Differentiate between epoch 409 and coherency 409 errors (#4874)

microsoft · Jan 22, 2021 · 23c1d41 · 23c1d41
1 parent ca8bea2
commit 23c1d41
Showing 1 changed file with 32 additions and 17 deletions.
diff --git a/packages/drivers/odsp-driver/src/epochTracker.ts b/packages/drivers/odsp-driver/src/epochTracker.ts
@@ -6,6 +6,7 @@
 import { assert } from "@fluidframework/common-utils";
 import { ITelemetryLogger } from "@fluidframework/common-definitions";
 import { fluidEpochMismatchError, OdspErrorType } from "@fluidframework/odsp-doclib-utils";
+import { ThrottlingError } from "@fluidframework/driver-utils";
 import { fetchAndParseAsJSONHelper, fetchHelper, IOdspResponse } from "./odspUtils";
 import { ICacheEntry, IFileEntry, LocalPersistentCacheAdapter } from "./odspCache";
 import { RateLimiter } from "./rateLimiter";
@@ -159,12 +160,7 @@ export class EpochTracker {
         fetchType: FetchType,
         fromCache: boolean = false,
     ) {
-        // If epoch is undefined, then don't compare it because initially for createNew or TreesLatest
-        // initializes this value. Sometimes response does not contain epoch as it is still in
-        // implementation phase at server side. In that case also, don't compare it with our epoch value.
-        if (this.fluidEpoch && epochFromResponse && (this.fluidEpoch !== epochFromResponse)) {
-            throwOdspNetworkError("Epoch Mismatch", fluidEpochMismatchError);
-        }
+        this.checkForEpochErrorCore(epochFromResponse);
         if (epochFromResponse) {
             if (this._fluidEpoch === undefined) {
                 this.logger.sendTelemetryEvent(
@@ -187,17 +183,36 @@ export class EpochTracker {
         fromCache: boolean = false,
     ) {
         if (error.errorType === OdspErrorType.epochVersionMismatch) {
-            const err = {
-                ...error,
-                fromCache,
-                clientEpoch: this.fluidEpoch,
-                serverEpoch: epochFromResponse ?? undefined,
-                fetchType,
-            };
-            this.logger.sendErrorEvent({ eventName: "EpochVersionMismatch" }, err);
-            assert(!!this.fileEntry, "File Entry should be set to clear the cached entries!!");
-            // If the epoch mismatches, then clear all entries for such file entry from cache.
-            await this.persistedCache.removeEntries(this.fileEntry);
+            try {
+                // This will only throw if it is an epoch error.
+                this.checkForEpochErrorCore(epochFromResponse, error.errorMessage);
+            } catch (epochError) {
+                const err = {
+                    ...epochError,
+                    fromCache,
+                    clientEpoch: this.fluidEpoch,
+                    fetchType,
+                };
+                this.logger.sendErrorEvent({ eventName: "EpochVersionMismatch" }, err);
+                assert(!!this.fileEntry, "File Entry should be set to clear the cached entries!!");
+                // If the epoch mismatches, then clear all entries for such file entry from cache.
+                await this.persistedCache.removeEntries(this.fileEntry);
+                throw epochError;
+            }
+            // If it was categorised as epoch error but the epoch returned in response matches with the client epoch
+            // then it was coherency 409, so rethrow it as throttling error so that it can retried. Default throttling
+            // time is 1s.
+            this.logger.sendErrorEvent({ eventName: "Coherency409" }, error);
+            throw new ThrottlingError(error.errorMessage, 1000, 429);
+        }
+    }
+
+    private checkForEpochErrorCore(epochFromResponse: string | null | undefined, message?: string) {
+        // If epoch is undefined, then don't compare it because initially for createNew or TreesLatest
+        // initializes this value. Sometimes response does not contain epoch as it is still in
+        // implementation phase at server side. In that case also, don't compare it with our epoch value.
+        if (this.fluidEpoch && epochFromResponse && (this.fluidEpoch !== epochFromResponse)) {
+            throwOdspNetworkError(message ?? "Epoch Mismatch", fluidEpochMismatchError);
         }
     }
 }