[receiver/carbonreceiver] fix carbon receiver server start order

.chloggen/change_carbon_receiver_start_order.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: carbonreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Create the carbon receiver server when the `Start` method is called, and only close it if created.
+
+# One or more tracking issues related to the change
+issues: [17404]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

receiver/carbonreceiver/receiver.go

@@ -74,13 +74,6 @@ func New(
 		return nil, err
 	}
 
-	// This should be the last one built, or if any other error is raised after
-	// it, the server should be closed.
-	server, err := buildTransportServer(config)
-	if err != nil {
-		return nil, err
-	}
-
 	rep, err := newReporter(set)
 	if err != nil {
 		return nil, err
@@ -90,7 +83,6 @@ func New(
 		settings:     set,
 		config:       &config,
 		nextConsumer: nextConsumer,
-		server:       server,
 		reporter:     rep,
 		parser:       parser,
 	}
@@ -113,6 +105,11 @@ func buildTransportServer(config Config) (transport.Server, error) {
 // By convention the consumer of the received data is set when the receiver
 // instance is created.
 func (r *carbonReceiver) Start(_ context.Context, host component.Host) error {
+	server, err := buildTransportServer(*r.config)
+	if err != nil {
+		return err
+	}
+	r.server = server
 	go func() {
 		if err := r.server.ListenAndServe(r.parser, r.nextConsumer, r.reporter); err != nil {
 			host.ReportFatalError(err)
@@ -124,5 +121,8 @@ func (r *carbonReceiver) Start(_ context.Context, host component.Host) error {
 // Shutdown tells the receiver that should stop reception,
 // giving it a chance to perform any necessary clean-up.
 func (r *carbonReceiver) Shutdown(context.Context) error {
+	if r.server == nil {
+		return nil
+	}
 	return r.server.Close()
 }

receiver/carbonreceiver/receiver_test.go

@@ -84,43 +84,68 @@ func Test_carbonreceiver_New(t *testing.T) {
 			wantErr: errEmptyEndpoint,
 		},
 		{
-			name: "invalid_transport",
+			name: "regex_parser",
 			args: args{
 				config: Config{
 					NetAddr: confignet.NetAddr{
 						Endpoint:  "localhost:2003",
-						Transport: "unknown_transp",
+						Transport: "tcp",
 					},
 					Parser: &protocol.Config{
-						Type:   "plaintext",
-						Config: &protocol.PlaintextConfig{},
+						Type: "regex",
+						Config: &protocol.RegexParserConfig{
+							Rules: []*protocol.RegexRule{
+								{
+									Regexp: `(?P<key_root>[^.]*)\.test`,
+								},
+							},
+						},
 					},
 				},
 				nextConsumer: consumertest.NewNop(),
 			},
-			wantErr: errors.New("unsupported transport \"unknown_transp\""),
 		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := New(receivertest.NewNopCreateSettings(), tt.args.config, tt.args.nextConsumer)
+			assert.Equal(t, tt.wantErr, err)
+			if err == nil {
+				require.NotNil(t, got)
+				assert.NoError(t, got.Shutdown(context.Background()))
+			} else {
+				assert.Nil(t, got)
+			}
+		})
+	}
+}
+
+func Test_carbonreceiver_Start(t *testing.T) {
+	type args struct {
+		config       Config
+		nextConsumer consumer.Metrics
+	}
+	tests := []struct {
+		name    string
+		args    args
+		wantErr error
+	}{
 		{
-			name: "regex_parser",
+			name: "invalid_transport",
 			args: args{
 				config: Config{
 					NetAddr: confignet.NetAddr{
 						Endpoint:  "localhost:2003",
-						Transport: "tcp",
+						Transport: "unknown_transp",
 					},
 					Parser: &protocol.Config{
-						Type: "regex",
-						Config: &protocol.RegexParserConfig{
-							Rules: []*protocol.RegexRule{
-								{
-									Regexp: `(?P<key_root>[^.]*)\.test`,
-								},
-							},
-						},
+						Type:   "plaintext",
+						Config: &protocol.PlaintextConfig{},
 					},
 				},
 				nextConsumer: consumertest.NewNop(),
 			},
+			wantErr: errors.New("unsupported transport \"unknown_transp\""),
 		},
 		{
 			name: "negative_tcp_idle_timeout",
@@ -144,13 +169,10 @@ func Test_carbonreceiver_New(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			got, err := New(receivertest.NewNopCreateSettings(), tt.args.config, tt.args.nextConsumer)
+			require.NoError(t, err)
+			err = got.Start(context.Background(), componenttest.NewNopHost())
 			assert.Equal(t, tt.wantErr, err)
-			if err == nil {
-				require.NotNil(t, got)
-				assert.NoError(t, got.Shutdown(context.Background()))
-			} else {
-				assert.Nil(t, got)
-			}
+			assert.NoError(t, got.Shutdown(context.Background()))
 		})
 	}
 }