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13 files changed

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‎CHANGELOG.md‎

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@@ -17,6 +17,8 @@ Increment the:
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* [TEST] Remove workaround for metrics cardinality limit test
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[#3663](https://github.com/open-telemetry/opentelemetry-cpp/pull/3663)
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* [METRICS] Allow registering one callback for multiple instruments
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[#3667](https://github.com/open-telemetry/opentelemetry-cpp/pull/3667)
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* [SDK] Fix typo in hashmap method GetEnteries
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[#3680](https://github.com/open-telemetry/opentelemetry-cpp/pull/3680)

‎api/include/opentelemetry/metrics/meter.h‎

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#pragma once
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#include <cstdint>
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#include "opentelemetry/version.h"
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#include "opentelemetry/nostd/shared_ptr.h"
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#include "opentelemetry/nostd/span.h"
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#include "opentelemetry/nostd/string_view.h"
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#include "opentelemetry/nostd/unique_ptr.h"
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class Gauge;
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class ObservableInstrument;
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class MultiObserverResult;
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using MultiObservableCallbackPtr = void (*)(MultiObserverResult &, void *);
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/**
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* Handles instrument creation and provides a facility for batch recording.
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nostd::string_view name,
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nostd::string_view description = "",
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nostd::string_view unit = "") noexcept = 0;
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#if OPENTELEMETRY_ABI_VERSION_NO >= 2
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/**
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* Registers a callback to be invoked when metrics are collected by this meter. The callback will
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* be passed a MultiObserverResult which it can use to make observations for any or all of the
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* instruments provided in this registration. Any measurements recorded for instruments _not_ in
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* the initial RegisterCallback call will be discarded.
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*
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* @param callback the callback to be invoked.
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* @param state the state to be passed to the callback.
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* @param instruments the instruments to be observed.
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* @return a unique identifier for the registered callback, which can be used to unregister the
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* callback in DeregisterCallback.
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*/
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virtual uintptr_t RegisterCallback(MultiObservableCallbackPtr callback,
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void *state,
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nostd::span<ObservableInstrument *> instruments) noexcept = 0;
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/**
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* Unregisters a callback previously registered with RegisterCallback.
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*
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* @param callback_id the unique identifier returned by RegisterCallback.
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*/
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virtual void DeregisterCallback(uintptr_t callback_id) noexcept = 0;
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#endif
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};
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} // namespace metrics
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OPENTELEMETRY_END_NAMESPACE

‎api/include/opentelemetry/metrics/multi_observer_result.h‎

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// Copyright The OpenTelemetry Authors
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// SPDX-License-Identifier: Apache-2.0
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#pragma once
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#include <cstdint>
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#include "opentelemetry/metrics/async_instruments.h"
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#include "opentelemetry/metrics/observer_result.h"
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#include "opentelemetry/version.h"
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OPENTELEMETRY_BEGIN_NAMESPACE
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namespace metrics
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{
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class MultiObserverResult
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{
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public:
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virtual ~MultiObserverResult() = default;
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/**
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* Obtain an ObserverResultT<T> for the given instrument, that can be used to record
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* a measurement on said instrument from a multi-observer callback registered with
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* Meter::RegisterCallback. The instrument _must_ have been included in the original
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* call to Meter::RegisterCallback; any data points set on other instruments will be
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* discarded.
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*
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* @param instrument The instrument for which to obtain an ObserverResult.
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* @return An ObserverResultT<T> for the given instrument.
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*/
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template <typename T>
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ObserverResultT<T> &ForInstrument(const ObservableInstrument *instrument) = delete;
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protected:
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// You can't have a virtual template, and you can't overload on return type, so we need to
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// enumerate the options for the observer result type as separate methods to override.
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virtual ObserverResultT<double> &ForInstrumentDouble(const ObservableInstrument *instrument) = 0;
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virtual ObserverResultT<int64_t> &ForInstrumentInt64(const ObservableInstrument *instrument) = 0;
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};
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template <>
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inline ObserverResultT<double> &MultiObserverResult::ForInstrument<double>(
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const ObservableInstrument *instrument)
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{
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return ForInstrumentDouble(instrument);
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}
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template <>
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inline ObserverResultT<int64_t> &MultiObserverResult::ForInstrument<int64_t>(
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const ObservableInstrument *instrument)
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{
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return ForInstrumentInt64(instrument);
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}
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} // namespace metrics
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OPENTELEMETRY_END_NAMESPACE

‎api/include/opentelemetry/metrics/noop.h‎

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return nostd::shared_ptr<ObservableInstrument>(
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new NoopObservableInstrument(name, description, unit));
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}
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#if OPENTELEMETRY_ABI_VERSION_NO >= 2
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uintptr_t RegisterCallback(
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MultiObservableCallbackPtr /* callback */,
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void * /* state */,
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nostd::span<ObservableInstrument *> /* instruments */) noexcept override
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{
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return 0;
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}
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void DeregisterCallback(uintptr_t /* callback_id */) noexcept override {}
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#endif
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};
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/**

‎sdk/include/opentelemetry/sdk/metrics/meter.h‎

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std::vector<MetricData> Collect(CollectorHandle *collector,
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opentelemetry::common::SystemTimestamp collect_ts) noexcept;
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#if OPENTELEMETRY_ABI_VERSION_NO >= 2
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uintptr_t RegisterCallback(
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opentelemetry::metrics::MultiObservableCallbackPtr callback,
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void *state,
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nostd::span<opentelemetry::metrics::ObservableInstrument *> instruments) noexcept override;
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void DeregisterCallback(uintptr_t callback_id) noexcept override;
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#endif
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private:
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// order of declaration is important here - instrumentation scope should destroy after
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// meter-context.

‎sdk/include/opentelemetry/sdk/metrics/multi_observer_result.h‎

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// Copyright The OpenTelemetry Authors
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// SPDX-License-Identifier: Apache-2.0
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#pragma once
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#include <unordered_map>
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#include "opentelemetry/metrics/async_instruments.h"
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#include "opentelemetry/metrics/multi_observer_result.h"
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#include "opentelemetry/metrics/observer_result.h"
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#include "opentelemetry/nostd/function_ref.h"
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#include "opentelemetry/nostd/variant.h"
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#include "opentelemetry/sdk/metrics/observer_result.h"
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#include "opentelemetry/version.h"
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OPENTELEMETRY_BEGIN_NAMESPACE
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namespace sdk
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{
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namespace metrics
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{
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class OPENTELEMETRY_EXPORT MultiObserverResult final
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: public opentelemetry::metrics::MultiObserverResult
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{
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public:
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void RegisterInstrument(opentelemetry::metrics::ObservableInstrument *instrument);
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void DeregisterInstrument(opentelemetry::metrics::ObservableInstrument *instrument);
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size_t InstrumentCount() const;
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bool HasInstrument(const opentelemetry::metrics::ObservableInstrument *instrument) const;
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void GetInstruments(
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nostd::function_ref<void(opentelemetry::metrics::ObservableInstrument *)> callback);
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void Reset();
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void StoreResults(opentelemetry::common::SystemTimestamp collection_ts);
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protected:
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opentelemetry::metrics::ObserverResultT<double> &ForInstrumentDouble(
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const opentelemetry::metrics::ObservableInstrument *instrument) override;
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opentelemetry::metrics::ObserverResultT<int64_t> &ForInstrumentInt64(
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const opentelemetry::metrics::ObservableInstrument *instrument) override;
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private:
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// This is _different_ to opentelemetry::metrics::ObserverResult because this variant is
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// a variant directly of ObserverResultT, not of _pointers_ to ObserverResultT.
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// This allows us to avoid an unnescessary layer of inderection and a bunch of allocations.
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using ObserverResultDirect =
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nostd::variant<nostd::monostate, ObserverResultT<double>, ObserverResultT<int64_t>>;
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std::unordered_map<opentelemetry::metrics::ObservableInstrument *, ObserverResultDirect>
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observer_results_;
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};
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} // namespace metrics
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} // namespace sdk
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OPENTELEMETRY_END_NAMESPACE

‎sdk/include/opentelemetry/sdk/metrics/state/observable_registry.h‎

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#pragma once
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#include <cstdint>
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#include <memory>
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#include <mutex>
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#include <vector>
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#include "opentelemetry/version.h"
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#include "opentelemetry/common/timestamp.h"
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#include "opentelemetry/metrics/async_instruments.h"
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#include "opentelemetry/metrics/meter.h"
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#include "opentelemetry/sdk/metrics/multi_observer_result.h"
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#include "opentelemetry/version.h"
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#if OPENTELEMETRY_ABI_VERSION_NO >= 2
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# include <unordered_map>
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# include "opentelemetry/nostd/span.h"
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#endif
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OPENTELEMETRY_BEGIN_NAMESPACE
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namespace sdk
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{
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namespace metrics
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{
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struct ObservableCallbackRecord
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{
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opentelemetry::metrics::ObservableCallbackPtr callback;
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void *state;
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opentelemetry::metrics::ObservableInstrument *instrument;
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};
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struct ObservableCallbackRecord;
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class OPENTELEMETRY_EXPORT_TYPE ObservableRegistry
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{
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public:
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// Constructor & destructor need to be defined in the observable_registry.cc TU, rather
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// than implicitly defaulted here, so that we can have a unique_ptr to an incomplete
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// class as a member.
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ObservableRegistry();
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~ObservableRegistry();
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// Add a callback of the single-instrument form
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void AddCallback(opentelemetry::metrics::ObservableCallbackPtr callback,
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void *state,
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opentelemetry::metrics::ObservableInstrument *instrument);
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// Add a callback with the multi-instrument signature
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uintptr_t AddCallback(opentelemetry::metrics::MultiObservableCallbackPtr callback,
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void *state,
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nostd::span<opentelemetry::metrics::ObservableInstrument *> instruments);
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// Callbacks added with Meter::RegisterCallback have can be removed by passing back the handle
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// returned
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void RemoveCallback(uintptr_t id);
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// Callbacks added with ObservableInstrument::AddCallback can be removed by passing back the
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// original (callback function, state, instrument).
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void RemoveCallback(opentelemetry::metrics::ObservableCallbackPtr callback,
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void *state,
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opentelemetry::metrics::ObservableInstrument *instrument);
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void Observe(opentelemetry::common::SystemTimestamp collection_ts);
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private:
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std::vector<std::unique_ptr<ObservableCallbackRecord>> callbacks_;
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std::unordered_map<uintptr_t, std::unique_ptr<ObservableCallbackRecord>> callbacks_;
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std::mutex callbacks_m_;
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};
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‎sdk/src/metrics/CMakeLists.txt‎

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meter_context.cc
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meter_context_factory.cc
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metric_reader.cc
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multi_observer_result.cc
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instrument_metadata_validator.cc
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export/periodic_exporting_metric_reader.cc
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export/periodic_exporting_metric_reader_factory.cc

‎sdk/src/metrics/meter.cc‎

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# include "opentelemetry/sdk/metrics/exemplar/reservoir_utils.h"
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#endif
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#if OPENTELEMETRY_ABI_VERSION_NO >= 2
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# include "opentelemetry/metrics/meter.h"
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#endif
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namespace
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{
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return metric_data_list;
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}
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#if OPENTELEMETRY_ABI_VERSION_NO >= 2
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uintptr_t Meter::RegisterCallback(
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opentelemetry::metrics::MultiObservableCallbackPtr callback,
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void *state,
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nostd::span<opentelemetry::metrics::ObservableInstrument *> instruments) noexcept
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{
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return observable_registry_->AddCallback(callback, state, instruments);
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}
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void Meter::DeregisterCallback(uintptr_t callback_id) noexcept
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{
681+
observable_registry_->RemoveCallback(callback_id);
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}
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#endif
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// Implementation of the log message recommended by the SDK specification for duplicate instruments.
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// See
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// https://github.com/open-telemetry/opentelemetry-specification/blob/9c8c30631b0e288de93df7452f91ed47f6fba330/specification/metrics/sdk.md?plain=1#L882

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