use official rubocop hook

.pre-commit-config.yaml

@@ -5,11 +5,7 @@ repos:
     -   id: trailing-whitespace
     -   id: end-of-file-fixer
     -   id: check-yaml
--   repo: local
+-   repo: https://github.com/rubocop/rubocop
+    rev: v1.29.0
     hooks:
     -   id: rubocop
-        name: rubocop
-        entry: rubocop --auto-correct
-        types: [ruby]
-        language: ruby
-        additional_dependencies: ['rubocop:0.63.1']

.rubocop.yml

@@ -1,3 +1,11 @@
+AllCops:
+  NewCops: enable
+  TargetRubyVersion: '2.6'
+
+Layout:
+  Metrics/LineLength:
+    IgnoreCopDirectives: true
+
 Metrics/AbcSize:
   Max: 30
 Metrics/BlockLength:
@@ -6,7 +14,5 @@ Metrics/CyclomaticComplexity:
   Max: 10
 Metrics/MethodLength:
   Max: 30
-Metrics/LineLength:
-  IgnoreCopDirectives: true
 Style/Documentation:
   Enabled: false

Gemfile

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 source 'https://rubygems.org/'
 
 gem 'fernet', '>=2'

hiera-eyaml-sshagent.gemspec

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 lib = File.expand_path('lib', __dir__)
 $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
 require 'hiera/backend/eyaml/encryptors/sshagent/version'
@@ -15,6 +17,8 @@ Gem::Specification.new do |gem|
   gem.test_files    = gem.files.grep(%r{^(test|spec|features)/})
   gem.require_paths = ['lib']
 
+  gem.required_ruby_version = '>=2.6'
   gem.add_dependency('fernet', '>=2')
   gem.add_dependency('hiera-eyaml', '>=1.3.8')
+  gem.metadata['rubygems_mfa_required'] = 'true'
 end

lib/hiera/backend/eyaml/encryptors/sshagent.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'base64'
 require 'json'
 require 'socket'
@@ -12,13 +14,13 @@ module Encryptors
         class SSHAgent < Encryptor
           self.tag = 'SSHAGENT'
 
-          SSH2_AGENTC_REQUEST_IDENTITIES = "\x0b".freeze
-          SSH2_AGENT_IDENTITIES_ANSWER = "\x0c".freeze
-          SSH2_AGENTC_SIGN_REQUEST = "\x0d".freeze
-          SSH2_AGENT_SIGN_RESPONSE = "\x0e".freeze
+          SSH2_AGENTC_REQUEST_IDENTITIES = "\x0b"
+          SSH2_AGENT_IDENTITIES_ANSWER = "\x0c"
+          SSH2_AGENTC_SIGN_REQUEST = "\x0d"
+          SSH2_AGENT_SIGN_RESPONSE = "\x0e"
 
           def self.read_u32(sock)
-            sock.read(4).unpack('L>')[0]
+            sock.read(4).unpack1('L>')
           end
 
           def self.read_s(sock)
@@ -39,9 +41,7 @@ def self.sign(sock, key_blob, challenge)
             sock.write(encode_s(request))
 
             sio = StringIO.new(read_s(sock))
-            if sio.read(1) != SSH2_AGENT_SIGN_RESPONSE
-              raise 'Expected SSH2_AGENT_SIGN_RESPONSE'
-            end
+            raise 'Expected SSH2_AGENT_SIGN_RESPONSE' if sio.read(1) != SSH2_AGENT_SIGN_RESPONSE
 
             sio = StringIO.new(read_s(sio))
             raise 'Expected ssh-rsa' if read_s(sio) != 'ssh-rsa'
@@ -53,9 +53,7 @@ def self.get_key_blob(sock, keyid)
             sock.write(encode_s(SSH2_AGENTC_REQUEST_IDENTITIES))
 
             sio = StringIO.new(read_s(sock))
-            if sio.read(1) != SSH2_AGENT_IDENTITIES_ANSWER
-              raise 'expected SSH2_AGENT_IDENTITIES_ANSWER'
-            end
+            raise 'expected SSH2_AGENT_IDENTITIES_ANSWER' if sio.read(1) != SSH2_AGENT_IDENTITIES_ANSWER
 
             (0...read_u32(sio)).each do
               key_blob = read_s(sio)
@@ -65,9 +63,7 @@ def self.get_key_blob(sock, keyid)
           end
 
           class Encrypted
-            attr_reader :challenge
-            attr_reader :salt
-            attr_reader :payload
+            attr_reader :challenge, :salt, :payload
 
             def initialize(challenge, salt, payload)
               @challenge = challenge
@@ -93,7 +89,7 @@ def self.from_dct(dct)
           end
 
           def self.get_key(keyid, challenge, salt)
-            signature_blob = Socket.unix(ENV['SSH_AUTH_SOCK']) do |sock|
+            signature_blob = Socket.unix(ENV.fetch('SSH_AUTH_SOCK', nil)) do |sock|
               key_blob = get_key_blob(sock, keyid)
               break sign(sock, key_blob, challenge)
             end
@@ -103,7 +99,7 @@ def self.get_key(keyid, challenge, salt)
               salt,
               100_000,
               32,
-              OpenSSL::Digest::SHA256.new
+              OpenSSL::Digest.new('SHA256')
             )
             Base64.encode64(kdf)
           end
@@ -130,9 +126,7 @@ def self.decrypt_contents(keyid, contents)
 
           def self.keyid
             keyid = option :keyid
-            if keyid.nil? || keyid.empty?
-              raise ArgumentError, 'No keyid configured!'
-            end
+            raise ArgumentError, 'No keyid configured!' if keyid.nil? || keyid.empty?
 
             keyid
           end
@@ -147,7 +141,7 @@ def self.decrypt(ciphertext)
           end
 
           def self.create_keys
-            STDERR.puts 'This encryptor does not support creation of keys'
+            warn 'This encryptor does not support creation of keys'
           end
         end
       end

lib/hiera/backend/eyaml/encryptors/sshagent/eyaml_init.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'hiera/backend/eyaml/encryptors/sshagent'
 
 Hiera::Backend::Eyaml::Encryptors::SSHAgent.register

lib/hiera/backend/eyaml/encryptors/sshagent/version.rb

@@ -1,9 +1,11 @@
+# frozen_string_literal: true
+
 class Hiera
   module Backend
     module Eyaml
       module Encryptors
         module SSHAgent
-          VERSION = '0.1'.freeze
+          VERSION = '0.1'
         end
       end
     end