Merge pull request #143 from chrschn/expressions

Expressions

Readme.md

@@ -251,6 +251,32 @@ metrics:
     # If not specified, parsing error will occur.
     error_value: 1
   # The name of the metric in prometheus
+ - prom_name: total_light_usage_seconds
+  # The name of the metric in a MQTT JSON message
+   mqtt_name: state
+  # Regular expression to only match sensors with the given name pattern
+   sensor_name_filter: "^.*-light$"
+  # The prometheus help text for this metric
+   help: Total time the light was on, in seconds
+  # The prometheus type for this metric. Valid values are: "gauge" and "counter"
+   type: counter
+  # according to prometheus exposition format timestamp is not mandatory, we can omit it if the reporting from the sensor is sporadic
+   omit_timestamp: true
+  # 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
+  # Sum up the time the light is on, see the section "Expressions" below.
+  expression: "value > 0 ? last_result + elapsed.Seconds() : last_result"
+  # The name of the metric in prometheus
  - prom_name: total_energy
   # The name of the metric in a MQTT JSON message
    mqtt_name: aenergy.total
@@ -260,9 +286,8 @@ metrics:
    help: Total energy used
   # The prometheus type for this metric. Valid values are: "gauge" and "counter"
    type: counter
-  # This setting requires an almost monotonic counter as the source. When monotonicy is enforced, the metric value is regularly written to disk. Thus, resets in the source counter can be detected and corrected by adding an offset as if the reset did not happen. The result is a strict monotonic increasing time series, like an ever growing counter.
+  # This setting requires an almost monotonic counter as the source. When monotonicy is enforced, the metric value is regularly written to disk. Thus, resets in the source counter can be detected and corrected by adding an offset as if the reset did not happen. The result is a true monotonic increasing time series, like an ever growing counter.
    force_monotonicy: true
-
 ```
 
 ### Environment Variables
@@ -308,7 +333,43 @@ Create a docker secret to store the password(`mqtt-credential` in the example be
         - config-tasmota.yml:/config.yaml:ro
 ```
 
+### Expressions
+
+Metric values can be derived from sensor inputs using complex expressions. Set the metric config option `expression` to the desired formular to calculate the result from the input. Here's an example which integrates all positive values over time:
+
+```yaml
+expression: "value > 0 ? last_result + value * elapsed.Seconds() : last_result"
+```
+
+During the evaluation, the following variables are available to the expression:
+* `value` - the current sensor value (after string-value mapping, if configured)
+* `last_value` - the `value` during the previous expression evaluation
+* `last_result` - the result from the previous expression evaluation
+* `elapsed` - the time that passed since the previous evaluation, as a [Duration](https://pkg.go.dev/time#Duration) value
+
+The [language definition](https://expr-lang.org/docs/v1.9/Language-Definition) describes the expression syntax. In addition, the following functions are available:
+* `now()` - the current time as a [Time](https://pkg.go.dev/time#Time) value
+* `int(x)` - convert `x` to an integer value
+* `float(x)` - convert `x` to a floating point value
+* `round(x)` - rounds value `x` to the nearest integer
+* `ceil(x)` - rounds value `x` up to the next higher integer
+* `floor(x)` - rounds value `x` down to the next lower integer
+* `abs(x)` - returns the `x` as a positive number
+* `min(x, y)` - returns the minimum of `x` and `y`
+* `max(x, y)` - returns the maximum of `x` and `y`
+
+[Time](https://pkg.go.dev/time#Time) and [Duration](https://pkg.go.dev/time#Duration) values come with their own methods which can be used in expressions. For example, `elapsed.Milliseconds()` yields the number of milliseconds that passed since the last evaluation, while `now().Sub(elapsed).Weekday()` returns the day of the week during the previous evaluation.
+
+The `last_value`, `last_result`, and the timestamp of the last evaluation are regularly stored on disk. When mqtt2prometheus is restarted, the data is read back for the next evaluation. This means that you can calculate stable, long-running time serious which depend on the previous result.
+
+#### Evaluation Order
+
+It is important to understand the sequence of transformations from a sensor input to the final output which is exported to Prometheus. The steps are as follows:
 
+1. The sensor input is converted to a number. If a `string_value_mapping` is configured, it is consulted for the conversion.
+1. If an `expression` is configured, it is evaluated using the converted number. The result of the evaluation replaces the converted sensor value.
+1. If `force_monotonicy` is set to `true`, any new value that is smaller than the previous one is considered to be a counter reset. When a reset is detected, the previous value becomes the value offset which is automatically added to each consecutive value. The offset is persistet between restarts of mqtt2prometheus.
+1. If `mqtt_value_scale` is set to a non-zero value, it is applied to the the value to yield the final metric value.
 
 ## Frequently Asked Questions
 

go.mod

@@ -3,6 +3,7 @@ module github.com/hikhvar/mqtt2prometheus
 go 1.14
 
 require (
+	github.com/antonmedv/expr v1.8.9
 	github.com/eclipse/paho.mqtt.golang v1.3.5
 	github.com/go-kit/kit v0.10.0
 	github.com/patrickmn/go-cache v2.1.0+incompatible

go.sum

@@ -34,6 +34,7 @@ dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7
 github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
+github.com/DATA-DOG/go-sqlmock v1.3.3/go.mod h1:f/Ixk793poVmq4qj/V1dPUg2JEAKC73Q5eFN3EC/SaM=
 github.com/Knetic/govaluate v3.0.1-0.20171022003610-9aa49832a739+incompatible/go.mod h1:r7JcOSlj0wfOMncg0iLm8Leh48TZaKVeNIfJntJ2wa0=
 github.com/Shopify/sarama v1.19.0/go.mod h1:FVkBWblsNy7DGZRfXLU0O9RCGt5g3g3yEuWXgklEdEo=
 github.com/Shopify/toxiproxy v2.1.4+incompatible/go.mod h1:OXgGpZ6Cli1/URJOF1DMxUHB2q5Ap20/P/eIdh4G0pI=
@@ -44,6 +45,8 @@ github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751/go.mod h1:LOuy
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/alecthomas/units v0.0.0-20190717042225-c3de453c63f4/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d/go.mod h1:rBZYJk541a8SKzHPHnH3zbiI+7dagKZ0cgpgrD7Fyho=
+github.com/antonmedv/expr v1.8.9 h1:O9stiHmHHww9b4ozhPx7T6BK7fXfOCHJ8ybxf0833zw=
+github.com/antonmedv/expr v1.8.9/go.mod h1:5qsM3oLGDND7sDmQGDXHkYfkjYMUX14qsgqmHhwGEk8=
 github.com/apache/thrift v0.12.0/go.mod h1:cp2SuWMxlEZw2r+iP2GNCdIi4C1qmUzdZFSVb+bacwQ=
 github.com/apache/thrift v0.13.0/go.mod h1:cp2SuWMxlEZw2r+iP2GNCdIi4C1qmUzdZFSVb+bacwQ=
 github.com/armon/circbuf v0.0.0-20150827004946-bbbad097214e/go.mod h1:3U/XgcO3hCbHZ8TKRvWD2dDTCfh9M9ya+I9JpbB7O8o=
@@ -76,6 +79,7 @@ github.com/coreos/go-systemd v0.0.0-20180511133405-39ca1b05acc7/go.mod h1:F5haX7
 github.com/coreos/pkg v0.0.0-20160727233714-3ac0863d7acf/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/creack/pty v1.1.7/go.mod h1:lj5s0c3V2DBrqTV7llrYr5NG6My20zk30Fl46Y7DoTY=
+github.com/davecgh/go-spew v0.0.0-20161028175848-04cdfd42973b/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -96,6 +100,8 @@ github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5Kwzbycv
 github.com/franela/goblin v0.0.0-20200105215937-c9ffbefa60db/go.mod h1:7dvUGVsVBjqR7JHJk0brhHOZYGmfBYOrK0ZhYMEtBr4=
 github.com/franela/goreq v0.0.0-20171204163338-bcd34c9993f8/go.mod h1:ZhphrRTfi2rbfLwlschooIH4+wKKDR4Pdxhh+TRoA20=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
+github.com/gdamore/encoding v1.0.0/go.mod h1:alR0ol34c49FCSBLjhosxzcPHQbf2trDkoo5dl+VrEg=
+github.com/gdamore/tcell v1.3.0/go.mod h1:Hjvr+Ofd+gLglo7RYKxxnzCBmev3BzsS67MebKS4zMM=
 github.com/ghodss/yaml v1.0.0/go.mod h1:4dBDuWmgqj2HViK6kFavaiC9ZROes6MMH2rRYeMEF04=
 github.com/go-gl/glfw v0.0.0-20190409004039-e6da0acd62b1/go.mod h1:vR7hzQXu2zJy9AVAgeJqvqgH9Q5CA+iKCZ2gyEVpxRU=
 github.com/go-gl/glfw/v3.3/glfw v0.0.0-20191125211704-12ad95a8df72/go.mod h1:tQ2UAYgL5IevRw8kRxooKSPJfGvJ9fJQFa0TUsXzTg8=
@@ -232,11 +238,15 @@ github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/lightstep/lightstep-tracer-common/golang/gogo v0.0.0-20190605223551-bc2310a04743/go.mod h1:qklhhLq1aX+mtWk9cPHPzaBjWImj5ULL6C7HFJtXQMM=
 github.com/lightstep/lightstep-tracer-go v0.18.1/go.mod h1:jlF1pusYV4pidLvZ+XD0UBX0ZE6WURAspgAczcDHrL4=
+github.com/lucasb-eyer/go-colorful v1.0.2/go.mod h1:0MS4r+7BZKSJ5mw4/S5MPN+qHFF1fYclkSPilDOKW0s=
+github.com/lucasb-eyer/go-colorful v1.0.3/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
 github.com/lyft/protoc-gen-validate v0.0.13/go.mod h1:XbGvPuh87YZc5TdIa2/I4pLk0QoUACkjt2znoq26NVQ=
 github.com/mattn/go-colorable v0.0.9/go.mod h1:9vuHe8Xs5qXnSaW/c/ABM9alt+Vo+STaOChaDxuIBZU=
 github.com/mattn/go-isatty v0.0.3/go.mod h1:M+lRXTBqGeGNdLjl/ufCoiOlB5xdOkqRJdNxMWT7Zi4=
 github.com/mattn/go-isatty v0.0.4/go.mod h1:M+lRXTBqGeGNdLjl/ufCoiOlB5xdOkqRJdNxMWT7Zi4=
 github.com/mattn/go-runewidth v0.0.2/go.mod h1:LwmH8dsx7+W8Uxz3IHJYH5QSwggIsqBzpuz5H//U1FU=
+github.com/mattn/go-runewidth v0.0.4/go.mod h1:LwmH8dsx7+W8Uxz3IHJYH5QSwggIsqBzpuz5H//U1FU=
+github.com/mattn/go-runewidth v0.0.8/go.mod h1:H031xJmbD/WCDINGzjvQ9THkh0rPKHF+m2gUSrubnMI=
 github.com/matttproud/golang_protobuf_extensions v1.0.1 h1:4hp9jkHxhMHkqkrB3Ix0jegS5sx/RkqARlsWZ6pIwiU=
 github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
 github.com/miekg/dns v1.0.14/go.mod h1:W1PPwlIAgtquWBMBEV9nkV9Cazfe8ScdGz/Lj7v3Nrg=
@@ -289,6 +299,7 @@ github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINE
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/profile v1.2.1/go.mod h1:hJw3o1OdXxsrSjjVksARp5W95eeEaEfptyVZyv6JUPA=
+github.com/pmezard/go-difflib v0.0.0-20151028094244-d8ed2627bdf0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/posener/complete v1.1.1/go.mod h1:em0nMJCgc9GFtwrmVmEMR/ZL6WyhyjMBndrE9hABlRI=
@@ -324,11 +335,14 @@ github.com/prometheus/procfs v0.1.3/go.mod h1:lV6e/gmhEcM9IjHGsFOCxxuZ+z1YqCvr4O
 github.com/prometheus/procfs v0.6.0 h1:mxy4L2jP6qMonqmq+aTtOx1ifVWUgG/TAmntgbh3xv4=
 github.com/prometheus/procfs v0.6.0/go.mod h1:cz+aTbrPOrUb4q7XlbU9ygM+/jj0fzG6c1xBZuNvfVA=
 github.com/rcrowley/go-metrics v0.0.0-20181016184325-3113b8401b8a/go.mod h1:bCqnVzQkZxMG4s8nGwiZ5l3QUCyqpo9Y+/ZMZ9VjZe4=
+github.com/rivo/tview v0.0.0-20200219210816-cd38d7432498/go.mod h1:6lkG1x+13OShEf0EaOCaTQYyB7d5nSbb181KtjlS+84=
+github.com/rivo/uniseg v0.1.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
 github.com/rogpeppe/fastuuid v0.0.0-20150106093220-6724a57986af/go.mod h1:XWv6SoW27p1b0cqNHllgS5HIMJraePCO15w5zCzIWYg=
 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
 github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/ryanuber/columnize v0.0.0-20160712163229-9b3edd62028f/go.mod h1:sm1tb6uqfes/u+d4ooFouqFdy9/2g9QGwK3SQygK0Ts=
 github.com/samuel/go-zookeeper v0.0.0-20190923202752-2cc03de413da/go.mod h1:gi+0XIa01GRL2eRQVjQkKGqKF3SF9vZR/HnPullcV2E=
+github.com/sanity-io/litter v1.2.0/go.mod h1:JF6pZUFgu2Q0sBZ+HSV35P8TVPI1TTzEwyu9FXAw2W4=
 github.com/sean-/seed v0.0.0-20170313163322-e2103e2c3529/go.mod h1:DxrIzT+xaE7yg65j358z/aeFdxmN0P9QXhEzd20vsDc=
 github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
@@ -345,10 +359,13 @@ github.com/streadway/amqp v0.0.0-20190827072141-edfb9018d271/go.mod h1:AZpEONHx3
 github.com/streadway/handy v0.0.0-20190108123426-d5acb3125c2a/go.mod h1:qNTQ5P5JnDBl6z3cMAg/SywNDC5ABu5ApDIw6lUbRmI=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v0.0.0-20161117074351-18a02ba4a312/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H4=
+github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
 github.com/thedevsaddam/gojsonq/v2 v2.5.2 h1:CoMVaYyKFsVj6TjU6APqAhAvC07hTI6IQen8PHzHYY0=
 github.com/thedevsaddam/gojsonq/v2 v2.5.2/go.mod h1:bv6Xa7kWy82uT0LnXPE2SzGqTj33TAEeR560MdJkiXs=
 github.com/tmc/grpc-websocket-proxy v0.0.0-20170815181823-89b8d40f7ca8/go.mod h1:ncp9v5uamzpCO7NfCPTXjqaC+bZgJeR0sMTm6dMHP7U=
@@ -493,6 +510,7 @@ golang.org/x/sys v0.0.0-20190502145724-3ef323f4f1fd/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20190507160741-ecd444e8653b/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190606165138-5da285871e9c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190624142023-c5567b49c5d0/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190626150813-e07cf5db2756/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190726091711-fc99dfbffb4e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190826190057-c7b8b68b1456/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191001151750-bb3f8db39f24/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

pkg/config/config.go

@@ -138,6 +138,7 @@ type MetricConfig struct {
 	Help               string                    `yaml:"help"`
 	ValueType          string                    `yaml:"type"`
 	OmitTimestamp      bool                      `yaml:"omit_timestamp"`
+	Expression         string                    `yaml:"expression"`
 	ForceMonotonicy    bool                      `yaml:"force_monotonicy"`
 	ConstantLabels     map[string]string         `yaml:"const_labels"`
 	StringValueMapping *StringValueMappingConfig `yaml:"string_value_mapping"`
@@ -233,7 +234,7 @@ func LoadConfig(configFile string) (Config, error) {
 	}
 	if forcesMonotonicy {
 		if err := os.MkdirAll(cfg.Cache.StateDir, 0755); err != nil {
-			return Config{}, err
+			return Config{}, fmt.Errorf("failed to create directory %q: %w", cfg.Cache.StateDir, err)
 		}
 	}
 

pkg/metrics/extractor.go

@@ -32,55 +32,51 @@ func NewJSONObjectExtractor(p Parser) Extractor {
 				continue
 			}
 
-			// Find a valid metrics config
-			config, found := p.findMetricConfig(path, deviceID)
-			if !found {
-				continue
-			}
-
-			id := metricID(topic, path, deviceID, config.PrometheusName)
-			m, err := p.parseMetric(config, id, rawValue)
-			if err != nil {
-				return nil, fmt.Errorf("failed to parse valid metric value: %w", err)
+			// Find all valid metric configs
+			for _, config := range p.findMetricConfigs(path, deviceID) {
+				id := metricID(topic, path, deviceID, config.PrometheusName)
+				m, err := p.parseMetric(config, id, rawValue)
+				if err != nil {
+					return nil, fmt.Errorf("failed to parse valid value from '%v' for metric %q: %w", rawValue, config.PrometheusName, err)
+				}
+				m.Topic = topic
+				mc = append(mc, m)
 			}
-			m.Topic = topic
-			mc = append(mc, m)
 		}
 		return mc, nil
 	}
 }
 
 func NewMetricPerTopicExtractor(p Parser, metricNameRegex *config.Regexp) Extractor {
 	return func(topic string, payload []byte, deviceID string) (MetricCollection, error) {
+		var mc MetricCollection
 		metricName := metricNameRegex.GroupValue(topic, config.MetricNameRegexGroup)
 		if metricName == "" {
 			return nil, fmt.Errorf("failed to find valid metric in topic path")
 		}
 
-		// Find a valid metrics config
-		config, found := p.findMetricConfig(metricName, deviceID)
-		if !found {
-			return nil, nil
-		}
-
-		var rawValue interface{}
-		if config.PayloadField != "" {
-			parsed := gojsonq.New(gojsonq.SetSeparator(p.separator)).FromString(string(payload))
-			rawValue = parsed.Find(config.PayloadField)
-			parsed.Reset()
-			if rawValue == nil {
-				return nil, fmt.Errorf("failed to extract field %s from payload %s", config.PayloadField, payload)
+		// Find all valid metric configs
+		for _, config := range p.findMetricConfigs(metricName, deviceID) {
+			var rawValue interface{}
+			if config.PayloadField != "" {
+				parsed := gojsonq.New(gojsonq.SetSeparator(p.separator)).FromString(string(payload))
+				rawValue = parsed.Find(config.PayloadField)
+				parsed.Reset()
+				if rawValue == nil {
+					return nil, fmt.Errorf("failed to extract field %q from payload %q for metric %q", config.PayloadField, payload, metricName)
+				}
+			} else {
+				rawValue = string(payload)
 			}
-		} else {
-			rawValue = string(payload)
-		}
 
-		id := metricID(topic, metricName, deviceID, config.PrometheusName)
-		m, err := p.parseMetric(config, id, rawValue)
-		if err != nil {
-			return nil, fmt.Errorf("failed to parse metric: %w", err)
+			id := metricID(topic, metricName, deviceID, config.PrometheusName)
+			m, err := p.parseMetric(config, id, rawValue)
+			if err != nil {
+				return nil, fmt.Errorf("failed to parse valid value from '%v' for metric %q: %w", rawValue, config.PrometheusName, err)
+			}
+			m.Topic = topic
+			mc = append(mc, m)
 		}
-		m.Topic = topic
-		return MetricCollection{m}, nil
+		return mc, nil
 	}
 }