Specify rails' tmp path in the Railtie

.gitignore

@@ -9,3 +9,4 @@
 /tmp/
 .byebug_history
 tags
+percona_migrator_error.log

lib/percona_migrator.rb

@@ -16,7 +16,8 @@ class << self
     attr_accessor :configuration
   end
 
-  def self.config
+  def self.configure
     self.configuration ||= Configuration.new
+    yield(configuration)
   end
 end

lib/percona_migrator/railtie.rb

@@ -51,5 +51,11 @@ def reconnect_with_percona
         end
       end
     end
+
+    initializer 'percona_migrator.configure' do |app|
+      PerconaMigrator.configure do |config|
+        config.tmp_path = app.paths['tmp'].first
+      end
+    end
   end
 end

lib/percona_migrator/runner.rb

@@ -46,7 +46,7 @@ class Runner
     # @param cli_generator [CliGenerator]
     # @param mysql_adapter [ActiveRecord::ConnectionAdapter] it must implement
     #   #execute and #raw_connection
-    def initialize(logger, cli_generator, mysql_adapter, config = PerconaMigrator.config)
+    def initialize(logger, cli_generator, mysql_adapter, config = PerconaMigrator.configuration)
       @logger = logger
       @cli_generator = cli_generator
       @mysql_adapter = mysql_adapter

spec/percona_migrator/runner_spec.rb

@@ -10,8 +10,9 @@
   let(:mysql_adapter) do
     instance_double(ActiveRecord::ConnectionAdapters::Mysql2Adapter)
   end
+  let(:config) { instance_double(PerconaMigrator::Configuration, tmp_path: 'percona_migrator_error.log') }
 
-  let(:runner) { described_class.new(logger, cli_generator, mysql_adapter) }
+  let(:runner) { described_class.new(logger, cli_generator, mysql_adapter, config) }
 
   describe '#query' do
   end
@@ -47,8 +48,7 @@
     end
     let(:stdout) { temp_file.open }
     let(:wait_thread) { instance_double(Thread, value: status) }
-    let(:error_log_path) { 'percona_migrator_error.log' }
-    let(:expected_command) { "#{command} 2> #{error_log_path}" }
+    let(:expected_command) { "#{command} 2> #{config.tmp_path}" }
 
     before do
       allow(Open3).to(
@@ -93,7 +93,7 @@
     end
 
     context 'on failure' do
-      let(:expected_command) { "#{command} 2> #{error_log_path}" }
+      let(:expected_command) { "#{command} 2> #{config.tmp_path}" }
 
       before do
         allow(Open3).to(

spec/percona_migrator_spec.rb

@@ -1,8 +1,11 @@
 require 'spec_helper'
 
 describe PerconaMigrator do
-  describe '.config' do
-    subject { described_class.config }
-    it { is_expected.to be_a(PerconaMigrator::Configuration) }
+  describe '.configure' do
+    it 'yields the configuration object' do
+      expect do |b|
+        described_class.configure(&b)
+      end.to yield_with_args(kind_of(PerconaMigrator::Configuration))
+    end
   end
 end

spec/spec_helper.rb

@@ -32,6 +32,10 @@
 RSpec.configure do |config|
   ActiveRecord::Migration.verbose = false
 
+  # Needs an empty block to initialize the config with the default values
+  PerconaMigrator.configure do |config|
+  end
+
   config.around(:each) do |example|
 
     # Cleans up the database before each example, so the current example doesn't