jars()
         if len(missing_jars) > 0:
-            print self.warning_string(missing_jars)
+            print(self.warning_string(missing_jars))
 
 if __name__ == '__main__':
     setup(