Drop mapstructure and report even more when options can't be parsed

Author: mstoykov

go.mod

@@ -7,7 +7,6 @@ require (
 	github.com/influxdata/influxdb1-client v0.0.0-20190402204710-8ff2fc3824fc
 	github.com/kelseyhightower/envconfig v1.4.0
 	github.com/kubernetes/helm v2.9.0+incompatible
-	github.com/mitchellh/mapstructure v1.1.2
 	github.com/sirupsen/logrus v1.8.1
 	github.com/stretchr/testify v1.7.0
 	github.com/xdg/scram v1.0.3

pkg/kafka/config.go

@@ -29,7 +29,6 @@ import (
 	"github.com/Shopify/sarama"
 	"github.com/kelseyhightower/envconfig"
 	"github.com/kubernetes/helm/pkg/strvals"
-	"github.com/mitchellh/mapstructure"
 	"gopkg.in/guregu/null.v3"
 
 	"go.k6.io/k6/lib/types"
@@ -55,12 +54,6 @@ type Config struct {
 	InfluxDBConfig influxdbConfig `json:"influxdb"`
 }
 
-// config is a duplicate of ConfigFields as we can not mapstructure.Decode into
-// null types so we duplicate the struct with primitive types to Decode into
-type config struct {
-	Brokers []string `mapstructure:"brokers"`
-}
-
 // NewConfig creates a new Config instance with default values for some fields.
 func NewConfig() Config {
 	return Config{
@@ -186,29 +179,38 @@ func ParseArg(arg string) (Config, error) {
 		delete(params, "format")
 	}
 
-	var cfg config
 	if v, ok := params["brokers"].(string); ok {
-		params["brokers"] = []string{v}
+		c.Brokers = []string{v}
+
+		delete(params, "brokers")
 	}
-	err = mapstructure.Decode(params, &cfg)
-	if err != nil {
-		return c, err
+	if v, ok := params["brokers"].([]interface{}); ok {
+		c.Brokers = interfaceSliceToStringSlice(v)
+		delete(params, "brokers")
 	}
-	delete(params, "brokers")
-
-	c.Brokers = cfg.Brokers
 
 	if len(params) > 0 {
-		var s string
-		for k, v := range params {
-			s += fmt.Sprintf("%s=%v,", k, v)
-		}
-		s = s[:len(s)-1]
-		return c, errors.New("Unknown or unparsed options '" + s + "'")
+		return c, errors.New("Unknown or unparsed options '" + mapToString(params) + "'")
 	}
 	return c, nil
 }
 
+func mapToString(m map[string]interface{}) string {
+	var s string
+	for k, v := range m {
+		s += fmt.Sprintf("%s=%v,", k, v)
+	}
+	return s[:len(s)-1]
+}
+
+func interfaceSliceToStringSlice(input []interface{}) []string {
+	output := make([]string, len(input))
+	for i, v := range input {
+		output[i] = fmt.Sprintf("%v", v)
+	}
+	return output
+}
+
 // GetConsolidatedConfig combines {default config values + JSON config +
 // environment vars + arg config values}, and returns the final result.
 func GetConsolidatedConfig(jsonRawConf json.RawMessage, env map[string]string, arg string) (Config, error) {

pkg/kafka/config_test.go

@@ -137,6 +137,10 @@ func TestConfigParseArg(t *testing.T) {
 	c, err = ParseArg("ssl=nottrue")
 	assert.Error(t, err)
 	assert.Contains(t, err.Error(), `Unknown or unparsed options 'ssl=nottrue'`)
+
+	c, err = ParseArg("brokers={broker2,broker3:9092},topic=someTopic,format=influxdb,influxdb.tagsAsFields=fake,influxdb.something=else")
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), `Unknown or unparsed options 'something=else'`)
 }
 
 func TestConsolidatedConfig(t *testing.T) {

pkg/kafka/format_influxdb.go

@@ -21,14 +21,13 @@
 package kafka
 
 import (
+	"errors"
 	"fmt"
 	"strconv"
 	"strings"
 
 	client "github.com/influxdata/influxdb1-client/v2"
-	"github.com/mitchellh/mapstructure"
 	"github.com/sirupsen/logrus"
-	"go.k6.io/k6/lib/types"
 	"go.k6.io/k6/stats"
 )
 
@@ -172,18 +171,17 @@ func (c influxdbConfig) Apply(cfg influxdbConfig) influxdbConfig {
 func influxdbParseMap(m map[string]interface{}) (influxdbConfig, error) {
 	c := influxdbConfig{}
 	if v, ok := m["tagsAsFields"].(string); ok {
-		m["tagsAsFields"] = []string{v}
+		c.TagsAsFields = []string{v}
+		delete(m, "tagsAsFields")
 	}
-	dec, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{
-		DecodeHook: types.NullDecoder,
-		Result:     &c,
-	})
-	if err != nil {
-		return c, err
+	if v, ok := m["tagsAsFields"].([]interface{}); ok {
+		c.TagsAsFields = interfaceSliceToStringSlice(v)
+		delete(m, "tagsAsFields")
 	}
-
-	err = dec.Decode(m)
-	return c, err
+	if len(m) > 0 {
+		return c, errors.New("Unknown or unparsed options '" + mapToString(m) + "'")
+	}
+	return c, nil
 }
 
 type influxdbConfig struct {