sectool 0.0.14

A tool for keeping secrets during software builds and deployments

SECTOOL

A tool for keeping secrets during software builds and deployments.

Challenge

The secrets like API keys or passwords should be used during run time and provided by execution environment. The simple solution is keeping them as environment variables. But values of the variables are usually kept as plain text inside files like Dockerfile or docker-compose.yml which is not secure.

Way to solve

The tool solves the issue, it allows you to keep secrets in an encrypted file and inject the values during software builds.

How it works?

1. You create an .ini file where in section secrets you keep all your secrets.
2. Encrypt the file. Later you can use the file (or files if you need different secrets for different environments).
3. Run sectool by specifying the file and your deployment config file. The tool reads your deployment config, injects the corresponding values and print the result to stdout.
4. Here is the step when Linux magic begins, the stdout can be piped to your building or deployment tool, also xargs can help.

Examples

First of all, install sectool:

python3 -m pip install sectool

And develop a shell code that calls sectool:

# The function has three arguments 
# * path to encrypted file keeping secrets
# * password for decrypting the file
# * path to file where we need to merge variables
merge() {
read -r -d '' script <<-"----EOF"
import os
from sectool import process
process(os.environ['SEC_FILE'], os.environ['PASS'], os.environ['TMPL_FILE'])
----EOF
SEC_FILE="$1" PASS="$2" TMPL_FILE="$3" python3 -c "$script"
}

Inject to Dockerfile and build a Docker image:

echo -n "Enter your password: "
read PASSWORD
merge "secrets.dat" $PASSWORD "Dockerfile" | docker build -t tulip -f - .

Inject to docker-compose.yml and build all images mentioned there:

echo -n "Enter your password: "
read PASSWORD
merge "secrets.dat" $PASSWORD "docker-compose.yml" | docker-compose -f - build

Inject to AWS Task Definition:

echo -n "Enter your password: "
read PASSWORD
merge "secrets.dat" $PASSWORD "my-aws-task-def.json" | xargs -0 aws ecs register-task-definition --region eu-west-1 --cli-input-json

How do I encrypt .ini file?

Easy. You need openssl, the software is very popular and included in almost popular Linux/Unix distributions.

How do I encrypt file?

openssl enc -aes-256-cbc -in secrets.ini -out secrets.dat

Don't forget password that the tool will ask! If you forget it, you won't be able to get access to your secrets.

How do I decrypt to check if everything okay?

openssl enc -aes-256-cbc -k <password> -d -in secrets.dat

How do I mention secret variables in my, for instance, Dockerfile?

Just use a name of the variable in double curly brackets {{api_key}}

Example of .ini file:

[secrets]
api_key = AGTDBLWLB5BGG7NNVHV

Example of Dockerfile:

FROM ubuntu:20.04
USER wheel

ENV API_KEY={{api_key}}