feat: Support pidfile in CLI & Server (defaults to puma.pid)

lib/functions_framework/cli.rb

@@ -36,6 +36,7 @@ def initialize
       @source = ::ENV["FUNCTION_SOURCE"] || ::FunctionsFramework::DEFAULT_SOURCE
       @env = nil
       @port = nil
+      @pidfile = nil
       @bind = nil
       @min_threads = nil
       @max_threads = nil
@@ -67,6 +68,12 @@ def error?
     #
     attr_reader :error_message
 
+    ##
+    # @return [String] The pidfile.
+    # @return [nil] if not running.
+    #
+    attr_reader :pidfile
+
     ##
     # Parse the given command line arguments.
     # Exits if argument parsing failed.
@@ -89,6 +96,9 @@ def parse_args argv # rubocop:disable Metrics/MethodLength,Metrics/AbcSize
               "Supported values are 'http' and 'cloudevent'." do |val|
           @signature_type = val
         end
+        op.on "-P", "--pidfile PIDFILE", "Set the pidfile for the server (defaults to puma.pid)" do |val|
+          @pidfile = val
+        end
         op.on "-p", "--port PORT", "Set the port to listen to (defaults to 8080)" do |val|
           @port = val.to_i
         end
@@ -218,6 +228,7 @@ def start_server
       ::FunctionsFramework.start function do |config|
         config.rack_env = @env
         config.port = @port
+        config.pidfile = @pidfile
         config.bind_addr = @bind
         config.show_error_details = @detailed_errors
         config.min_threads = @min_threads

lib/functions_framework/server.rb

@@ -152,6 +152,24 @@ def running?
       @server&.thread&.alive?
     end
 
+    ##
+    # Returns pidfile if server is currently running
+    #
+    # @return [String, nil]
+    #
+    def pidfile
+      @config.pidfile if running?
+    end
+
+    ##
+    # Returns whether pidfile is present.
+    #
+    # @return [Boolean]
+    #
+    def pidfile?
+      [email protected] && running?
+    end
+
     ##
     # Cause this server to respond to SIGTERM, SIGINT, and SIGHUP by shutting
     # down gracefully.
@@ -214,6 +232,7 @@ def initialize
         self.rack_env = nil
         self.bind_addr = nil
         self.port = nil
+        self.pidfile = nil
         self.min_threads = nil
         self.max_threads = nil
         self.show_error_details = nil
@@ -245,6 +264,14 @@ def port= port
         @port = (port || ::ENV["PORT"] || 8080).to_i
       end
 
+      ##
+      # Set the pidfile string, or `nil` to use the default.
+      # @param path [String,nil]
+      #
+      def pidfile= path
+        @pidfile = (path || ::ENV["PIDFILE"] || "puma.pid").to_s
+      end
+
       ##
       # Set the minimum number of worker threads, or `nil` to use the default.
       # @param min_threads [Integer,nil]
@@ -306,6 +333,14 @@ def port
         @port
       end
 
+      ##
+      # Returns the current pidfile string.
+      # @return [String]
+      #
+      def pidfile
+        @pidfile
+      end
+
       ##
       # Returns the minimum number of worker threads in the thread pool.
       # @return [Integer]

test/test_cli.rb

@@ -27,6 +27,7 @@
   let(:retry_count) { 10 }
   let(:retry_interval) { 0.5 }
   let(:port) { "8066" }
+  let(:pidfile) { "server.pid" }
   let(:timeout) { 10 }
 
   def run_with_retry cli
@@ -104,6 +105,21 @@ def run_in_timeout cli
     assert_equal "I received a request: GET http://127.0.0.1:#{port}/", response.body
   end
 
+  it "runs an http server with a pidfile" do
+    args = [
+      "--source", http_source,
+      "--target", "simple_http",
+      "--port", port,
+      "--pidfile", pidfile,
+      "-q"
+    ]
+    cli = FunctionsFramework::CLI.new.parse_args args
+    _response = run_with_retry cli do
+      Net::HTTP.get_response URI("http://127.0.0.1:#{port}/")
+    end
+    assert_equal pidfile, cli.pidfile
+  end
+
   it "runs an http server with a function that includes a return" do
     args = [
       "--source", http_return_source,

test/test_server.rb

@@ -38,6 +38,7 @@
     end
   }
   let(:port) { 8077 }
+  let(:pidfile) { "server.pid" }
   let(:server_url) { "http://127.0.0.1:#{port}" }
   let(:quiet_logger) {
     logger = ::Logger.new $stderr
@@ -56,6 +57,7 @@ def make_basic_server function, show_error_details: true
       config.min_threads = 1
       config.max_threads = 1
       config.port = port
+      config.pidfile = pidfile
       config.bind_addr = "127.0.0.1"
       config.rack_env = "development"
       config.logger = quiet_logger
@@ -94,6 +96,19 @@ def query_server_with_retry server
     http_server.stop.wait_until_stopped timeout: 10
   end
 
+  it "uses a pidfile" do
+    refute http_server.pidfile?
+    refute http_server.pidfile
+    http_server.start
+    assert http_server.pidfile?
+    assert http_server.pidfile
+    http_server.stop.wait_until_stopped timeout: 10
+    refute http_server.running?
+    refute http_server.pidfile?
+  ensure
+    http_server.stop.wait_until_stopped timeout: 10
+  end
+
   it "handles post requests" do
     response = query_server_with_retry http_server do
       ::Net::HTTP.post URI("#{server_url}/"), "Hello, world!", "Content-Type" => "text/plain"