ssm-get-parameter

The simple utility can be used the configure the environment of an application with values from the AWS SSM Parameter store.

How does it work?

It is simple. Specify one or more environment variables with a URI of the ssm: protocol, as follows:

export MYSQL_PASSWORD=ssm:///mysql/root/password
ssm-get-parameter bash -c 'echo $MYSQL_PASSWORD'

the utility will lookup the value of /mysql/root/password in the SSM parameter store and replace the environment variable. The program on the command line will be exec'ed with MYSQL_PASSWORD set to the actual value.

Query parameters

The utility supports the following query parameters:

• default - value if the value could not be retrieved from the parameter store.
• destination - the filename to write the value to. value replaced with file: url.
• chmod - file permissions of the destination, left to default if not specified. recommended 0600.
• template - the template to use for writing the value, defaults to '{{.}}'

If no default nor destination is specified and the parameter is not found, the utility will return an error. If a default is specified and the parameter is not found, the utility will use the default. If a destination file exists and no default is specified, the file will be read as the default value. The destination file may contain the ~ to designate the home directory. home directories of other users are not supported.

For example:

$ export ORACLE_PASSWORD=ssm:///oracle/scott/password?default=tiger&destination=/tmp/password
$ ssm-get-parameter bash -c 'echo $ORACLE_PASSWORD'
/tmp/password
$ cat /tmp/password
tiger

template formatting

To format the secret, you can use the template query parameter. For example:

$ export PGPASSFILE=ssm:///postgres/kong/password?template='localhost:5432:kong:kong:{{.}}%0A&destination=$HOME/.pgpass'
$ ssm-get-parameter bash -c 'cat $PGPASSFILE'
localhost:5432:kong:kong:@CypJqmqZ@TYQ2GDnUD@MQGuKyhrl!

Environment substitution

The URI may contain an environment variable reference. For example:

$ export ENV=dev
$ export 'PASSWORD=ssm:///${ENV}/mysql/root/password'
ssm-get-parameter bash -c 'echo $PASSWORD'

will print out the value of /dev/mysql/root/password.

Alternatively, you can use --export as follows:

$ export PASSWORD=ssm:///password
$ eval $(ssm-get-parameter --export)
$ echo $PASSWORD

Dockerfile usage

To idiomatic way to use the utility is as follows:

FROM binxio/ssm-get-parameter

FROM alpine:3.6
COPY --from=0 /ssm-get-parameter /usr/local/bin/

ENV PGPASSWORD=ssm:///postgres/root/password
ENTRYPOINT [ "/usr/local/bin/ssm-get-parameter"]
CMD [ "/bin/sh", "-c", "echo $PGPASSWORD"]

installation

If you have golang installed, type:

go get github.com/binxio/ssm-get-parameter

installation in Docker

With Docker you can use the multi-stage build:

FROM binxio/ssm-get-parameter

FROM alpine:3.6
COPY --from=0 /ssm-get-parameter /usr/local/bin/

download

you can download a 64 bit Linux or MacOS binary from https://github.com/binxio/ssm-get-parameter/releases.