env-aws-params

env-aws-params is a tool that injects AWS EC2 Systems Manager (SSM) Parameter Store Key / Value pairs as Environment Variables when executing an application. It is intended to be used as a Docker Entrypoint, but can really be used to launch applications outside of Docker as well.

The primary goal is to provide a way of injecting environment variables for 12 Factor applications that have their configuration defined in the SSM Parameter store. It was directly inspired by envconsul.

Example Usage

Create parameters in Parameter Store:

aws ssm put-parameter --name /service-prefix/ENV_VAR1 --value example
aws ssm put-parameter --name /service-prefix/ENV_VAR2 --value test-value

Then use env-aws-params to have bash display the env vars it was called with:

env-aws-params --prefix /service-prefix /bin/bash -c set

If you want to include common and service specific values, --prefix can be specified multiple times:

env-aws-params --prefix /common /bin/bash -c set

To get a plaintext output of your environment variables to use with other utilities, we can use printenv:

env-aws-params --pristine --silent --prefix /service-prefix /usr/bin/printenv > ~/some-file.sh

Which will write your environment variables in plain text, for example:

# ~/some-file.sh Contents:
ENV_VAR1=example
ENV_VAR2=test-value

CLI Options

NAME:
   env-aws-params - Application entry-point that injects SSM Parameter Store values as Environment Variables

USAGE:
   env-aws-params [global options] -p prefix command [command arguments]

COMMANDS:
     help, h  Shows a list of commands or help for one command

GLOBAL OPTIONS:
   --aws-region value        The AWS region to use for the Parameter Store API [$AWS_REGION]
   --prefix value, -p value  Key prefix that is used to retrieve the environment variables - supports multiple use
   --pristine                Only use values retrieved from Parameter Store, do not inherit the existing environment variables
   --sanitize                Replace invalid characters in keys to underscores
   --strip                   Strip invalid characters in keys
   --upcase                  Force keys to uppercase
   --debug                   Log additional debugging information [$PARAMS_DEBUG]
   --silent                  Silence all logs [$PARAMS_SILENT]
   --help, -h                show help
   --version, -v             print the version

Building

This project uses go modules. To build the project:

go mod download
go mod verify
go build

Building an environment is also provided as a docker image based on Alpine Linux. See the Dockerfile for more information.

docker build -t env-aws-params; # Build the image
docker run --rm -it -v $HOME/.aws/:/root/.aws/ env-aws-params [your options]