Bug 1848331 - Add ability to configure precise event timestamps through Nimbus r=TravisLong

Differential Revision: https://phabricator.services.mozilla.com/D188325

toolkit/components/glean/src/init/mod.rs

@@ -155,12 +155,16 @@ fn build_configuration(
 
     extern "C" {
         fn FOG_MaxPingLimit() -> u32;
+        fn FOG_EventTimestampsEnabled() -> bool;
     }
 
     // SAFETY NOTE: Safe because it returns a primitive by value.
     let pings_per_interval = unsafe { FOG_MaxPingLimit() };
     metrics::fog::max_pings_per_minute.set(pings_per_interval.into());
 
+    // SAFETY NOTE: Safe because it returns a primitive by value.
+    let enable_event_timestamps = unsafe { FOG_EventTimestampsEnabled() };
+
     let rate_limit = Some(glean::PingRateLimit {
         seconds_per_interval: 60,
         pings_per_interval,
@@ -178,7 +182,7 @@ fn build_configuration(
         trim_data_to_registered_pings: true,
         log_level: None,
         rate_limit,
-        enable_event_timestamps: false,
+        enable_event_timestamps,
     };
 
     Ok((configuration, client_info))

toolkit/components/glean/xpcom/FOG.cpp

@@ -122,6 +122,13 @@ extern "C" uint32_t FOG_MaxPingLimit(void) {
                                 "gleanMaxPingsPerMinute"_ns, 15);
 }
 
+// This allows us to pass whether to enable precise event timestamps to Rust.
+// Default is false.
+extern "C" bool FOG_EventTimestampsEnabled(void) {
+  return NimbusFeatures::GetBool("gleanInternalSdk"_ns,
+                                 "enableEventTimestamps"_ns, false);
+}
+
 NS_IMETHODIMP
 FOG::InitializeFOG(const nsACString& aDataPathOverride,
                    const nsACString& aAppIdOverride) {

toolkit/components/nimbus/FeatureManifest.yaml

@@ -1161,6 +1161,9 @@ glean:
 gleanInternalSdk:
   description: "The Glean internal SDK feature intended only for internal Glean Team use"
   hasExposure: false
+  # Some variables are used through the C++ API and thus require pref-storage.
+  # We rely on those values at Glean.init time, which happens at startup.
+  isEarlyStartup: true
   variables:
     finalInactive:
       type: "boolean"
@@ -1175,6 +1178,9 @@ gleanInternalSdk:
       type: int
       description: >-
         Maximum number of pings that can be sent in a 60 second interval
+    enableEventTimestamps:
+      type: "boolean"
+      description: "Enables precise event timestamps for Glean events"
 
 majorRelease2022:
   description: Major Release 2022