[processor/deltatocumulative]: mdatagen telemetry

Uses recently introducted `telemetry:` feature of `mdatagen` to define
the internal telemetry exported from this component.

Leaves the general `telemetry` package in-place, as it also does error
handling (for now). Changing so requires a deeper refactor that will be
done later

processor/deltatocumulativeprocessor/README.md

@@ -36,15 +36,5 @@ There is no further configuration required. All delta samples are converted to c
 
 ## Troubleshooting
 
-The following metrics are recorded when [telemetry is
-enabled](https://opentelemetry.io/docs/collector/configuration/#telemetry):
-
-| Name                                     | Description                                                                           | Unit          |
-|------------------------------------------|---------------------------------------------------------------------------------------|---------------|
-| `deltatocumulative.streams.tracked`      | Number of streams currently tracked by the aggregation state                          | `{stream}`    |
-| `deltatocumulative.streams.limit`        | Upper limit of tracked streams                                                        | `{stream}`    |
-| `deltatocumulative.streams.evicted`      | Number of streams removed from tracking to ingest newer streams                       | `{stream}`    |
-| `deltatocumulative.streams.max_stale`    | Duration without new samples after which streams are dropped                          | `second`      |
-| `deltatocumulative.datapoints.processed` | Total number of datapoints processed, whether successful or not                       | `{datapoint}` |
-| `deltatocumulative.datapoints.dropped`   | Faulty datapoints that were dropped due to the reason given in the `reason` attribute | `{datapoint}` |
-| `deltatocumulative.gaps.length`          | Total length of all gaps in the streams, which occur e.g. due to lost in transit      | `second`      |
+When [Telemetry is
+enabled](https://opentelemetry.io/docs/collector/configuration/#telemetry), this component exports [several metrics](./documentation.md). 

processor/deltatocumulativeprocessor/documentation.md

@@ -0,0 +1,63 @@
+[comment]: <> (Code generated by mdatagen. DO NOT EDIT.)
+
+# deltatocumulative
+
+## Internal Telemetry
+
+The following telemetry is emitted by this component.
+
+### deltatocumulative.datapoints.dropped
+
+number of datapoints dropped due to given 'reason'
+
+| Unit | Metric Type | Value Type | Monotonic |
+| ---- | ----------- | ---------- | --------- |
+| {datapoint} | Sum | Int | true |
+
+### deltatocumulative.datapoints.processed
+
+number of datapoints processed
+
+| Unit | Metric Type | Value Type | Monotonic |
+| ---- | ----------- | ---------- | --------- |
+| {datapoint} | Sum | Int | true |
+
+### deltatocumulative.gaps.length
+
+total duration where data was expected but not received
+
+| Unit | Metric Type | Value Type | Monotonic |
+| ---- | ----------- | ---------- | --------- |
+| s | Sum | Int | true |
+
+### deltatocumulative.streams.evicted
+
+number of streams evicted
+
+| Unit | Metric Type | Value Type | Monotonic |
+| ---- | ----------- | ---------- | --------- |
+| {stream} | Sum | Int | true |
+
+### deltatocumulative.streams.limit
+
+upper limit of tracked streams
+
+| Unit | Metric Type | Value Type |
+| ---- | ----------- | ---------- |
+| {stream} | Gauge | Int |
+
+### deltatocumulative.streams.max_stale
+
+duration after which streams inactive streams are dropped
+
+| Unit | Metric Type | Value Type |
+| ---- | ----------- | ---------- |
+| s | Gauge | Int |
+
+### deltatocumulative.streams.tracked
+
+number of streams tracked
+
+| Unit | Metric Type | Value Type | Monotonic |
+| ---- | ----------- | ---------- | --------- |
+| {dps} | Sum | Int | false |

processor/deltatocumulativeprocessor/factory.go

@@ -28,6 +28,10 @@ func createMetricsProcessor(_ context.Context, set processor.Settings, cfg compo
 		return nil, fmt.Errorf("configuration parsing error")
 	}
 
-	meter := metadata.Meter(set.TelemetrySettings)
-	return newProcessor(pcfg, set.Logger, meter, next), nil
+	telb, err := metadata.NewTelemetryBuilder(set.TelemetrySettings)
+	if err != nil {
+		return nil, err
+	}
+
+	return newProcessor(pcfg, set.Logger, telb, next), nil
 }

processor/deltatocumulativeprocessor/internal/telemetry/faults_test.go

@@ -7,12 +7,14 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/pdata/pcommon"
 	"go.opentelemetry.io/otel/metric/noop"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/internal/exp/metrics/identity"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/deltatocumulativeprocessor/internal/data"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/deltatocumulativeprocessor/internal/delta"
+	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/deltatocumulativeprocessor/internal/metadata"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/deltatocumulativeprocessor/internal/streams"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/deltatocumulativeprocessor/internal/telemetry"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/deltatocumulativeprocessor/internal/testdata/random"
@@ -112,10 +114,13 @@ func TestFaults(t *testing.T) {
 		},
 	}
 
+	telb, err := metadata.NewTelemetryBuilder(component.TelemetrySettings{MeterProvider: noop.NewMeterProvider()})
+	require.NoError(t, err)
+
 	for _, c := range cases {
 		t.Run(c.Name, func(t *testing.T) {
 			id, dp := sum.Stream()
-			tel := telemetry.New(noop.Meter{})
+			tel := telemetry.New(telb)
 
 			dps := c.Map
 			if dps == nil {