fix(metrics): Enable metrics by default (#1106)

Align runtime metrics capture with other SDKs while preserving explicit
opt-out via ClientOptions::enable_metrics.

Closes #1105
Closes
[RUST-207](https://linear.app/getsentry/issue/RUST-207/default-enable-metrics-to-true)

Author: szokeasaurusrex

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+### Fixes
+
+- Changed [`ClientOptions::enable_metrics`](https://docs.rs/sentry-core/latest/sentry_core/struct.ClientOptions.html#structfield.enable_metrics) to default to `true`, aligning metrics behavior with other Sentry SDKs ([#1106](https://github.com/getsentry/sentry-rust/issues/1106)). Metric capture APIs still require the `metrics` feature flag at compile time.
+
 ## 0.48.0
 
 ### Breaking Changes

sentry-core/src/clientoptions.rs

@@ -174,15 +174,16 @@ pub struct ClientOptions {
     /// This setting has no effect unless the `logs` feature is enabled at compile-time, as the
     /// feature is a pre-requisite to sending logs.
     pub enable_logs: bool,
-    /// Determines whether captured metrics should be sent to Sentry (defaults to false).
+    /// Determines whether metric capture APIs should capture metrics (defaults to true).
     ///
-    /// This setting has no effect unless the `metrics` feature is enabled at compile-time,
-    /// as the feature is a prerequisite for sending metrics.
+    /// Metric capture APIs are only available when the `metrics` feature is enabled at compile
+    /// time. If the `metrics` feature is enabled, set this to `false` to prevent metrics from
+    /// being captured and sent at runtime.
     pub enable_metrics: bool,
     /// Callback that is executed for each Metric before sending.
     ///
     /// This setting has no effect unless the `metrics` feature is enabled at compile-time,
-    /// as the feature is a prerequisite for sending metrics.
+    /// as the feature is a prerequisite for capturing metrics.
     pub before_send_metric: Option<BeforeCallback<Metric>>,
     // Other options not documented in Unified API
     /// Disable SSL verification.
@@ -329,7 +330,7 @@ impl Default for ClientOptions {
             max_request_body_size: MaxRequestBodySize::Medium,
             enable_logs: true,
             before_send_log: None,
-            enable_metrics: false,
+            enable_metrics: true,
             before_send_metric: None,
         }
     }

sentry-core/tests/metrics.rs

@@ -48,12 +48,28 @@ fn sent_when_enabled() {
     } if name == "test"));
 }
 
+/// Test that metrics are sent by default.
+#[test]
+fn metrics_enabled_by_default() {
+    let options = ClientOptions::default();
+
+    let envelopes =
+        test::with_captured_envelopes_options(|| metrics::counter("test", 1).capture(), options);
+    assert_eq!(
+        envelopes.len(),
+        1,
+        "expected exactly one envelope when metrics are enabled by default"
+    )
+}
+
 /// Test that metrics are disabled (not sent) when disabled in the
 /// [`ClientOptions`].
 #[test]
-fn metrics_disabled_by_default() {
-    // Metrics are disabled by default.
-    let options: ClientOptions = Default::default();
+fn metrics_disabled_when_configured() {
+    let options = ClientOptions {
+        enable_metrics: false,
+        ..Default::default()
+    };
 
     let envelopes =
         test::with_captured_envelopes_options(|| metrics::counter("test", 1).capture(), options);
@@ -67,10 +83,7 @@ fn metrics_disabled_by_default() {
 /// metrics enabled
 #[test]
 fn noop_sends_nothing() {
-    let options = ClientOptions {
-        enable_metrics: true,
-        ..Default::default()
-    };
+    let options = ClientOptions::default();
 
     let envelopes = test::with_captured_envelopes_options(|| (), options);
 
@@ -80,10 +93,7 @@ fn noop_sends_nothing() {
 /// Test that 100 metrics are sent in a single envelope.
 #[test]
 fn test_metrics_batching_at_limit() {
-    let options = ClientOptions {
-        enable_metrics: true,
-        ..Default::default()
-    };
+    let options = ClientOptions::default();
 
     let envelopes = test::with_captured_envelopes_options(
         || {
@@ -133,10 +143,7 @@ fn test_metrics_batching_at_limit() {
 /// Test that 101 envelopes are sent in two separate envelopes
 #[test]
 fn test_metrics_batching_over_limit() {
-    let options = ClientOptions {
-        enable_metrics: true,
-        ..Default::default()
-    };
+    let options = ClientOptions::default();
 
     let mut envelopes = test::with_captured_envelopes_options(
         || {
@@ -207,10 +214,7 @@ fn test_metrics_batching_over_limit() {
 
 #[test]
 fn metric_attributes_are_captured() {
-    let options = ClientOptions {
-        enable_metrics: true,
-        ..Default::default()
-    };
+    let options = ClientOptions::default();
 
     let envelopes = test::with_captured_envelopes_options(
         || {
@@ -265,10 +269,7 @@ fn metric_attributes_are_captured() {
 
 #[test]
 fn metric_unit_is_captured() {
-    let options = ClientOptions {
-        enable_metrics: true,
-        ..Default::default()
-    };
+    let options = ClientOptions::default();
 
     let envelopes = test::with_captured_envelopes_options(
         || metrics::gauge("test", 42).unit(Unit::Millisecond).capture(),
@@ -311,10 +312,7 @@ fn metric_unit_is_captured() {
 /// This tests that trace ID is set from the propagation context when there is no active span.
 #[test]
 fn metrics_share_trace_id_without_active_span() {
-    let options = ClientOptions {
-        enable_metrics: true,
-        ..Default::default()
-    };
+    let options = ClientOptions::default();
 
     let envelopes = test::with_captured_envelopes_options(
         || {
@@ -348,10 +346,7 @@ fn metrics_share_trace_id_without_active_span() {
 /// Test that span_id is set from the active span when one is present.
 #[test]
 fn metrics_span_id_from_active_span() {
-    let options = ClientOptions {
-        enable_metrics: true,
-        ..Default::default()
-    };
+    let options = ClientOptions::default();
 
     let mut expected_span_id = None;
     let envelopes = test::with_captured_envelopes_options(
@@ -389,7 +384,6 @@ fn metrics_span_id_from_active_span() {
 #[test]
 fn default_attributes_attached() {
     let options = ClientOptions {
-        enable_metrics: true,
         environment: Some("test-env".into()),
         release: Some("1.0.0".into()),
         server_name: Some("test-server".into()),
@@ -417,10 +411,7 @@ fn default_attributes_attached() {
 /// Test that optional default attributes are omitted when not configured.
 #[test]
 fn optional_default_attributes_omitted_when_not_configured() {
-    let options = ClientOptions {
-        enable_metrics: true,
-        ..Default::default()
-    };
+    let options = ClientOptions::default();
 
     let envelopes =
         test::with_captured_envelopes_options(|| metrics::counter("test", 1).capture(), options);
@@ -442,7 +433,6 @@ fn optional_default_attributes_omitted_when_not_configured() {
 #[test]
 fn default_attributes_do_not_overwrite_explicit() {
     let options = ClientOptions {
-        enable_metrics: true,
         environment: Some("default-env".into()),
         ..Default::default()
     };
@@ -475,7 +465,6 @@ fn default_attributes_do_not_overwrite_explicit() {
 #[test]
 fn user_attributes_absent_without_send_default_pii() {
     let options = ClientOptions {
-        enable_metrics: true,
         send_default_pii: false,
         ..Default::default()
     };
@@ -513,7 +502,6 @@ fn user_attributes_absent_without_send_default_pii() {
 #[test]
 fn metric_user_attributes_from_scope_are_applied_with_send_default_pii() {
     let options = ClientOptions {
-        enable_metrics: true,
         send_default_pii: true,
         ..Default::default()
     };
@@ -553,7 +541,6 @@ fn metric_user_attributes_from_scope_are_applied_with_send_default_pii() {
 #[test]
 fn metric_user_attributes_do_not_overwrite_explicit() {
     let options = ClientOptions {
-        enable_metrics: true,
         send_default_pii: true,
         ..Default::default()
     };
@@ -594,7 +581,6 @@ fn metric_user_attributes_do_not_overwrite_explicit() {
 #[test]
 fn before_send_metric_can_drop() {
     let options = ClientOptions {
-        enable_metrics: true,
         before_send_metric: Some(Arc::new(|_| None)),
         ..Default::default()
     };
@@ -611,7 +597,6 @@ fn before_send_metric_can_drop() {
 #[test]
 fn before_send_metric_can_modify() {
     let options = ClientOptions {
-        enable_metrics: true,
         before_send_metric: Some(Arc::new(|mut metric| {
             metric
                 .attributes