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By Date: October 2019

Deep Human Super Skills for a VUCA world


We live in a world dominated by volatility, uncertainty, complexity and ambiguity (VUCA). Our traditional approach to a working career, learning a specific skill and stick to it, doesn't fit anymore. What is needed instead, is the subject of the book Deep Human writen by Crystal Lim-Lange and Dr. Gregor Lim-Lange.

5 skills

5 human super skills

The 5 skills build on each other, forming the foundation and prerequisite for the next level. Here is my take, paraphrasing what I learned, how they fit together. Full details, including experiences how to get there are in the book.

  1. Mindfulness Being rooted in reality, seeing what is, without judgment and deep filters is the foundation of any progress. The practise of precisely observing your suroundings allows you to gather evidence for any assessment and action. The mindful person is master of their thoughs and doesn't fall prey easily to illusions. Of course it takes lifelong practise. The mind is like a muscle: once you start or stop training, it changes

  2. Self-Awarness Once the mind has been sharpened and silenced, you can turn attention to the self. What are the sensations, emotions, thoughts, fears, hopes and believes that drive you? Armed with focus and mindfulness you can wrestle the driver's seat back from the monkey mind. Clarity about yourself leads to freedom to decide who you want to be instead of running on auto-pilot

  3. Empathy Having honed the skill of self-awareness you can apply that to other sentients. Without clarity about yourself, this would fail, so self-awareness is the foundation of empathy, as mindfulness is the foundation of self-awareness. Learning to walk in someone elses shoes deepends your understanding of a complex world. Empathy isn't a woolsy-shoolsy be nice to everybody feeling, but the application of reality from a different viewpoint. As the late Lama Marut would say: "Be nice and don't take shit"

  4. Complex communication You are able to see things as they are, you recognise strength and weaknesses in yourself and others. You value reality over opinions and solutions over debate. Skilled like this, explaining the not-so-simple, cutting to the chase, getting your point across becomes your next level. You won't get there without the foundation of Empathy, Self-Awareness and Mindfulness

  5. Resillience and Adaptability Life changes, subtle or sudden, minimal or radical. You have practised to communicate clearly, see reality from different perspectives as it is and know yourself. These skills and the resulting confidence enables you to face whatever comes your way. Not clinging to illusions makes you flexible like the bamboo in the wind. You will clearly see what is needed and where you can find purpose. You adapt.

The whole book is an insightful and interesting read, so go and get your copy.


Posted by on 27 October 2019 | Comments (0) | categories: After Hours Singapore

A certificate wants a SAN


Following my recent blog about creating you own CA you will find out, like I did, that the certs are quite wanting.

The Subject Alternate Name (SAN)

Even after importing the ca-chain.cert.pem into your keyring / keystore Chrome will barf at the certificate, complaining about a missing SAN.

The idea of a SAN is to allow additional name variations to be recognised for one given certificate, reducing the effort for multi-purpose servers. E.g.: myawesomesite.com, www.myawesomesite.com, myawesomesite.io, www.myawesomesite.com, crazydata.com

I tried really hard, but at the time of writing, it seems the only way to create SAN for your certs is to provide a configuration file. I didn't find a command line option (short of various attempts on redirection and pipeing).

The hack I came up with:

Edit the intermediate\openssl.cnf and add to the [ server_cert ] section one line: subjectAltName = @alt_names. The @ sign tells OpenSSL to look for a section with that name and expand its content as the parameter.

Using the following shell script generates a certificate that works for:

  • www.domain (e.g. www.awesome.io)
  • domain (e.g. awesome.io)
  • domain.local (e.g. awesome.io.local)

The last one is helpful when you want to try SSL on localhost and amend your hosts file to contain awesome.io.local

#!/bin/bash
# Create new server certificates with the KEEP intermediate CA
if [ -z "$1" ]
  then
    echo "Usage: ./makecert.sh domain_name (without www) e.g. ./makecert.sh funsite.com"
    exit 1
fi
export SSL_DOMAIN_NAME=$1
export CONFNAME=intermediate/$1.cnf
cat intermediate/openssl.cnf > $CONFNAME
echo [alt_names] >> $CONFNAME
echo DNS.0 = $SSL_DOMAIN_NAME >> $CONFNAME
echo DNS.1 = www.$SSL_DOMAIN_NAME  >> $CONFNAME
echo DNS.2 = $SSL_DOMAIN_NAME.local  >> $CONFNAME
openssl ecparam -genkey -name prime256v1 -outform PEM -out intermediate/private/$SSL_DOMAIN_NAME.key.pem
chmod 400 intermediate/private/$SSL_DOMAIN_NAME.key.pem
openssl req  -config $CONFNAME  -key intermediate/private/$SSL_DOMAIN_NAME.key.pem -new -sha256 -out intermediate/csr/$SSL_DOMAIN_NAME.csr.pem
openssl ca -config $CONFNAME -extensions server_cert -days 375 -notext -md sha256 -in intermediate/csr/$SSL_DOMAIN_NAME.csr.pem -out intermediate/certs/$SSL_DOMAIN_NAME.cert.pem
chmod 444 intermediate/certs/$SSL_DOMAIN_NAME.cert.pem
openssl pkcs12 -export -in intermediate/certs/$SSL_DOMAIN_NAME.cert.pem -inkey intermediate/private/$SSL_DOMAIN_NAME.key.pem -out intermediate/private/$SSL_DOMAIN_NAME.pfx -certfile intermediate/certs/ca-chain.cert.pem
rm $CONFNAME

This will settle the Subject Alternate Name challenge. There are a more challenges to be had. Depending on what application you use, you need to import your intermediate keychain ca-chain.cert.pem in multiple places in different formats (Remember, I urged you not to do that in production!).

On Mac and Linux you have a keychain, but NodeJS and Java don't recognize them. Edge (and its older sibling) have their own key store, as has Firefox. Python, depending on version and library, has its own ideas about keys too. So manual management is a PITA.

As usual YMMV


Posted by on 26 October 2019 | Comments (0) | categories: OpenSource WebDevelopment

Create your own Certificate Authority (CA)


Warning Do NOT, never, ever do that to a production system!

Promised? OK! Here's the use case: you want to test your systems that have made up addresses like awesomeserver.local and don't want to deal with certificate warnings or fancy errors that arise when you just use a self signed cert. This post is a self-reference for my convenience. There are ample other instructions out there.

Disclaimer: I mostly followed this instructions short of updating some of the commands to use elliptic-curve cyphers.

Useful with a side of work

The process requires a series of steps:

  • Create the private key and root certificate
  • Create an intermediate key and certificate
  • Create certs for your servers
  • Convert them if necessary (e.g. for import in Java Keystors JKS)
  • Make the public key of the root and intermediate certs available
  • Import these certs in all browsers and runtimes that you will use for testing

Normal mortal users, without these imports will get scary error messages. While this doesn't deter the determined, it's good for a laugh.
We don't want old school certs, so we aim at a modern Elliptic-curve cert (Details here). Here we go:

Setting up the directory structure

mkdir -pv -m 600 /root/ca/intermediate
cd /root/ca
curl https://jamielinux.com/docs/openssl-certificate-authority/_downloads/root-config.txt -o openssl.cnf
curl https://jamielinux.com/docs/openssl-certificate-authority/_downloads/intermediate-config.txt -o intermediate/openssl.cnf
mkdir certs crl newcerts private
chmod 700 private
touch index.txt
echo 1000 > serial
cd intermediate
mkdir certs crl csr newcerts private
chmod 700 private
touch index.txt
echo 1000 > serial
echo 1000 > crlnumber
cd ..

You want to check the downloaded files and eventually change the path in case you have chosen to us a different one.

The Root CA

export OPENSSL_CONF=./openssl.cnf
openssl ecparam -genkey -name prime256v1 -outform PEM | openssl ec -aes256 -out private/ca.key.pem
chmod 400 private/ca.key.pem
openssl req -config openssl.cnf -key private/ca.key.pem -new -x509 -days 7300 -SHA384 -extensions v3_ca -out certs/ca.cert.pem

Keep them save - remember: its on my harddrive only isn't save!!!
You want to check the file using openssl x509 -noout -text -in certs/ca.cert.pem or on macOS just hit the space key in finder.


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Posted by on 16 October 2019 | Comments (0) | categories: Domino WebDevelopment

What's on your gRPC wire, Protocol Buffers or JSON?


The hot kid on the block for microservice APIs is gRPC, a Google developed, OpenSource binary wire protocol.

Its native serialization format is Protocol Buffers, advertised as "Protocol buffers are a language-neutral, platform-neutral extensible mechanism for serializing structured data". How does that fit into Domino picture?

Same same, but different

When old bags, like me, hear the word RPC a flood of memories and technologies come to mind:

  • DCOM Microsoft's take on: like Java, but Windows only, superceded by WCF for dotNet
  • Corba a standard defined by a commitee, mainly Java (and YES Domino still ships with a Corba Server)
  • SOAP with our beloved (or was the word: cursed?) WSDL

There are a few more modern contenders like Apache Thrift, Apache Avro or the KF - TEE. Good to have so many open standards.

the good

Especially with SOAP the common reaction to the rise of REST was: Good riddance RPC. I'm using the term REST fast and loose here, since a lot of the APIs are more like "http endpoints accepting JSON payloads" rather than REST in the formal sense of the definition.

So what's different with gRPC, so it got adopted by the Cloud Native Computing Foundation? IMHO there are several reasons:

  • It is designed by really smart engineers to run up to Google scale
  • It is ground up optimized, not bothering with legacy, but betting on HTTP/2 and its wire efficiencies
  • It is a compact binary protocol, making it efficient in low bandwidth and/or high volume use cases (Google scale anyone)
  • It transmits data only, no repeated meta data as in JSON or XML based approaches (at least when you use Protocol Buffers)
  • It focused on code generation, functioning more like an SDK than an API
  • It has versioning support built in
  • It uses rich structured data types (15 on last count) including enumerations. Notably absent: date/time and currency

And of course: it's the current fashion. RedHat provides a compehensive comparison to OpenAPI, as do others. Poking around YouTube I gained the impression, that most comparisons are made to REST and its limitations, almost similar to sessions about GraphQL. Mr. Sandoval tries to describe differentiators and use cases, go read it, it is quite good.


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Posted by on 15 October 2019 | Comments (0) | categories: Domino gRPC WebDevelopment

A calDAV reference server


After having a look at the many standards involved, it is time to check out a standard or reference implementation. Cutting a long story short: it looks to me the OpenSource Apple Calendar and Contacts Server (ccs) is my best bet. While the documentation is rather light, it has been battle tested with my range of targeted clients

To Docker or to VM?

Trying to avoid the Works on my machine certification, a native install was out of the question. So Docker or VM? A search yielded one hit (with explanation) and none for for a ready baked VM. On closer inspection, the docker image, being 2 years old, didn't use the current version, so we had to re-create the image. While on it, I decided to give a VM a shot:

Apple calendar server on Ubuntu 18.04

To keep things light, I started with the current LTS version 18.04 desktop and a minimal install with 4G RAM. First order after the install is to get updates and install modules for the VirtualBox extensions:

sudo apt update
sudo apt install gcc make perl
sudo apt dist-upgrade

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Posted by on 11 October 2019 | Comments (0) | categories: calDAV Domino

The calDAV Standard - navigating the RFC jungle


Application interoperability is key to wide spread adoption. Luckily there are so many open standards that one can claim to be open without being interoperable. On a protocol level HTTP and SMTP were huge successes, as well as HTML/MIME for message content. Beyond that it gets murky. None of the big vendors (outside the OpenSource space) has adopted an open protocol for chat and presence.

For other standards, most notably Calendaring, support is murkey. On key contributor might be the RFC process that produces documents that are hard to follow and lack sample implementations. They are work outcomes of a committee after all. In this series of blog entries I will (try to) highlight the moving parts of a calendar server implementation. The non-moving parts here are the calendar clients to target: Apple calendar on iOS and macOS, Thurnderbird and a few others.

Involved standards

There is a series of RFC that cover calendar operation, with various degrees of relevance:

  • RFC 4918: webDAV. Defines additional HTTP verbs and XML formats
  • RFC 4791: calDAV. Defines again additional HTTP verbs
  • RFC 5545: iCalendar. Calendar data as plain text, or XML or JSON
  • RFC 7953: vAvailability. Free/Busy lookup specification
  • RFC 7986: Extended properties for iCalendar
  • RFC 6638: Scheduling extensions
  • RFC 8607: Managed attachments in calendar entries
  • RFC 8144: Use of Prefer Header field in webDAV
  • RFC 5785: Definitions for the /.well-known/ URL

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Posted by on 09 October 2019 | Comments (0) | categories: calDAV Domino