Simple tool to dump env variables to json, potentially filtering by prefix, stripping it and also with ability to put this json into placeholder in existing file (which is useful to pass settings from environment variables in staticfiles builds).
For example we define settings for our application in environment variables
# env
APP_ENV_API_URL=https://example.com/api
APP_ENV_SENTRY_URL=https://sentry.com
SOME_UNSAFE_ENV_VAR=secret
We can inject these settings into our static application by replacing some placeholder. First we put a placeholder into an html file.
<script>/*APP_ENV*/</script>Replace /*APP_ENV*/ with window.APP_ENV = {...environment variables values...} in index.html
inject-env -o index.html -r '/*APP_ENV*/' --prefix APP_ENV_ --format 'window.APP_ENV = {}'The result html should be
<scritp>window.APP_ENV = {"API_URL":"https://example.com/api", "SENTRY_URL": "https://sentry.com"}</script>Only environment variables with prefix end up in the result json. For security reasons you should always use prefix to avoid secrets in your publicly accessible files.
See inject-env -h for more options
FROM node:16-alpine as builder
WORKDIR /app
COPY package.json package-lock.json /app/
RUN npm ci
COPY . /app
RUN npm run build
FROM nginx:1.23-alpine
RUN wget -O inject-env.tar.gz https://github.com/anton-fomin/inject-env/releases/download/v0.1.1/inject-env-v0.1.1-x86_64-unknown-linux-musl.tar.gz && \
tar -xzf inject-env.tar.gz && mv inject-env /usr/local/bin/
COPY deploy/bin/entrypoint.sh /
RUN chmod +x /entrypoint.sh
COPY deploy/nginx/default.conf /etc/nginx/conf.d/default.conf
ENTRYPOINT ["/entrypoint.sh"]
EXPOSE 80
COPY --from=builder /app/dist /usr/share/nginx/html
CMD ["nginx", "-g", "daemon off;"]
Where entrypoint is
#!/bin/sh
inject-env -o /usr/share/nginx/html/index.html -r '/*APP_ENV*/' --prefix APP_ENV_ --format 'window.APP_ENV = {}'
exec "$@"
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