Add "spring server" command

This command to start a Spring server explicitly in the foreground,
which logging to stdout.

This will be useful to those who want to run spring more explicitly, but
the real impetus was to enable running a spring server inside a Docker
container.

CHANGELOG.md

@@ -1,6 +1,11 @@
-## 1.6.5
+## Next release
 
 * Auto-restart server when server and client versions do not match
+* Add `spring server` command to explicitly start a Spring server
+  process in the foreground, which logging to stdout. This will be
+  useful to those who want to run spring more explicitly, but the real
+  impetus was to enable running a spring server inside a Docker
+  container.
 
 ## 1.6.4
 

lib/spring/application.rb

@@ -6,10 +6,10 @@ module Spring
   class Application
     attr_reader :manager, :watcher, :spring_env, :original_env
 
-    def initialize(manager, original_env)
+    def initialize(manager, original_env, spring_env = Env.new)
       @manager      = manager
       @original_env = original_env
-      @spring_env   = Env.new
+      @spring_env   = spring_env
       @mutex        = Mutex.new
       @waiting      = Set.new
       @preloaded    = false

lib/spring/application/boot.rb

@@ -5,7 +5,8 @@
 
 app = Spring::Application.new(
   UNIXSocket.for_fd(3),
-  Spring::JSON.load(ENV.delete("SPRING_ORIGINAL_ENV").dup)
+  Spring::JSON.load(ENV.delete("SPRING_ORIGINAL_ENV").dup),
+  Spring::Env.new(log_file: IO.for_fd(4))
 )
 
 Signal.trap("TERM") { app.terminate }

lib/spring/application_manager.rb

@@ -2,9 +2,9 @@ module Spring
   class ApplicationManager
     attr_reader :pid, :child, :app_env, :spring_env, :status
 
-    def initialize(app_env)
+    def initialize(app_env, spring_env)
       @app_env    = app_env
-      @spring_env = Env.new
+      @spring_env = spring_env
       @mutex      = Mutex.new
       @state      = :running
     end
@@ -104,7 +104,8 @@ def start_child(preload = false)
           "-I", File.expand_path("../..", $LOADED_FEATURES.grep(/bundler\/setup\.rb$/).first),
           "-I", File.expand_path("../..", __FILE__),
           "-e", "require 'spring/application/boot'",
-          3 => child_socket
+          3 => child_socket,
+          4 => spring_env.log_file,
         )
       end
 

lib/spring/client.rb

@@ -9,6 +9,7 @@
 require "spring/client/status"
 require "spring/client/rails"
 require "spring/client/version"
+require "spring/client/server"
 
 module Spring
   module Client
@@ -22,6 +23,7 @@ module Client
       "rails"     => Client::Rails,
       "-v"        => Client::Version,
       "--version" => Client::Version,
+      "server"    => Client::Server,
     }
 
     def self.run(args)

lib/spring/client/server.rb

@@ -0,0 +1,14 @@
+module Spring
+  module Client
+    class Server < Command
+      def call
+        require "spring/server"
+        Spring::Server.boot(foreground: true)
+      end
+
+      def self.description
+        "Explicitly start a Spring server in the foreground"
+      end
+    end
+  end
+end

lib/spring/env.rb

@@ -14,10 +14,10 @@ module Spring
   class Env
     attr_reader :log_file
 
-    def initialize(root = nil)
-      @root         = root
-      @project_root = root
-      @log_file     = File.open(ENV["SPRING_LOG"] || File::NULL, "a")
+    def initialize(options = {})
+      @root         = options[:root]
+      @project_root = options[:root]
+      @log_file     = options[:log_file] || File.open(ENV["SPRING_LOG"] || File::NULL, "a")
     end
 
     def root

lib/spring/server.rb

@@ -10,19 +10,24 @@ module Spring
 
 module Spring
   class Server
-    def self.boot
-      new.boot
+    def self.boot(options = {})
+      new(options).boot
     end
 
     attr_reader :env
 
-    def initialize(env = Env.new)
-      @env          = env
-      @applications = Hash.new { |h, k| h[k] = ApplicationManager.new(k) }
+    def initialize(options = {})
+      @foreground   = options.fetch(:foreground, false)
+      @env          = options[:env] || default_env
+      @applications = Hash.new { |h, k| h[k] = ApplicationManager.new(k, env) }
       @pidfile      = env.pidfile_path.open('a')
       @mutex        = Mutex.new
     end
 
+    def foreground?
+      @foreground
+    end
+
     def log(message)
       env.log "[server] #{message}"
     end
@@ -31,8 +36,8 @@ def boot
       Spring.verify_environment
 
       write_pidfile
-      set_pgid
-      ignore_signals
+      set_pgid unless foreground?
+      ignore_signals unless foreground?
       set_exit_hook
       set_process_title
       start_server
@@ -42,6 +47,7 @@ def start_server
       server = UNIXServer.open(env.socket_name)
       log "started on #{env.socket_name}"
       loop { serve server.accept }
+    rescue Interrupt
     end
 
     def serve(client)
@@ -126,5 +132,19 @@ def set_process_title
         "spring server | #{env.app_name} | started #{distance} ago"
       }
     end
+
+    private
+
+    def default_env
+      Env.new(log_file: default_log_file)
+    end
+
+    def default_log_file
+      if foreground? && !ENV["SPRING_LOG"]
+        $stdout
+      else
+        nil
+      end
+    end
   end
 end

lib/spring/test/acceptance_test.rb

@@ -28,6 +28,10 @@ def app
         @app ||= Spring::Test::Application.new("#{Spring::Test.root}/apps/tmp")
       end
 
+      def spring_env
+        app.spring_env
+      end
+
       def assert_output(artifacts, expected)
         expected.each do |stream, output|
           assert artifacts[stream].include?(output),
@@ -92,14 +96,14 @@ def without_gem(name)
 
       test "help message when called without arguments" do
         assert_success "bin/spring", stdout: 'Usage: spring COMMAND [ARGS]'
-        assert app.spring_env.server_running?
+        assert spring_env.server_running?
       end
 
       test "shows help" do
         assert_success "bin/spring help", stdout: 'Usage: spring COMMAND [ARGS]'
         assert_success "bin/spring -h", stdout: 'Usage: spring COMMAND [ARGS]'
         assert_success "bin/spring --help", stdout: 'Usage: spring COMMAND [ARGS]'
-        refute app.spring_env.server_running?
+        refute spring_env.server_running?
       end
 
       test "tells the user that spring is being used when used automatically via binstubs" do
@@ -184,10 +188,10 @@ def self.omg
 
       test "stop command kills server" do
         app.run app.spring_test_command
-        assert app.spring_env.server_running?, "The server should be running but it isn't"
+        assert spring_env.server_running?, "The server should be running but it isn't"
 
         assert_success "bin/spring stop"
-        assert !app.spring_env.server_running?, "The server should not be running but it is"
+        assert !spring_env.server_running?, "The server should not be running but it is"
       end
 
       test "custom commands" do
@@ -508,6 +512,19 @@ def exec_name
           2.times { assert_success "bundle exec rails runner ''" }
         end
       end
+
+      test "booting a foreground server" do
+        FileUtils.cd(app.root) do
+          assert !spring_env.server_running?
+          app.run "spring server &"
+
+          Timeout.timeout(1) do
+            sleep 0.1 until spring_env.server_running?
+          end
+
+          assert_success app.spring_test_command
+        end
+      end
     end
   end
 end

lib/spring/test/application.rb

@@ -9,7 +9,7 @@ class Application
 
       def initialize(root)
         @root       = Pathname.new(root)
-        @spring_env = Spring::Env.new(root)
+        @spring_env = Spring::Env.new(root: root)
       end
 
       def exists?