opentelemetry/global/
metrics.rs

1use crate::metrics::{self, Meter, MeterProvider};
2use crate::{otel_error, otel_info, InstrumentationScope};
3use std::sync::{Arc, OnceLock, RwLock};
4
5type GlobalMeterProvider = Arc<dyn MeterProvider + Send + Sync>;
6
7/// The global `MeterProvider` singleton.
8static GLOBAL_METER_PROVIDER: OnceLock<RwLock<GlobalMeterProvider>> = OnceLock::new();
9
10#[inline]
11fn global_meter_provider() -> &'static RwLock<GlobalMeterProvider> {
12    GLOBAL_METER_PROVIDER
13        .get_or_init(|| RwLock::new(Arc::new(crate::metrics::noop::NoopMeterProvider::new())))
14}
15
16/// Sets the given [`MeterProvider`] instance as the current global meter
17/// provider.
18/// Libraries should NOT call this function. It is intended for applications/executables.
19///
20/// **NOTE:** This function should be called before getting [`Meter`] instances via [`meter()`] or [`meter_with_scope()`]. Otherwise, you could get no-op [`Meter`] instances.
21pub fn set_meter_provider<P>(new_provider: P)
22where
23    P: metrics::MeterProvider + Send + Sync + 'static,
24{
25    // Try to set the global meter provider. If the RwLock is poisoned, we'll log an error.
26    let mut global_provider = global_meter_provider().write();
27    if let Ok(ref mut provider) = global_provider {
28        **provider = Arc::new(new_provider);
29        otel_info!(name: "MeterProvider.GlobalSet", message = "Global meter provider is set. Meters can now be created using global::meter() or global::meter_with_scope().");
30    } else {
31        otel_error!(name: "MeterProvider.GlobalSetFailed", message = "Setting global meter provider failed. Meters created using global::meter() or global::meter_with_scope() will not function. Report this issue in OpenTelemetry repo.");
32    }
33}
34
35/// Returns an instance of the currently configured global [`MeterProvider`].
36pub fn meter_provider() -> GlobalMeterProvider {
37    // Try to get the global meter provider. If the RwLock is poisoned, we'll log an error and return a NoopMeterProvider.
38    let global_provider = global_meter_provider().read();
39    if let Ok(provider) = global_provider {
40        provider.clone()
41    } else {
42        otel_error!(name: "MeterProvider.GlobalGetFailed", message = "Getting global meter provider failed. Meters created using global::meter() or global::meter_with_scope() will not function. Report this issue in OpenTelemetry repo.");
43        Arc::new(crate::metrics::noop::NoopMeterProvider::new())
44    }
45}
46
47/// Creates a named [`Meter`] via the currently configured global [`MeterProvider`].
48///
49/// This is a more convenient way of expressing `global::meter_provider().meter(name)`.
50///
51/// **NOTE:** Calls to [`meter()`] return a [`Meter`] backed by the global [`MeterProvider`] configured during the method invocation.
52/// If the global [`MeterProvider`] is changed after getting [`Meter`] instances from these calls, the [`Meter`] instances returned will not reflect the change.
53pub fn meter(name: &'static str) -> Meter {
54    meter_provider().meter(name)
55}
56
57/// Creates a [`Meter`] with the given instrumentation scope.
58///
59/// This is a simpler alternative to `global::meter_provider().meter_with_scope(...)`
60///
61/// **NOTE:** Calls to [`meter_with_scope()`] return a [`Meter`] backed by the global [`MeterProvider`] configured during the method invocation.
62/// If the global [`MeterProvider`] is changed after getting [`Meter`] instances from these calls, the [`Meter`] instances returned will not reflect the change.
63///
64/// # Example
65///
66/// ```
67/// use std::sync::Arc;
68/// use opentelemetry::global::meter_with_scope;
69/// use opentelemetry::InstrumentationScope;
70/// use opentelemetry::KeyValue;
71///
72/// let scope = InstrumentationScope::builder("io.opentelemetry")
73///     .with_version("0.17")
74///     .with_schema_url("https://opentelemetry.io/schema/1.2.0")
75///     .with_attributes(vec![(KeyValue::new("key", "value"))])
76///     .build();
77///
78/// let meter = meter_with_scope(scope);
79/// ```
80pub fn meter_with_scope(scope: InstrumentationScope) -> Meter {
81    meter_provider().meter_with_scope(scope)
82}
opentelemetry/global/metrics.rs

opentelemetry/global/
metrics.rs
