Copyright	(c) Ian Duncan 2026
License	BSD-3
Stability	experimental
Safe Haskell	None
Language	Haskell2010

OpenTelemetry.Metric.Core

Contents

Provider
Meter
Instruments
Instrument name validation (for SDK implementers)

Description

Overview

This module defines the Metrics API for recording measurements in your application. Libraries use this API to record metrics; the SDK provides the actual aggregation and export.

Application authors should import OpenTelemetry.Metric from the SDK package instead, which re-exports everything here plus SDK initialization.

Quick example

import OpenTelemetry.Metric.Core

main :: IO ()
main = do
  -- Obtain the global MeterProvider (set up by the SDK)
  mp <- getGlobalMeterProvider
  meter <- getMeter mp myInstrumentationLibrary

  -- Create instruments
  requestCounter <- meterCreateCounterInt64 meter "http.requests" "" Nothing defaultAdvisoryParameters
  latencyHist    <- meterCreateHistogram meter "http.request.duration" "ms" Nothing defaultAdvisoryParameters

  -- Record measurements
  counterAdd requestCounter 1 [("method", toAttribute GET)]
  histogramRecord latencyHist 42.5 [("method", toAttribute GET)]

Instrument types

Synchronous instruments

These are called inline with your application code:

Counter : monotonically increasing sum (e.g. request count, bytes sent). Use counterAdd counter value attrs.
UpDownCounter : sum that can increase or decrease (e.g. active connections, queue depth). Use upDownCounterAdd counter value attrs.
Histogram : distribution of values (e.g. request latency, payload size). Use histogramRecord histogram value attrs.
Gauge : point-in-time value (e.g. CPU temperature, memory usage). Use gaugeRecord gauge value attrs.

Asynchronous (observable) instruments

These are read by callbacks during export:

ObservableCounter : monotonic sum read on demand (e.g. CPU time).
ObservableUpDownCounter : bidirectional sum read on demand.
ObservableGauge : snapshot value read on demand (e.g. disk free space).

Register a callback when creating the instrument:

obsGauge <- meterCreateObservableGaugeDouble meter
  "system.memory.usage" By Nothing defaultAdvisoryParameters
  (result -> do
    memInfo <- getMemoryUsage
    observeDouble result memInfo [("state", toAttribute "used")]
  )

No-op behavior

Before the SDK is installed, noopMeterProvider is the global default. All measurements are silently discarded. This makes it safe for libraries to instrument unconditionally.

Spec reference

https://opentelemetry.io/docs/specs/otel/metrics/api/

Synopsis

data MeterProvider = MeterProvider {
- meterProviderGetMeter :: !(InstrumentationLibrary -> IO Meter)
- meterProviderShutdown :: !(Maybe Int -> IO ShutdownResult)
- meterProviderForceFlush :: !(Maybe Int -> IO FlushResult)
}
getMeter :: MeterProvider -> InstrumentationLibrary -> IO Meter
noopMeterProvider :: MeterProvider
noopMeter :: InstrumentationLibrary -> Meter
shutdownMeterProvider :: MeterProvider -> Maybe Int -> IO ShutdownResult
forceFlushMeterProvider :: MeterProvider -> Maybe Int -> IO FlushResult
getGlobalMeterProvider :: MonadIO m => m MeterProvider
setGlobalMeterProvider :: MonadIO m => MeterProvider -> m ()
data Meter = Meter {
- meterInstrumentationScope :: !InstrumentationLibrary
- meterCreateCounterInt64 :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> IO (Counter Int64))
- meterCreateCounterDouble :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> IO (Counter Double))
- meterCreateUpDownCounterInt64 :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> IO (UpDownCounter Int64))
- meterCreateUpDownCounterDouble :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> IO (UpDownCounter Double))
- meterCreateHistogram :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> IO Histogram)
- meterCreateGaugeInt64 :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> IO (Gauge Int64))
- meterCreateGaugeDouble :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> IO (Gauge Double))
- meterCreateObservableCounterInt64 :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> [ObservableResult Int64 -> IO ()] -> IO (ObservableCounter Int64))
- meterCreateObservableCounterDouble :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> [ObservableResult Double -> IO ()] -> IO (ObservableCounter Double))
- meterCreateObservableUpDownCounterInt64 :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> [ObservableResult Int64 -> IO ()] -> IO (ObservableUpDownCounter Int64))
- meterCreateObservableUpDownCounterDouble :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> [ObservableResult Double -> IO ()] -> IO (ObservableUpDownCounter Double))
- meterCreateObservableGaugeInt64 :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> [ObservableResult Int64 -> IO ()] -> IO (ObservableGauge Int64))
- meterCreateObservableGaugeDouble :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> [ObservableResult Double -> IO ()] -> IO (ObservableGauge Double))
}
data InstrumentKind
- = KindCounter
- | KindAsyncCounter
- | KindUpDownCounter
- | KindAsyncUpDownCounter
- | KindHistogram
- | KindGauge
- | KindAsyncGauge
data HistogramAggregation
- = HistogramAggregationExplicit !(Vector Double)
- | HistogramAggregationExponential !Int32
data AdvisoryParameters = AdvisoryParameters {
- advisoryExplicitBucketBoundaries :: !(Maybe [Double])
- advisoryAttributeKeys :: !(Maybe [Text])
- advisoryHistogramAggregation :: !(Maybe HistogramAggregation)
}
defaultAdvisoryParameters :: AdvisoryParameters
data Counter a = Counter {
- counterAdd :: !(a -> Attributes -> IO ())
- counterEnabled :: !(IO Bool)
}
data UpDownCounter a = UpDownCounter {
- upDownCounterAdd :: !(a -> Attributes -> IO ())
- upDownCounterEnabled :: !(IO Bool)
}
data Histogram = Histogram {
- histogramRecord :: !(Double -> Attributes -> IO ())
- histogramEnabled :: !(IO Bool)
}
data Gauge a = Gauge {
- gaugeRecord :: !(a -> Attributes -> IO ())
- gaugeEnabled :: !(IO Bool)
}
newtype ObservableResult a = ObservableResult {
- observe :: a -> Attributes -> IO ()
}
newtype ObservableCallbackHandle = ObservableCallbackHandle {
- unregisterObservableCallback :: IO ()
}
data ObservableCounter a = ObservableCounter {
- observableCounterRegisterCallback :: !((ObservableResult a -> IO ()) -> IO ObservableCallbackHandle)
- observableCounterInstrumentScope :: !InstrumentationLibrary
- observableCounterInstrumentName :: !Text
- observableCounterEnabled :: !(IO Bool)
}
data ObservableUpDownCounter a = ObservableUpDownCounter {
- observableUpDownCounterRegisterCallback :: !((ObservableResult a -> IO ()) -> IO ObservableCallbackHandle)
- observableUpDownCounterInstrumentScope :: !InstrumentationLibrary
- observableUpDownCounterInstrumentName :: !Text
- observableUpDownCounterEnabled :: !(IO Bool)
}
data ObservableGauge a = ObservableGauge {
- observableGaugeRegisterCallback :: !((ObservableResult a -> IO ()) -> IO ObservableCallbackHandle)
- observableGaugeInstrumentScope :: !InstrumentationLibrary
- observableGaugeInstrumentName :: !Text
- observableGaugeEnabled :: !(IO Bool)
}
validateInstrumentName :: Text -> Maybe Text
validateInstrumentUnit :: Text -> Maybe Text

Provider

data MeterProvider Source #

Entry point for metrics API (spec: global default SHOULD exist).

Since: 0.0.1.0

Constructors

MeterProvider

Fields

meterProviderGetMeter :: !(InstrumentationLibrary -> IO Meter)
Get or create a Meter for the given instrumentation scope.
meterProviderShutdown :: !(Maybe Int -> IO ShutdownResult)
Shut down the provider, flushing and releasing resources. Optional timeout in microseconds; Nothing uses the SDK default (5s).
meterProviderForceFlush :: !(Maybe Int -> IO FlushResult)
Force a collection and export cycle. Optional timeout in microseconds; Nothing uses the SDK default (5s).

getMeter :: MeterProvider -> InstrumentationLibrary -> IO Meter Source #

Preferred accessor for obtaining a Meter (spec: Get a Meter).

Since: 0.0.1.0

noopMeterProvider :: MeterProvider Source #

No-op provider: safe for libraries; all measurements are discarded.

Since: 0.0.1.0

noopMeter :: InstrumentationLibrary -> Meter Source #

A Meter that records no telemetry (used by noopMeterProvider).

Since: 0.0.1.0

shutdownMeterProvider Source #

Arguments

:: MeterProvider
-> Maybe Int	Optional timeout in microseconds. `Nothing` uses the SDK default (5s).
-> IO ShutdownResult

Since: 0.0.1.0

forceFlushMeterProvider Source #

Arguments

:: MeterProvider
-> Maybe Int	Optional timeout in microseconds. `Nothing` uses the SDK default (5s).
-> IO FlushResult

Since: 0.0.1.0

getGlobalMeterProvider :: MonadIO m => m MeterProvider Source #

Since: 0.0.1.0

setGlobalMeterProvider :: MonadIO m => MeterProvider -> m () Source #

Since: 0.0.1.0

Meter

data Meter Source #

Creates instruments for a single instrumentation scope.

| All instrument factory functions take: name, optional unit, optional description, advisory parameters. Observable factories additionally take initial callbacks.

Since: 0.0.1.0

Constructors

Meter

Fields

meterInstrumentationScope :: !InstrumentationLibrary
The scope that owns instruments created by this meter.
meterCreateCounterInt64 :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> IO (Counter Int64))
Create a synchronous monotonic Int64 counter.
meterCreateCounterDouble :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> IO (Counter Double))
Create a synchronous monotonic Double counter.
meterCreateUpDownCounterInt64 :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> IO (UpDownCounter Int64))
Create a synchronous Int64 up-down counter.
meterCreateUpDownCounterDouble :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> IO (UpDownCounter Double))
Create a synchronous Double up-down counter.
meterCreateHistogram :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> IO Histogram)
Create a synchronous histogram.
meterCreateGaugeInt64 :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> IO (Gauge Int64))
Create a synchronous Int64 gauge.
meterCreateGaugeDouble :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> IO (Gauge Double))
Create a synchronous Double gauge.
meterCreateObservableCounterInt64 :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> [ObservableResult Int64 -> IO ()] -> IO (ObservableCounter Int64))
Create an asynchronous Int64 counter with initial callbacks.
meterCreateObservableCounterDouble :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> [ObservableResult Double -> IO ()] -> IO (ObservableCounter Double))
Create an asynchronous Double counter with initial callbacks.
meterCreateObservableUpDownCounterInt64 :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> [ObservableResult Int64 -> IO ()] -> IO (ObservableUpDownCounter Int64))
Create an asynchronous Int64 up-down counter with initial callbacks.
meterCreateObservableUpDownCounterDouble :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> [ObservableResult Double -> IO ()] -> IO (ObservableUpDownCounter Double))
Create an asynchronous Double up-down counter with initial callbacks.
meterCreateObservableGaugeInt64 :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> [ObservableResult Int64 -> IO ()] -> IO (ObservableGauge Int64))
Create an asynchronous Int64 gauge with initial callbacks.
meterCreateObservableGaugeDouble :: !(Text -> Maybe Text -> Maybe Text -> AdvisoryParameters -> [ObservableResult Double -> IO ()] -> IO (ObservableGauge Double))
Create an asynchronous Double gauge with initial callbacks.

Instruments

data InstrumentKind Source #

Instrument kinds from the metrics API specification.

Since: 0.0.1.0

Constructors

KindCounter
KindAsyncCounter
KindUpDownCounter
KindAsyncUpDownCounter
KindHistogram
KindGauge
KindAsyncGauge

Instances

Instances details

Generic InstrumentKind Source #

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

Associated Types

type Rep InstrumentKind

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

type Rep InstrumentKind = D1 ('MetaData "InstrumentKind" "OpenTelemetry.Internal.Metric.Types" "hs-opentelemetry-api-1.0.0.0-inplace" 'False) ((C1 ('MetaCons "KindCounter" 'PrefixI 'False) (U1 :: Type -> Type) :+: (C1 ('MetaCons "KindAsyncCounter" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "KindUpDownCounter" 'PrefixI 'False) (U1 :: Type -> Type))) :+: ((C1 ('MetaCons "KindAsyncUpDownCounter" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "KindHistogram" 'PrefixI 'False) (U1 :: Type -> Type)) :+: (C1 ('MetaCons "KindGauge" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "KindAsyncGauge" 'PrefixI 'False) (U1 :: Type -> Type))))

Methods

from :: InstrumentKind -> Rep InstrumentKind x #

to :: Rep InstrumentKind x -> InstrumentKind #

Show InstrumentKind Source #

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

Methods

showsPrec :: Int -> InstrumentKind -> ShowS #

show :: InstrumentKind -> String #

showList :: [InstrumentKind] -> ShowS #

Eq InstrumentKind Source #

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

Methods

(==) :: InstrumentKind -> InstrumentKind -> Bool #

(/=) :: InstrumentKind -> InstrumentKind -> Bool #

Ord InstrumentKind Source #

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

Methods

compare :: InstrumentKind -> InstrumentKind -> Ordering #

(<) :: InstrumentKind -> InstrumentKind -> Bool #

(<=) :: InstrumentKind -> InstrumentKind -> Bool #

(>) :: InstrumentKind -> InstrumentKind -> Bool #

(>=) :: InstrumentKind -> InstrumentKind -> Bool #

max :: InstrumentKind -> InstrumentKind -> InstrumentKind #

min :: InstrumentKind -> InstrumentKind -> InstrumentKind #

Hashable InstrumentKind Source #

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

Methods

hashWithSalt :: Int -> InstrumentKind -> Int #

hash :: InstrumentKind -> Int #

type Rep InstrumentKind Source #

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

type Rep InstrumentKind = D1 ('MetaData "InstrumentKind" "OpenTelemetry.Internal.Metric.Types" "hs-opentelemetry-api-1.0.0.0-inplace" 'False) ((C1 ('MetaCons "KindCounter" 'PrefixI 'False) (U1 :: Type -> Type) :+: (C1 ('MetaCons "KindAsyncCounter" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "KindUpDownCounter" 'PrefixI 'False) (U1 :: Type -> Type))) :+: ((C1 ('MetaCons "KindAsyncUpDownCounter" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "KindHistogram" 'PrefixI 'False) (U1 :: Type -> Type)) :+: (C1 ('MetaCons "KindGauge" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "KindAsyncGauge" 'PrefixI 'False) (U1 :: Type -> Type))))

data HistogramAggregation Source #

Histogram aggregation chosen for an instrument (explicit bounds vs exponential).

Since: 0.0.1.0

Constructors

HistogramAggregationExplicit !(Vector Double)
HistogramAggregationExponential !Int32	Exponential histogram scale (OTel mapping index uses `2^scale`).

Instances

Instances details

Generic HistogramAggregation Source #

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

Associated Types

type Rep HistogramAggregation

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

type Rep HistogramAggregation = D1 ('MetaData "HistogramAggregation" "OpenTelemetry.Internal.Metric.Types" "hs-opentelemetry-api-1.0.0.0-inplace" 'False) (C1 ('MetaCons "HistogramAggregationExplicit" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 (Vector Double))) :+: C1 ('MetaCons "HistogramAggregationExponential" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 Int32)))

Methods

from :: HistogramAggregation -> Rep HistogramAggregation x #

to :: Rep HistogramAggregation x -> HistogramAggregation #

Show HistogramAggregation Source #

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

Methods

showsPrec :: Int -> HistogramAggregation -> ShowS #

show :: HistogramAggregation -> String #

showList :: [HistogramAggregation] -> ShowS #

Eq HistogramAggregation Source #

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

Methods

(==) :: HistogramAggregation -> HistogramAggregation -> Bool #

(/=) :: HistogramAggregation -> HistogramAggregation -> Bool #

Hashable HistogramAggregation Source #

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

Methods

hashWithSalt :: Int -> HistogramAggregation -> Int #

hash :: HistogramAggregation -> Int #

type Rep HistogramAggregation Source #

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

type Rep HistogramAggregation = D1 ('MetaData "HistogramAggregation" "OpenTelemetry.Internal.Metric.Types" "hs-opentelemetry-api-1.0.0.0-inplace" 'False) (C1 ('MetaCons "HistogramAggregationExplicit" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 (Vector Double))) :+: C1 ('MetaCons "HistogramAggregationExponential" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 Int32)))

data AdvisoryParameters Source #

Advisory parameters (spec: implementations MAY ignore; SDK SHOULD honor where defined).

Since: 0.0.1.0

Constructors

AdvisoryParameters

Fields

advisoryExplicitBucketBoundaries :: !(Maybe [Double])
Histogram explicit bucket boundaries (sorted ascending in SDK when applied).
advisoryAttributeKeys :: !(Maybe [Text])
Recommended attribute keys for the resulting metric stream (development in spec).
advisoryHistogramAggregation :: !(Maybe HistogramAggregation)
Prefer explicit buckets or exponential histogram when set; views may override.

Instances

Instances details

Generic AdvisoryParameters Source #

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

Associated Types

type Rep AdvisoryParameters

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

type Rep AdvisoryParameters = D1 ('MetaData "AdvisoryParameters" "OpenTelemetry.Internal.Metric.Types" "hs-opentelemetry-api-1.0.0.0-inplace" 'False) (C1 ('MetaCons "AdvisoryParameters" 'PrefixI 'True) (S1 ('MetaSel ('Just "advisoryExplicitBucketBoundaries") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 (Maybe [Double])) :*: (S1 ('MetaSel ('Just "advisoryAttributeKeys") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 (Maybe [Text])) :*: S1 ('MetaSel ('Just "advisoryHistogramAggregation") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 (Maybe HistogramAggregation)))))

Methods

from :: AdvisoryParameters -> Rep AdvisoryParameters x #

to :: Rep AdvisoryParameters x -> AdvisoryParameters #

Show AdvisoryParameters Source #

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

Methods

showsPrec :: Int -> AdvisoryParameters -> ShowS #

show :: AdvisoryParameters -> String #

showList :: [AdvisoryParameters] -> ShowS #

Eq AdvisoryParameters Source #

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

Methods

(==) :: AdvisoryParameters -> AdvisoryParameters -> Bool #

(/=) :: AdvisoryParameters -> AdvisoryParameters -> Bool #

type Rep AdvisoryParameters Source #

Instance details

Defined in OpenTelemetry.Internal.Metric.Types

type Rep AdvisoryParameters = D1 ('MetaData "AdvisoryParameters" "OpenTelemetry.Internal.Metric.Types" "hs-opentelemetry-api-1.0.0.0-inplace" 'False) (C1 ('MetaCons "AdvisoryParameters" 'PrefixI 'True) (S1 ('MetaSel ('Just "advisoryExplicitBucketBoundaries") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 (Maybe [Double])) :*: (S1 ('MetaSel ('Just "advisoryAttributeKeys") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 (Maybe [Text])) :*: S1 ('MetaSel ('Just "advisoryHistogramAggregation") 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 (Maybe HistogramAggregation)))))

defaultAdvisoryParameters :: AdvisoryParameters Source #

Since: 0.0.1.0

data Counter a Source #

Synchronous counter (non-negative increments). a is Int64 or Double.

Since: 0.0.1.0

Constructors

Counter
Fields counterAdd :: !(a -> Attributes -> IO ()) Record an increment. Negative values are silently dropped for monotonic counters. counterEnabled :: !(IO Bool) Whether this instrument is active. Noop instruments return `False`.

data UpDownCounter a Source #

Synchronous additive instrument that may increase or decrease.

Since: 0.0.1.0

Constructors

UpDownCounter
Fields upDownCounterAdd :: !(a -> Attributes -> IO ()) Record an increment (positive) or decrement (negative). upDownCounterEnabled :: !(IO Bool) Whether this instrument is active.

data Histogram Source #

Synchronous histogram (records Double measurements).

Since: 0.0.1.0

Constructors

Histogram
Fields histogramRecord :: !(Double -> Attributes -> IO ()) Record a measurement. NaN and Infinity are silently dropped. histogramEnabled :: !(IO Bool) Whether this instrument is active.

data Gauge a Source #

Synchronous gauge (last value wins per collect cycle semantics in SDK).

Since: 0.0.1.0

Constructors

Gauge
Fields gaugeRecord :: !(a -> Attributes -> IO ()) Record a value. The last value per attribute set wins at collection time. gaugeEnabled :: !(IO Bool) Whether this instrument is active.

newtype ObservableResult a Source #

Result handle passed to observable callbacks (spec: observe measurements at one logical instant).

Since: 0.0.1.0

Constructors

ObservableResult
Fields observe :: a -> Attributes -> IO () Report a measurement for the given attribute set.

newtype ObservableCallbackHandle Source #

Handle to unregister a callback registered after instrument creation.

Since: 0.0.1.0

Constructors

ObservableCallbackHandle
Fields unregisterObservableCallback :: IO () Remove this callback so it is no longer invoked during collection.

data ObservableCounter a Source #

Asynchronous counter: monotonic cumulative values observed per collection.

Since: 0.0.1.0

Constructors

ObservableCounter

Fields

observableCounterRegisterCallback :: !((ObservableResult a -> IO ()) -> IO ObservableCallbackHandle)
Register an additional callback after creation; returns a handle to unregister it.
observableCounterInstrumentScope :: !InstrumentationLibrary
The instrumentation scope that created this instrument.
observableCounterInstrumentName :: !Text
The instrument name (case-insensitive for matching in the SDK).
observableCounterEnabled :: !(IO Bool)
Whether this instrument is active.

data ObservableUpDownCounter a Source #

Asynchronous up-down counter.

Since: 0.0.1.0

Constructors

ObservableUpDownCounter

Fields

observableUpDownCounterRegisterCallback :: !((ObservableResult a -> IO ()) -> IO ObservableCallbackHandle)
Register an additional callback after creation.
observableUpDownCounterInstrumentScope :: !InstrumentationLibrary
The instrumentation scope that created this instrument.
observableUpDownCounterInstrumentName :: !Text
The instrument name.
observableUpDownCounterEnabled :: !(IO Bool)
Whether this instrument is active.

data ObservableGauge a Source #

Asynchronous gauge.

Since: 0.0.1.0

Constructors

ObservableGauge
Fields observableGaugeRegisterCallback :: !((ObservableResult a -> IO ()) -> IO ObservableCallbackHandle) Register an additional callback after creation. observableGaugeInstrumentScope :: !InstrumentationLibrary The instrumentation scope that created this instrument. observableGaugeInstrumentName :: !Text The instrument name. observableGaugeEnabled :: !(IO Bool) Whether this instrument is active.

Instrument name validation (for SDK implementers)

validateInstrumentName :: Text -> Maybe Text Source #

Nothing if valid; Just err with a short English reason if invalid. Implements the stable rules from specificationmetricsapi.md (instrument name ABNF; ASCII only).

Since: 0.0.1.0

validateInstrumentUnit :: Text -> Maybe Text Source #

Unit is optional; when present it must be ASCII and at most 63 code units (specificationmetricsapi.md).

Since: 0.0.1.0