Add truncating output on tailing data based on verbosity. Closes #154. (

#231)

* Add truncating output on tailing data based on verbosity. Closes #154.

* code review comment updates.

requirements.txt

@@ -1,6 +1,7 @@
 ansible
 pexpect
 future
+sh
 
 # These requirements are for DEVELOPMENT ONLY!
 -r dev-requirements.txt

rho.spec

@@ -23,6 +23,7 @@ Requires: python-enum34
 Requires: python-yaml
 Requires: epel-release
 Requires: python2-future
+Requires: python2-sh
 
 %description
 Rho is a tool for scanning your network, logging into systems via SSH, and

rho/scancommand.py

@@ -19,7 +19,6 @@
 import re
 import time
 import json
-import subprocess
 from collections import defaultdict
 import pexpect
 import yaml
@@ -304,8 +303,7 @@ def run_ansible_with_vault(cmd_string, vault_pass, ssh_key_passphrase=None,
                                   env=env)
 
             if log_to_stdout:
-                tail = subprocess.Popen(['tail', '-f', '-n', '+0',
-                                         log_path])
+                utilities.threaded_tailing(log_path, ansible_verbosity)
 
             result = child.expect('Vault password:')
             child.sendline(vault_pass)
@@ -324,7 +322,6 @@ def run_ansible_with_vault(cmd_string, vault_pass, ssh_key_passphrase=None,
                 child.wait()
             if log_to_stdout:
                 time.sleep(2)
-                tail.terminate()
 
         return child
     except pexpect.EOF:

rho/utilities.py

@@ -17,8 +17,15 @@
 import csv
 import tempfile
 from shutil import move
+import sh
 from rho.translation import _
 
+if sys.version_info > (3,):
+    import _thread
+else:
+    import thread as _thread  # pylint: disable=import-error
+
+
 CREDENTIALS_PATH = 'data/credentials'
 PROFILES_PATH = 'data/profiles'
 
@@ -118,6 +125,50 @@
     + CONNECTION_FACTS_TUPLE
 
 
+def threaded_tailing(path, ansible_verbosity=0):
+    """Follow and provide output using a thread
+    :param path: path to file to follow
+    :param ansible_verbosity: the verbosity level
+    """
+
+    _thread.start_new_thread(tail_and_follow, (path, ansible_verbosity))
+
+
+def tail_and_follow(path, ansible_verbosity):
+    """Follow and provide output
+    :param path: tuple containing thepath to file to follow
+    :param ansible_verbosity: the verbosity level
+    """
+    if len(path) > 0:  # pylint: disable=len-as-condition
+        truncate = 1
+        if ansible_verbosity:
+            truncate = ansible_verbosity
+
+        print_line = truncate
+        plabook_started = False
+        truncated = False
+
+        # pylint: disable=no-member
+        for line in sh.tail('-f', '-n', '+0', path, _iter=True):
+            line = line.strip('\n')
+            if line.startswith('TASK') or line.startswith('PLAY'):
+                print(line)
+                print_line = truncate
+                plabook_started = True
+                truncated = False
+            elif print_line > 0:
+                line_len = len(line)
+                char_truncate = truncate * 100
+                if line_len > char_truncate:
+                    print(line[0:char_truncate] + '...')
+                else:
+                    print(line)
+                print_line = print_line - 1
+            elif print_line == 0 and not truncated and plabook_started:
+                print(_('-- output truncated --'))
+                truncated = True
+
+
 def ensure_config_dir_exists():
     """Ensure the Rho configuration directory exists."""
 

test/test_utilities.py

@@ -9,13 +9,37 @@
 
 """Unit tests for rho/utilities.py."""
 
+import contextlib
+import sys
+import os
+import time
 import unittest
+import six
 from rho import utilities
 
 # pylint: disable=missing-docstring
+TMP_FOLLOW = "/tmp/follow.txt"
+
+
+@contextlib.contextmanager
+def redirect_stdout(stream):
+    """Run a code block, capturing stdout to the given stream"""
+
+    old_stdout = sys.stdout
+    try:
+        sys.stdout = stream
+        yield
+    finally:
+        sys.stdout = old_stdout
 
 
 class TestValidatePort(unittest.TestCase):
+    def setUp(self):
+        if os.path.isfile(TMP_FOLLOW):
+            os.remove(TMP_FOLLOW)
+        with open(TMP_FOLLOW, 'w') as follow_file:
+            follow_file.write('follow\n')
+
     def test_wrong_type(self):
         with self.assertRaises(ValueError):
             utilities.validate_port([1, 2, 3])
@@ -37,3 +61,10 @@ def test_valid_string_port(self):
 
     def test_valid_int_port(self):
         self.assertEqual(utilities.validate_port(123), 123)
+
+    def test_threaded_tailing(self):
+        follow_list_out = six.StringIO()
+        with redirect_stdout(follow_list_out):
+            utilities.threaded_tailing(TMP_FOLLOW, 3)
+            time.sleep(2)
+            self.assertEqual(follow_list_out.getvalue(), 'follow\n')