add must use notice as well functions to customize timeout and period

autometrics/src/otel_push_exporter.rs

@@ -1,12 +1,13 @@
 use opentelemetry_api::metrics::MetricsError;
-use opentelemetry_otlp::OtlpMetricPipeline;
 use opentelemetry_otlp::{ExportConfig, Protocol, WithExportConfig};
+use opentelemetry_otlp::{OtlpMetricPipeline, OTEL_EXPORTER_OTLP_TIMEOUT_DEFAULT};
 use opentelemetry_sdk::metrics::MeterProvider;
 use opentelemetry_sdk::runtime;
 use std::ops::Deref;
 use std::time::Duration;
 
 #[repr(transparent)]
+#[must_use = "Assign this to a unused variable instead: `let _meter = ...` (NOT `let _ = ...`), as else it will be dropped immediately - which will cause it to be shut down"]
 pub struct OtelMeterProvider(MeterProvider);
 
 impl Deref for OtelMeterProvider {
@@ -26,34 +27,62 @@ impl Drop for OtelMeterProvider {
 
 #[cfg(feature = "otel-push-exporter-http")]
 pub fn init_http(url: impl Into<String>) -> Result<OtelMeterProvider, MetricsError> {
+    init_http_with_timeout_period(
+        url,
+        Duration::from_secs(OTEL_EXPORTER_OTLP_TIMEOUT_DEFAULT),
+        Duration::from_secs(1),
+    )
+}
+
+#[cfg(feature = "otel-push-exporter-http")]
+pub fn init_http_with_timeout_period(
+    url: impl Into<String>,
+    timeout: Duration,
+    period: Duration,
+) -> Result<OtelMeterProvider, MetricsError> {
     runtime()
         .with_exporter(
             opentelemetry_otlp::new_exporter()
                 .http()
                 .with_export_config(ExportConfig {
                     endpoint: url.into(),
                     protocol: Protocol::HttpBinary,
+                    timeout,
                     ..Default::default()
                 }),
         )
-        .with_period(Duration::from_secs(1))
+        .with_period(period)
         .build()
         .map(OtelMeterProvider)
 }
 
 #[cfg(feature = "otel-push-exporter-grpc")]
 pub fn init_grpc(url: impl Into<String>) -> Result<OtelMeterProvider, MetricsError> {
+    init_grpc_with_timeout_period(
+        url,
+        Duration::from_secs(OTEL_EXPORTER_OTLP_TIMEOUT_DEFAULT),
+        Duration::from_secs(1),
+    )
+}
+
+#[cfg(feature = "otel-push-exporter-grpc")]
+pub fn init_grpc_with_timeout_period(
+    url: impl Into<String>,
+    timeout: Duration,
+    period: Duration,
+) -> Result<OtelMeterProvider, MetricsError> {
     runtime()
         .with_exporter(
             opentelemetry_otlp::new_exporter()
                 .tonic()
                 .with_export_config(ExportConfig {
                     endpoint: url.into(),
                     protocol: Protocol::Grpc,
+                    timeout,
                     ..Default::default()
                 }),
         )
-        .with_period(Duration::from_secs(1))
+        .with_period(period)
         .build()
         .map(OtelMeterProvider)
 }

examples/opentelemetry-push/src/main.rs

@@ -12,6 +12,8 @@ async fn do_stuff() {
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn Error + Send + Sync + 'static>> {
+    // NOTICE: the variable gets assigned to `_meter_provider` instead of just `_`, as the later case
+    // would cause it to be dropped immediately and thus shut down.
     let _meter_provider = otel_push_exporter::init_http("http://0.0.0.0:4318")?;
     // or: otel_push_exporter::init_grpc("http://0.0.0.0:4317");