Convert Listen into its own executable to run in separate process

lib/retest.rb

@@ -1,5 +1,3 @@
-require 'listen'
-
 require 'string/similarity'
 require 'observer'
 
@@ -17,8 +15,6 @@
 require "retest/sounds"
 require "retest/watcher"
 
-Listen.adapter_warn_behavior = :log
-
 module Retest
   class Error < StandardError; end
   class FileNotFound < StandardError; end

lib/retest/runner.rb

@@ -1,3 +1,4 @@
+require 'forwardable'
 require_relative "runner/cached_test_file"
 
 module Retest

lib/retest/watcher.rb

@@ -1,3 +1,5 @@
+require 'pathname'
+
 module Retest
   module Watcher
     def self.for(watcher)
@@ -24,25 +26,19 @@ def self.installed?
         true
       end
 
+      def self.extensions_regex(extensions)
+        Regexp.new("\\.(?:#{extensions.join("|")})$")
+      end
+
       def self.watch(dir:, extensions:, polling: false)
+        command = "./lib/scripts/listen --exts #{extensions.join(',')} -w #{dir} --polling #{polling}"
+
+        watch_rd, watch_wr = IO.pipe
         # Process needs its own process group otherwise the process gets killed on INT signal
         # We need the process to still run when trying to stop the current test run
         # Maybe there is another way to prevent killing these but for now a new process groups works
-        # Process group created with: Process.setsid
-        watch_rd, watch_wr = IO.pipe
-        pid = fork do
-          Process.setsid
-          Listen.to(dir, only: extensions_regex(extensions), relative: true, polling: polling) do |modified, added, removed|
-            if modified.any?
-              watch_wr.write "modify:#{modified.first}"
-            elsif added.any?
-              watch_wr.write "create:#{added.first}"
-            elsif removed.any?
-              watch_wr.write "remove:#{removed.first}"
-            end
-          end.start
-          sleep
-        end
+        # Process group created with: pgroup: true
+        pid = Process.spawn(command, out: watch_wr, pgroup: true)
 
         at_exit do
           Process.kill("TERM", pid) if pid
@@ -59,23 +55,20 @@ def self.watch(dir:, extensions:, polling: false)
               change = /^(?<action>create|remove|modify):(?<path>.*)/.match(data.strip)
 
               next unless change
+              path = Pathname(change[:path]).relative_path_from(Dir.pwd).to_s
 
               modified, added, removed = result = [[], [], []]
               case change[:action]
-              when 'modify' then modified << change[:path]
-              when 'create' then added << change[:path]
-              when 'remove' then removed << change[:path]
+              when 'modify' then modified << path
+              when 'create' then added << path
+              when 'remove' then removed << path
               end
 
               yield result
             end
           end
         end
       end
-
-      def self.extensions_regex(extensions)
-        Regexp.new("\\.(?:#{extensions.join("|")})$")
-      end
     end
 
     module Watchexec
@@ -85,7 +78,6 @@ def self.installed?
 
       def self.watch(dir:, extensions:, polling: false)
         command = "watchexec --exts #{extensions.join(',')} -w #{dir} --emit-events-to stdio --no-meta --only-emit-events"
-        files = VersionControl.files(extensions: extensions).zip([]).to_h
 
         watch_rd, watch_wr = IO.pipe
         # Process needs its own process group otherwise the process gets killed on INT signal
@@ -101,11 +93,15 @@ def self.watch(dir:, extensions:, polling: false)
         end
 
         Thread.new do
+          files = VersionControl.files(extensions: extensions).zip([]).to_h
+
           loop do
             ready = IO.select([watch_rd])
             readable_connections = ready[0]
             readable_connections.each do |conn|
               data = conn.readpartial(4096)
+              # Watchexec is not great at figuring out whether a file has been deleted and comes as an update.
+              # This is why we're not looking at the action like we do with Listen.
               change = /^(?:create|remove|rename|modify):(?<path>.*)/.match(data.strip)
 
               next unless change
@@ -129,41 +125,6 @@ def self.watch(dir:, extensions:, polling: false)
             end
           end
         end
-
-        # require 'open3'
-        # Thread.new do
-        #   files = VersionControl.files(extensions: extensions).zip([]).to_h
-
-        #   Open3.popen3(command) do |stdin, stdout, stderr, wait_thr|
-        #     loop do
-        #       ready = IO.select([stdout])
-        #       readable_connections = ready[0]
-        #       readable_connections.each do |conn|
-        #         data = conn.readpartial(4096)
-        #         change = /^(?:create|remove|rename|modify):(?<path>.*)/.match(data.strip)
-
-        #         next unless change
-
-        #         path = Pathname(change[:path]).relative_path_from(Dir.pwd).to_s
-        #         file_exist = File.exist?(path)
-        #         file_cached = files.key?(path)
-
-        #         modified, added, removed = result = [[], [], []]
-        #         if file_exist && file_cached
-        #           modified << path
-        #         elsif file_exist && !file_cached
-        #           added << path
-        #           files[path] = nil
-        #         elsif !file_exist && file_cached
-        #           removed << path
-        #           files.delete(path)
-        #         end
-
-        #         yield result
-        #       end
-        #     end
-        #   end
-        # end
       end
     end
   end

lib/scripts/listen

@@ -0,0 +1,57 @@
+#!/usr/bin/env ruby
+
+$stdout.sync = true
+
+require 'listen'
+require 'optparse'
+
+options = {}
+OptionParser.new do |opts|
+  opts.banner = "Usage: scripts/listen.rb [options]"
+
+  opts.on("--exts rb,js,ts", Array, "Extensions to watch for") do |list|
+    options[:extensions] = list
+  end
+
+  opts.on("--polling BOOLEAN", "Force Listen to use polling") do |value|
+    options[:polling] = value
+  end
+
+  opts.on("-w", "--watch .", "Directory to listen to") do |value|
+    options[:dir] = value
+  end
+
+  opts.on("-h", "--help", "Prints help") do
+    puts opts
+    exit
+  end
+end.parse!
+
+unless options.key?(:extensions)
+  raise ArgumentError, 'must provide the files extensions to watch for'
+end
+
+unless options.key?(:polling)
+  raise ArgumentError, 'must provide the polling option'
+end
+
+unless options.key?(:dir)
+  raise ArgumentError, 'must provide the directory path to watch'
+end
+
+def extensions_regex(extensions)
+  Regexp.new("\\.(?:#{extensions.join("|")})$")
+end
+
+Listen.adapter_warn_behavior = :log
+
+Listen.to(options[:dir], only: extensions_regex(options[:extensions]), polling: options[:polling]) do |modified, added, removed|
+  if modified.any?
+    $stdout.puts "modify:#{modified.first}"
+  elsif added.any?
+    $stdout.puts "create:#{added.first}"
+  elsif removed.any?
+    $stdout.puts "remove:#{removed.first}"
+  end
+end.start
+sleep