metric.WithExplicitBucketBoundaries is not working as expected

[huliang-microsoft]

Description

metric.WithExplicitBucketBoundaries is not working with metric historgram.

Update 5/26/2024: Looks like I can set the histogram bucket in exporter selector but not the metric itself. Is this expected? So we cannot create per histogram metric buckets? and must be using the same buckets for all hostogram?

func MyAggregationSelector(ik metric.InstrumentKind) metric.Aggregation {
	switch ik {
	case metric.InstrumentKindCounter, metric.InstrumentKindUpDownCounter, metric.InstrumentKindObservableCounter, metric.InstrumentKindObservableUpDownCounter:
		return metric.AggregationSum{}
	case metric.InstrumentKindObservableGauge:
		return metric.AggregationLastValue{}
	case metric.InstrumentKindHistogram:
		return metric.AggregationExplicitBucketHistogram{
			Boundaries: []float64{0, 1, 2, 3, 4, 5, 6},
			NoMinMax:   false,
		}
	}
	panic("unknown instrument kind")
}


func createExporter() {
        ...........
	exporter, err := otlpmetrichttp.New(
		ctx,
		otlpmetrichttp.WithHeaders(kv),
		otlpmetrichttp.WithEndpointURL("http://localhost:4318"),
		otlpmetrichttp.WithTemporalitySelector(
			func(metric.InstrumentKind) metricdata.Temporality {
				return metricdata.DeltaTemporality
			},
		),
		otlpmetrichttp.WithAggregationSelector(MyAggregationSelector),
	)
}

Environment

• OS: Ubuntu 22.04
• Architecture: x86
• Go Version: 1.22
• opentelemetry-go version: 1.24

Steps To Reproduce

The code I am using

meter := otel.Meter("my.session"),
histogram, err = meter.Float64Histogram(
    "my hist",
    metric.WithDescription("my histogram."),
    metric.WithUnit("s"),
    metric.WithExplicitBucketBoundaries(.005, .01, .025, .05, .075, .1, .25, .5, .75, 1, 2.5, 5, 7.5, 10),
)

Expected behavior

I expected the boundaries will be used but I see the data in collector is still using the default buckets. But the Description and Unit are set correctly. The otel collector I am using is otel/opentelemetry-collector-contrib:0.93.0

Descriptor:
     -> Name: my hist
     -> Description: my histogram.
     -> Unit: s
     -> DataType: Histogram
     -> AggregationTemporality: Cumulative
...
ExplicitBounds #0: 0.000000
ExplicitBounds #1: 5.000000
ExplicitBounds #2: 10.000000
ExplicitBounds #3: 25.000000
ExplicitBounds #4: 50.000000
ExplicitBounds #5: 75.000000
ExplicitBounds #6: 100.000000
ExplicitBounds #7: 250.000000
ExplicitBounds #8: 500.000000
ExplicitBounds #9: 750.000000
ExplicitBounds #10: 1000.000000
ExplicitBounds #11: 2500.000000
ExplicitBounds #12: 5000.000000
ExplicitBounds #13: 7500.000000
ExplicitBounds #14: 10000.000000
Buckets #0, Count: 0
Buckets #1, Count: 10
Buckets #2, Count: 0
Buckets #3, Count: 0
Buckets #4, Count: 0
Buckets #5, Count: 0
Buckets #6, Count: 0
Buckets #7, Count: 0
Buckets #8, Count: 0
Buckets #9, Count: 0
Buckets #10, Count: 0
Buckets #11, Count: 0
Buckets #12, Count: 0
Buckets #13, Count: 0
Buckets #14, Count: 0
Buckets #15, Count: 0

[MrAlias]

Please provide a complete example that can be run. I'm not able to reproduce your issue.

[huliang-microsoft]

Thanks for the response @MrAlias , I dont know how to provide a complete example? A link to some github repo? I can create one if it is needed. Are you saying you can set the buckets by this method when creating the histogram?

metric.WithExplicitBucketBoundaries(.005, .01, .025, .05, .075, .1, .25, .5, .75, 1, 2.5, 5, 7.5, 10),

Did you mean that you can set the buckets like this and observe the updated buckets on a collector side?

[dmathieu]

A complete example would be a simple main.go that reproduces the issue.

[koungkub]

I am faced with the same problem. The buckets don't apply to the metrics.

[huliang-microsoft]

I think I know what went wrong in my case. There is a package version mismatch. After I upgraded all pakcages to 1.27, this setting works.