Only configure docker wrapper on macOS.

lib/tasks/docker.rake

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require 'macos'
+
+task :docker => :'brew:formulae_and_casks' do
+  docker_dir = File.expand_path('~/.docker')
+
+  if macos?
+    fish_function = Pathname('~/.config/fish/functions/docker.fish').expand_path
+    fish_function.dirname.mkpath
+    fish_function.write <<~FISH
+      # This file was created automatically, do not edit it directly.
+
+      function docker --wraps docker
+        if contains -- -h $argv || contains -- --help $argv || test (count $argv) = 0; else
+          if ! pgrep Docker >&-
+            open -jga Docker
+          end
+
+          while true
+            set -l ping_status (curl --fail --unix-socket ~/.docker/run/docker.sock 'http://localhost/_ping' 2>&-)
+
+            if test "$ping_status" = OK
+              break
+            else
+              sleep 1
+            end
+          end
+        end
+
+        command docker $argv
+      end
+    FISH
+  end
+end