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Debugging

Notes from watching Stuart Halloway's "Debugging with the Scientific Method" from Clojure/conj 2015.

Overview

Clear problem statement: steps you took, what you expected, what actually happened.

Efficient hypothesis: bisect the problem.

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;; This macro is also available in: https://github.com/wdhowe/clj-contrib

(defmacro as-some->
  "as->, with the nil checking of some->.
   Binds name to expr. When name is not nil, evaluates the first
   form in the lexical context of that binding. When that result
   is not nil, then binds name to result, repeating for each
   successive form."
  [expr name & forms]
  (let [steps (map (fn [step] `(if (nil? ~name) nil ~step))

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.PHONY: build test deploy

##-- Environment Variables --#

# Image and container registry
IMAGE_NAME := my-image-name
IMAGE_PATH := mygroup/myproject
REGISTRY   := registry-url:port
IMAGE      := $(REGISTRY)/$(IMAGE_PATH)/$(IMAGE_NAME)

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Docker Image Running/Building Examples

The docker images can all be run/built similar to the following.

Variables

Setup the variables per image.

GitHub Example

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Leiningen Plugins

Lein can be extended via plugins.

Some useful plugins are:

• lein-ancient -> Check your project for outdated dependencies and plugins, as well as upgrade them if desired.
• lein-exec -> Allows single clojure files to be executed and their requirements resolved.
• lein-localrepo -> Work with local Maven repository.
• lein-pprint -> Pretty-print a representation of the project map.

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Leiningen Projects

Leiningen is another method for managing Clojure projects. It is similar to pipenv in the Python world, in that it manages project space and dependent packages.

Offical Site: https://leiningen.org/

Install Leiningen

Mac

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Clojure CLI/deps Projects

Clojure CLI tools (with deps.edn) allow for a built in way to create projects.

Official CLI/deps guide: https://clojure.org/guides/deps_and_cli

• Pre-reqs: Clojure and dependencies installed.

Clojure Tools + Deps New

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Clojure REPL Help

Commands that can be entered in the REPL for finding help, documentation, and more.

Load clojure REPL helper functions

(require '[clojure.repl :refer :all])

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Install Clojure

Official site: https://www.clojure.org/index

Mac

brew install openjdk clojure rlwrap

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# Export a sensitive environment variable, hiding it from command history and the terminal.
read -rs my_var ; export my_var

# Don't forget to unset it later, when done
unset my_var