PythonTail: a Unix tail implementation in python. Version: 0.9

Table of Contents

• Getting Started
  • Unix version comparison
  • Installation process
  • Usage
  • Examples
• License

Getting Started

Unix version comparison

Unix tail implementation list (adapted)

• item: default output line = 10
  descrtption: default output with 10 lines for each tailed file
  status: [OK]
• item: -c, --bytes=[+]NUM
  description: output the last NUM bytes; or use -c +NUM to output starting
  with byte NUM of each file
  status: [PENDING]
• item: -f, --follow
  description: output appended data as the file grows;
  status: [OK]
• item: -n, --lines=NUM
  description: output the last NUM lines, instead of the last 10; or use -n
  status: [OK]
• item: --max-unchanged-stats=N
  description: with --follow=name, reopen a FILE which has not
  changed size after N (default 5) iterations to see if it has
  been unlinked or renamed (this is the usual case of rotated
  log files); with inotify, this option is rarely useful
  status: [PENDING]
• item: --pid=PID
  description: with -f, terminate after process ID, PID dies
  status: [PENDING]
• item: -q, --quiet, --silent
  description: never output headers giving file names
  status: [OK]
• item: --retry
  description: keep trying to open a file if it is inaccessible
  status: [PENDING]
• item: -s, --sleep-interval=N
  description: with -f, sleep for approximately N seconds (default 0)
  between iterations; at least once every N seconds
  status: [OK]
• item: -v, --verbose
  description: always output headers giving file names
  status: [PENDING]
• item: -z, --zero-terminated
  description: line delimiter is NUL, not newline
  status: [PENDING]
• item: --help
  description: display this help and exit
  status: [OK]
• item: --version
  description: output version information and exit
  status: [OK]
• item: multiple files support
  description: tail as many files as wanted with all available parameters working as well
  status: [OK]

Unique tail implementations

• item: usage as both terminal command and as python module
  description: the use of all parameters within terminal command line
  and by importing as a module inside a python script
  status: [OK]
• item: -d, --debug
  description: create a log file and register all ocurrencies of regular
  behavior information, debug and errors as the timestamp and logged user
  status: [OK]
• item: --logless
  description: send all output to stdout with no log folder or file being created
  status: [OK]
• item: ?
  description: tail files over tcp/ip
  status: [PENDING]

Via Bash

Installation Process

install as a module:

pip install pythontail

and use it as:

from pythontail import tail
tail.run(["dir/log/file.log"])

use as terminal command:

git clone https://github.com/natanaelfneto/pythontail.git
python pythontail.py -h

enjoy

Usage

this messagem can also be found with python pythontail.py -h command

usage: pythontail.py [-h] [-f | -n LINES] [-q] [-s SLEEP] [-d] [-v] sources [sources ...]

Unix tail implementation in python 

optional arguments:
-h, --help                  show this help message and exit
-f, --follow                flag to not limit number of lines tailed
-n LINES, --lines LINES     number of lines to follow in total array of sources

-q, --quiet, --silent       never output headers giving file names

-s SLEEP, --sleep SLEEP, --sleep-interval SLEEP
                            with --follow, sleep for approximately N seconds
                            (default 0) between iterations; least once every N seconds

-d, --debug                 process debug flag
-v, --version               output software version

Examples

First we need a fake log file

Generate many live fake logs files by running:

python pythontail/test/fake_log_generator.py <integer> &

for the example1.py, generate the minimum of 2 fake log files
This will create two fake_n.log files in ~/log/fake_n.log that can be tailed

Using it as console command for tail files

python pythontail/pythontail.py -f ~/log/fake_1.log ~/log/fake_2.log

Using it as python module for tail files

Create a virtual env and activate it (can be pyenv or virtualenv or any other)

mkvirtualenv pythontail
workon pythontail

Install pythontail module

pip install pythontail

Create your code as the available in pythontail/examples/example1.py\

from pythontail import tail
from pathlib import Path

import os


# get as many valid files paths you want to be tailed
log_file_1 = str(Path(f"{os.path.expanduser("~")}/log/fake_1.log"))
log_file_2 = str(Path(f"{os.path.expanduser("~")}/log/fake_2.log"))

# tail them
tail.run(
    # debug=False,
    # quiet=False,
    # lines=10,
    # sleep=0,
    sources=[
        log_file_1, 
        log_file_2
    ]
)

# for a --follow atribute, set the maximum number of lines to zero [lines=0]
# optional --sleep atribute only works with --follow flag, done by making [lines=0]

Check the output of example1 by running the script file:

python pythontail/examples/example1.py

License

MIT License

Copyright (c) 2017 Natanael F. Neto (natanaelfneto)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.