skauk/fileenv repository overview

⁠About

fileenv helps you use Docker secrets easily.

⁠TL;DR

• You need MY_SECRET to hold your Docker secret, <secret-name>
• Set MY_SECRET_FILE=/run/secrets/<secret-name>
• Set your container command as fileenv <your cmd> <your args...>
• Profit!

⁠Why

When using Docker Composer or Swarm, it's desirable to use Docker secrets⁠ to manage secrets instead of passing secrets in environment variables⁠.

Many apps don't support reading from Docker secrets because they only read directly from environment variables.

fileenv is a stop-gap solution to read Docker secrets (or any file) and set environment variables for your app.

⁠Usage

Usage: fileenv [flags...] /path/to/program [program arguments...]
Flags:
  -debug
    	print debug info messages
  -fail
    	immediately exit on warning

Note: -debug will print the contents of variables it sets. If you don't want secrets printed in your logs, don't use -debug!

fileenv will read through each environment variable. If the name of the environment variable ends with _FILE when upper-cased, fileenv will open the file referenced by the variable, read its contents, and set the enviroment variable without _FILE at the end to the TrimSpace⁠'d contents of the file.

If any of these steps fails, a warning will be printed to stderr. If -fail is set, fileenv will immediately exit with status 1. Otherwise fileenv will continue on.

Once all environment variables are set, fileenv will execute the given program and arguments, passing through stdin, stdout, and stderr. If the program fails to start, or returns a non-zero exit status, the error will be logged to stderr. fileenv will return the same exit status as the child program.

You can include fileenv to your Dockerfile like this:

COPY --from=skauk/fileenv /usr/bin/fileenv /usr/bin/fileenv