Add different defaults for when RC fetch failed

Author: mrober

firebase-perf/src/main/java/com/google/firebase/perf/config/ConfigResolver.java

@@ -290,7 +290,8 @@ public double getTraceSamplingRate() {
     // Order of precedence is:
     // 1. If the value exists through Firebase Remote Config, cache and return this value.
     // 2. If the value exists in device cache, return this value.
-    // 3. Otherwise, return default value.
+    // 3. If the Firebase Remote Config fetch failed, return the default "rc failure" value.
+    // 4. Otherwise, return default value.
     TraceSamplingRate config = TraceSamplingRate.getInstance();
 
     // 1. Reads value from Firebase Remote Config, saves this value in cache layer if valid.
@@ -306,7 +307,12 @@ public double getTraceSamplingRate() {
       return deviceCacheValue.get();
     }
 
-    // 3. Returns default value if there is no valid value from above approaches.
+    // 3. Check if RC fetch failed.
+    if (remoteConfigManager.isLastFetchFailed()) {
+      return config.getDefaultOnRcFetchFail();
+    }
+
+    // 4. Returns default value if there is no valid value from above approaches.
     return config.getDefault();
   }
 
@@ -315,7 +321,8 @@ public double getNetworkRequestSamplingRate() {
     // Order of precedence is:
     // 1. If the value exists through Firebase Remote Config, cache and return this value.
     // 2. If the value exists in device cache, return this value.
-    // 3. Otherwise, return default value.
+    // 3. If the Firebase Remote Config fetch failed, return the default "rc failure" value.
+    // 4. Otherwise, return default value.
     NetworkRequestSamplingRate config = NetworkRequestSamplingRate.getInstance();
 
     // 1. Reads value from Firebase Remote Config, saves this value in cache layer if valid.
@@ -331,7 +338,12 @@ public double getNetworkRequestSamplingRate() {
       return deviceCacheValue.get();
     }
 
-    // 3. Returns default value if there is no valid value from above approaches.
+    // 3. Check if RC fetch failed.
+    if (remoteConfigManager.isLastFetchFailed()) {
+      return config.getDefaultOnRcFetchFail();
+    }
+
+    // 4. Returns default value if there is no valid value from above approaches.
     return config.getDefault();
   }
 
@@ -342,7 +354,8 @@ public double getSessionsSamplingRate() {
     // and return this value.
     // 2. If the value exists through Firebase Remote Config, cache and return this value.
     // 3. If the value exists in device cache, return this value.
-    // 4. Otherwise, return default value.
+    // 4. If the Firebase Remote Config fetch failed, return the default "rc failure" value.
+    // 5. Otherwise, return default value.
     SessionsSamplingRate config = SessionsSamplingRate.getInstance();
 
     // 1. Reads value in Android Manifest (it is set by developers during build time).
@@ -368,7 +381,12 @@ public double getSessionsSamplingRate() {
       return deviceCacheValue.get();
     }
 
-    // 4. Returns default value if there is no valid value from above approaches.
+    // 4. Check if RC fetch failed.
+    if (remoteConfigManager.isLastFetchFailed()) {
+      return config.getDefaultOnRcFetchFail();
+    }
+
+    // 5. Returns default value if there is no valid value from above approaches.
     return config.getDefault();
   }
 

firebase-perf/src/main/java/com/google/firebase/perf/config/ConfigurationConstants.java

@@ -152,6 +152,12 @@ protected Double getDefault() {
       return 1.0;
     }
 
+    @Override
+    protected Double getDefaultOnRcFetchFail() {
+      // Reduce the typical default by 2 orders of magnitude.
+      return getDefault() / 100;
+    }
+
     @Override
     protected String getRemoteConfigFlag() {
       return "fpr_vc_trace_sampling_rate";
@@ -185,6 +191,12 @@ protected Double getDefault() {
       return 1.0;
     }
 
+    @Override
+    protected Double getDefaultOnRcFetchFail() {
+      // Reduce the typical default by 2 orders of magnitude.
+      return getDefault() / 100;
+    }
+
     @Override
     protected String getRemoteConfigFlag() {
       return "fpr_vc_network_request_sampling_rate";
@@ -553,6 +565,12 @@ protected Double getDefault() {
       return 0.01;
     }
 
+    @Override
+    protected Double getDefaultOnRcFetchFail() {
+      // Reduce the typical default by 2 orders of magnitude.
+      return getDefault() / 100;
+    }
+
     @Override
     protected String getDeviceCacheFlag() {
       return "com.google.firebase.perf.SessionSamplingRate";

firebase-perf/src/main/java/com/google/firebase/perf/config/ConfigurationFlag.java

@@ -27,6 +27,12 @@ abstract class ConfigurationFlag<T> {
   /* Default value for this flag. */
   protected abstract T getDefault();
 
+  /* Default value for this flag in the case that RC fetch explicitly failed. */
+  protected T getDefaultOnRcFetchFail() {
+    // Same as typical default unless overridden.
+    return getDefault();
+  }
+
   /* Configuration flag ID for Firebase Remote Config. */
   @Nullable
   String getRemoteConfigFlag() {

firebase-perf/src/main/java/com/google/firebase/perf/config/RemoteConfigManager.java

@@ -344,7 +344,8 @@ private void triggerFirebaseRemoteConfigFetchAndActivateOnSuccessfulFetch() {
         .addOnSuccessListener(executor, result -> syncConfigValues(firebaseRemoteConfig.getAll()))
         .addOnFailureListener(
             executor,
-            task -> {
+            ex -> {
+              logger.debug("Remote config fetch failed: %s", ex);
               firebaseRemoteConfigLastFetchTimestampMs = FETCH_NEVER_HAPPENED_TIMESTAMP_MS;
             });
   }

firebase-perf/src/test/java/com/google/firebase/perf/config/ConfigResolverTest.java

@@ -1653,6 +1653,17 @@ public void getTraceSamplingRate_noRemoteConfig_returnsDefault() {
     assertThat(testConfigResolver.getTraceSamplingRate()).isEqualTo(1.00);
   }
 
+  @Test
+  public void getTraceSamplingRate_remoteConfigFetchFailed_returnsRCFailureDefault() {
+    when(mockRemoteConfigManager.getDouble(TRACE_SAMPLING_RATE_FRC_KEY))
+        .thenReturn(Optional.absent());
+    when(mockDeviceCacheManager.getDouble(TRACE_SAMPLING_RATE_CACHE_KEY))
+        .thenReturn(Optional.absent());
+    when(mockRemoteConfigManager.isLastFetchFailed()).thenReturn(true);
+
+    assertThat(testConfigResolver.getTraceSamplingRate()).isEqualTo(1.00 / 100);
+  }
+
   @Test
   public void getTraceSamplingRate_noRemoteConfigHasCache_returnsCache() {
     when(mockRemoteConfigManager.getDouble(TRACE_SAMPLING_RATE_FRC_KEY))
@@ -1714,6 +1725,17 @@ public void getNetworkRequestSamplingRate_noRemoteConfig_returnsDefault() {
     assertThat(testConfigResolver.getNetworkRequestSamplingRate()).isEqualTo(1.00);
   }
 
+  @Test
+  public void getNetworkRequestSamplingRate_remoteConfigFetchFailed_returnsRCFailureDefault() {
+    when(mockRemoteConfigManager.getDouble(NETWORK_REQUEST_SAMPLING_RATE_FRC_KEY))
+        .thenReturn(Optional.absent());
+    when(mockDeviceCacheManager.getDouble(NETWORK_REQUEST_SAMPLING_RATE_CACHE_KEY))
+        .thenReturn(Optional.absent());
+    when(mockRemoteConfigManager.isLastFetchFailed()).thenReturn(true);
+
+    assertThat(testConfigResolver.getNetworkRequestSamplingRate()).isEqualTo(1.00 / 100);
+  }
+
   @Test
   public void getNetworkRequestSamplingRate_noRemoteConfigHasCache_returnsCache() {
     when(mockRemoteConfigManager.getDouble(NETWORK_REQUEST_SAMPLING_RATE_FRC_KEY))
@@ -1935,6 +1957,18 @@ public void getSessionsSamplingRate_invalidRemoteConfig_returnCacheValue() {
     verify(mockDeviceCacheManager, never()).setValue(any(), any());
   }
 
+
+  @Test
+  public void getSessionsSamplingRate_remoteConfigFetchFailed_returnsRCFailureDefault() {
+    when(mockDeviceCacheManager.getDouble(SESSION_SAMPLING_RATE_CACHE_KEY))
+        .thenReturn(Optional.absent());
+    when(mockRemoteConfigManager.getDouble(SESSION_SAMPLING_RATE_FRC_KEY))
+        .thenReturn(Optional.absent());
+    when(mockRemoteConfigManager.isLastFetchFailed()).thenReturn(true);
+
+    assertThat(testConfigResolver.getSessionsSamplingRate()).isEqualTo(0.01 / 100);
+  }
+
   @Test
   public void getSessionsSamplingRate_validCache_returnCacheValue() {
     when(mockDeviceCacheManager.getDouble(SESSION_SAMPLING_RATE_CACHE_KEY))