Skip to content

Getting Started with Karafka Pro


To activate Karafka Pro, you need to do three things:

  1. Follow the standard Karafka installation procedure.

  2. Obtain credentials to a registry hosting a custom karafka-license gem. This gem contains all the code for Karafka to detect the Pro components. You can get them here.

  3. Add this to your Gemfile and bundle install:

source '' do
  gem 'karafka-license', 'LICENSE_ID'

gem 'karafka'
# other gems...

You still need to have the standard gem 'karafka' definition in your Gemfile. License gem is just providing the license.

License gem integrity verification

Using Karafka Pro means we are part of your Open Source Supply Chain. We take this exceptionally seriously, and that is why we encourage you to verify the integrity of the license gem we provide in your CI/CD.

You can do it with the following script:

#!/usr/bin/env bash

set -e


if [ "$MODE" != "after" ]; then
  # Check the remote license prior to bundle installing
  curl \
    --fail \
    --retry 5 \
    --retry-delay 1 \
    -o ./karafka-license.gem
  # Check the local cached one after bundle install
  cache_path=`ruby -e 'puts "#{Gem.dir}/cache/"'`
  cp "$cache_path/karafka-license-$KARAFKA_PRO_LICENSE_ID.gem" ./karafka-license.gem

detected=`sha256sum ./karafka-license.gem | awk '{ print $1 }'`

rm ./karafka-license.gem

echo -n "Karafka Pro license artifact checksum verification result: "

if [ "$detected" = "$KARAFKA_PRO_LICENSE_CHECKSUM" ]; then
  echo "Success"
  echo -e "\033[0;31mFailure!\033[0m"
  exit 1

Due to the nature of how Bundler works, it is recommended to run this script twice in the CI/CD:

  1. First, before bundle install is executed, to ensure that the gem server is serving the correct data.
  2. Second time after bundle install to ensure consistency of the fetched package.

To use it:

  1. Store above script in your repository preferably under bin/verify_karafka_license_checksum.

  2. Set the KARAFKA_PRO_USERNAME, KARAFKA_PRO_PASSWORD, KARAFKA_PRO_LICENSE_ID and KARAFKA_PRO_LICENSE_CHECKSUM based on data provided to you in the license issuing email or set those values as your CI/CD ENV variables.

  3. Run MODE=before bin/verify_karafka_license_checksum as part of your CI/CD before running bundle install.

  4. Run bundle install

  5. Run MODE=after bin/verify_karafka_license_checksum to ensure that the stored artefact was not compromised.

In case the verification fails, script will exit with the exit code 1.

Due to security reasons, license checksum is not available through the license Web UI. It is only sent once via email.