use curses for in-place updates on status

README.md

@@ -88,6 +88,8 @@ I've knocked this up really quickly, and it's pretty MVP-ish. Ideas for future i
 
 After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake spec` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
 
+To test the presenter that displays progress to the terminal: `ruby ./spec/presenter_test.rb`
+
 To install this gem (as in, your development copy of the code) onto your local machine, run `bundle exec rake install`.
 
 To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org).

lib/safe_update.rb

@@ -10,6 +10,7 @@
 require 'safe_update/outdated_gem'
 require 'safe_update/bundle_outdated_parser'
 require 'safe_update/git_repo'
+require 'safe_update/presenter'
 
 module SafeUpdate
 end

lib/safe_update/outdated_gem.rb

@@ -1,21 +1,24 @@
 module SafeUpdate
   class OutdatedGem
-    attr_reader :gem_name, :newest, :installed, :requested
+    STATUS_PENDING    = 'pending'
+    STATUS_UPDATING   = 'updating'
+    STATUS_TESTING    = 'testing'
+    STATUS_UPDATED    = 'updated'
+    STATUS_UNCHANGED  = 'unchanged'
+    STATUS_TESTS_FAIL = 'tests_fail'
+
+    attr_reader :gem_name, :newest, :installed, :requested, :current_status
     def initialize(opts = {})
       @gem_name  = opts[:gem_name]
       @newest    = opts[:newest]
       @installed = opts[:installed]
       @requested = opts[:requested]
       @git_repo  = opts[:git_repo] || GitRepo.new
+      @current_status = STATUS_PENDING
     end
 
     def attempt_update(test_command = nil)
-      puts '-------------'
-      puts "OUTDATED GEM: #{@gem_name}"
-      puts "   Newest: #{@newest}. "
-      puts "Installed: #{@installed}."
-      puts "Running `bundle update #{@gem_name}`..."
-
+      @current_status = STATUS_UPDATING
       `bundle update #{@gem_name}`
 
       # sometimes the gem may be outdated, but it's matching the
@@ -26,16 +29,15 @@ def attempt_update(test_command = nil)
       end
 
       if test_command
-        puts "Running tests with: #{test_command}"
+        @current_status = STATUS_TESTING
         result = system(test_command)
         if result != true
-          puts "tests failed - this gem won't be updated (test result: #{$?.to_i})"
+          @current_status = STATUS_TESTS_FAIL
           @git_repo.discard_local_changes
           return
         end
       end
 
-      puts "committing changes (message: '#{commit_message}')..."
       @git_repo.commit_gemfile_lock(commit_message)
     end
 

lib/safe_update/presenter.rb

@@ -0,0 +1,93 @@
+require 'curses'
+
+Curses.noecho
+Curses.init_screen
+
+module SafeUpdate
+  class Presenter
+    # outdated_gems is an array of instances of SafeUpdate::OutdatedGem
+
+    SPINNER_STATES = ['|', '/', '-', '\\']
+
+    def initialize
+      @tick = 1
+      @running = true
+    end
+
+    def call(outdated_gems)
+      @outdated_gems = outdated_gems
+      while @running do
+        @tick += 1
+        update_screen
+        sleep 0.3
+      end
+    end
+
+    def stop
+      @running = false
+      print_final_output
+    end
+
+    private
+
+    def print_final_output
+      Curses.close_screen
+      puts title
+      puts header
+      @outdated_gems.each do |outdated_gem|
+        puts present_single_gem(outdated_gem)
+      end
+    end
+
+    def update_screen
+      Curses.setpos(0, 0)
+      Curses.addstr(title)
+      Curses.refresh
+
+      Curses.setpos(1, 0)
+      Curses.addstr(header)
+      Curses.refresh
+
+      @outdated_gems.each_with_index do |outdated_gem, i|
+        Curses.setpos(i + 2, 0)
+        line = present_single_gem(outdated_gem)
+        Curses.addstr(line)
+        Curses.refresh
+      end
+    end
+
+    def title
+      '=> Updating your gems... safely   ' + current_spinner_state
+    end
+
+    def current_spinner_state
+      div, remainder = @tick.divmod(SPINNER_STATES.length)
+      SPINNER_STATES[remainder]
+    end
+
+    def header
+      return [
+        fixed_length_string('GEM', 10),
+        fixed_length_string('INSTALLED', 10),
+        fixed_length_string('REQUESTED', 10),
+        fixed_length_string('NEWEST', 7),
+        fixed_length_string('STATUS', 10)
+        ].join(' | ')
+    end
+
+    def present_single_gem(outdated_gem)
+      return [
+        fixed_length_string(outdated_gem.gem_name, 10),
+        fixed_length_string(outdated_gem.installed, 10),
+        fixed_length_string(outdated_gem.requested || '    -', 10),
+        fixed_length_string(outdated_gem.newest, 7),
+        fixed_length_string(outdated_gem.current_status, 10)
+      ].join(' | ')
+    end
+
+    # inspired by http://stackoverflow.com/questions/14714936/fix-ruby-string-to-n-characters
+    def fixed_length_string(str, length)
+      "%-#{length}.#{length}s" % str
+    end
+  end
+end

lib/safe_update/updater.rb

@@ -15,6 +15,11 @@ def run(push: nil, test_command: nil)
       push_interval = push.to_i if run_git_push
 
       puts 'Finding outdated gems...'
+      outdated_gems = BundleOutdatedParser.new.call
+
+      presenter = SafeUpdate::Presenter.new
+      Thread.new { presenter.call(outdated_gems) }
+
       outdated_gems.to_enum.with_index(1) do |outdated_gem, index|
         outdated_gem.attempt_update(test_command)
         @git_repo.push if run_git_push && index % push_interval == 0
@@ -23,19 +28,7 @@ def run(push: nil, test_command: nil)
       # run it once at the very end, so the final commit can be tested in CI
       @git_repo.push if run_git_push
 
-      display_finished_message
-    end
-
-    private
-
-    def outdated_gems
-      BundleOutdatedParser.new.call
-    end
-
-    def display_finished_message
-      puts '-------------'
-      puts '-------------'
-      puts 'FINISHED'
+      presenter.stop
     end
   end
 end

safe_update.gemspec

@@ -21,4 +21,6 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "bundler", "~> 1.11"
   spec.add_development_dependency "rake", "~> 10.0"
   spec.add_development_dependency "rspec", "~> 3.0"
+
+  spec.add_runtime_dependency 'curses', '~> 1.0.1'
 end

spec/presenter_test.rb

@@ -0,0 +1,57 @@
+$LOAD_PATH.unshift File.expand_path('../../lib', __FILE__)
+require 'safe_update'
+
+outdated_gems = []
+outdated_gems << SafeUpdate::OutdatedGem.new(
+  gem_name: 'rails',
+  newest: '1.2.3',
+  installed: '1.2.1',
+  requested: '~> 1.2.0',
+)
+
+outdated_gems << SafeUpdate::OutdatedGem.new(
+  gem_name: 'rspec',
+  newest: '1.2.3',
+  installed: '1.2.1',
+  requested: '~> 1.2.0',
+)
+
+outdated_gems << SafeUpdate::OutdatedGem.new(
+  gem_name: 'byebug',
+  newest: '1.2.3',
+  installed: '1.2.1',
+  requested: '~> 1.2.0',
+)
+
+outdated_gems << SafeUpdate::OutdatedGem.new(
+  gem_name: 'bullet',
+  newest: '3.2.1',
+  installed: '1.2.1',
+)
+
+states = [
+  SafeUpdate::OutdatedGem::STATUS_PENDING,
+  SafeUpdate::OutdatedGem::STATUS_UPDATING,
+  SafeUpdate::OutdatedGem::STATUS_TESTING,
+  SafeUpdate::OutdatedGem::STATUS_UPDATED,
+  SafeUpdate::OutdatedGem::STATUS_UNCHANGED,
+  SafeUpdate::OutdatedGem::STATUS_TESTS_FAIL,
+]
+
+outdated_gems.map do |outdated_gem|
+  outdated_gem.instance_variable_set(
+    :@current_status,
+    states.sample
+  )
+end
+
+presenter = SafeUpdate::Presenter.new
+Thread.new { presenter.call(outdated_gems) }
+20.times do
+  sleep 0.25
+  outdated_gems.sample.instance_variable_set(
+    :@current_status,
+    states.sample
+  )
+end
+presenter.stop