Parse more value types

* Parse bools as 0 for false and 1 for true
* Allow mapping between string and float values

config.yaml.dist

@@ -11,7 +11,7 @@ mqtt:
   qos: 0
 cache:
   # Timeout. Each received metric will be presented for this time if no update is send via MQTT
-  timeout: 2min
+  timeout: 2m
 # This is a list of valid metrics. Only metrics listed here will be exported
 metrics:
     # The name of the metric in prometheus
@@ -46,4 +46,23 @@ metrics:
     type: gauge
     # A map of string to string for constant labels. This labels will be attached to every prometheus metric
     const_labels:
-      sensor_type: dht22
+      sensor_type: dht22
+  - prom_name: state
+    # The name of the metric in a MQTT JSON message
+    mqtt_name: state
+    # The prometheus help text for this metric
+    help: Light state
+    # The prometheus type for this metric. Valid values are: "gauge" and "counter"
+    type: gauge
+    # A map of string to string for constant labels. This labels will be attached to every prometheus metric
+    const_labels:
+      sensor_type: ikea
+    # When specified, enables mapping between string values to metric values.
+    string_value_mapping:
+      # A map of string to metric value.
+      map:
+        off: 0
+        low: 0
+      # Metric value to use if a match cannot be found in the map above.
+      # If not specified, parsing error will occur.
+      error_value: 1

pkg/config/config.go

@@ -1,8 +1,9 @@
 package config
 
 import (
-	"time"
 	"io/ioutil"
+	"time"
+
 	"github.com/prometheus/client_golang/prometheus"
 	"gopkg.in/yaml.v2"
 )
@@ -40,11 +41,19 @@ type MQTTConfig struct {
 
 // Metrics Config is a mapping between a metric send on mqtt to a prometheus metric
 type MetricConfig struct {
-	PrometheusName string            `yaml:"prom_name"`
-	MQTTName       string            `yaml:"mqtt_name"`
-	Help           string            `yaml:"help"`
-	ValueType      string            `yaml:"type"`
-	ConstantLabels map[string]string `yaml:"const_labels"`
+	PrometheusName     string                    `yaml:"prom_name"`
+	MQTTName           string                    `yaml:"mqtt_name"`
+	Help               string                    `yaml:"help"`
+	ValueType          string                    `yaml:"type"`
+	ConstantLabels     map[string]string         `yaml:"const_labels"`
+	StringValueMapping *StringValueMappingConfig `yaml:"string_value_mapping"`
+}
+
+// StringValueMappingConfig defines the mapping between from string to float
+type StringValueMappingConfig struct {
+	// ErrorValue is used when no mapping is found in Map
+	ErrorValue *float64           `yaml:"error_value"`
+	Map        map[string]float64 `yaml:"map"`
 }
 
 func (mc *MetricConfig) PrometheusDescription() *prometheus.Desc {

pkg/metrics/ingest.go

@@ -45,30 +45,55 @@ func (i *Ingest) store(deviceID string, rawMetrics MQTTPayload) error {
 	var mc MetricCollection
 
 	for metricName, value := range rawMetrics {
-		if cfg, found := i.validMetrics[metricName]; found {
-			var floatValue float64
-			var isFloat bool
-			var err error
-			floatValue, isFloat = value.(float64)
-			if !isFloat {
-				stringValue, isString := value.(string)
+		cfg, cfgFound := i.validMetrics[metricName]
+		if !cfgFound {
+			continue
+		}
 
-				if !isString || ! validNumber.MatchString(stringValue) {
-					return fmt.Errorf("got data with unexpectd type: %T ('%s')", value, value)
+		var metricValue float64
+
+		if boolValue, ok := value.(bool); ok {
+			if boolValue {
+				metricValue = 1
+			} else {
+				metricValue = 0
+			}
+		} else if strValue, ok := value.(string); ok {
+
+			// If string value mapping is defined, use that
+			if cfg.StringValueMapping != nil {
+
+				floatValue, ok := cfg.StringValueMapping.Map[strValue]
+				if ok {
+					metricValue = floatValue
+				} else if cfg.StringValueMapping.ErrorValue != nil {
+					metricValue = *cfg.StringValueMapping.ErrorValue
+				} else {
+					return fmt.Errorf("got unexpected string data '%s'", strValue)
 				}
 
-				floatValue, err = strconv.ParseFloat(stringValue, 64)
+			} else {
+
+				// otherwise try to parse float
+				floatValue, err := strconv.ParseFloat(strValue, 64)
 				if err != nil {
 					return fmt.Errorf("got data with unexpectd type: %T ('%s') and failed to parse to float", value, value)
 				}
+				metricValue = floatValue
+
 			}
 
-			mc = append(mc, Metric{
-				Description: cfg.PrometheusDescription(),
-				Value:       floatValue,
-				ValueType:   cfg.PrometheusValueType(),
-			})
+		} else if floatValue, ok := value.(float64); ok {
+			metricValue = floatValue
+		} else {
+			return fmt.Errorf("got data with unexpectd type: %T ('%s')", value, value)
 		}
+
+		mc = append(mc, Metric{
+			Description: cfg.PrometheusDescription(),
+			Value:       metricValue,
+			ValueType:   cfg.PrometheusValueType(),
+		})
 	}
 	i.collector.Observe(deviceID, mc)
 	return nil