forgejo-federation/vendor/go.opentelemetry.io/otel/metric/registry/registry.go
2021-02-28 18:08:33 -05:00

170 lines
5.1 KiB
Go
Vendored

// 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 registry // import "go.opentelemetry.io/otel/metric/registry"
import (
"context"
"fmt"
"sync"
"go.opentelemetry.io/otel/label"
"go.opentelemetry.io/otel/metric"
)
// MeterProvider is a standard MeterProvider for wrapping `MeterImpl`
type MeterProvider struct {
impl metric.MeterImpl
}
var _ metric.MeterProvider = (*MeterProvider)(nil)
// uniqueInstrumentMeterImpl implements the metric.MeterImpl interface, adding
// uniqueness checking for instrument descriptors. Use NewUniqueInstrumentMeter
// to wrap an implementation with uniqueness checking.
type uniqueInstrumentMeterImpl struct {
lock sync.Mutex
impl metric.MeterImpl
state map[key]metric.InstrumentImpl
}
var _ metric.MeterImpl = (*uniqueInstrumentMeterImpl)(nil)
type key struct {
instrumentName string
instrumentationName string
InstrumentationVersion string
}
// NewMeterProvider returns a new provider that implements instrument
// name-uniqueness checking.
func NewMeterProvider(impl metric.MeterImpl) *MeterProvider {
return &MeterProvider{
impl: NewUniqueInstrumentMeterImpl(impl),
}
}
// Meter implements MeterProvider.
func (p *MeterProvider) Meter(instrumentationName string, opts ...metric.MeterOption) metric.Meter {
return metric.WrapMeterImpl(p.impl, instrumentationName, opts...)
}
// ErrMetricKindMismatch is the standard error for mismatched metric
// instrument definitions.
var ErrMetricKindMismatch = fmt.Errorf(
"a metric was already registered by this name with another kind or number type")
// NewUniqueInstrumentMeterImpl returns a wrapped metric.MeterImpl with
// the addition of uniqueness checking.
func NewUniqueInstrumentMeterImpl(impl metric.MeterImpl) metric.MeterImpl {
return &uniqueInstrumentMeterImpl{
impl: impl,
state: map[key]metric.InstrumentImpl{},
}
}
// RecordBatch implements metric.MeterImpl.
func (u *uniqueInstrumentMeterImpl) RecordBatch(ctx context.Context, labels []label.KeyValue, ms ...metric.Measurement) {
u.impl.RecordBatch(ctx, labels, ms...)
}
func keyOf(descriptor metric.Descriptor) key {
return key{
descriptor.Name(),
descriptor.InstrumentationName(),
descriptor.InstrumentationVersion(),
}
}
// NewMetricKindMismatchError formats an error that describes a
// mismatched metric instrument definition.
func NewMetricKindMismatchError(desc metric.Descriptor) error {
return fmt.Errorf("metric was %s (%s %s)registered as a %s %s: %w",
desc.Name(),
desc.InstrumentationName(),
desc.InstrumentationVersion(),
desc.NumberKind(),
desc.InstrumentKind(),
ErrMetricKindMismatch)
}
// Compatible determines whether two metric.Descriptors are considered
// the same for the purpose of uniqueness checking.
func Compatible(candidate, existing metric.Descriptor) bool {
return candidate.InstrumentKind() == existing.InstrumentKind() &&
candidate.NumberKind() == existing.NumberKind()
}
// checkUniqueness returns an ErrMetricKindMismatch error if there is
// a conflict between a descriptor that was already registered and the
// `descriptor` argument. If there is an existing compatible
// registration, this returns the already-registered instrument. If
// there is no conflict and no prior registration, returns (nil, nil).
func (u *uniqueInstrumentMeterImpl) checkUniqueness(descriptor metric.Descriptor) (metric.InstrumentImpl, error) {
impl, ok := u.state[keyOf(descriptor)]
if !ok {
return nil, nil
}
if !Compatible(descriptor, impl.Descriptor()) {
return nil, NewMetricKindMismatchError(impl.Descriptor())
}
return impl, nil
}
// NewSyncInstrument implements metric.MeterImpl.
func (u *uniqueInstrumentMeterImpl) NewSyncInstrument(descriptor metric.Descriptor) (metric.SyncImpl, error) {
u.lock.Lock()
defer u.lock.Unlock()
impl, err := u.checkUniqueness(descriptor)
if err != nil {
return nil, err
} else if impl != nil {
return impl.(metric.SyncImpl), nil
}
syncInst, err := u.impl.NewSyncInstrument(descriptor)
if err != nil {
return nil, err
}
u.state[keyOf(descriptor)] = syncInst
return syncInst, nil
}
// NewAsyncInstrument implements metric.MeterImpl.
func (u *uniqueInstrumentMeterImpl) NewAsyncInstrument(
descriptor metric.Descriptor,
runner metric.AsyncRunner,
) (metric.AsyncImpl, error) {
u.lock.Lock()
defer u.lock.Unlock()
impl, err := u.checkUniqueness(descriptor)
if err != nil {
return nil, err
} else if impl != nil {
return impl.(metric.AsyncImpl), nil
}
asyncInst, err := u.impl.NewAsyncInstrument(descriptor, runner)
if err != nil {
return nil, err
}
u.state[keyOf(descriptor)] = asyncInst
return asyncInst, nil
}