Dont append to slices in mergeStruct

agent.go

@@ -177,11 +177,7 @@ func (a *Agent) LoadPlugins(filters []string, config *Config) ([]string, error)
 
 	for name, plugin := range config.PluginsDeclared() {
 		if sliceContains(name, filters) || len(filters) == 0 {
-			config, err := config.ApplyPlugin(name, plugin)
-			if err != nil {
-				return nil, err
-			}
-
+			config := config.GetPluginConfig(name)
 			a.plugins = append(a.plugins, &runningPlugin{name, plugin, config})
 			names = append(names, name)
 		}

config.go

@@ -139,19 +139,8 @@ func (c *Config) ApplyAgent(a *Agent) error {
 	return nil
 }
 
-// ApplyPlugin loads the Plugin struct built from the config into the given Plugin struct.
-// Overrides only values in the given struct that were set in the config.
-// Additionally return a ConfiguredPlugin, which is always generated from the config.
-func (c *Config) ApplyPlugin(name string, v interface{}) (*ConfiguredPlugin, error) {
-	if c.plugins[name] != nil {
-		err := mergeStruct(v, c.plugins[name], c.pluginFieldsSet[name])
-		if err != nil {
-			return nil, err
-		}
-		return c.pluginConfigurations[name], nil
-	}
-
-	return nil, nil
+func (c *Config) GetPluginConfig(name string) *ConfiguredPlugin {
+	return c.pluginConfigurations[name]
 }
 
 // Couldn't figure out how to get this to work with the declared function.
@@ -405,11 +394,7 @@ func mergeStruct(base, overlay interface{}, fields []string) error {
 				overlayValue.Type(), field)
 		}
 		baseFieldValue := findField(field, baseValue)
-		if overlayFieldValue.Kind() == reflect.Slice {
-			baseFieldValue.Set(reflect.AppendSlice(baseFieldValue, overlayFieldValue))
-		} else {
-			baseFieldValue.Set(overlayFieldValue)
-		}
+		baseFieldValue.Set(overlayFieldValue)
 	}
 	return nil
 }

config_test.go

@@ -39,7 +39,8 @@ type MergeStructSuite struct {
 }
 
 func (s *MergeStructSuite) SetupSuite() {
-	s.AllFields = []string{"string_field", "integer_field", "float_field", "boolean_field", "date_time_field", "array_field", "table_array_field"}
+	s.AllFields = []string{"string_field", "integer_field", "float_field",
+		"boolean_field", "date_time_field", "array_field", "table_array_field"}
 }
 
 func (s *MergeStructSuite) SetupTest() {
@@ -90,7 +91,8 @@ func (s *MergeStructSuite) TestEmptyMerge() {
 	if err != nil {
 		s.T().Error(err)
 	}
-	s.Equal(s.FullStruct, s.EmptyStruct, fmt.Sprintf("Full merge of %v onto an empty struct failed.", s.FullStruct))
+	s.Equal(s.FullStruct, s.EmptyStruct,
+		fmt.Sprintf("Full merge of %v onto an empty struct failed.", s.FullStruct))
 }
 
 func (s *MergeStructSuite) TestFullMerge() {
@@ -100,16 +102,8 @@ func (s *MergeStructSuite) TestFullMerge() {
 		FloatField:    2.2,
 		BooleansField: true,
 		DatetimeField: time.Date(1965, time.March, 25, 17, 0, 0, 0, time.UTC),
-		ArrayField:    []string{"one", "two", "three", "four", "five", "six"},
+		ArrayField:    []string{"four", "five", "six"},
 		TableArrayField: []subTest{
-			subTest{
-				AField:       "one",
-				AnotherField: 1,
-			},
-			subTest{
-				AField:       "two",
-				AnotherField: 2,
-			},
 			subTest{
 				AField:       "three",
 				AnotherField: 3,
@@ -125,7 +119,8 @@ func (s *MergeStructSuite) TestFullMerge() {
 	if err != nil {
 		s.T().Error(err)
 	}
-	s.Equal(result, s.FullStruct, fmt.Sprintf("Full merge of %v onto FullStruct failed.", s.AnotherFullStruct))
+	s.Equal(result, s.FullStruct,
+		fmt.Sprintf("Full merge of %v onto FullStruct failed.", s.AnotherFullStruct))
 }
 
 func (s *MergeStructSuite) TestPartialMergeWithoutSlices() {
@@ -148,11 +143,14 @@ func (s *MergeStructSuite) TestPartialMergeWithoutSlices() {
 		},
 	}
 
-	err := mergeStruct(s.FullStruct, s.AnotherFullStruct, []string{"string_field", "float_field", "date_time_field"})
+	err := mergeStruct(s.FullStruct, s.AnotherFullStruct,
+		[]string{"string_field", "float_field", "date_time_field"})
 	if err != nil {
 		s.T().Error(err)
 	}
-	s.Equal(result, s.FullStruct, fmt.Sprintf("Partial merge without slices of %v onto FullStruct failed.", s.AnotherFullStruct))
+	s.Equal(result, s.FullStruct,
+		fmt.Sprintf("Partial merge without slices of %v onto FullStruct failed.",
+			s.AnotherFullStruct))
 }
 
 func (s *MergeStructSuite) TestPartialMergeWithSlices() {
@@ -164,14 +162,6 @@ func (s *MergeStructSuite) TestPartialMergeWithSlices() {
 		DatetimeField: time.Date(1965, time.March, 25, 17, 0, 0, 0, time.UTC),
 		ArrayField:    []string{"one", "two", "three"},
 		TableArrayField: []subTest{
-			subTest{
-				AField:       "one",
-				AnotherField: 1,
-			},
-			subTest{
-				AField:       "two",
-				AnotherField: 2,
-			},
 			subTest{
 				AField:       "three",
 				AnotherField: 3,
@@ -183,11 +173,14 @@ func (s *MergeStructSuite) TestPartialMergeWithSlices() {
 		},
 	}
 
-	err := mergeStruct(s.FullStruct, s.AnotherFullStruct, []string{"string_field", "float_field", "date_time_field", "table_array_field"})
+	err := mergeStruct(s.FullStruct, s.AnotherFullStruct,
+		[]string{"string_field", "float_field", "date_time_field", "table_array_field"})
 	if err != nil {
 		s.T().Error(err)
 	}
-	s.Equal(result, s.FullStruct, fmt.Sprintf("Partial merge with slices of %v onto FullStruct failed.", s.AnotherFullStruct))
+	s.Equal(result, s.FullStruct,
+		fmt.Sprintf("Partial merge with slices of %v onto FullStruct failed.",
+			s.AnotherFullStruct))
 }
 
 func TestConfig_mergeStruct(t *testing.T) {
@@ -240,8 +233,10 @@ func TestConfig_parsePlugin(t *testing.T) {
 		Interval: 5 * time.Second,
 	}
 
-	assert.Equal(t, kafka, c.plugins["kafka"], "Testdata did not produce a correct kafka struct.")
-	assert.Equal(t, kConfig, c.pluginConfigurations["kafka"], "Testdata did not produce correct kafka metadata.")
+	assert.Equal(t, kafka, c.plugins["kafka"],
+		"Testdata did not produce a correct kafka struct.")
+	assert.Equal(t, kConfig, c.pluginConfigurations["kafka"],
+		"Testdata did not produce correct kafka metadata.")
 }
 
 func TestConfig_LoadDirectory(t *testing.T) {
@@ -257,7 +252,7 @@ func TestConfig_LoadDirectory(t *testing.T) {
 	kafka := plugins.Plugins["kafka"]().(*kafka_consumer.Kafka)
 	kafka.ConsumerGroupName = "telegraf_metrics_consumers"
 	kafka.Topic = "topic_with_metrics"
-	kafka.ZookeeperPeers = []string{"localhost:2181", "test.example.com:2181"}
+	kafka.ZookeeperPeers = []string{"test.example.com:2181"}
 	kafka.BatchSize = 10000
 
 	kConfig := &ConfiguredPlugin{
@@ -281,10 +276,6 @@ func TestConfig_LoadDirectory(t *testing.T) {
 
 	ex := plugins.Plugins["exec"]().(*exec.Exec)
 	ex.Commands = []*exec.Command{
-		&exec.Command{
-			Command: "/usr/bin/mycollector --foo=bar",
-			Name:    "mycollector",
-		},
 		&exec.Command{
 			Command: "/usr/bin/myothercollector --foo=bar",
 			Name:    "myothercollector",
@@ -305,12 +296,18 @@ func TestConfig_LoadDirectory(t *testing.T) {
 
 	pConfig := &ConfiguredPlugin{Name: "procstat"}
 
-	assert.Equal(t, kafka, c.plugins["kafka"], "Merged Testdata did not produce a correct kafka struct.")
-	assert.Equal(t, kConfig, c.pluginConfigurations["kafka"], "Merged Testdata did not produce correct kafka metadata.")
+	assert.Equal(t, kafka, c.plugins["kafka"],
+		"Merged Testdata did not produce a correct kafka struct.")
+	assert.Equal(t, kConfig, c.pluginConfigurations["kafka"],
+		"Merged Testdata did not produce correct kafka metadata.")
 
-	assert.Equal(t, ex, c.plugins["exec"], "Merged Testdata did not produce a correct exec struct.")
-	assert.Equal(t, eConfig, c.pluginConfigurations["exec"], "Merged Testdata did not produce correct exec metadata.")
+	assert.Equal(t, ex, c.plugins["exec"],
+		"Merged Testdata did not produce a correct exec struct.")
+	assert.Equal(t, eConfig, c.pluginConfigurations["exec"],
+		"Merged Testdata did not produce correct exec metadata.")
 
-	assert.Equal(t, pstat, c.plugins["procstat"], "Merged Testdata did not produce a correct procstat struct.")
-	assert.Equal(t, pConfig, c.pluginConfigurations["procstat"], "Merged Testdata did not produce correct procstat metadata.")
+	assert.Equal(t, pstat, c.plugins["procstat"],
+		"Merged Testdata did not produce a correct procstat struct.")
+	assert.Equal(t, pConfig, c.pluginConfigurations["procstat"],
+		"Merged Testdata did not produce correct procstat metadata.")
 }

testdata/subconfig/procstat.conf

@@ -0,0 +1,5 @@
+[procstat]
+  [[procstat.specifications]]
+  pid_file = "/var/run/grafana-server.pid"
+  [[procstat.specifications]]
+  pid_file = "/var/run/influxdb/influxd.pid"