fix(superchain): use entrypoint to set up nvm (#2736)

This ensures node is always in the PATH at the start of a container (unless
the user replaced the entrypoint). This attempts to minimize overhead of the
overall setup by using exec in the run.sh script.

superchain/Dockerfile

@@ -87,26 +87,21 @@ VOLUME /var/lib/docker
 # between them. $NVM_USE_VERSION becomes a global variable the container responds to to pick a Node version on startup,
 # if set.
 ENV NVM_DIR /usr/local/nvm
-
-RUN mkdir -p $NVM_DIR && curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.37.2/install.sh | bash - \
- && echo 'source "$NVM_DIR/nvm.sh"' >> $HOME/.bash_profile \
- && echo '[[ -z "$NVM_USE_VERSION" ]] || nvm use "$NVM_USE_VERSION"' >> $HOME/.bash_profile
-
-# Because we wrote things to .bash_profile, make the default shell a login shell so it gets sourced.
-# Also set BASH_ENV to make bash source this EVEN if it's not a login shell (later on when the container
-# gets executed)
-SHELL [ "/bin/bash", "--login", "-c" ]
-ENV BASH_ENV /root/.bash_profile
-
-# Source NVM into this shell and install Node 10 and 14. First installed version (10) becomes default.
-RUN nvm install 10 \
+COPY run.sh /usr/local/bin/
+
+RUN mkdir -p $NVM_DIR && curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.37.2/install.sh | bash - \
+ && chmod a+x /usr/local/bin/run.sh \
+ # Source NVM into this shell
+ && source $NVM_DIR/nvm.sh \
+ # Install Node 10 and yarn on node 10. First installed version becomes default.
+ && nvm install 10 \
+ && nvm exec 10 npm install -g yarn \
+ # Install Node 14 and yarn on node 14.
  && nvm install 14 \
+ && nvm exec 14 npm install -g yarn \
+ # Make npm play nicer with Docker containers running as "root".
  && npm set unsafe-perm true
 
-# Can't install Yarn using yum anymore now that we're using nvm, so install it using NPM
-RUN nvm exec 10 npm install -g yarn \
- && nvm exec 14 npm install -g yarn
-
 # Install some configuration
 COPY ssh_config /root/.ssh/config
 RUN chmod 600 /root/.ssh/config
@@ -126,4 +121,5 @@ LABEL org.opencontainers.image.created=${BUILD_TIMESTAMP}
  org.opencontainers.image.revision=$COMMIT_ID \
  org.opencontainers.image.authors="Amazon Web Services (https://aws.amazon.com)"
 
-CMD ["/bin/bash", "--login"]
+ENTRYPOINT ["/usr/local/bin/run.sh"]
+CMD ["/bin/bash"]

superchain/README.md

@@ -8,24 +8,26 @@ required in order to package [jsii] projects in all supported languages.
 
 ## Included Language SDKs
 
-SDK | Version
-----------------|-------------------------------------------
-`OpenJDK 8` | Amazon Corretto `>= 8.242.08.1`
-`.NET SDK` | `>= 3.1.101`
-`mono` | `>= 6.8.0.105`
-`Javascript` | `node >= 10.19.0` with `npm >= 6.13.4`
- | `node >= 14.24.0` with `npm >= 6.13.4`
- | (both managed via NVM)
-`PowerShell` | `pwsh >= 6.2.3`
-`Python 3` | `python3 >= 3.7.4` with `pip3 >= 20.0.2`
-`Go` | `go >= 1.16`
+SDK | Version
+--------------|-------------------------------------------
+`OpenJDK 8` | Amazon Corretto `>= 8.242.08.1`
+`.NET SDK` | `>= 3.1.101`
+`mono` | `>= 6.8.0.105`
+`Node` | `node >= 10.19.0` with `npm >= 6.13.4`
+`Node` (Alt) | `node >= 14.24.0` with `npm >= 6.13.4` (see [notes] below)
+`PowerShell` | `pwsh >= 6.2.3`
+`Python 3` | `python3 >= 3.7.4` with `pip3 >= 20.0.2`
+`Go` | `go >= 1.16`
+
+[notes]: #notes-on-node.js
 
 ### Notes on Node.js
 
-You *must* use `bash` (not `sh`) to run commands in this container.
+By default, Node.js will be at version 10. To switch to Node 14, pass
+`-e NVM_USE_VERSION=14` into the container at startup, or use
+[`nvm` commands][nvm] to switch between versions or to install other versions.
 
-By default, Node.js will be at version 10. To switch to Node 14,
-pass `-e NVM_USE_VERSION=14` into the container at startup.
+[nvm]: https://github.com/nvm-sh/nvm
 
 ## Included Tools & Utilities
 

superchain/run.sh

@@ -0,0 +1,6 @@
+#!/bin/sh
+
+source "$NVM_DIR/nvm.sh"
+[[ -z "$NVM_USE_VERSION" ]] || nvm use "$NVM_USE_VERSION"
+
+exec "$@"