Updated line counting to use wc -l

tests/kafkatest/sanity_checks/test_console_consumer.py

@@ -24,6 +24,7 @@ import time
 
 
 def file_exists(node, file):
+    """Quick and dirty check for existence of remote file."""
     try:
         node.account.ssh("cat " + file, allow_fail=False)
         return True
@@ -31,6 +32,15 @@ def file_exists(node, file):
         return False
 
 
+def line_count(node, file):
+    """Return the line count of file on node"""
+    out = [line for line in node.account.ssh_capture("wc -l %s" % file)]
+    if len(out) != 1:
+        raise Exception("Expected single line of output from wc -l")
+
+    return int(out[0].strip().split(" ")[0])
+
+
 class ConsoleConsumerTest(Test):
     """Sanity checks on console consumer service class."""
     def __init__(self, test_context):
@@ -58,12 +68,10 @@ class ConsoleConsumerTest(Test):
         # Verify that log output is happening
         if not wait_until(lambda: file_exists(node, ConsoleConsumer.LOG_FILE), timeout_sec=10):
             raise Exception("Timed out waiting for log file to exist")
-        consumer_log_lines = [line for line in node.account.ssh_capture("cat %s" % ConsoleConsumer.LOG_FILE)]
-        assert len(consumer_log_lines) > 0
+        assert line_count(node, ConsoleConsumer.LOG_FILE) > 0
 
         # Verify no consumed messages
-        consumed = [line for line in node.account.ssh_capture("cat %s" % ConsoleConsumer.STDOUT_CAPTURE)]
-        assert len(consumed) == 0
+        assert line_count(node, ConsoleConsumer.STDOUT_CAPTURE) == 0
 
         self.consumer.stop_node(node)
         if not wait_until(lambda: not self.consumer.alive(node), timeout_sec=10, backoff_sec=.2):