tail support, log filtering, executable, and splitlines bug fix

Change-Id: I81e928fb5222d055f248d50a5332ea39d4b9ebc1

oslo_log/cmds/convert_json.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 #    Licensed under the Apache License, Version 2.0 (the "License"); you may
 #    not use this file except in compliance with the License. You may obtain
 #    a copy of the License at
@@ -16,15 +17,16 @@ import argparse
 import collections
 import functools
 import sys
+import time
 
 from oslo_serialization import jsonutils
 from oslo_utils import importutils
 import six
 
-termcolor = importutils.try_import('termcolor')
-
 from oslo_log import log
 
+termcolor = importutils.try_import('termcolor')
+
 
 _USE_COLOR = False
 
@@ -33,9 +35,29 @@ def main():
     global _USE_COLOR
     args = parse_args()
     _USE_COLOR = args.color
-    formatter = functools.partial(console_format, args.prefix, args.locator)
+    formatter = functools.partial(
-    for line in reformat_json(args.file, formatter):
+        console_format,
-        print(line)
+        args.prefix,
+        args.locator,
+        loggers=args.loggers,
+        levels=args.levels,
+        )
+    if args.lines:
+        # Read backward until we find all of our newline characters
+        # or reach the beginning of the file
+        args.file.seek(0, 2)
+        newlines = 0
+        pos = args.file.tell()
+        while newlines <= args.lines and pos > 0:
+            pos = pos - 1
+            args.file.seek(pos)
+            if args.file.read(1) == '\n':
+                newlines = newlines + 1
+    try:
+        for line in reformat_json(args.file, formatter, args.follow):
+            print(line)
+    except KeyboardInterrupt:
+        sys.exit(0)
 
 
 def parse_args():
@@ -55,6 +77,21 @@ def parse_args():
     parser.add_argument("-c", "--color",
                         action='store_true', default=False,
                         help="Color log levels (requires `termcolor`)")
+    parser.add_argument("-f", "--follow",
+                        action='store_true', default=False,
+                        help="Continue parsing new data until"
+                             " KeyboardInterrupt")
+    parser.add_argument("-n", "--lines",
+                        required=False, type=int,
+                        help="Last N number of records to view."
+                             " (May show less than N records when used"
+                             " in conjuction with --loggers or --levels)")
+    parser.add_argument("--loggers",
+                        nargs='*', default=[],
+                        help="only return results matching given logger(s)")
+    parser.add_argument("--levels",
+                        nargs='*', default=[],
+                        help="Only return lines matching given log level(s)")
     args = parser.parse_args()
     if args.color and not termcolor:
         raise ImportError("Coloring requested but `termcolor` is not"
@@ -85,12 +122,16 @@ def warn(prefix, msg):
     return "%s: %s" % (colorise('exc', prefix), msg)
 
 
-def reformat_json(fh, formatter):
+def reformat_json(fh, formatter, follow=False):
     # using readline allows interactive stdin to respond to every line
     while True:
         line = fh.readline()
         if not line:
-            break
+            if follow:
+                time.sleep(0.1)
+                continue
+            else:
+                break
         line = line.strip()
         if not line:
             continue
@@ -103,11 +144,19 @@ def reformat_json(fh, formatter):
             yield out_line
 
 
-def console_format(prefix, locator, record):
+def console_format(prefix, locator, record, loggers=[], levels=[]):
     # Provide an empty string to format-specifiers the record is
     # missing, instead of failing. Doesn't work for non-string
     # specifiers.
     record = collections.defaultdict(str, record)
+    # skip if the record doesn't match a logger we are looking at
+    if loggers:
+        name = record.get('name')
+        if not any(name.startswith(n) for n in loggers):
+            return
+    if levels:
+        if record.get('levelname') not in levels:
+            return
     levelname = record.get('levelname')
     if levelname:
         record['levelname'] = colorise(levelname)
@@ -130,7 +179,7 @@ def console_format(prefix, locator, record):
 
     tb = record.get('traceback')
     if tb:
-        for tb_line in tb.splitlines():
+        for tb_line in tb:
             yield ' '.join([prefix, tb_line])