Fix more PY3 issues in check_rabbitmq_queues.py

Note that, for PY3, the unbuffered IO in the check_rabbitmq.py script
has to be switched off as PY3 doesn't support unbuffered IO for text
(think str) rather than binary byte streams.

Change-Id: I79af54cdbd7381f88732b24f65e94451350b9ab9
Closes-Bug: #1804349
Closes-Bug: #1804348

hooks/rabbitmq_server_relations.py

@@ -79,6 +79,11 @@ from charmhelpers.contrib.hardening.harden import harden
 from charmhelpers.fetch import (
     add_source,
 )
+from charmhelpers.fetch import (
+    apt_install,
+    apt_update,
+    filter_installed_packages,
+)
 
 from charmhelpers.core.hookenv import (
     open_port,
@@ -747,6 +752,14 @@ def upgrade_charm():
     # Ensure all client connections are up to date on upgrade
     update_clients()
 
+    # BUG:#1804348
+    # for the check_rabbitmq.py script, python3-amqplib needs to be installed;
+    # if previous version was a python2 version of the charm this won't happen
+    # unless the source is changed.  Ensure it is installed here if needed.
+    apt_update(fatal=True)
+    if filter_installed_packages(['python3-amqplib']):
+        apt_install(['python3-amqplib'], fatal=True)
+
 
 MAN_PLUGIN = 'rabbitmq_management'
 

scripts/check_rabbitmq.py

@@ -181,7 +181,10 @@ def main_loop(conn, exname):
 
 def main(host, port, exname, extype, user, password, vhost, ssl, ssl_ca):
     """ setup the connection and the communication channel """
-    sys.stdout = os.fdopen(os.dup(1), "w", 0)
+    # BUG:#1804348 - can't have unbuffered text output in PY3 (unlike PY2), and
+    # this is essentially duping stdout which has to use text (str) and not
+    # bytes.  The only compromise is to lose the unbuffered output.
+    sys.stdout = os.fdopen(os.dup(1), "w")
     host_port = "{}:{}".format(host, port)
     conn = get_connection(host_port, user, password, vhost, ssl, ssl_ca)
 
@@ -240,9 +243,13 @@ if __name__ == '__main__':
 
     (options, args) = parser.parse_args()
     if options.verbose:
-        print("""
-Using AMQP setup: host:port={}:{} exchange_name={} exchange_type={}
-""".format(options.host, options.port, options.exchange, options.type))
+        print("")
+        print("Using AMQP setup: host:port={}:{} exchange_name={} "
+              "exchange_type={} "
+              .format(options.host,
+                      options.port,
+                      options.exchange,
+                      options.type))
     ret = main(options.host, options.port, options.exchange, options.type,
                options.user, options.password, options.vhost, options.ssl,
                options.ssl_ca)

scripts/check_rabbitmq_queues.py

@@ -12,7 +12,7 @@ import sys
 
 
 def gen_data_lines(filename):
-    with open(filename, "rb") as fin:
+    with open(filename, "rt") as fin:
         for line in fin:
             if not line.startswith("#"):
                 yield line