auto_ssh_keys

#!/usr/bin/env bash

# Import SSH keys from Github to ~/.ssh/authorize_keys for all members of a
# given Github organization.
#
# Will replace authorized_keys, if it looks like authorized_keys was not
# previously created by this script then a backup copy is made.
#
# Depends on jq, will download it if not available (assumes Linux) to ~/bin/jq
#
# GITHUB_ORG can be set, defaults to lambdaisland
# SSH_DIR and/or KEYS_FILE can be set, default to ~/.ssh and ~/.ssh/authorized_keys
#
# Will create the SSH_DIR if it does not exist, and set permissions on dir and
# file (700 and 600 respectively).
#
# Only works when OVERWRITE_SSH_AUTHORIZED_KEYS=OK
#
# Will exit early if anything goes wrong, so authorized_keys is only touched if
# all Github API/HTTP calls succeed.

if [[ "${OVERWRITE_SSH_AUTHORIZED_KEYS}" != "OK" ]]; then
    echo "CAREFUL! This script will replace your ~/.ssh/authorized_keys. If you are sure that is what you want then run it with OVERWRITE_SSH_AUTHORIZED_KEYS=OK to continue."
    exit 1
fi

GITHUB_ORG=${GITHUB_ORG:-"lambdaisland"}
JQ="$(command -v jq)"

set -e

# Follow links, no extraneous output, fail (non-zero exit) on non-200 responses
CURL="curl -Ls --fail"

if [[ ! -x "$JQ" ]]; then
    JQ="$HOME/bin/jq"
    if [[ ! -x "$JQ" ]]; then
        mkdir -p "$HOME/bin"
        $CURL https://github.com/stedolan/jq/releases/download/jq-1.6/jq-linux64 -o ~/bin/jq
        chmod +x "$JQ"
    fi
fi

MEMBERS=$($CURL "https://api.github.com/orgs/${GITHUB_ORG}/public_members")

AUTHORIZED_KEYS="# $(date)\n# Created by: ${0}\n# Imported keys for: https://github.com/${GITHUB_ORG}"

for keys_link in $(echo $MEMBERS | "$JQ" -r '.[].html_url+".keys"'); do
    KEYS=$($CURL $keys_link)
    AUTHORIZED_KEYS="${AUTHORIZED_KEYS}\n\n# ${keys_link}\n${KEYS}"
done

SSH_DIR=${SSH_DIR:-"$HOME/.ssh"}
mkdir -p $SSH_DIR
chmod 700 $SSH_DIR

KEYS_FILE=${KEYS_FILE:-"$SSH_DIR/authorized_keys"}

if [[ -f "$KEYS_FILE" ]] && ! grep 'Imported keys for' "$KEYS_FILE" >/dev/null; then
    cp "$KEYS_FILE" "${KEYS_FILE}.$(date +'%Y%m%d_%H%M%S')"
fi

echo -e "$AUTHORIZED_KEYS" > "$KEYS_FILE"
chmod 600 "$KEYS_FILE"