chore(remote-settings): RMST-586: Use glean-sym

components/remote_settings/Cargo.toml

@@ -13,6 +13,9 @@ default = []
 signatures = ["dep:canonical_json", "dep:rc_crypto"]
 # submitting glean telemetry is tricky on desktop for now.
 telemetry-submission = []
+# Record metrics directly from Rust via glean-sym, instead of through the
+# `RemoteSettingsTelemetry` foreign callback.
+glean-sym = ["dep:glean-sym", "glean-sym/active"]
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
@@ -35,9 +38,11 @@ firefox-versioning = { path = "../support/firefox-versioning" }
 sha2 = "^0.10"
 canonical_json = { version = "0.5", optional = true }
 rc_crypto = { path = "../support/rc_crypto", optional = true }
+glean-sym = { version = "71", optional = true }
 
 [build-dependencies]
 uniffi = { version = "0.32", features = ["build"] }
+glean-build = { git = "https://github.com/mozilla/glean", tag = "v71.0.0" }
 
 [dev-dependencies]
 expect-test = "1.4"

components/remote_settings/build.rs

@@ -0,0 +1,11 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+fn main() {
+    glean_build::Builder::default()
+        .file("metrics.yaml")
+        .format("rust_sym")
+        .generate()
+        .expect("Error generating Glean Rust bindings");
+}

components/remote_settings/metrics.yaml

@@ -5,11 +5,12 @@
 # This file defines the metrics that will be gathered for the Remote Settings
 # component.  Changes to these metrics require data review.
 #
-# We can't record metrics from Rust directly.  To work around that we:
-#   - Define the metrics in application-services
-#   - Define API calls in application-services that return the metrics
-#     alongside the normal results.
-#   - Record the metrics with Glean in the consumer code
+# Metrics are recorded in one of two ways:
+#   - With the `glean-sym` feature, they are recorded directly from Rust.
+#     `build.rs` generates the Rust bindings from this file, and `glean-sym`
+#     does the magic at runtime.
+#   - Otherwise, the consumer (Android, iOS) implements the `RemoteSettingsTelemetry`
+#     trait and records the metrics with its own Glean-generated bindings.
 
 ---
 $schema: moz://mozilla.org/schemas/glean/metrics/2-0-0

components/remote_settings/src/lib.rs

@@ -20,6 +20,11 @@ pub mod telemetry;
 pub(crate) mod jexl_filter;
 mod macros;
 
+#[cfg(feature = "glean-sym")]
+mod glean_metrics {
+    include!(concat!(env!("OUT_DIR"), "/glean_metrics.rs"));
+}
+
 pub use client::{Attachment, RemoteSettingsRecord, RsJsonObject};
 pub use config::{BaseUrl, RemoteSettingsConfig, RemoteSettingsServer};
 pub use context::RemoteSettingsContext;

components/remote_settings/src/service.rs

@@ -91,6 +91,7 @@ impl RemoteSettingsService {
                 client: Client::new(ClientSettings::default()),
                 remote_state: RemoteState::default(),
             }),
+            // TODO: elegant plug and play here?
             telemetry: Mutex::new(RemoteSettingsTelemetryWrapper::noop()),
         }
     }

components/remote_settings/src/telemetry.rs

@@ -94,6 +94,8 @@ impl RemoteSettingsTelemetry for NoopRemoteSettingsTelemetry {
 /// Wrapper around [RemoteSettingsTelemetry] used internally.
 #[derive(Clone)]
 pub struct RemoteSettingsTelemetryWrapper {
+    // Unused with `glean-sym`: metrics are recorded directly from Rust.
+    #[cfg_attr(feature = "glean-sym", allow(dead_code))]
     inner: Arc<dyn RemoteSettingsTelemetry>,
 }
 
@@ -108,8 +110,40 @@ impl RemoteSettingsTelemetryWrapper {
         }
     }
 
+    #[cfg(feature = "glean-sym")]
+    fn report_uptake(&self, event: UptakeEventExtras) {
+        // With glean-sym, telemetry is sent directly from the
+        // Glean SDK. The wrapped inner implementation is not
+        // called.
+        // This allows us to transition to glean-sym without
+        // breaking changes.
+        // Once this ships and gets enabled in builds, we can
+        // remove the telemetry wrapper code in iOS and Android.
+        use crate::glean_metrics::remote_settings::{
+            uptake_remotesettings, UptakeRemotesettingsExtra,
+        };
+        uptake_remotesettings.record(UptakeRemotesettingsExtra {
+            value: event.value,
+            source: event.source,
+            age: event.age,
+            trigger: event.trigger,
+            timestamp: event.timestamp,
+            duration: event.duration,
+            errorname: event.error_name,
+        });
+    }
+
+    #[cfg(not(feature = "glean-sym"))]
+    fn report_uptake(&self, event: UptakeEventExtras) {
+        // Call the native implementation of Glean.
+        // Note: feature is disabled on desktop.
+        // When `glean-sym` is enabled, the wrapper isn't called at all
+        // and events are sent directly by the Glean SDK.
+        self.inner.report_uptake(event)
+    }
+
     pub fn report_uptake_success(&self, source: &str, duration: Option<u64>) {
-        self.inner.report_uptake(UptakeEventExtras {
+        self.report_uptake(UptakeEventExtras {
             value: Some(SyncStatus::Success.to_string()),
             source: Some(source.to_string()),
             age: None,
@@ -121,7 +155,7 @@ impl RemoteSettingsTelemetryWrapper {
     }
 
     pub fn report_uptake_up_to_date(&self, source: &str, duration: Option<u64>) {
-        self.inner.report_uptake(UptakeEventExtras {
+        self.report_uptake(UptakeEventExtras {
             value: Some(SyncStatus::UpToDate.to_string()),
             source: Some(source.to_string()),
             age: None,
@@ -143,7 +177,8 @@ impl RemoteSettingsTelemetryWrapper {
             .unwrap_or("")
             .trim()
             .to_string();
-        self.inner.report_uptake(UptakeEventExtras {
+
+        self.report_uptake(UptakeEventExtras {
             value: Some(error_to_status(error).to_string()),
             source: Some(source.to_string()),
             age: None,