Add way to change default separator for json pathes

.gitignore

@@ -2,3 +2,4 @@ config.yaml
 bin/
 vendor
 dist
+.vscode

cmd/mqtt2prometheus.go

@@ -211,7 +211,7 @@ func setupGoKitLogger(l *zap.Logger) log.Logger {
 }
 
 func setupExtractor(cfg config.Config) (metrics.Extractor, error) {
-	parser := metrics.NewParser(cfg.Metrics)
+	parser := metrics.NewParser(cfg.Metrics, cfg.JsonParsing.Separator)
 	if cfg.MQTT.ObjectPerTopicConfig != nil {
 		switch cfg.MQTT.ObjectPerTopicConfig.Encoding {
 		case config.EncodingJSON:

config.yaml.dist

@@ -25,6 +25,11 @@ cache:
   # Set the timeout to -1 to disable the deletion of metrics from the cache. The exporter presents the ingest timestamp
   # to prometheus.
   timeout: 24h
+json_parsing:
+  # Separator. Used to split path to elements when accessing json fields.
+  # You can access json fields with dots in it. F.E. {"key.name": {"nested": "value"}}
+  # Just set separator to -> and use key.name->nested as mqtt_name
+  separator: .
 # This is a list of valid metrics. Only metrics listed here will be exported
 metrics:
     # The name of the metric in prometheus

fuzzing/json_per_topic/fuzz.go

@@ -28,7 +28,7 @@ func Fuzz(data []byte) int {
 			PrometheusName: "kartoffeln",
 			ValueType:      "counter",
 		},
-	})
+	}, ".")
 	json := metrics.NewJSONObjectExtractor(p)
 	mc, err := json("foo", data, "bar")
 	if err != nil && len(mc) > 0 {

pkg/config/config.go

@@ -29,6 +29,10 @@ var CacheConfigDefaults = CacheConfig{
 	Timeout: 2 * time.Minute,
 }
 
+var JsonParsingConfigDefaults = JsonParsingConfig{
+	Separator: ".",
+}
+
 type Regexp struct {
 	r       *regexp.Regexp
 	pattern string
@@ -83,15 +87,20 @@ func MustNewRegexp(pattern string) *Regexp {
 }
 
 type Config struct {
-	Metrics []MetricConfig `yaml:"metrics"`
-	MQTT    *MQTTConfig    `yaml:"mqtt,omitempty"`
-	Cache   *CacheConfig   `yaml:"cache,omitempty"`
+	JsonParsing *JsonParsingConfig `yaml:json_parsing,omitempty`
+	Metrics     []MetricConfig     `yaml:"metrics"`
+	MQTT        *MQTTConfig        `yaml:"mqtt,omitempty"`
+	Cache       *CacheConfig       `yaml:"cache,omitempty"`
 }
 
 type CacheConfig struct {
 	Timeout time.Duration `yaml:"timeout"`
 }
 
+type JsonParsingConfig struct {
+	Separator string `yaml:"separator"`
+}
+
 type MQTTConfig struct {
 	Server               string                `yaml:"server"`
 	TopicPath            string                `yaml:"topic_path"`
@@ -167,6 +176,9 @@ func LoadConfig(configFile string) (Config, error) {
 	if cfg.Cache == nil {
 		cfg.Cache = &CacheConfigDefaults
 	}
+	if cfg.JsonParsing == nil {
+		cfg.JsonParsing = &JsonParsingConfigDefaults
+	}
 	if cfg.MQTT.DeviceIDRegex == nil {
 		cfg.MQTT.DeviceIDRegex = MQTTConfigDefaults.DeviceIDRegex
 	}

pkg/metrics/extractor.go

@@ -3,6 +3,7 @@ package metrics
 import (
 	"errors"
 	"fmt"
+
 	"github.com/hikhvar/mqtt2prometheus/pkg/config"
 	gojsonq "github.com/thedevsaddam/gojsonq/v2"
 )
@@ -12,7 +13,7 @@ type Extractor func(topic string, payload []byte, deviceID string) (MetricCollec
 func NewJSONObjectExtractor(p Parser) Extractor {
 	return func(topic string, payload []byte, deviceID string) (MetricCollection, error) {
 		var mc MetricCollection
-		parsed := gojsonq.New().FromString(string(payload))
+		parsed := gojsonq.New(gojsonq.SetSeparator(p.separator)).FromString(string(payload))
 
 		for path := range p.config() {
 			rawValue := parsed.Find(path)

pkg/metrics/extractor_test.go

@@ -0,0 +1,103 @@
+package metrics
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/hikhvar/mqtt2prometheus/pkg/config"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+func TestNewJSONObjectExtractor_parseMetric(t *testing.T) {
+	now = testNow
+	type fields struct {
+		metricConfigs map[string][]config.MetricConfig
+	}
+	type args struct {
+		metricPath string
+		deviceID   string
+		value      string
+	}
+	tests := []struct {
+		name      string
+		separator string
+		fields    fields
+		args      args
+		want      Metric
+		wantErr   bool
+	}{
+		{
+			name:      "string value",
+			separator: "->",
+			fields: fields{
+				map[string][]config.MetricConfig{
+					"SDS0X1->PM2->5": []config.MetricConfig{
+						{
+							PrometheusName: "temperature",
+							MQTTName:       "SDS0X1.PM2.5",
+							ValueType:      "gauge",
+						},
+					},
+				},
+			},
+			args: args{
+				metricPath: "topic",
+				deviceID:   "dht22",
+				value:      "{\"SDS0X1\":{\"PM2\":{\"5\":4.9}}}",
+			},
+			want: Metric{
+				Description: prometheus.NewDesc("temperature", "", []string{"sensor", "topic"}, nil),
+				ValueType:   prometheus.GaugeValue,
+				Value:       4.9,
+				IngestTime:  testNow(),
+				Topic:       "topic",
+			},
+		}, {
+			name:      "string value with dots in path",
+			separator: "->",
+			fields: fields{
+				map[string][]config.MetricConfig{
+					"SDS0X1->PM2.5": []config.MetricConfig{
+						{
+							PrometheusName: "temperature",
+							MQTTName:       "SDS0X1->PM2.5",
+							ValueType:      "gauge",
+						},
+					},
+				},
+			},
+			args: args{
+				metricPath: "topic",
+				deviceID:   "dht22",
+				value:      "{\"SDS0X1\":{\"PM2.5\":4.9,\"PM10\":8.5}}",
+			},
+			want: Metric{
+				Description: prometheus.NewDesc("temperature", "", []string{"sensor", "topic"}, nil),
+				ValueType:   prometheus.GaugeValue,
+				Value:       4.9,
+				IngestTime:  testNow(),
+				Topic:       "topic",
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			p := Parser{
+				separator:     tt.separator,
+				metricConfigs: tt.fields.metricConfigs,
+			}
+			extractor := NewJSONObjectExtractor(p)
+
+			got, err := extractor(tt.args.metricPath, []byte(tt.args.value), tt.args.deviceID)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("parseMetric() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if len(got) != 1 {
+				t.Errorf("parseMetric() got = %v, want %v", nil, tt.want)
+			} else if !reflect.DeepEqual(got[0], tt.want) {
+				t.Errorf("parseMetric() got = %v, want %v", got[0], tt.want)
+			}
+		})
+	}
+}

pkg/metrics/parser.go

@@ -3,28 +3,31 @@ package metrics
 import (
 	"errors"
 	"fmt"
-	"github.com/hikhvar/mqtt2prometheus/pkg/config"
 	"strconv"
 	"time"
+
+	"github.com/hikhvar/mqtt2prometheus/pkg/config"
 )
 
 type metricNotConfiguredError error
 
 var metricNotConfigured metricNotConfiguredError = errors.New("metric not configured failed to parse")
 
 type Parser struct {
+	separator     string
 	metricConfigs map[string][]config.MetricConfig
 }
 
 var now = time.Now
 
-func NewParser(metrics []config.MetricConfig) Parser {
+func NewParser(metrics []config.MetricConfig, separator string) Parser {
 	cfgs := make(map[string][]config.MetricConfig)
 	for i := range metrics {
 		key := metrics[i].MQTTName
 		cfgs[key] = append(cfgs[key], metrics[i])
 	}
 	return Parser{
+		separator:     separator,
 		metricConfigs: cfgs,
 	}
 }