Mieubrisse/docker image with dynamic envvars

packages/frontend/.dockerignore

@@ -1,4 +1,9 @@
 **/.git
 **/node_modules
+.gitignore
 dist
 .cache
+
+# Docker will read these during run anyways, so no need to invalidate the cache if we change these
+Dockerfile
+.dockerignore

packages/frontend/Dockerfile

@@ -2,8 +2,6 @@
 
 FROM phusion/baseimage:0.11
 
-ENTRYPOINT ["/sbin/my_init", "--"]
-
 RUN curl -o /tmp/node_setup.sh "https://deb.nodesource.com/setup_11.x"
 RUN bash /tmp/node_setup.sh
 RUN curl -sL https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add -
@@ -13,16 +11,28 @@ RUN apt-get update -qq && apt-get install -y \
     nginx \
     rsync
 
-# near-wallet
+# Set up 
 RUN mkdir /near-wallet
-COPY . /near-wallet/
 WORKDIR /near-wallet
+# We'll replace the sites-enabled down below
+RUN rm /etc/nginx/sites-enabled/default
+
+# 'npm install' takes ~3 minutes, so copy just the package.json and do an install before we copy the rest of the code
+#   so that Docker will cache these instructions so long as package.json isn't changed
+COPY package.json .
 RUN npm install
-RUN npm run build
-RUN mkdir -p /var/www/html/wallet
-RUN rsync -ar /near-wallet/dist/ /var/www/html/wallet
 
-# nginx
-RUN rm /etc/nginx/sites-enabled/default
+# Now, copy the rest of the code for the build
+COPY . .
+RUN mkdir -p /var/www/html/wallet
 COPY /scripts/wallet.nginx /etc/nginx/sites-enabled/wallet
 COPY /scripts/init_nginx.sh /etc/my_init.d/
+
+# NOTE1: Because the Wallet uses Parcel for its build and environment variables in Parcel can only be set at build time, we run an 'npm build'
+#  as part of container startup so that the Wallet will respond to environment variables set on container startup
+# NOTE2: The last command, /sbin/my_init, is the command to run the NginX server bundled inside the phusion base image
+#  See https://hub.docker.com/layers/phusion/baseimage/0.11/images/sha256-14e6c478b00aa0a6f68391a53f7d510d9a062efcf509ea55ee9a125969592b79?context=explore for more details
+CMD bash -c "./scripts/generate_env_file_for_build_inside_docker.sh && \
+    npm run build && \
+    rsync -ar /near-wallet/dist/ /var/www/html/wallet && \
+    /sbin/my_init"

packages/frontend/scripts/generate_env_file_for_build_inside_docker.sh

@@ -0,0 +1,46 @@
+#!/usr/bin/env bash
+
+# The wallet app's environment variables can only be configured at build time due to Parcel being used to build the wallet, which means that passing 
+#  environment variables to a Docker container running a wallet wouldn't do anything.
+# Parcel *does* store environment variables in a '.env' file in the root of the project though, so when we launch a Wallet Docker image we a) write a .env
+#  file with the environment variables we want the wallet to have and b) rebuild the Wallet as part of the Docker container startup
+# This script does the first part - taking environment variables set in the shell environment and writing them to a .env file for Parcel
+
+set -euo pipefail   # Bash "strict mode"
+script_dirpath="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+project_root_dirpath="$(dirname "${script_dirpath}")"
+
+
+# ==================================================================================================
+#                                             Constants
+# ==================================================================================================
+# Parcel, which is used to build the project, will read this file at build time and 'process.env.SOMEVAR' calls
+#  in the Javascript code will use the variables set in this file
+OUTPUT_FILENAME=".env"
+
+# Environment variables that will be set in the shell environment when the container is started, and which should be propagated
+#  to the .env file for Parcel to use
+ENVVARS_TO_STORE=(
+    "REACT_APP_ACCOUNT_HELPER_URL"
+    "EXPLORER_URL"
+    "REACT_APP_NODE_URL"
+    "REACT_APP_IS_MAINNET"
+    "REACT_APP_NETWORK_ID"
+    "REACT_APP_ACCOUNT_ID_SUFFIX"
+    "REACT_APP_ACCESS_KEY_FUNDING_AMOUNT"
+)
+
+# ==================================================================================================
+#                                             Main Logic
+# ==================================================================================================
+output_abs_filepath="${project_root_dirpath}/${OUTPUT_FILENAME}"
+
+for envvar in "${ENVVARS_TO_STORE[@]}"; do
+    value="${!envvar:-}"
+    if [ -z "${value}" ]; then
+        # Safety guard to make sure someone running from the Docker image sets all the expected envvars
+        echo "Error: Expected environment variable '${envvar}' to have a value, but none was passed in" >&2
+        exit 1
+    fi
+    echo "${envvar}=\"${value}\"" >> "${output_abs_filepath}"
+done