Getting git credentials from AWS Systems Manager

0-intro.md

Introduction

This is a short description of how to get git credentials in an EC2 instance set-up for CI/CD scripts. In the following scripts, we do the following:

• Install the AWS CLI. See here for description of steps on Linux.
• Install jq to parse the JSON output from CLI.
• Run the aws CLI for ssm (AWS Systems Manager) to extract parameter values for git user.
• Set the git user name globally.
• Set the name of the script in GIT_ASKPASS that will return the git password.

To use the script, first, add the following parameters in AWS Systems Manager. Then, set CREDS_SCRIPT to a location where git-pass.sh can be reached. Run git-creds.sh.

Parameter name	Value
GIT_USER	Git user name
GIT_PASSWORD	Git password

git-creds.sh

#!/bin/bash

## Install unzip, jq and build tools
sudo apt-get update
sudo apt-get install -y unzip jq

## Install AWS CLI
curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o "awscliv2.zip"
unzip awscliv2.zip
sudo ./aws/install

## Get git user
GIT_USER=`aws ssm get-parameter --with-decryption --name GIT_USER | jq -r .Parameter.Value`

## Set git configuration
git config --global credential.https://github.com.username ${GIT_USER}
export GIT_ASKPASS=${CREDS_SCRIPT}/git-pass.sh

git-pass.sh

#!/bin/bash
GIT_PASS=`aws ssm get-parameter --with-decryption --name GIT_PASSWORD | jq -r .Parameter.Value`
echo ${GIT_PASS}