Script to trim Helm's history

trim-helm-history.rb

#!/usr/bin/env ruby
# encoding: UTF-8

# Prints kubectl commands to trim Helm history in excess of the parameter below
# Assumes the default Helm history storage (Secrets)

HISTORY_ENTRIES_TO_RETAIN = 2

namespaces = `kubectl get ns -o name`
    .split
    .map do |namespace|
        namespace.delete_prefix("namespace/")
    end

secrets = namespaces.map do |namespace|
    `kubectl get secret --namespace #{namespace} -o name`
        .split
        .map do |name|
            if name =~ /^secret\/(sh\.helm\.release\.v1\..+)\.v([0-9]+)$/
                { namespace: namespace, base_name: $1, name: $1 + ".v" + $2, version: $2.to_i }
            else
                nil
            end
        end.compact
end.flatten

secrets_to_drop = secrets.group_by do |secret|
    secret[:namespace] + "/" + secret[:base_name] 
end.map do |group_key, group_values|
    sorted = group_values.sort_by do |secret|
        secret[:version]
    end.reverse
    sorted[HISTORY_ENTRIES_TO_RETAIN..-1]
end.compact.flatten

secrets_to_drop.each do |secret|
    puts "kubectl delete secret --namespace #{secret[:namespace]} #{secret[:name]}"
end