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Index ¶
Constants ¶
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Variables ¶
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Functions ¶
func NewInconsistentAggregatorError ¶
func NewInconsistentAggregatorError(a1, a2 Aggregator) error
NewInconsistentAggregatorError formats an error describing an attempt to Checkpoint or Merge different-type aggregators. The result can be unwrapped as an ErrInconsistentType.
func RangeTest ¶
func RangeTest(num number.Number, descriptor *sdkapi.Descriptor) error
RangeTest is a common routine for testing for valid input values. This rejects NaN values. This rejects negative values when the metric instrument does not support negative values, including monotonic counter metrics and absolute Histogram metrics.
Types ¶
type Aggregator ¶ added in v0.27.0
type Aggregator interface {
// Aggregation returns an Aggregation interface to access the
// current state of this Aggregator. The caller is
// responsible for synchronization and must not call any the
// other methods in this interface concurrently while using
// the Aggregation.
Aggregation() aggregation.Aggregation
// Update receives a new measured value and incorporates it
// into the aggregation. Update() calls may be called
// concurrently.
//
// Descriptor.NumberKind() should be consulted to determine
// whether the provided number is an int64 or float64.
//
// The Context argument comes from user-level code and could be
// inspected for a `correlation.Map` or `trace.SpanContext`.
Update(ctx context.Context, number number.Number, descriptor *sdkapi.Descriptor) error
// SynchronizedMove is called during collection to finish one
// period of aggregation by atomically saving the
// currently-updating state into the argument Aggregator AND
// resetting the current value to the zero state.
//
// SynchronizedMove() is called concurrently with Update(). These
// two methods must be synchronized with respect to each
// other, for correctness.
//
// After saving a synchronized copy, the Aggregator can be converted
// into one or more of the interfaces in the `aggregation` sub-package,
// according to kind of Aggregator that was selected.
//
// This method will return an InconsistentAggregatorError if
// this Aggregator cannot be copied into the destination due
// to an incompatible type.
//
// This call has no Context argument because it is expected to
// perform only computation.
//
// When called with a nil `destination`, this Aggregator is reset
// and the current value is discarded.
SynchronizedMove(destination Aggregator, descriptor *sdkapi.Descriptor) error
// Merge combines the checkpointed state from the argument
// Aggregator into this Aggregator. Merge is not synchronized
// with respect to Update or SynchronizedMove.
//
// The owner of an Aggregator being merged is responsible for
// synchronization of both Aggregator states.
Merge(aggregator Aggregator, descriptor *sdkapi.Descriptor) error
}
Aggregator implements a specific aggregation behavior, e.g., a behavior to track a sequence of updates to an instrument. Counter instruments commonly use a simple Sum aggregator, but for the distribution instruments (Histogram, GaugeObserver) there are a number of possible aggregators with different cost and accuracy tradeoffs.
Note that any Aggregator may be attached to any instrument--this is the result of the OpenTelemetry API/SDK separation. It is possible to attach a Sum aggregator to a Histogram instrument.
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