Published

britishearways.com

Screenshot of britishearways.com

Last month, I completed a major overhaul of the British Earways website. The design by Valerio di Lucente of Julia is almost entirely unchanged, the adjustments were largely performance-related and under the hood, geared towards modern browsers. Here’s brief rundown of the changes:

  • Style the full-window player layouts using CSS Grid Layout + 100% height (not 100vh since that can lead to unexpected behaviour on mobile browsers), and use CSS Scroll Snap w/ polyfill for scroll behaviour
  • Achieve flexible typography and spacing with “CSS Locks
  • On non-touch screens, implement invisible DragDealer instances so that each player’s scrubber can be dragged
  • On touch screens, add click event listeners that advance the relevant scrubber to the click target
  • Use styled HTML5 progress elements for each player since these are easily manipulated via their max and value attributes and don’t require adjustment if the window is resized
  • Use the Web Audio API to initialise each audio file and trigger the necessary state changes as the time updates
  • Switch the audio preload attribute from auto to metadata to reduce the size of the page when it initially loads
  • Update CMS to Kirby 3 (this was a joy, IMO the panel layout options make v3 much more client-friendly)
  • Adjust post_max_size, memory_limit, max_execution_time, and upload_max_filesize to allow upload of large (150MB+) audio files

I ran in to one issue that isn’t yet resolved. Kirby copies all uploaded media from the private /content folder to the publicly-accessible /media folder. This copying normally happens almost instantly, even with very large files. On the BE site however, the copy is pretty slow. Since the site pulls the audio duration from the audio file itself via the Web Audio API, the displayed duration is incorrect until the file has finished copying. This is almost certainly related to some rate limiting done by the shared hosting company, a legacy from the preexisting site. It isn’t a huge deal since the copying always finishes eventually, but it isn’t the best behaviour. I’d like to raise the issue with the hosting company but don’t have high hopes, shared hosting providers use rate limiting for a reason.

At any rate, I’m really looking forward to seeing how DB uses the site over the next year and listening to the new mixes.

Published

TODOs: automation, films, pens, reading, etc.

This week has been absolute chaos. Good though! A few things to remember, and to follow up on.


I keep coming across Automate the Boring Stuff, and keep forgetting to look in to it. Python was the first language I learned back in college with Prof. Maxwell, so would be nice to revisit it.

Same thing with films like Idiocracy and The Skeleton Twins. Made a mental note to see them years ago and then promptly forgot, so I’m noting them here as an ever-so-slightly more effective reminder. Idiocracy seems particularly weird, on paper it should have been a huge hit but it got absolutely sidelined by Fox and was screened in the bare-minimum of theaters. The reviews are crazy mixed. Still, I’d like to see it.

Something I *have* watched recently on SB’s recommendation is the BBC’s Ghosts. It’s hilarious and completely charming, a lot of the same faces as the original Horrible Histories but a completely different format. I’d watch the whole thing again, hope they do another series.

Last weekend was Offprint book fair in the Turbine Hall at the Tate, and probably my last event with OP. It was nice to see a few familiar faces including the guys at Here Press. Richard Hollis did a talk to a full house on his newest book about Henry van de Velde followed by a book signing at OP’s table. It was nice to see him again. He was using a blue Uni-ball Air for the signing. I’m going to keep my eye out for that one in the stationery shops, it’s a ball point that writes like a fountain pen (line thickness varies with pressure, but very little risk of leaks). The price seems super reasonable, the web’s retail giant offers a three-pack for just under £5.

GC recommended The Mushroom at the End of the World, and if there’s anyone I trust to give me great book recommendations, it’s her. I’m just hoping it leans towards the glass-half-full end of things, I’m not sure I can take more pessimism right now.

I might have a little bit of downtime while travelling over the next few weeks. If I do, I’m hoping to spend a little time looking in to Commotion, “a free, open-source communication tool that uses wireless devices to create decentralized mesh networks”. Could use SiteSucker to grab all of the docs before I leave for offline reading. I came across Commotion for the first time via a link to Learn Networking Basics from Measurement Lab’s learning resources.

Big data? No thanks

Gandi published a long blog post titled “Mass manipulation and platform privacy: where we’re at”. It’s summarises some talks and Gandi’s perspective following a conference on “democracy in the face of cybersecurity threats”. I’d like to follow up on a few of the points from the post. I’d also like to find out what public educational efforts are under way. Surely someone is working on PSA-style messaging about the dangers of misinformation and how to identify it. It’s easy to be skeptical about that sort of thing, but it can stick. What’s the cyber-awareness version of “Only you can prevent forest fires” or “A slip of the lip will sink a ship”? James Bridle’s “Big data? No thanks” is related, but the version I’m talking about is more personal, about confronting your own confirmation bias. But not too ominous, also catchy and friendly? Tall order.

Every time I sit down on the tube I wonder about what other people see when they look at me, what they perceive about me precisely because they are *not* me. There is this slippery divide when it comes to understanding yourself. There are elements of yourself that you can never understand since it’s impossible to get outside your own head (one of the reasons that talking to someone else about a problem can be so helpful). There are other things about yourself that only you can ever understand, no matter how much time you spend attempting to express that thing. I have trouble articulating why this feels like a catch, but surely someone out there has tried. Just need to find them.

Published

Could NemID exist in other countries? And should it?

Front of a NemID card

Last Monday, I met with some friends at the Cock in Hackney. One of them had just returned from Copenhagen and mentioned having to sort out something related to his NemID. I’d never heard of it before.

Apparently NemID is a common login tool that Danish residents use to access online banking and services offered by public institutions. It’s a little credit card-sized booklet of 148 key pairs that you use alongside a user ID and a password. It’s like an analogue version of two-factor authentication. Each time you log in to something with NemID, the key pair you use is invalidated and is never used again. When you’ve used up all of your key pairs, you’re sent a new NemID booklet.

It seems like a great system. Unlike biometric data, it would be easy to replace if it were compromised. Unlike most other two-factor authentication methods, it doesn’t require an additional (usually smart) device of some sort.

There are downsides though. NemID is administered by a single organisation, Nets DanID A/S, and all of the data seems to be held in one place. This was a problem in 2013 when a DDoS attack knocked it offline temporarily. The oversight also seems pretty iffy, see this January 2016 blog article: “NemID is not cryptologically secure – and the authorities do not care”.

It’s also hard to say how this could be rolled out in countries with larger populations… Denmark’s population is around 5.7 million. That’s a bit more manageable than the UK (~ 66 million), Brazil (~ 209 million), or India (~ 1.3 billion).

Apparently NemID is going to be replaced by MitID in the next few years, so it will be interesting to see if the Danish government forces any changes to make the system less centralised.

And it makes me wonder (again) if something like Dark Crystal could ever work on a national scale.

Published

Seviyan kheer, or spiced rice noodle pudding

We made some vermicelli (rice noodles) for dinner the other day and came across a recipe for seviyan kheer on the packet. I’d never heard of it. Since we had leftover noodles and wanted something sweet, I gave it a try following this seviyan kheer recipe on vegrecipesofindia.com. Differences: I omitted the almonds and rose petals, used oat milk, and fried the leftover, chopped-up cooked noodles instead of broken raw noodles. It was really tasty! A lot like rice pudding, but better IMO.

Published

Assertive Californian seeds

Graphite drawing of a filaree seed

In southern California, there are a few seeds that assert themselves in late summer as things get drier. A lot of prickly, pointy things that stick to you or make themselves known in more painful ways.

Graphite drawing of dried burclover

A few of them were fun to play with as a kid. If you pick at the center of a dry burclover seedpod and pinch the end of it in your fingers, you can pull it away until all that’s left are a few seeds and one long coil of tiny spikes. Filaree seeds wind up tight to make a little drill when peeled away from the plant. And you can make foxtails travel on their own if you put your forearms together from wrist to elbow, hands facing up, and then have a friend place one on your wrists with the point facing you. Rub your forearms back and forth and it will travel down your arms.

Graphite drawing of puncturevine or Goats Head seed

But some seeds were just annoying. If you went for a walk through a field, chances are you’d come out with your socks and shoelaces absolutely covered in hedge parsley hitchhikers. Sandbur and puncturevine were the worst. Puncturevine has a few other nicknames. Goat’s Head, for the shape of the seed pod sections, and caltrop. It often grows on the dry, sandy areas near the beach making it particularly perilous for the bare-footed.

Published

Setting up a Raspberry server + daemonized Homebase for pinning Dat websites

This suite of tutorials is the result of a recent Agorama Server Co-op workshop day. They cover how to set up a Raspberry Pi, how to use an Ansible playbook to easily get a Pi set up as a server, and how to run Homebase on a Raspberry server.

A Raspberry Pi 3 Model B+


Introduction

Mise en scène

For almost all of the tutorials below, you’ll need: a computer, a Raspberry Pi, a power supply for your Pi (read more), an SD card appropriate to your requirements (read more), and an SD card reader. You may also find an ethernet cable useful if your Pi has an ethernet port.

Personally, I’m working with: a 15ʺ MacBook Pro with an SD card port; a Raspberry Pi 3 Model B+; a SanDisk Ultra 16GB micro SD card with an 80Mbps read speed that came with a microSD adapter; and the charger from an old Android phone.

Glossary

Some of these tutorials are like a mini crash course in server administration. You don’t need to know much to get started and mess around, but it is useful to be aware of a few terms. If you’re unfamiliar with any of the terms used, see below for very brief explanations.

Ansible
An IT automation tool
Beaker
Primarily a browser for Dat and HTTP/S websites; also offers website seeding and other features
booting
The startup sequence that happens when you turn on a computer
command line
A text interface where you can write in commands for your computer; on a Mac, you can open the command line by firing up the Terminal application
daemon
A computer program that runs as a background process; most people pronounce it “DEE-muhn”
Dat
A peer-to-peer protocol for sharing websites, files, and other data over the internet
Etcher
Software that can be used to flash OS images on to SD cards or USB drives; a free and open-source Electron app developed by Balena
flashing
To update a drive with a new program such as an operating system
Git
A version control system widely used by programmers and web developers
Homebase
“A self-deployable tool for managing websites published with the Dat protocol”; by the Beaker team
image
A serialized copy of an entire computer system stored safely in a file
IP address
A series of numbers separated by periods that is assigned to each computer connected to a network
mount
Making a drive such as an SD card or an external hard drive accessible to your computer; in theory, all you should usually have to do to mount a drive is plug it in to your computer
Nano
A simple command line text editor; for more complex editing, emacs or vi may be preferable
operating system (OS)
System software that manages a computer’s software and hardware; if you compared all of the software on a computer to a house, the OS would be the foundations
pinning
Synonymous with seeding or hosting for Dat sites; read more in the Beaker documentation
pip
Python package manager
playbook
A defined set of scripts and variables used by Ansible for server configuration
Python
A programming language
Raspbian
The Raspberry Pi Foundation’s officially supported operating system
root (directory)
The top-level directory in a filesystem; if you compared the filesystem to a family tree, the root would be the oldest ancestor at the very top of the tree
root (user)
The user with administrative privileges; it’s a powerful user so should be kept very secure
SD card
A memory card often used in portable devices; SD stands for “secure digital”
service
With computers, a service is usually a program that runs in the background; if you were to compare a computer with a human, you might compare a service to breathing
SSH
A protocol for connecting to a server securely over a potentially insecure network; SSH stands for “Secure Shell”
SSH key
An SSH key is used to log in to SSH; it is considered much more secure than a simple username + password combo
user
With servers, a “user” is an account with a particular set of privileges and permissions
wpa_supplicant
Cross-platform software that implements WiFi security protocols including WPA and WPA2; the wpa_supplicant.conf file configures wpa_supplicant

Set up a Raspberry Pi for the first time

Flash Raspbian on an SD card using Etcher
  1. If you don’t already have it installed, download and install Etcher.
  2. Download your preferred Raspbian image as a .zip file. If you will only be using the Raspberry Pi as a server, such as with Homebase, you may wish to go with Raspbian Lite.
  3. Plug your SD card in to your card reader so that it mounts on your computer.
  4. Flash the Raspbian image on to your SD card by opening the downloaded image in Etcher, selecting your mounted SD card, and then clicking flash. Use caution. Flashing will overwrite anything on the selected drive. If you accidentally select an external hard drive instead of your SD, you’re going to have a bad time.
  5. When Etcher is done, remove the SD card. It should have been unmounted as part of the flashing process, but double-check before you pull it out of the card reader.

Flashing the Raspbian image on to an SD can be done manually instead of using Etcher. For further info, see the base of the “Installing operating system images” page on raspberrypi.org.

If you want to connect the Pi to a WiFi network or enable SSH, complete those steps before booting the Pi.

Connect a Raspberry Pi to WiFi on the command line

This tutorial assumes you have flashed Raspbian on an SD card but have not yet booted the Pi. If you have already booted the Pi, see instructions on how to change the existing WiFi configuration on the command line.

Plug your SD card in to your card reader so that it mounts on your computer.

Open the command line and run:

nano /Volumes/boot/wpa_supplicant.conf

This will open a blank file using nano. Paste in the configuration below:

country=gb
update_config=1
ctrl_interface=/var/run/wpa_supplicant

network={
  scan_ssid=1
  ssid="YOUR_NETWORK_NAME"
  psk="YOUR_NETWORK_PASSWORD"
}

Be sure to change the ssid and psk values to your WiFi network name and password respectively. The country value should be set to the ISO 3166-1 alpha-2 code for the country the Pi is in.

If you are planning to use the Raspberry Pi on a few networks, you should add any other required networks to this file as so:

country=gb
update_config=1
ctrl_interface=/var/run/wpa_supplicant

network={
  scan_ssid=1
  ssid="YOUR_NETWORK_NAME_1"
  psk="YOUR_NETWORK_PASSWORD_1"
  priority = 1
}

network={
  scan_ssid=1
  ssid="YOUR_NETWORK_NAME_2"
  psk="YOUR_NETWORK_PASSWORD_2"
  priority = 2
}

When you are done editing the credentials, save the wpa_supplicant.conf file and close Nano.

If you want to enable SSH but haven’t yet done so, complete that step before you boot the Pi for the first time.

When you are ready to boot the Pi for the first time and test the WiFi connection, insert the SD card in the Raspberry Pi and plug the Pi in to a power source. Give it a minute or two, then view the devices on the network. If the Pi shows up, you’re ready to go.

If you are planning to use the Raspberry Pi as a server, such as to run Homebase, you may wish to keep it plugged in to the ethernet for a more stable connection.

Enable SSH on a Raspberry Pi

As of late 2016, Raspbian has SSH disabled by default. This is to protect users from accidentally making their Pi accessible to the internet with default credentials. This tutorial assumes you have flashed Raspbian on an SD card but have not yet booted the Pi.

Plug your SD card in to your card reader so that it mounts on your computer.

Next, open the command line and run

touch /Volumes/boot/ssh

This will create a new empty file titled ssh in the root of your SD card. This empty file will allow you to connect via SSH when the Pi is first booted.

If you get an error after running the touch command that says No such file or directory, check that your SD card has mounted correctly and check that Raspbian is installed on the SD card.

If you want to connect the Pi to a WiFi network but haven’t yet done so, complete that step before you boot the Pi for the first time.

Log in to a Raspberry Pi via SSH as the root user pi

This tutorial assumes you have already flashed Raspbian on an SD card, have enabled SSH, have connected the Pi to the internet via WiFi or ethernet, and have booted the Pi.

Open the command line and run:

ssh pi@raspberrypi.local

If this is the first time you are connecting via SSH then type in the default password raspberry. If you don’t plan to use Agorama’s Ansible playbook to configure your SSH credentials, you must change your default password by using the passwd command (read more). Keeping the default password in place and enabling SSH just invites bad guys to do shady things with your Pi.

If this is not the first time you are connecting via SSH, use the password you configured with passwd or the password you added to the Ansible playbook.

For security reasons, nothing will show on the screen while you are typing your password.

If nothing happens when you attempt to log in, your Pi may not be connected to the internet.

If you receive a Permission denied error, you will need to find the Pi’s IP address. View the devices on the network to determine the IP. Once you have the Pi’s IP address, try logging in as instructed above but replace raspberrypi.local with your Pi’s IP address. If you had to take this step, you may want to write down your Pi’s IP address for use in other steps on this page.

If you receive an error relating to the ECDSA host key changing, see the guidance below guidance below related to ECDSA errors.


Use Ansible playbook to configure Raspberry Pi server

About Agorama’s Ansible playbook

Agorama’s Ansible Raspberry server playbook automates a number of fiddly tasks that are required to get a Raspberry Pi set up as a server geared towards use with Homebase. You can get a feel for the tasks that will be performed by the playbook by browsing the files within the playbook, working backwards from all.yml.

As of late April 2019, the tasks performed by the playbook include:

  • Set up user accounts and apply basic updates & security
  • Prepare Raspberry Pi to run Node.js apps
    • Run nodesource.node
    • Create global package directory
    • Add global package directory to .npmrc
    • Add global package directory to PATH
  • Install nginx web server

Future tasks planned for the playbook include DNS configuration and HTTPS support.

Regardless of what method you use to set up a server, and no matter where the server “lives” – on a Raspberry Pi, a DigitalOcean droplet, or anywhere else – the most important thing to remember is that it is your responsibility to keep it secure and up-to-date.

Install Ansible and get the playbook

This tutorial assumes you have Python, pip, and git installed on your computer.

Open the command line.

Install the Python packages Ansible and Passlib by running:

pip install ansible passlib

Next, clone Agorama’s ansible-raspberry-server repository:

git clone https://github.com/agoramaHub/ansible-raspberry-server.git

and change directories in to the root of that repository by running:

cd ansible-raspberry-server

Now you are ready to add your SSH credentials to this Ansible playbook and configure a Raspberry Pi.

Add your SSH credentials and timezone to the playbook

This tutorial assumes you have already set up Ansible and the playbook. It also assumes that you have set up SSH keys (see tutorial on DigitalOcean).

Open the command line and change directories to the root directory of the cloned Ansible playbook by running the command below. Replace the path with the correct path on your computer.

cd /path/to/your/ansible-raspberry-server

To add your SSH key and change the password for the root pi user, run the command:

ansible-playbook 01-auth.yml

You will be prompted to add your public key path and set a password for the root user. The default key path should be fine unless you placed your public key somewhere other than the default path when you created it. Set the password to the password you would prefer to use when you log in to the root pi user via SSH. Note that you will not need to use this password often since you are adding your SSH key, however you will need it when you first run the playbook.

When you have finished answering each prompt, the output will be saved to vars/auth.yml with the password encrypted by passlib.

To check and edit the timezone, run:

nano vars/base.yml

to open the base variables file with nano. If you need to change the timezone, edit the ntp_timezone value and save this file.

Run the playbook

This tutorial assumes you have already set up Ansible and the playbook, have configured your SSH credentials in the playbook, have flashed Raspbian, have enabled SSH, have connected the Pi to the internet via WiFi or ethernet, and have booted the Pi.

Open the command line and change directories to the root directory of the cloned Ansible playbook by running the command below. Replace the path with the correct path on your computer.

cd /path/to/your/ansible-raspberry-server

When you’re ready, run the playbook:

ansible-playbook all.yml --ask-pass

If the command fails because it cannot find the Pi, you need to change the hosts file so that the script can find the Pi via its IP address. View the devices on the network to determine the IP, then run:

nano hosts

to open the hosts file with nano. Replace raspberrypi.local with your Raspberry Pi’s IP address. You may add additional Raspberry Pi IP addresses to this file if you want to run the playbook on multiple Pis. When you are done editing, save and close this file and then run the ansible-playbook command above again.

You will be prompted for the password you added to the playbook. If your SSH key is added and you can log in successfully then the playbook will proceed to configure the Raspberry Pi, logging tasks as they are performed.

Note: if you configured a passphrase for your SSH key when you set it up, you will be asked for this as well and will be asked for it each time you connect to your Raspberry Pi via SSH in the future. See this StackExchange thread for a few suggestions on how to avoid being asked for the passphrase every time.


Run Homebase on a Raspberry Pi server

Install dat and homebase

This tutorial assumes that you have set up a Raspberry Pi and have configured it for use as a server using Agorama’s Ansible playbook or via other means. It also assumes that your configured Raspberry Pi is on and connected to the internet and that you have logged in via SSH.

For security purposes, the Ansible playbook configures worker user on Raspberry server so that we’re not using the root user pi to install and run software. When you first log in with SSH you are logged in as the root user, so we need to switch to worker by running:

sudo su worker

Next, install dat:

npm install -g dat

Test whether or not the dat installation works with the Pi configuration by running:

dat doctor

When prompted, select the peer-to-peer test and send the command it returns to a friend that has dat installed. Ask the friend to run the command. If dat doctor returns successful, then you’re all good. Disconnect from dat doctor by typing ctrl + c.

Install homebase by running:

npm install -g @beaker/homebase

Change directory to the user root:

cd

and then create a Homebase config. Run:

nano .homebase.yml

to open up the Homebase config with nano, then paste in:

dats:
  - url: dat://01cd482f39eb729cdcbb479b03b0c76c6def9cfc9cff276a564a17c99c4432f4/
  - url: dat://b0bc462c23e3ca1fee7731d0a1a2dc38bd9b9385daa413520e25aea0a26237a6/
  - url: dat://f707397e8dacc1893dced5afa285bab1715b70fe40135c2e14aac7de52f2c6bb/

directory: ~/.homebase        # where your data will be stored

# For API service. Establish API endpoint through port 80 (http)
ports:
  http: 8080                  # HTTP port for redirects or non-TLS serving

This config will set up a pinning service without DNS support that pins three Agorama-related URLs. Feel free to replace them with URLs of your choice. Save and close the file when you’re done editing.

Next, run homebase:

homebase

The response should indicate success and that your URLs from the .homebase.yml file are being pinned.

If you get an error message here or when you ran dat doctor, you may need to check the configuration of your Raspberry Pi.

Daemonize homebase with systemd

This tutorial assumes that you have set up a Raspberry Pi, have configured it with Agorama’s Ansible Raspberry playbook according to the instructions above, and have installed dat and homebase on the Pi. It also assumes that your configured Raspberry Pi is on and connected to the internet and that you have logged in via SSH.

Daemonizing homebase means that it will constantly run in the background as long as the service hasn’t failed, the server is on, and the server is connected to the internet. This is important because the whole point is that we want the Dat sites specified in .homebase.yml to run in perpetuity.

First, add a service configuration for homebase. As the root user pi, run:

nano /etc/systemd/system/homebase.service

to open a new file with nano. Paste in:

[Unit]
Description=homebase

[Service]
Type=simple
ExecStart=/usr/bin/env .npm-packages/bin/homebase
WorkingDirectory=/home/worker/
Restart=on-failure
StandardInput=null
StandardOutput=syslog
StandardError=syslog
Restart=always
SyslogIdentifier=homebase
User=worker
Group=worker

[Install]
WantedBy=multi-user.target

This configuration file indicates (amongst other things) which user will run the service, where to find homebase, and whether or not to restart when the system is rebooted.

To start the service, run:

sudo service homebase start

To stop the service, run:

sudo service homebase stop

To read the logs, run:

journalctl -u homebase

If the service is running and is working as it should, you should be able to visit any of the URLs you added to your .homebase.yml config file in Beaker Browser.

NOTE
A few friendly folks have suggested pm2 for daemonizing Homebase (see Twitter thread). This is also what is suggested in the Homebase readme, and it’s what I used previously when getting Homebase set up on DigitalOcean. It worked great for me, but this time round we used systemd because two people at the workshop had rough experiences using pm2 with Homebase on a Raspberry Pi. I think it had something to do with a crazy amount of memory usage? Not 100% sure, I think we may cover this in a future workshop.


Related tasks, troubleshooting, and edits

Useful commands

These are very basic examples of some useful commands. Have a search online for more powerful examples.

To change directory:

cd preferred/directory

To list the files in a directory (omit directoryname if you want to list the files in the current directory):

ls directoryname

To display the contents of a file:

cat filename

To edit a file using nano (the file will be created in the current directory if it doesn’t exist):

nano filename

To reboot a Raspberry Pi, be sure you are connected via SSH as the pi root user and then run:

sudo reboot

To disconnect from an SSH session, type ctrl + d

It isn’t a great idea to just pull the plug on a Raspberry Pi to turn it off since it can cause problems with your SD card or the file system. To shut down a Raspberry Pi:

sudo shutdown -h now
View all devices connected to a network

It can be useful to view all devices connected to a network if you want to check your Raspberry Pi’s WiFi connection or need to identify its IP address.

You can use your router’s admin interface, the mobile app Fing, or the network scanning tool nmap to view a list of the devices connected to your network.

If you are trying to find a Raspberry Pi’s IP address and there are a lot of devices connected, you may need to use the list of devices and the process of elimination (i.e. turn devices on and off and see what disappears).

If the SD card will not mount

If you plug in an SD card and it will not mount, try to use your system tools such as Disk Utility to check for the drive. If that doesn’t work, try restarting your computer. If that doesn’t work, try different hardware such as a friend’s computer or an external card reader. I know at least four people with Macbook Pros that have dealt with defective card reader ports.

Fixing ECDSA error triggered at SSH login when a Raspberry Pi has been connected to a new network

If you added your SSH key using Agorama’s Ansible Raspberry playbook and then move your Pi on to a new network, you will probably receive an error relating to the ECDSA host key changing. The base of the warning message should indicate that you can fix this by adding the correct host key in ~/.ssh/known_hosts.

One way to resolve this is to re-add your SSH credentials to the Ansible playbook and then run the playbook so that your SSH keys are added again.

Changing the WiFi configuration for an existing Raspberry Pi on the command line

If you did not add your new network to your wpa_supplicant.config file when you first set up WiFi on your Pi, you will need to add your new network to this file.

If your Raspberry Pi does not have an ethernet port, it may be easiest to start from scratch (flash Raspbian on to the SD card and configure the wpa_supplicant.conf file).

If your Raspberry Pi has an ethernet port, connect it to the network via ethernet. Open the command line and connect via SSH, then run:

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

This will open up the wpa_supplicant.conf with nano. Scroll down the file and edit the network details as per the WiFi connection instructions above.

When you are done editing, save and close the file then disconnect your Raspberry Pi from the ethernet. To test the connection, check for the Raspberry Pi by viewing all of the devices connected to the network. If the Pi is not connected after a couple minutes, try rebooting the Raspberry Pi.

List of edits
  • 03.03.19 – Added note about pm2 to “Daemonize homebase with systemd” tutorial

Next steps include configuring HTTPS support, DNS support, and getting more familiar with the maintenance involved in this setup. I think there is also some complication involving DMZ and routers, but I’m very unfamiliar with those implications at this point. I have a feeling we’ll dig in to a lot of this during the upcoming Agorama Server Co-op evenings and workshops. See the Agorama site and their Twitter account for dates.

Thanks to the Agorama folks – organisers and fellow attendees – for a very fun workshop.

Published

Agorama #7: Raspberry Pis, SSH, Ansible, Dat, and Homebase

Raised wallpaper in Rebecca’s Flat at Raven Row, London

Saturday was an Agorama Server Co-op workshop day. A bunch of us spent the afternoon getting Homebase set up on various Raspberry Pis, a lot of trial and error! The main reference material we used was the README from Agorama’s ansible-raspberry-server repo, Agorama’s Dat Server Node Tutorial, and the brainpower of some of the more knowledgeable people present.

I learned a *lot* from the process and the people there, particularly Max, Ali, and Harry. I’m in the process of writing it all up in to a series of tutorials, will add it here.

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Published

Falafel wraps

Falafel wrap with chili sauce, lettuce, cucumber, pickled onion, and hummus

We made falafel wraps for lunch today using this falafel recipe from BBC Good Food. It was a decent, simple recipe that I’d be happy to use again with a few caveats:

  • The title says “spicy” but there is no heat in it… might actually be good to add some cayenne next time
  • Use the softest canned chickpeas you can find; East End brand is the softest I’ve found in London (and super cheap)
  • Use all of the parsley, stems and all, and chop it super fine
  • Chop the onion very fine, and cook the onion and garlic in olive oil instead of veg oil
  • Add a good pinch of salt (it says “seasoning to taste” but it’s kind of easy to miss that)
  • Half a beaten egg is plenty, any more and it would be way too wet
  • Use two large-ish spoons to ease decently-sized dollops in to the pan since the mixture is too wet to shape in to patties

We had it with pickled red onions (red onions + red wine vinegar + sugar + salt), shredded lettuce, diced cucumber, yogurt, this hummus, and some leftover chili sauce from the best Turkish place in Leyton.

Maybe not quite up to the standard of the guys on Ridley Road Market, but pretty good! To get closer to theirs, we’d need a spicier chili sauce and more tangy pickles.