envpp

Replaces all environment variable references in a text file with their corresponding values in currently set environment variables.

$ echo 'foo: $(bar)' > config.yaml
$ cat config.yaml
foo: $(bar)

$ bar="foobar" envpp < config.yaml
foo: foobar

The sole reason this exists is to allow me to easily work with configuration files I have defined in Azure pipelines. For example, I may have a values file for some helm chart whose installation is automated through Azure pipelines. In Azure pipelines I have the following values file defined:

global:
  username: "$(USERNAME)"
  password: "$(PASSWORD)"

$(USERNAME) and $(PASSWORD) are custom variables I have defined, so azure pipelines conviniently replaces them for me in the file. Now, sometimes when the installation is failing in Azure I do try to test out things on my computer locally. Before I had this, I had to copy the file then manually edit it to replace the variables and then use it (helm values files can get hairy). With this tool, that's changed. Right now, I copy the file then save it locally. I leave the variables in the original file as is (if need be I add some more) and then generate copies using this tool.

$ source .env
$ envpp < values.yaml.source > values.yaml

When I am done, I copy the source file with any modifications I have made back to azure devops.

Installation

Grab an x86-64 binary from the releases page or clone this project and build it yourself.

$ shards install
$ crystal build --release src/envpp --release src/envpp

Usage

# Replaces variables in source file using existing .env file
$ envpp < source-file > output-file

# Replaces variables using specified .env file
$ envpp --dotenv-file=/path/to/.env < source-file > output-file

# Replaces variables using system environment variables
$ envpp --use-system-env < source-file > output-file

Development

Install dependencies:

$ shards install

Make your changes then run tests:

$ crystal spec

Build application:

$ crystal build src/envpp.cr

Contributing

1. Fork it (https://github.com/your-github-user/envpp/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• Walter Kaunda - creator and maintainer