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Generating a Preview on LeanPub Using Rake

While working on the e-books I published on LeanPub, I have developed a number of useful approaches to get fast(er) feedback on how the book looks. Two earlier blog posts describe some of this:

While this provides a nice feedback cycle, sometimes I like to generate a new preview without pushing to the GitHub repository I am using to share the book content with LeanPub. This happens, when I change settings on the Leanpub site that affect the generation of the book (the title image, font faces and sizes are set via the book’s pages on LeanPub, not a configuration file in the repository).

While I could click thought the UI and navigate to the page where I can generate a new preview, I prefer using a command line tool from my local machine: Rake

The Setup

A warning: The LeanPub API documentation says: “Using the Leanpub API requires a Pro plan.

To use the LeanPub API, an API key is needed. The link to the API documentation above has information where to get that key. To easily use this API key, I store it in an environment variable LEANPUB_API_KEY.

The Rake Task Definition

In the repository of my book I have a Rakefile containing the task definitions. Here’s the one to trigger the generation of a preview on Leanpub:

require 'rest-client'

namespace :leanpub do
  LEANPUB_BASE_URL = "https://leanpub.com/<book_id_on_leanpub>"
  namespace :preview do
    desc "Generate new Preview on LeanPub"
    task :generate do |t|
      what_to_generate = t.name.split(':')[1]
      url = "#{LEANPUB_BASE_URL}/#{what_to_generate}.json"
      begin
        RestClient.post url, api_key: ENV['LEANPUB_API_KEY']
      rescue RestClient::Exception => e
        puts "Got error #{e.message} in", caller.first
        exit 1
      end
      puts "Generation of preview was triggered"
    end
  end
end

I can now easily generate a preview, without having to leave the IDE I’m using to write the book (or the command line) using this:

$ rake leanpub:preview:generate
Generation of preview was triggered

The Rakefile will likely change, for example to also support publishing a new version of the current ebook, or to make it more flexible in order to handle different ebooks.

Update (8. Jan 2021): It turns out that this is really useful: LeanPub provides a web hook to generate a _sub set_ of the book that also generates the PDF (but not the ebook and mobi file). This saves some time from pushing to GitHub to being able to review the generated file. I now use this web hook most of the time.

I now only generate for full book in all formats when I want to check that the book looks good enough to be published. Since this happens less regularly than pushing to the repository, I use the Rake task.

A Double Self Retro On Its Way To A Multi Self Retro

So, I read Bruce’s post (and the blog post it links to, as well 😄) over on Twitter:

I liked the post and Bruce wrote:

If you wanna join in, please feel free and I’m sure we’ll both be happy to share what you write!

Bruce, the legend

Thank you the invitation, Bruce (and Chris, I assume)!

What is this and why did you agree to do a double self retro?

We’re approaching the end of a year that swooshed by rather quickly (especially the part after mid-March) and which was … different, to say the least. To me, it’s worthwhile reflecting on what happened and where it has led to.

What did you think your goals were when you started the year?

Simply put: To survive. After battling cancer in 2018 & a good part of 2019, I hoped to return to some form of normal life. — As far as that’s desirable or possible after that time. I hoped to find a project to work on. And I did. In fact, I had the opportunity to (re-) join the same project (but different team), that I left way to abruptly due to the illness. It’s incredible to find such acceptance.

How did your goals change through the year?

After the first follow-up examination, when it was clear that everything’s totally fine, my doctor advised me to enjoy the summer. I took this as a goal, and am pleased to say: It worked well. I started to go swimming in the North Sea — and didn’t stop going (but I do stay in the water a lot shorter!).

How did you recalibrate in the year, when things changed?

They didn’t change that much. During the chemo therapy part of my treatment, I had to pretty much self-isolate, so I was used to it. It was ‘just’ that everybody else now also kept a good distance.

I also started working on “Softwarepeople … Work From Home“, a free ebook with contributions by people from all over the planet. I helped me to have a reason to contact folks and see what the situation is like elsewhere.

Highest point of the year

When people whom I admire & respect a lot agreed to contribute to the book.

Lowest point of the year

I had to have one (small, compared to what I went through before) surgery early March. Coming out of the hospital, into a lock-down, was frustrating.

Which item of clothing have you worn the most?

Probably this super-cosy jacket I bought on Rømø in Denmark. It has a few labels on it saying “Alive And Kicking”. Apart from being really comfy, I find that to be a nice fit to the whole situation.

Have you discovered any new tools?

I rediscovered GraphViz, a tool to, well, visualise graphs. I even wrote a small tool to turn tables that describe paths though a set of steps in to a graph description, that GraphViz then turns into an image file. I wrote posts about GraphViz and how I used it:

Best coping mechanisms

I started going to the gym very regularly, well until they had to close due to the pandemic.

Did any songs help you cope with the year?

  • Amy MacDonald – Pride
  • Neil Diamond – Beautiful Noise

and, I admit it,

  • Adriano Celentano – Prisencolinensinainciusol

TV shows that helped you cope

None.

Who is your favourite new friend of 2020, and why is it Chris?

Because, he’s Chris (Baumann). With apologies to the other Chrisses I know. I took the question verbatim from Bruce, and it explicitly asked for Chris (but not which Chris). 😃

What have you learnt about yourself this year?

Swimming helps me to focus.

Any regrets?

If any: That I didn’t switch from gym-based sport to home-alone sport faster.

What have you enjoyed?

Swimming, even since the temperature dropped below comfortable, working in my new team, the online edition of the Agile Testing Days and the coding puzzles at AdventOfCode.

What advice would you give to past you…January 2020?

I’d use the words of Douglas Adams: ‘Don’t Panic!’

After Updating to macOS 11.0 Big Sur

The Context

In my current project, we’re using Apache Tomat and Eclipse as the IDE. The Java Platform is Amazon Corretto 11. I’m using macOS and the working setup before upgrading was this:

  • Tomcat is installed using Homebrew:
    brew install tomcat
  • Java was installed by downloading the package (see link above) and running the installer.
  • I have set
    export JAVA_HOME=/Library/…/amazon-corretto-11.jdk/Contents/Home
    in .zprofile so the right Java version is used.
  • I’d start Tomcat from the command line and our tests from inside Eclipse.

This worked nicely.

After The Upgrade

The upgrade went smoothly for most of the software I am using: Other IDEs, installations of Ruby, Elixir, databases, REST clients, git, etc. all continued to work nicely.

The tests however failed in an interesting way: While basic REST calls worked (e.g. a GET request to retrieve version info), the tests that were using the actual functionality were receiving a plain “Internal Server Error” from Tomcat and the application logs showed some getContext method that ended up receiving null instead of the expected object.

Running the same tests on the same machine using the way the tests are started in CI still worked well. The difference between running from within the IDE & the command line: The command line starts Tomcat and runs the tests against that (and then stops Tomcat), while the IDE uses the already running Tomcat. — Aha!

The Solution

Tomcat logs several environment variables it’s using when it starts, among them JRE_HOME.

And this environment variable pointed to another Java environment, that came from a different source, had a different Java version, and furthermore was (obviously) incompatible with the Java environment set up in JAVA_HOME.

Pointing JRE_HOME to the same Java environment solved the problem and tests are running just fine again. Phew!

The documentation has a section about this (docs can be so useful!):

(3.2) Set JRE_HOME or JAVA_HOME (required)

These variables are used to specify location of a Java Runtime
Environment or of a Java Development Kit that is used to start Tomcat.

The JRE_HOME variable is used to specify location of a JRE. The JAVA_HOME
variable is used to specify location of a JDK.

Using JAVA_HOME provides access to certain additional startup options that
are not allowed when JRE_HOME is used.

If both JRE_HOME and JAVA_HOME are specified, JRE_HOME is used.

The recommended place to specify these variables is a “setenv” script. See
below.

…/tomcat/9.0.39/libexec/webapps/docs/RUNNING.txt in my Tomcat installation

Furthermore, there are comments explaining what to expect with respect to JAVA_HOME & JRE_HOME in catalina.sh:

# JRE_HOME Must point at your Java Runtime installation.
# Defaults to JAVA_HOME if empty. If JRE_HOME and JAVA_HOME
# are both set, JRE_HOME is used.

…/9.0.39/libexec/bin/catalina.sh. lns 61 ff

It’s still not entirely clear what caused this behaviour.
If you have an idea or ran into a similar problem, I’d definitely like to known about it.

Agile Testing Days 2020 (and 2009)

These are some insights I had today, posted as Tweets:

And last, but certainly not least Miroslava Nikolova made me (re?) post a message on a piece of cardboard that circled around at the Agile Testing Days 2009.

I think it is still valid and covers the spirit of this very conference and the attitude of everyone taking part so well.

Here’s the plain text (and if you know who’s the original author, I would really like to know who they are):

We are a community of professionals. We are dedicated of our own continuing education and take responsibility for our careers. We support each other in learning and advancing our craft. We certify ourselves.

— Unknown author(s?) at the Agile Testing Days 2009

I thank everyone who made this day so great!

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