02 Aug 2015, 00:32

Host your blog on Github with autodeploy

I’ve always developed my own blog system, that’s a good way to learn a new langage.
But having to maintain a working server or hosting is no fun, there are some solutions like Jekyll or Hugo they generate static web pages based on some Markdown files you wrote.

As it’s just basic html files, they can be served by Github gh-pages.
It opens the door to blogging from anywhere without internet connection or your own laptop, just write some Markdown then publish to github later or event edit your new blog post from the Github editor.
Coupled with a Wercker auto deploy, publishing is automated, no excuse anymore.

Here is some tips for this to work smoothly with Hugo.

Github setup

First create 2 repositories on Github, one for the HTML pages, one for the markdown itself.
Let’s call them blog & hugo-blog.

DNS setup

You can use your own domain, if so you need to enable a CNAME file for your gh-pages to the blog repo, then add a CNAME to your DNS provider:
blog.mydomain.com. IN CNAME username.github.io.

Hugo setup

Clone the hugo-blog repo, put your new hugo blog files in it (created via hugo new).
Choose a theme for your blog (don’t forger to remove the .git directory from it) and set it up in your config.yml as follow:

baseurl = "http://blog.mydomain.com/"
languageCode = "en-us"
title = "My supa blog"
canonifyurls = true
theme = "hyde"

Then run hugo server --buildDrafts, point your browser to http://localhost:1313, no need to reload all modifications appear directly.

Wercker setup

For the auto deploy to occur after each commits you need a build & deploy system, Wercker is very cool as you can reproduce the exact same system on your host with Docker, subscribe to the service (it’s free) and register your hugo-blog repo, hit next, next …

Add a wercker.yml file in your hugo-blog that looks exactly like this.

box: debian
    - arjen/hugo-build:
        version: "0.14"
        theme: purehugo
        flags: --disableSitemap=true
deploy :
  steps :
    - script:
        name: Configure git
        code: |-
          sudo apt-get -y update
          sudo apt-get -y install git-core
          git config --global user.email "pleasemailus@wercker.com"
          git config --global user.name "wercker"

          # remove current .git folder
          rm -rf .git
    - script:
        name: Deploy to Github pages
        code: |-
          cd public
          # if you are using a custom domain set it here
          echo "blog.mydomain.com" > CNAME
          git init
          git add .
          git commit -m "deploy commit from $WERCKER_STARTED_BY"
          git push -f $GIT_REMOTE master:gh-pages 2> /dev/null

It will use Hugo to generate the pages then deploy to your Github repo on every commit to the blog repo.

Last step is to get a token from Github for the deploy to occur without your credentials.
Go to your Github settings, Personal access tokens, generate a token.

Go to your Wercker app settings, Deploy targets, add a new target, check auto deploy successful builds to branch(es): and type master.
Add a new variable named GIT_REMOTE check protected and type https://{TOKEN}@github.com/yourusername/blog.git replace {TOKEN} with the token from Github.
You can use this outdated blogpost from Wercker for the screenshot but don’t follow what they said.

You are all set, happy blogging, you can check the exact same config on my repos under my username Github@akhenakh.

01 Aug 2015, 22:36

Migrate to Hugo

This blog is running Hugo with an auto deploy via Wercker and hosted on Github Page. Take #2

Previous blog was hosted on Google App Engine with a Python blog system, to get the previous articles, I had to run in a small data migration.

Make a backup from GAE admin web interface: Go to Datastore admin and backup your entity mine was Post and then backup to blobstore, go to Blob Viewer and download your file named around datastore_backup_datastore_backup_2015_08_02_Post-157413521680733022360302ADC43E4-output-1-attempt-1

I put the migration code I’ve used here, it’s super ugly but helped me to migrate from GAE to Hugo, so it may be help you too.

I’ve used html2text to convert my HTML data back to Markdown.

import sys
import os
import json
import html2text
import errno
import datetime

from google.appengine.api.files import records
from google.appengine.datastore import entity_pb
from google.appengine.api import datastore

def mkdir_p(path):
    except OSError as exc:
        if exc.errno == errno.EEXIST and os.path.isdir(path):
        else: raise

raw = open("datastore", 'r')
titles = open("titles.txt", 'r').readlines()
reader = records.RecordsReader(raw)
i = 0
for record in reader:
    entity_proto = entity_pb.EntityProto(contents=record)
    entity = datastore.Entity.FromPb(entity_proto)

    if entity.get("status") == 1:
        path = titles[i].rstrip()
        content = html2text.html2text(entity["content_html"], "http://blog.nobugware.com/")
        directory = os.path.dirname(path)
        mkdir_p("post" + directory)

        # get current local time and utc time
        localnow = datetime.datetime.now()
        utcnow = datetime.datetime.utcnow()

        # compute the time difference in seconds
        tzd = localnow - utcnow
        secs = tzd.days * 24 * 3600 + tzd.seconds

        # get a positive or negative prefix
        prefix = '+'
        if secs < 0:
            prefix = '-'
            secs = abs(secs)

        # print the local time with the difference, correctly formatted
        suffix = "%s%02d:%02d" % (prefix, secs/3600, secs/60%60)
        now = localnow.replace(microsecond=0)
        date = "%s%s" % (entity["creation_date"].isoformat(' '), suffix)
        tags_string = ""
        tags_cleaned = []
        if entity.get("tags") is not None:
            tags = entity.get("tags")
            for tag in tags:
                tags_cleaned.append("\""+ tag + "\"")
            tags_string = ",".join(tags_cleaned)

        print tags_string
        page = """+++
date = "%s"
title = "%s"
tags = [%s]

""" % ( date, entity["title"] , tags_string, content)
    md=open("post" + path + ".md", 'w')
    i = i + 1

02 Apr 2015, 12:49

A 10 minutes walk into Grafana & Influxdb

This is a 10 minute tutorial to set up an InfluxDB + Grafana with Go on your Mac, but should work with minor modifcations on your favorite Unix too, it assumes you already have a working Go compiler.

InfluxDB is a database specialized into time series, think store everything associated with a time, makes it perfect for monitoring and graphing values. Grafana is a js frontend capable of reading the data from InfluxDB and graphing it.

brew install influxdb

Start InfluxDB, and then point your browser to http://localhost:8083 default user is root, password is root and default port is 8086.

influxdb -config /usr/local/etc/influxdb.conf Create a database called test.

Let’s test the connection with the db and Go, first install the InfluxDB driver for Go:

go get github.com/influxdb/influxdb/client Test your setup with some code:

package main

import (


func main() {
    c, err := client.NewClient(&client.ClientConfig{
        Username: "root",
        Password: "root",
        Database: "test",

    if err != nil {

    dbs, err := c.GetDatabaseList()
    if err != nil {


If you are good you should see a map containing all your created InfluxDB databases.

Now let’s measure something real: the time it takes for your http handler to answer.

package main

import (


var c *client.Client

func mySuperFastHandler(rw http.ResponseWriter, r *http.Request) {
    start := time.Now()
    // sleeping some random time
    i := rand.Intn(1000)
    time.Sleep(time.Duration(time.Duration(i) * time.Millisecond))
    fmt.Fprintf(rw, "Waiting %dms", i)
    t := time.Since(start)

    // sending the serie
    s := &client.Series{
        Name:    "myhostname.nethttp.mySuperFastHandler.resp_time",
        Columns: []string{"duration", "code", "url", "method"},
        Points: [][]interface{}{
            []interface{}{int64(t / time.Millisecond), 200, r.RequestURI, r.Method},
    err := c.WriteSeries([]*client.Series{s})
    if err != nil {

func main() {
    var err error
    c, err = client.NewClient(&client.ClientConfig{
        Username: "root",
        Password: "root",
        Database: "test",
    if err != nil {

    http.HandleFunc("/", mySuperFastHandler)
    http.ListenAndServe(":8080", nil)

This is not very useful as it’s measuring the time to write to the ResponseWriter that’s why I’ve added some random time but you get the sense. It will save a serie per request as: duration, status code, url, http method, the name of the serie is important as many tools (as Graphite) are using the dots as separator, so think twice before naming your serie. Point your browser to http://localhost:8080 and reload the page several times.

Now that we have data let’s browse them with the InfluxDB browser, go to the InfluxDB admin and hit “explore data” and select with:

SELECT duration FROM myhostname.nethttp.mySuperFastHandler.resp_time WHERE code = 200;

Image Alt

You should be able to see the inserted data points.

Now let’s work with Grafana, download the tar gz, uncompress it somewhere, copy this demo config.js file in the root directory of Grafana. Go to the InfluxDB admin with your browser and add a new database called “grafana”.

In your web browser, open the file index.html in the Grafana directory, you should see a the Grafana interface edit the default graph, enter the query as follow:

  • click on series it will complete with myhostname.nethttp.mySuperFastHandler.resp_time
  • In alias type $0 $2, it will use the 1st part and the 3rd part of the name (remember the dots) so it will display myhostname mySuperFastHandler
  • Finally click on mean and choose duration in the completion, then add code = 200 as where clause.

Hit save and you are done !

Image Alt

There is so much more you can do with InfluxDB & Grafana, it’s really simple to collect and display, hope you want to go further after this. You can look at my generic net/http handler for InfluxDB on Github that can be integrated into your code.

02 Jan 2015, 17:50

Run a full Wikipedia copy from any computers

Today I’m releasing Gozim a side project written in Go.

It’s a set of tools to serve ZIM files, (compressed copy of Wiki articles), use it to run your full copy of Wikipedia off the grid.

It runs great on a small computer as the Raspberry Pi or your own laptop.

It could be a solution to give access to knowledge in countries without stable internet connections.

13 Dec 2014, 07:55

Airspy on Linux

Airspy is an SDR with amazing specs, but drivers are slowly coming to your prefered os.

This apply to Arch but should apply to any recent Linux.

I’ve first compiled libairspy but always had the error AIRSPY_ERROR_NOT_FOUND and "usbfs: interface 0 claimed by airspy while 'airspy_info' sets config #1"

Since Linux 3.17 comes with an airspy v4l autoloaded driver making impossible to use it with libusb: no airspy_info and no gqrx.

Simply get rid of it with a modprobe config like /etc/modprobe.d/airspy.conf

blacklist airspy

You need some deps: the airspy lib, gnuradio-osmosdr (gr-osmosdr) and a recent gqrx

Here are my Arch AUR pkg that will build airspy-git, gr-osmosdr-git and gqrx-git (note that you need to uninstall the packages from community to avoid conflict).

Have fun

28 Nov 2014, 20:29

FreeBSD on Google Compute Engine

First you need to create a VirtualBox FreeBSD install using a 10G qcow format, use an SCSI controller for the install as the disk will be visible as da0 inside GCE.

On FreeBSD 10.1 I had to load virtio manually, so set this in /boot/loader.conf


Copy your ssh key in your home user .ssh/authorized_keys, be sure to be in the wheel group.

On a Mac you need to install GNU tar (brew install gnu-tar), shutdown your VirtualBox vm and upload your image to GCE

`VBoxManage clonehd -format RAW ../VirtualBox\ VMs/FreeBSDGCE/BSDGCE.qcow
gtar -Szcf freebsd.tar.gz disk.raw
gsutil mb gs://bsdimage
gsutil cp freebsd.tar.gz gs://bsdimage/gce-bsd.tar.gz
gcutil addimage freebsd  gs://bsdimage/gce-bsd.tar.gz`

You should now see “freebsd” as available install image in your console

28 Jul 2014, 17:36


APRS is a tactical digital communications system used between amateurs radio, to exchange positions & messages, here I blog my experience decoding/encoding APRS with a small Arduino as it may help some of you too.

Some transceivers are incorporating this functionalities but most of them don’t, a lot of new technicians start with cheap Baofeng radios (30$) which don’t provide advanced functionnalities but here is a way to solve that.

I’ve first looked at Bertos project, a realtime os for micro controllers as Atmel 328p (Arduinos), you can see my 1st attempt there:

This was the receiver only, a simple divider, the “hard” part was to understand the Baofeng/Kenwood mic jacks.

It takes me a long time to figure out that the Baofeng was too slow to trigger the squelch, so the Arduino missed the beginning of the message, hopefully I have a Kenwood too …

So for a Baofeng using this kind of APRS decoder, you have to disable the squelsh completly, and set the volume very high it has to reach a proper signal on the arduino around -3v/+3v.

For the AFSK modulation, the Bertos project use a DAC made with 4 resistors.

Later, I’ve discovered the wonderful work of Mark Qvist MicroAPRS, mostly the same circuit as the Bertos project but with an awesome documentation of the code, it’s a pleasure to read & learn.

So I’ve started to work on a circuit using a Bluno Nano an Arduino Nano with Bluetooth Low Energy, as an iPhone developer, this piece of electronics is just incredible and gives me the capabilites to connect my circuits to iphone Apps.

It’s working but hardly a mobile solution :)

Later I’ve designed a PCB for it you can find the full Gerber files in my Github.

I’m using Frizting to design and then export to OSHPark for the PCB manufacturing, it’s far from perfect but I will improve the circuit and publish it soon !

This plus an iPhone app and you’ll rock APRS !

73 de KK6NXK

08 Jul 2014, 01:22

Got my amateur radio license KK6NXK

When I was a young child, I remember listening to an old radio receiver with my grandfather, looking for morse transmission.

30 years later, I take the opportunity to get my radio amateur license in the US, it was not difficult (Technicial license is easy), especially cause US radio amateurs are using the metric system (almost all the time …), the only difficulties were to learn some terms and simple formulas from french to english and to know some parts of regulation by heart (I have never been able to learn by heart).

A lot of people keep asking me why are you doing this? Do you want to speak to a microphone to a stranger?

First why not, it’s not the craziest thing I’ve ever done :)

Then they probably have forgotten that every single piece of technology today are using radio waves, from your 4G phone to wifi to Bluetooth, learning and understanding that is really useful.

For example Radio amateur bands overlap some of the “civil” bands, it gives some extended privileges to a radio amateur to experiment with long distance wifi transmissions.

So it’s not just about voice but data too.

Another aspect is electronic, a lot of radio amateur are sharing hardware and electronic circuits to build your own receiver/transceiver, before it was cool on the Internet.

Learning electronic to build something real is a lot more rewarding than it was at school…

Even without a license this is a brand new world to explore, receiving satellite images of the Earth is one of the many possibilities you can get entering radio world.

This is the beginning of a new knowledge branch to conquer !

See my work on an APRS bluetooth Modem

73 de KK6NXK

By the way in french it’s radio amateur and not amateur radio :)

19 Feb 2014, 05:05

FreeBSD 10 on Dedibox SC gen 2 or any remote server with a rescue shell

FreeBSD 10 is out and it’s time to replace your Linux boxes cheeky

SC gen 2 is a VIA U2250 with 2Gb memory.

Start the rescue shell in amd64 12.04 Ubuntu, connect to the box via SSH with the temporary password

sudo -s
cd /tmp
wget http://ftp1.fr.freebsd.org/pub/FreeBSD/snapshots/ISO-
apt-get update
apt-get install qemu-kvm

sudo qemu-system-x86_64 -no-kvm -hda /dev/sda -cdrom ./FreeBSD-10.0-STABLE-
amd64-20140216-r261948-disc1.iso -net nic,model=e1000 -vnc :1,yourpassword
-boot d

This install qemu and run the FreeBSD installer from the downloaded CD.

Run a VNC client on your computer and connect to your dedibox ip, you should watch FreeBSD boot from the CDROM.

Complete a normal installation, at the end it will ask if you want to run a shell **answer is YES **and then type this to reinstall the bootloader.

If you are using UFS (default)

fdisk -B -b /boot/boot0 /dev/ada0

If you are using ZFS:

gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 1 ada0

Type exit and reboot to the normal mode.

Happy FreeBSD !

Further notes:

  • If you are not using ZFS, you can enable softupdate and TRIM as the SC gen 2 contains an hybrid SSD, you should theoretically have better performance
  • The last fdisk command is not the normal process but it was the only way I get it boot
  • Do not use qemu with KVM as there is a bug with this particular cpu, so yes the installation will be dead slow
  • The DHCP won’t answer it’s ok

30 Jan 2014, 17:37

FreeBSD on RaspBerry Pi

FreeBSD images for arm are now built from the FreeBSD Foundation ! So it’s an easy process to get it on your Pi.

Download your image from the ftp repository

Insert a 4Gb or more SD card in your PC and copy the FreeBSD image into it, here are the commands for a Mac:

sudo diskutil list​
sudo diskutil unmountDisk /dev/disk1​
sudo dd if=/Users/akh/Downloads/FreeBSD-10.0-STABLE-arm-
armv6-RPI-B-20140127-r261200.img  of=/dev/rdisk1 bs=1m​
sudo diskutil eject /dev/disk1​

Boot your pi with the card and welcome to FreeBSD !

If you are using the wifi dongle from Adafruit this may help:

echo legal.realtek.license_ack=1 >> /boot/loader.conf
echo wlans_urtwn0="wlan0" >> /etc/rc.conf
echo ifconfig_wlan0="wpa DHCP" >> /etc/rc.conf`

And set your wifi password with wpa_passphrase

wpa_passphrase yourssid yourwifipassword >> /etc/wpa_supplicant.conf