04/12/18

Pip Quick Reference

Basic pip usage

Upgrade PIP
python -m pip install --upgrade pip
Find outdated/updatable pip packages
pip list --outdated
Getting info on your python environment
python -m site

08/09/18

Git Hooks - A way to automate deploy tasks

During my work I use git for automate the deploy on production system. Sometimes I need execute some command or script immediately after checkout. Git has a very powerful mechanism called hooks (you can read more about it on official documentation follow this link).
On client side to install hooks what you have to do is to create a dir called hooks under .git/ . But  you do not have to do any of this because when you have initialized your project git create it for you.
If you list the content of hooks dir you can found a list of samples script to use (all of them are bash scripts). Most of this script start with the prefix  pre- or post- followed by action name.
The script that I found helpful is post-checkout that is automatically executed after a successful git checkout. My post-checkout script contain commands for adjust permissions on files and ask to restart web server.

#!/bin/bash
git ls-files -z --with-tree="$2" --directory | xargs -0 chmod o-rxw --
git ls-files -z --with-tree="$2" --directory | xargs -0 chown www-data:www-data --
find . -type d | xargs -I {} chown www-data:www-data {}
find . -type d | xargs -I {} chmod o-rwx {}
exec < /dev/tty

while true;
   do
      read -p "Do you want to restart apache?  [Y/N]:" choice
      case "$choice" in
         y|Y) service apache2 restart;break;;
         n|N) break;;
         *) echo "invalid" && break;;
      esac
   done

Remember to add execute permission to this script or git won't execute it after the checkout.

16/03/18

Git Handbook

Git Setup

How to setup git with SSH Key

git remote set-url origin [email protected]:<Username>/<Project>.git

Configure username and mail

git config --global user.name "Name Surname"
git config --global user.email "mymail(at)mydomain.com"

Filename too long in git for windows

git config --system core.longpaths true

Note: You need to run as administrator.
Ref: https://stackoverflow.com/questions/22575662/filename-too-long-in-git-for-windows

Windows CRLF chars.

Su windows bisogna disattivare questa funziona altrimenti non funzionano i caratteri CRLF.
git config core.autocrlf false

How can I debug git/git-shell related problems?

If you have problem with Git and you need to debug you can run this:

GIT_CURL_VERBOSE=1 GIT_TRACE=1 git pull
Ref: https://stackoverflow.com/questions/6178401/how-can-i-debug-git-git-shell-related-problems

How to get list of files between change log ?

If you need to get list of files (included directory tree) from change list you can use:

git diff-tree -r --name-only 2c636a^ 5b47402 | xargs -I {} rsync -aR {} output/

Delete files from git index when they are already deleted

git ls-files --deleted -z | xargs -0 git rm

How do I show my global git config?

git config --list

Show remote branches

git branch -vr

Git Commands

How to commit only staged modified and deleted files?

git add -u

List log with tag date


git log --date-order --graph --tags --simplify-by-decoration --pretty=format:'%ai %h %d'

02/03/18

How to improve reading of log files

There are hard times when a sysadmin have to read a lot of rows of log files for troubleshoot a system error. In this times can be helpful to use some tools to improve reading of these files.

I've found two tools:

  • Generic Colouriser (GRC)https://github.com/garabik/grc - there are programs: grc and grcat. The main is grcat, which acts as a filter, i.e. taking standard input, colourising it and writing to standard output. Then you can use configuration files for customize color ouput depend on you application output log. 
  • Log File Navigator (LNAV)http://lnav.org/ - this is a real log file navigator that parse content of file and follow the stream for read latest lines. Lnav can help highlight the parts that are important and filter out the noise.