1 files changed, 200 insertions, 0 deletions
diff --git a/vendor/go.opentelemetry.io/otel/sdk/metric/reader.go b/vendor/go.opentelemetry.io/otel/sdk/metric/reader.go
new file mode 100644
index 000000000..65cedaf3c
--- /dev/null
+++ b/vendor/go.opentelemetry.io/otel/sdk/metric/reader.go
@@ -0,0 +1,200 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metric // import "go.opentelemetry.io/otel/sdk/metric"
+
+import (
+	"context"
+	"fmt"
+
+	"go.opentelemetry.io/otel/sdk/metric/metricdata"
+)
+
+// errDuplicateRegister is logged by a Reader when an attempt to registered it
+// more than once occurs.
+var errDuplicateRegister = fmt.Errorf("duplicate reader registration")
+
+// ErrReaderNotRegistered is returned if Collect or Shutdown are called before
+// the reader is registered with a MeterProvider.
+var ErrReaderNotRegistered = fmt.Errorf("reader is not registered")
+
+// ErrReaderShutdown is returned if Collect or Shutdown are called after a
+// reader has been Shutdown once.
+var ErrReaderShutdown = fmt.Errorf("reader is shutdown")
+
+// errNonPositiveDuration is logged when an environmental variable
+// has non-positive value.
+var errNonPositiveDuration = fmt.Errorf("non-positive duration")
+
+// Reader is the interface used between the SDK and an
+// exporter.  Control flow is bi-directional through the
+// Reader, since the SDK initiates ForceFlush and Shutdown
+// while the exporter initiates collection.  The Register() method here
+// informs the Reader that it can begin reading, signaling the
+// start of bi-directional control flow.
+//
+// Typically, push-based exporters that are periodic will
+// implement PeroidicExporter themselves and construct a
+// PeriodicReader to satisfy this interface.
+//
+// Pull-based exporters will typically implement Register
+// themselves, since they read on demand.
+//
+// Warning: methods may be added to this interface in minor releases.
+type Reader interface {
+	// register registers a Reader with a MeterProvider.
+	// The producer argument allows the Reader to signal the sdk to collect
+	// and send aggregated metric measurements.
+	register(sdkProducer)
+
+	// temporality reports the Temporality for the instrument kind provided.
+	//
+	// This method needs to be concurrent safe with itself and all the other
+	// Reader methods.
+	temporality(InstrumentKind) metricdata.Temporality
+
+	// aggregation returns what Aggregation to use for an instrument kind.
+	//
+	// This method needs to be concurrent safe with itself and all the other
+	// Reader methods.
+	aggregation(InstrumentKind) Aggregation // nolint:revive  // import-shadow for method scoped by type.
+
+	// Collect gathers and returns all metric data related to the Reader from
+	// the SDK and stores it in out. An error is returned if this is called
+	// after Shutdown or if out is nil.
+	//
+	// This method needs to be concurrent safe, and the cancellation of the
+	// passed context is expected to be honored.
+	Collect(ctx context.Context, rm *metricdata.ResourceMetrics) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Shutdown flushes all metric measurements held in an export pipeline and releases any
+	// held computational resources.
+	//
+	// This deadline or cancellation of the passed context are honored. An appropriate
+	// error will be returned in these situations. There is no guaranteed that all
+	// telemetry be flushed or all resources have been released in these
+	// situations.
+	//
+	// After Shutdown is called, calls to Collect will perform no operation and instead will return
+	// an error indicating the shutdown state.
+	//
+	// This method needs to be concurrent safe.
+	Shutdown(context.Context) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}
+
+// sdkProducer produces metrics for a Reader.
+type sdkProducer interface {
+	// produce returns aggregated metrics from a single collection.
+	//
+	// This method is safe to call concurrently.
+	produce(context.Context, *metricdata.ResourceMetrics) error
+}
+
+// Producer produces metrics for a Reader from an external source.
+type Producer interface {
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Produce returns aggregated metrics from an external source.
+	//
+	// This method should be safe to call concurrently.
+	Produce(context.Context) ([]metricdata.ScopeMetrics, error)
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}
+
+// produceHolder is used as an atomic.Value to wrap the non-concrete producer
+// type.
+type produceHolder struct {
+	produce func(context.Context, *metricdata.ResourceMetrics) error
+}
+
+// shutdownProducer produces an ErrReaderShutdown error always.
+type shutdownProducer struct{}
+
+// produce returns an ErrReaderShutdown error.
+func (p shutdownProducer) produce(context.Context, *metricdata.ResourceMetrics) error {
+	return ErrReaderShutdown
+}
+
+// TemporalitySelector selects the temporality to use based on the InstrumentKind.
+type TemporalitySelector func(InstrumentKind) metricdata.Temporality
+
+// DefaultTemporalitySelector is the default TemporalitySelector used if
+// WithTemporalitySelector is not provided. CumulativeTemporality will be used
+// for all instrument kinds if this TemporalitySelector is used.
+func DefaultTemporalitySelector(InstrumentKind) metricdata.Temporality {
+	return metricdata.CumulativeTemporality
+}
+
+// AggregationSelector selects the aggregation and the parameters to use for
+// that aggregation based on the InstrumentKind.
+//
+// If the Aggregation returned is nil or DefaultAggregation, the selection from
+// DefaultAggregationSelector will be used.
+type AggregationSelector func(InstrumentKind) Aggregation
+
+// DefaultAggregationSelector returns the default aggregation and parameters
+// that will be used to summarize measurement made from an instrument of
+// InstrumentKind. This AggregationSelector using the following selection
+// mapping: Counter ⇨ Sum, Observable Counter ⇨ Sum, UpDownCounter ⇨ Sum,
+// Observable UpDownCounter ⇨ Sum, Observable Gauge ⇨ LastValue,
+// Histogram ⇨ ExplicitBucketHistogram.
+func DefaultAggregationSelector(ik InstrumentKind) Aggregation {
+	switch ik {
+	case InstrumentKindCounter, InstrumentKindUpDownCounter, InstrumentKindObservableCounter, InstrumentKindObservableUpDownCounter:
+		return AggregationSum{}
+	case InstrumentKindObservableGauge:
+		return AggregationLastValue{}
+	case InstrumentKindHistogram:
+		return AggregationExplicitBucketHistogram{
+			Boundaries: []float64{0, 5, 10, 25, 50, 75, 100, 250, 500, 750, 1000, 2500, 5000, 7500, 10000},
+			NoMinMax:   false,
+		}
+	}
+	panic("unknown instrument kind")
+}
+
+// ReaderOption is an option which can be applied to manual or Periodic
+// readers.
+type ReaderOption interface {
+	PeriodicReaderOption
+	ManualReaderOption
+}
+
+// WithProducers registers producers as an external Producer of metric data
+// for this Reader.
+func WithProducer(p Producer) ReaderOption {
+	return producerOption{p: p}
+}
+
+type producerOption struct {
+	p Producer
+}
+
+// applyManual returns a manualReaderConfig with option applied.
+func (o producerOption) applyManual(c manualReaderConfig) manualReaderConfig {
+	c.producers = append(c.producers, o.p)
+	return c
+}
+
+// applyPeriodic returns a periodicReaderConfig with option applied.
+func (o producerOption) applyPeriodic(c periodicReaderConfig) periodicReaderConfig {
+	c.producers = append(c.producers, o.p)
+	return c
+}