Use asdf to manage Elxir and Erlang

Author: kylos101

chunks/lang-elixir/Dockerfile

@@ -6,9 +6,23 @@ USER root
 # Dazzle does not rebuild a layer until one of its lines are changed. Increase this counter to rebuild this layer.
 ENV TRIGGER_REBUILD=1
 
-RUN cd /tmp \
-	&& wget https://packages.erlang-solutions.com/erlang-solutions_2.0_all.deb \
-	&& dpkg -i erlang-solutions_2.0_all.deb \
-	&& install-packages elixir
-
 USER gitpod
+
+# Install asdf to make it easier to manage elixir versions
+#
+# Why?
+# 1. At the time of this writing, `apt-get install elixir` was installing
+# a version that was not compatible with glibc in Ubuntu Focal.
+# 2. This makes it explicit as to what versions we're installing.
+# 3. It'll give users the ability to easily make changes at runtime to experiment
+RUN	git clone https://github.com/asdf-vm/asdf.git ~/.asdf --branch v0.11.1
+RUN echo ". "$HOME/.asdf/asdf.sh"" >> /home/gitpod/.bashrc.d/100-asdf
+RUN echo ". "$HOME/.asdf/completions/asdf.bash"" >> /home/gitpod/.bashrc.d/100-asdf
+ENV PATH=/home/gitpod/.asdf/bin:/home/gitpod/.asdf/shims:${PATH}
+
+RUN asdf plugin-add erlang https://github.com/asdf-vm/asdf-erlang.git
+RUN asdf plugin-add elixir https://github.com/asdf-vm/asdf-elixir.git
+RUN asdf install erlang 25.2.2
+RUN asdf install elixir 1.13.4-otp-25
+RUN asdf global erlang 25.2.2
+RUN asdf global elixir 1.13.4-otp-25

tests/lang-elixir.yaml

@@ -2,5 +2,5 @@
   command: [elixir,--version]
   assert:
   - status == 0
-  - stdout.indexOf("Erlang/OTP 2") != -1
-  - stdout.indexOf("Elixir 1.13.") != -1
+  - stdout.indexOf("Erlang/OTP 25") != -1
+  - stdout.indexOf("Elixir 1.13.4") != -1