Blog Page 10 :: Alasdair Keyes

Document versioning with GIT

Posted: 2016-01-05 23:43:55 by Alasdair Keyes

I've been at my new job for 3 months now and my home folder is slowly growing in size. Like most people often have files that are updated frequently, spreadsheets, build specs etc and I thought it would be quite nice to have a quick and dirty versioning system for my documents.

I didn't want to get too in-depth with log structured filesystems such as NILFS or really have to use a new FS or fuse-based FS as it seems an unnecessary length to go to. I don't have any requirement to store every single version, but just give me snapshots I could refer back to in future or easily restore mistakenly deleted files.

I decided that git would be a suitable base for this for the following reasons

It will allow me to create snapshots (commits) when I wanted using a manual git add/git commit
It will allow automated snapshots via scripts via either kernel notifications or cron
Git has builtin timestamping
Git has a built in roll-back feature to see old file versions
.gitignore will allow me to easily exclude files/folders I don't want versioned such as ISOs or other files

I started by initializing my docs

$ cd /home/akeyes/mydocs
$ git init
Initialised empty Git repository in /home/akeyes/mydocs/.git
$ git add .
$ git commit -m "Initial commit"
[master (root-commit) 4cbb3d8] Initial commit
 152 files changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 xxxxxx.docx
 create mode 100644 xxxxxx.odt
 ...
 create mode 100644 xxxxxx.txt

Now I have my initial commit, I wrote the followig script to add to cron

#!/bin/bash

FOLDER=/home/akeyes/mydocs
cd $FOLDER

if [ `git status --porcelain | wc -l` -gt 0 ]; then
    git add --all .
    git commit -m "Checkpoint"
fi

I was unaware of the --porcelain argument for git, but it essentially shows a simple machine parseable output of git status. For my usage if there's any output, it shows there's a change and it needs to be snapshotted

$ git status --porcelain
?? newfile
?? newfile1

the --all switch to git add allows git add to succesfully add in file deletions and not require git rm

To start with I just added this into my crontab

* * * * *    /home/akeyes/checkpoint_docs.sh

And now git log shows my versioning working

$ git log --name-only
commit d0544e40b856eb98cc2129f98383895708083deb
Author: Alasdair Keyes <x@x.com>
Date:   Tue Jan 5 19:47:00 2016 +0000

    Checkpoint

newfile2

commit 139fd9ff825232e0551bf570e4ac8957bc93c8b1
Author: Alasdair Keyes <x@x.com>
Date:   Tue Jan 5 19:46:00 2016 +0000

    Checkpoint

newfile
newfile2
newfile3

commit 8539658cd62581c3a514081c30d3c30a2a0a7ac9
Author: Alasdair Keyes <x@x.com>
Date:   Tue Jan 5 19:45:00 2016 +0000

    Checkpoint

newfile
newfile1

commit ba6ec4f43aecb81db0709ea18418d94d24cbb3d8
Author: Alasdair Keyes <x@x.com>
Date:   Tue Jan 5 19:42:33 2016 +0000

    Initial commit

xxxxxx.docx
xxxxxx.odt
xxxxxx.txt

It seems to work very well, on top of this I've created a .gitignore

# Libreoffice temp files
**/.~*#
# VIM swap files
**/.*.swp
# Keepass lock files
**/*.lock

Which stops temp files from LibreOffice being commited.

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Putt's Law

Posted: 2015-12-19 12:12:32 by Alasdair Keyes

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I've just become aquainted with this law today

Technology is dominated by two types of people:  those who understand what they do not manage and those who manage what they do not understand.

It's pretty much on the money

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Let's Encrypt webroot on NGINX

Posted: 2015-12-06 14:09:42 by Alasdair Keyes

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Like a number of people I've been looking forward to the release of Let's Encrypt, the free system to allow every one to get an SSL Certificate. It's now in open beta and can be used by all.

You can read how it works and how to get it setup here.

After some playing about I found the following setup good for my needs. My system is NGINX running on Debian Jessie.

Run the following with superuser access.

mkdir /var/le_root
chown www-data: /var/le_root
chmod 700 /var/le_root

Create /etc/nginx/snippets/lets_encrypt.conf with the following text

location /.well-known/acme-challenge/ {
    allow all;
    auth_basic off;
    root /var/le_root;
}

The allow all; and auth_basic off; is because some of my sites have IP or basic auth restrictions which I don't want taking effect on this folder as it'll stop Lets Encrypt validating the site.

In each website virtualhost config add the line

include snippets/lets_encrypt.conf;

This snippet aliases /.well-known/acme-challenge/ on any hosting space for the to /var/le_root, we can then tell Let's Encrypt to use /var/le_root for all its validation files so with one command, create certs for any site I have on my server

Then just run

./letsencrypt-auto certonly --webroot -w /var/le_root -d mydomain.com

And your cert/key will be available in /etc/letsencrypt/live/mydomain.com/

The Let's Encrypt certs only last 90 days, whilst this may increase in future, I've added it to my Nagios checks, however, you can also use the following bash script in a cron to check the expiry dates of your certificates. It's easily ammended to auto renew certificates if you wish, I'll update it to auto-renew once I've had to renew one of my own certs.

https://gitlab.com/snippets/1731323/raw

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xfreerdp clipboard

Posted: 2015-11-23 08:45:24 by Alasdair Keyes

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You can allow XfreeRDP under Linux to access your clipboard, run it with the following plugin enabled

xfreerdp --plugin cliprdr hostname

No more typing in 32 character passwords key by key!

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Inbox Zero

Posted: 2015-11-21 15:43:24 by Alasdair Keyes

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Having recently started a new job, I've started trying to implement Inbox Zero.

Although I don't stick to it's 5 points religiously, I find the basic premise extremely useful and have adapted it to a way that I find most useful.

I now use my inbox as part of my todo list, when I look at my inbox I now apply the following rules

It doesn't require action and I don't need to refer to it. (e.g. Marketing email from vendor). :: DELETE
It doesn't require action but has information I may need to refer back to it in future. (e.g. Message from colleague). :: FILE IT
It needs me to do something at a specific point in the future. (e.g. Meeting invitation or Message to call customer next Monday). :: ADD TO CALENDAR then FILE IT
It needs action that I can do quickly now. :: ACTION IT
Keep it in the inbox for processing later.

At this point, the only things I have to worry about are what's in the inbox as soon as I have dealt with them, I file it and move onto the next one.

So far, it's working well, after 7 weeks on the job my inbox this weekend is 1!

I'm now slowly trying to apply it to my personal emails too...

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OpenVPN and Android Lollipop connection problems

Posted: 2015-10-09 23:49:23 by Alasdair Keyes

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I recently bought myself a One Plus 2 Android based phone. My previous and trusty Samsung Galaxy S1 had been with me for over 4 years and was starting to be unusably slow.

I won't go on about the Oneplus, reviews can be found all over the internet, however I decided to connect it to my OpenVPN setup... which wasn't as easy as I thought it might be.

The Google Play store has the official OpenVPN Connect client, which connected to my server correctly but seemed to consistently fail to add in it's routes. After trying unsuccessfully for a while, I came to the conclusion that it couldn't be made to work.

I removed this app and went for OpenVPN for Android, setup was just as easy as OpenVPN Connect and still had an issue with adding pushed routes. It thankfully has the option of adding custom routes on the client, under Routing set a custom route of 0.0.0.0/0 and you will be routing all your non-local traffic to your VPN, much needed when you're regularly connecting to unknown wifi networks.

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Packtpub Free Learning eBooks

Posted: 2015-10-09 16:24:43 by Alasdair Keyes

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Yesterday Russ informed me of Packtpub's Free Learning offer.

Every day, a new eBook is available for free so you can continue learning at reduced cost.

Just visit https://www.packtpub.com/packt/offers/free-learning, sign up and click the "Claim Your Free eBook" button.

To make this a little easier, I created a quick Perl script you can add to cron once per day and it'll email you with details of the current eBook

wget -Oget_packtpub_botd.pl https://gitlab.com/snippets/1731322/raw
chmod 755 get_packtpub_botd.pl

Add to cron and you'll get an email once a day saying...

Today's book is 'Making Big Data Work for Your Business'

https://www.packtpub.com/packt/offers/free-learning

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Permission Denied when scanning in Linux Mint

Posted: 2015-10-05 20:28:03 by Alasdair Keyes

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I bought a Brother DCP-L2500D Printer/scanner yesterday. After some trepidation as to whether I would be able to use it under Linux, a quick Google search showed that Brother provided drivers for Windows, Mac and Linux. Kudos Brother, it's nice to see companies supporting all their customers not just the high volume users.

After installation of the Drivers into Linux Mint, I could print but not scan. Every time I tried I received the following error.

When trying to scan with XSane I would get

Failed to open device `brother4:bus1:dev1': Invalid argument

And under Simple Scan I would get

Failed to scan - Unable to connect to scanner

As I could print, I assumed the device was correct, so the failure to open device error indicated a permissions issue.

Although CUPS doesn't make use of the traditional device /dev/usb/lp0 (but instead uses a separate identifier usb://Brother/DCP-L2500D%20series?serial=XXXXXXXXXXXXXX), looking at this device showed that it was owned by the lp group

ls -al /dev/usb/lp0 
crw-rw---- 1 root lp 180, 0 Oct  5 20:13 /dev/usb/lp0

Although I was a member of the lpadmin group, I wasn't part of lp

$ id alasdair
uid=1000(alasdair) gid=1000(alasdair) groups=1000(alasdair),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),108(lpadmin),110(sambashare)

A quick change to my group ownership, then logging out and back in sorted it out and allowed me to scan.

$ sudo usermod -Ga lp alasdair
$ id alasdair
uid=1000(alasdair) gid=1000(alasdair) groups=1000(alasdair),4(adm),7(lp),24(cdrom),27(sudo),30(dip),46(plugdev),108(lpadmin),110(sambashare)

If you get this issue, remember to logout/login before trying to scan again, it's key as a usermod won't take effect until you do.

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Easier IE Development

Posted: 2015-08-20 12:03:54 by Alasdair Keyes

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If you ever need to do Web development, you know just how much of a pain cross-browser compatability is, specifically Internet Explorer. To make this a little easier, Microsoft have released a number of VMs to allow you to test lots of IE versions.

https://dev.modern.ie/tools/vms/windows/

They have VMs for a number of different Hypervisors across a number of platforms.

It's nice to see Microsoft providing support for Linux and Mac users.

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Spamassassin CountryFilter 0.02 Released - IPv6

Posted: 2015-08-12 12:09:57 by Alasdair Keyes

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An updated version of the CountryFilter plugin for SpamAssassin https://gitlab.com/alasdairkeyes/countryfilter-spamassassin has been released.

The new version now has Country Mapping and filtering support for IPv6 addresses. For Anyone using it, please make sure you check the README.md file on installation as the configuration file now has 2 new config lines to specify GeoIP database paths.

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