Set quiet mode from environment

CHANGELOG.md

@@ -4,6 +4,7 @@
 * Preserve comments right after the shebang line which might include magic comments such as `frozen_string_literal: true'
 * Fix binstub failures when Bundler's `BUNDLE_APP_CONFIG` environment variable is present (#545)
 * Properly suspend and resume on ctrl-z TSTP and CONT (#361)
+* Allow quiet mode to be set by environment variable `SPRING_QUIET`
 
 ## 2.0.2
 

README.md

@@ -404,7 +404,8 @@ The following environment variables are used by Spring:
 * `SPRING_SERVER_COMMAND` - The command to run to start up the Spring
   server when it is not already running. Defaults to `spring _[version]_
   server --background`.
-
+* `SPRING_QUIET` - If set, the "Running via Spring preloader" message will not
+  be shown each time a command runs (takes precedence over `Spring.quiet`).
 ## Troubleshooting
 
 If you want to get more information about what Spring is doing, you can

lib/spring/configuration.rb

@@ -2,7 +2,8 @@
 
 module Spring
   class << self
-    attr_accessor :application_root, :quiet
+    attr_accessor :application_root
+    attr_writer :quiet
 
     def gemfile
       ENV['BUNDLE_GEMFILE'] || "Gemfile"
@@ -16,6 +17,10 @@ def after_fork(&block)
       after_fork_callbacks << block
     end
 
+    def quiet
+      @quiet || ENV.key?('SPRING_QUIET')
+    end
+
     def verify_environment
       application_root_path
     end

lib/spring/test/acceptance_test.rb

@@ -117,6 +117,12 @@ def without_gem(name)
         refute_output_includes "bin/rails runner ''", stderr: 'Running via Spring preloader in process'
       end
 
+      test "configures quiet mode from environment" do
+        app.env['SPRING_QUIET'] = '1'
+        assert_success "bin/rails runner ''"
+        refute_output_includes "bin/rails runner ''", stderr: 'Running via Spring preloader in process'
+      end
+
       test "test changes are picked up" do
         assert_speedup do
           assert_success app.spring_test_command, stdout: "0 failures"