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Constants ¶
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Types ¶
type Accumulation ¶
type Accumulation struct {
Metadata
// contains filtered or unexported fields
}
Accumulation contains the exported data for a single metric instrument and attribute set, as prepared by an Accumulator for the Processor.
func NewAccumulation ¶
func NewAccumulation(descriptor *sdkapi.Descriptor, attrs *attribute.Set, aggregator aggregator.Aggregator) Accumulation
NewAccumulation allows Accumulator implementations to construct new Accumulations to send to Processors. The Descriptor, attributes, and Aggregator represent aggregate metric events received over a single collection period.
func (Accumulation) Aggregator ¶
func (r Accumulation) Aggregator() aggregator.Aggregator
Aggregator returns the checkpointed aggregator. It is safe to access the checkpointed state without locking.
type AggregatorSelector ¶
type AggregatorSelector interface {
// AggregatorFor allocates a variable number of aggregators of
// a kind suitable for the requested export. This method
// initializes a `...*Aggregator`, to support making a single
// allocation.
//
// When the call returns without initializing the *Aggregator
// to a non-nil value, the metric instrument is explicitly
// disabled.
//
// This must return a consistent type to avoid confusion in
// later stages of the metrics export process, i.e., when
// Merging or Checkpointing aggregators for a specific
// instrument.
//
// Note: This is context-free because the aggregator should
// not relate to the incoming context. This call should not
// block.
AggregatorFor(descriptor *sdkapi.Descriptor, aggregator ...*aggregator.Aggregator)
}
AggregatorSelector supports selecting the kind of Aggregator to use at runtime for a specific metric instrument.
type Checkpointer ¶
type Checkpointer interface {
// Processor processes metric data for export. The Process
// method is bracketed by StartCollection and FinishCollection
// calls. The embedded AggregatorSelector can be called at
// any time.
Processor
// Reader returns the current data set. This may be
// called before and after collection. The
// implementation is required to return the same value
// throughout its lifetime, since Reader exposes a
// sync.Locker interface. The caller is responsible for
// locking the Reader before initiating collection.
Reader() Reader
// StartCollection begins a collection interval.
StartCollection()
// FinishCollection ends a collection interval.
FinishCollection() error
}
Checkpointer is the interface used by a Controller to coordinate the Processor with Accumulator(s) and Exporter(s). The StartCollection() and FinishCollection() methods start and finish a collection interval. Controllers call the Accumulator(s) during collection to process Accumulations.
type CheckpointerFactory ¶
type CheckpointerFactory interface {
NewCheckpointer() Checkpointer
}
CheckpointerFactory is an interface for producing configured Checkpointer instances.
type Exporter ¶
type Exporter interface {
// Export is called immediately after completing a collection
// pass in the SDK.
//
// The Context comes from the controller that initiated
// collection.
//
// The InstrumentationLibraryReader interface refers to the
// Processor that just completed collection.
Export(ctx context.Context, resource *resource.Resource, reader InstrumentationLibraryReader) error
// TemporalitySelector is an interface used by the Processor
// in deciding whether to compute Delta or Cumulative
// Aggregations when passing Records to this Exporter.
aggregation.TemporalitySelector
}
Exporter handles presentation of the checkpoint of aggregate metrics. This is the final stage of a metrics export pipeline, where metric data are formatted for a specific system.
type InstrumentationLibraryReader ¶
type InstrumentationLibraryReader interface {
// ForEach calls the passed function once per instrumentation library,
// allowing the caller to emit metrics grouped by the library that
// produced them.
ForEach(readerFunc func(instrumentation.Library, Reader) error) error
}
InstrumentationLibraryReader is an interface for exporters to iterate over one instrumentation library of metric data at a time.
type Metadata ¶
type Metadata struct {
// contains filtered or unexported fields
}
Metadata contains the common elements for exported metric data that are shared by the Accumulator->Processor and Processor->Exporter steps.
func (Metadata) Attributes ¶ added in v0.30.0
Attributes returns the attribute set associated with the instrument and the aggregated data.
func (Metadata) Descriptor ¶
func (m Metadata) Descriptor() *sdkapi.Descriptor
Descriptor describes the metric instrument being exported.
type Processor ¶
type Processor interface {
// AggregatorSelector is responsible for selecting the
// concrete type of Aggregator used for a metric in the SDK.
//
// This may be a static decision based on fields of the
// Descriptor, or it could use an external configuration
// source to customize the treatment of each metric
// instrument.
//
// The result from AggregatorSelector.AggregatorFor should be
// the same type for a given Descriptor or else nil. The same
// type should be returned for a given descriptor, because
// Aggregators only know how to Merge with their own type. If
// the result is nil, the metric instrument will be disabled.
//
// Note that the SDK only calls AggregatorFor when new records
// require an Aggregator. This does not provide a way to
// disable metrics with active records.
AggregatorSelector
// Process is called by the SDK once per internal record, passing the
// export Accumulation (a Descriptor, the corresponding attributes, and
// the checkpointed Aggregator). This call has no Context argument because
// it is expected to perform only computation. An SDK is not expected to
// call exporters from with Process, use a controller for that (see
// ./controllers/{pull,push}.
Process(accum Accumulation) error
}
Processor is responsible for deciding which kind of aggregation to use (via AggregatorSelector), gathering exported results from the SDK during collection, and deciding over which dimensions to group the exported data.
The SDK supports binding only one of these interfaces, as it has the sole responsibility of determining which Aggregator to use for each record.
The embedded AggregatorSelector interface is called (concurrently) in instrumentation context to select the appropriate Aggregator for an instrument.
The `Process` method is called during collection in a single-threaded context from the SDK, after the aggregator is checkpointed, allowing the processor to build the set of metrics currently being exported.
type Reader ¶
type Reader interface {
// ForEach iterates over aggregated checkpoints for all
// metrics that were updated during the last collection
// period. Each aggregated checkpoint returned by the
// function parameter may return an error.
//
// The TemporalitySelector argument is used to determine
// whether the Record is computed using Delta or Cumulative
// aggregation.
//
// ForEach tolerates ErrNoData silently, as this is
// expected from the Meter implementation. Any other kind
// of error will immediately halt ForEach and return
// the error to the caller.
ForEach(tempSelector aggregation.TemporalitySelector, recordFunc func(Record) error) error
// Locker supports locking the checkpoint set. Collection
// into the checkpoint set cannot take place (in case of a
// stateful processor) while it is locked.
//
// The Processor attached to the Accumulator MUST be called
// with the lock held.
sync.Locker
// RLock acquires a read lock corresponding to this Locker.
RLock()
// RUnlock releases a read lock corresponding to this Locker.
RUnlock()
}
Reader allows a controller to access a complete checkpoint of aggregated metrics from the Processor for a single library of metric data. This is passed to the Exporter which may then use ForEach to iterate over the collection of aggregated metrics.
type Record ¶
type Record struct {
Metadata
// contains filtered or unexported fields
}
Record contains the exported data for a single metric instrument and attribute set, as prepared by the Processor for the Exporter. This includes the effective start and end time for the aggregation.
func NewRecord ¶
func NewRecord(descriptor *sdkapi.Descriptor, attrs *attribute.Set, aggregation aggregation.Aggregation, start, end time.Time) Record
NewRecord allows Processor implementations to construct export records. The Descriptor, attributes, and Aggregator represent aggregate metric events received over a single collection period.
func (Record) Aggregation ¶
func (r Record) Aggregation() aggregation.Aggregation
Aggregation returns the aggregation, an interface to the record and its aggregator, dependent on the kind of both the input and exporter.
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