add default values for timeout and period in otel push exporter (#168)

* add default values for `timeout` and `period` in otel push exporter

* update changelog

* pr review

* fix conversion from `OsString` into `String`

Author: mellowagain

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## Unreleased
 
 - Update `http` to `1.0`. This fixes compatibility with `axum 0.7` (#167)
+- Explicitly set default timeout and period for the OTEL push exporter (#168)
 
 ## [1.0.0](https://github.com/autometrics-dev/autometrics-rs/releases/tag/v1.0.0) - 2023-12-01
 

autometrics/src/otel_push_exporter.rs

@@ -1,6 +1,6 @@
 use opentelemetry::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 std::ops::Deref;
 use std::time::Duration;
@@ -33,18 +33,8 @@ impl Drop for OtelMeterProvider {
 /// from within code, consider using [`init_http_with_timeout_period`].
 #[cfg(feature = "otel-push-exporter-http")]
 pub fn init_http(url: impl Into<String>) -> Result<OtelMeterProvider, MetricsError> {
-    runtime()
-        .with_exporter(
-            opentelemetry_otlp::new_exporter()
-                .http()
-                .with_export_config(ExportConfig {
-                    endpoint: url.into(),
-                    protocol: Protocol::HttpBinary,
-                    ..Default::default()
-                }),
-        )
-        .build()
-        .map(OtelMeterProvider)
+    let (timeout, period) = timeout_and_period_from_env_or_default();
+    init_http_with_timeout_period(url, timeout, period)
 }
 
 /// Initialize the OpenTelemetry push exporter using HTTP transport with customized `timeout` and `period`.
@@ -78,18 +68,8 @@ pub fn init_http_with_timeout_period(
 /// from within code, consider using [`init_grpc_with_timeout_period`].
 #[cfg(feature = "otel-push-exporter-grpc")]
 pub fn init_grpc(url: impl Into<String>) -> Result<OtelMeterProvider, MetricsError> {
-    runtime()
-        .with_exporter(
-            opentelemetry_otlp::new_exporter()
-                .tonic()
-                .with_export_config(ExportConfig {
-                    endpoint: url.into(),
-                    protocol: Protocol::Grpc,
-                    ..Default::default()
-                }),
-        )
-        .build()
-        .map(OtelMeterProvider)
+    let (timeout, period) = timeout_and_period_from_env_or_default();
+    init_grpc_with_timeout_period(url, timeout, period)
 }
 
 /// Initialize the OpenTelemetry push exporter using gRPC transport with customized `timeout` and `period`.
@@ -115,6 +95,29 @@ pub fn init_grpc_with_timeout_period(
         .map(OtelMeterProvider)
 }
 
+/// returns timeout and period from their respective environment variables
+/// or the default, if they are not set or set to an invalid value
+fn timeout_and_period_from_env_or_default() -> (Duration, Duration) {
+    const OTEL_EXPORTER_TIMEOUT_ENV: &str = "OTEL_METRIC_EXPORT_TIMEOUT";
+    const OTEL_EXPORTER_INTERVAL_ENV: &str = "OTEL_METRIC_EXPORT_INTERVAL";
+
+    let timeout = Duration::from_secs(
+        std::env::var_os(OTEL_EXPORTER_TIMEOUT_ENV)
+            .and_then(|os_string| os_string.into_string().ok())
+            .and_then(|str| str.parse().ok())
+            .unwrap_or(OTEL_EXPORTER_OTLP_TIMEOUT_DEFAULT),
+    );
+
+    let period = Duration::from_secs(
+        std::env::var_os(OTEL_EXPORTER_INTERVAL_ENV)
+            .and_then(|os_string| os_string.into_string().ok())
+            .and_then(|str| str.parse().ok())
+            .unwrap_or(60),
+    );
+
+    (timeout, period)
+}
+
 #[cfg(all(
     feature = "otel-push-exporter-tokio",
     not(any(