keypair-functions

#!/bin/bash
#
# keypair-functions
#
# List, create and delete EC2 SSH Keypairs

keypairs() {

  # List EC2 SSH Keypairs in current Region
  #
  #     $ keypairs
  #     alice  8f:85:9a:1e:6c:76:29:34:37:45:de:7f:8d:f9:70:eb
  #     bob    56:73:29:c2:ad:7b:6f:b6:f2:f3:b4:de:e4:2b:12:d4

  local keypairs=$(skim-stdin)
  local filters=$(__bma_read_filters $@)

  aws ec2 describe-key-pairs                       \
    ${keypairs/#/'--key-names '}                   \
    --query 'KeyPairs[].[KeyName, KeyFingerprint]' \
    --output text       |
  grep -E -- "$filters" |
    columnise
}

keypair-create() {

  # Create SSH Keypair on local machine and import public key into new EC2 Keypair.
  #
  # Provides benefits over AWS creating the keypair:
  #
  # - Amazon never has access to private key.
  # - Private key is protected with passphrase before being written to disk.
  # - Keys is written to ~/.ssh with correct file permissions.
  # - You control the SSH Key type (algorithm, length, etc).
  #
  #     USAGE: keypair-create [key_name] [key_dir]
  #
  #     $ keypair-create yet-another-keypair
  #     Creating /home/m/.ssh/yet-another-keypair
  #     Generating public/private rsa key pair.
  #     Enter passphrase (empty for no passphrase):
  #     Enter same passphrase again:
  #     Your identification has been saved in /home/m/.ssh/yet-another-keypair.
  #     Your public key has been saved in /home/m/.ssh/yet-another-keypair.pub.
  #     The key fingerprint is:
  #     SHA256:zIpbxLo7rpQvKyezOLATk96B1kSL0QP41q6x8tUrySk m@localhost.localdomain
  #     The key's randomart image is:
  #     +---[RSA 4096]----+
  #     |..o              |
  #     |.. +             |
  #     | .+.o            |
  #     | .oo.. o         |
  #     | o+.  o S        |
  #     |=o.+.= .         |
  #     |+++==o+          |
  #     |XoE+*+ .         |
  #     |o@+**+.          |
  #     +----[SHA256]-----+
  #     {
  #         "KeyFingerprint": "21:82:f9:5b:79:d6:dc:0f:7b:79:43:7c:c5:34:6c:2d",
  #         "KeyName": "yet-another-keypair"
  #     }
  #
  # !!! Note
  #     KeyPair Name defaults to "$(aws-account-alias)-$(region)" if none provided

  KEY_NAME=${1:-"$(aws-account-alias)-$(region)"}
  KEY_DIR=${2:-"$HOME/.ssh"}

  if aws ec2 describe-key-pairs --key-names "$KEY_NAME" &>/dev/null; then
    __bma_error "Keypair already exists: '$KEY_NAME'"
    return 1
  fi

  echo "Creating ${KEY_DIR}/${KEY_NAME}"
  ssh-keygen -t rsa -m PEM -b 4096 -o -a 100 -f "${KEY_DIR}/${KEY_NAME}"
  chmod 0600 "${KEY_DIR}/${KEY_NAME}"
  aws ec2 import-key-pair                                 \
    --key-name "$KEY_NAME"                                \
    --public-key-material "fileb://${KEY_DIR}/${KEY_NAME}.pub"
}

keypair-delete() {

  # Delete EC2 SSH Keypairs by providing their names as arguments or via STDIN
  #
  #     USAGE: keypair-delete key_name [key_name]
  #
  #     $ keypair-delete alice bob
  #     You are about to delete the following EC2 SSH KeyPairs:
  #     alice
  #     bob
  #     Are you sure you want to continue? y
  #
  #     $ keypairs | keypair-delete
  #     You are about to delete the following EC2 SSH KeyPairs:
  #     yet-another-keypair
  #     Are you sure you want to continue? y

  local keypairs=$(skim-stdin "$@")
  [[ -z $keypairs ]] && __bma_usage "key_name [key_name]" && return 1

  echo "You are about to delete the following EC2 SSH KeyPairs:"
  echo "$keypairs" | tr ' ' "\n" | keypairs
  [ -t 0 ] || exec </dev/tty # reattach keyboard to STDIN
  local regex_yes="^[Yy]$"
  read -p "Are you sure you want to continue? " -n 1 -r
  echo
  if [[ $REPLY =~ $regex_yes ]]; then
    local keypair
    for keypair in $keypairs; do
      aws ec2 delete-key-pair --key-name "$keypair"
    done
  fi
}