ssm-env

ssm-env is a Rust utility for setting environment variables from AWS SSM parameters. It is analogous to the standard env utility, but instead of literally specifying values it pulls them from SSM.

In addition to explicitly mapping parameters to environment variables, ssm-env can also export all parameters in a given path as environment variables. This is useful for cases where you have a large number of parameters that you want to export as environment variables.

Note that (for now) it does not support recursive parameter fetching, so you can't do that (although it is not a significant change to add it).

Usage

ssm-env --help
set environment variables from AWS SSM Parameter Store

Usage: ssm-env [OPTIONS] <UTILITY> [ARGUMENTS]...

Arguments:
  <UTILITY>       The command to run after setting the environment variables from the ssm parameters
  [ARGUMENTS]...  The arguments to pass to the utility

Options:
      --no-decrypt            Decrypt SecureStrings
  -i, --ignore                Ignore (clear) existing environment variables
  -e, --export <ENV[=PARAM]>  Export an aws ssm parameter to an environment variable. The parameter name can be specified if it differs from the environment variable
  -P, --export-path <PATH>    Export one level of a path of aws ssm parameters to environment variables. All parameters under the prefix will be exported as environment variables
  -h, --help                  Print help
  -V, --version               Print version

If you have an SSM parameter named DATABASE_URL that you want to feed into your application my-app, assuming the following is run from an EC2 instance with an appropriate IAM role:

ssm-env -e DATABASE_URL -- /usr/local/bin/my-app

Note that ssm-env makes use of the aws sdk and honors all of the standard AWS environment variables and credentials.

Most of the time, ssm parameters will not be named the same as the environment variables and in that case you can append =PARAMETER_NAME to the environment variable name to map it to a different parameter name. For example, if you have a parameter named /my-app/database-url you can do:

ssm-env -e DATABASE_URL=/my-app/database-url -- /usr/local/bin/my-app

Technically database-url is a valid environment variable name if a bit unconventional. If you can either name your parameters in the same way as environment variables or you don't care about being unconventional, you can use the -P option to map a path.

ssm-env -P /my-app/ -- /usr/local/bin/my-app

Installation

ssm-env is available as binary releases for Linux, FreeBSD, and MacOS. You can download them from the releases page.

If you have Rust installed, you can also install it with cargo build --release and then copy the binary from target/release/ssm-env to wherever you want it.

Prior Art

There are a few other implementations of this idea in other languages, and it's such an obvious idea that I'm sure there are more. I find it a bit surprising this functionality isn't built into the aws cli.

I wrote this before I found the following, and I think I prefer my implementation more but perhaps these others will have fewer rough edges or be more suitable for your use case.

• https://github.com/remind101/ssm-env
• https://github.com/jamietsao/aws-ssm-env

License

MIT