Added retryOnConflict

Fixes #763.

Author: pluma

CHANGELOG.md

@@ -16,6 +16,13 @@ This driver uses semantic versioning:
 
 ## [Unreleased]
 
+### Added
+
+- Added `retryOnConflict` option to `db.query` and `route.request`
+
+  This option allows specifying the number of times the request will be retried
+  if it results in a write-write conflict.
+
 ## [7.7.0] - 2022-01-26
 
 ### Changed

src/connection.ts

@@ -16,10 +16,12 @@ import { Database } from "./database";
 import {
   ArangoError,
   HttpError,
+  isArangoError,
   isArangoErrorResponse,
   isSystemError,
 } from "./error";
 import { btoa } from "./lib/btoa";
+import { ERROR_ARANGO_CONFLICT } from "./lib/codes";
 import { Errback } from "./lib/errback";
 import { normalizeUrl } from "./lib/normalizeUrl";
 import {
@@ -254,6 +256,13 @@ export type RequestOptions = {
    * a non-authoritative server.
    */
   allowDirtyRead?: boolean;
+  /**
+   * If set to a positive number, the request will automatically be retried at
+   * most this many times if it results in a write-write conflict.
+   *
+   * Default: `0`
+   */
+  retryOnConflict?: number;
   /**
    * HTTP headers to pass along with this request in addition to the default
    * headers generated by arangojs.
@@ -288,6 +297,7 @@ type Task = {
   host?: number;
   stack?: () => string;
   allowDirtyRead: boolean;
+  retryOnConflict: number;
   resolve: (res: ArangojsResponse) => void;
   reject: (error: Error) => void;
   retries: number;
@@ -632,6 +642,13 @@ export class Connection {
           this._activeHost = (this._activeHost + 1) % this._hosts.length;
         }
         if (
+          isArangoError(err) &&
+          err.errorNum === ERROR_ARANGO_CONFLICT &&
+          task.retryOnConflict > 0
+        ) {
+          task.retryOnConflict -= 1;
+          this._queue.push(task);
+        } else if (
           !task.host &&
           this._shouldRetry &&
           task.retries < (this._maxRetries || this._hosts.length - 1) &&
@@ -878,6 +895,7 @@ export class Connection {
       expectBinary = false,
       isBinary = false,
       allowDirtyRead = false,
+      retryOnConflict = 0,
       timeout = 0,
       headers,
       ...urlInfo
@@ -911,6 +929,7 @@ export class Connection {
         retries: 0,
         host,
         allowDirtyRead,
+        retryOnConflict,
         options: {
           url: this._buildUrl(urlInfo),
           headers: { ...extraHeaders, ...headers },

src/database.ts

@@ -218,6 +218,13 @@ export type QueryOptions = {
    * `maxRuntime` option for limiting the execution time within ArangoDB.
    */
   timeout?: number;
+  /**
+   * If set to a positive number, the query will automatically be retried at
+   * most this many times if it results in a write-write conflict.
+   *
+   * Default: `0`
+   */
+  retryOnConflict?: number;
   /**
    * Unless set to `false`, the number of result values in the result set will
    * be returned in the `count` attribute. This may be disabled by default in
@@ -3579,6 +3586,7 @@ export class Database {
     }
     const {
       allowDirtyRead,
+      retryOnConflict,
       count,
       batchSize,
       cache,
@@ -3602,6 +3610,7 @@ export class Database {
           options: opts,
         },
         allowDirtyRead,
+        retryOnConflict,
         timeout,
       },
       (res) =>

src/lib/codes.ts

@@ -9,6 +9,7 @@
  */
 
 export const TRANSACTION_NOT_FOUND = 10;
+export const ERROR_ARANGO_CONFLICT = 1200;
 export const ANALYZER_NOT_FOUND = 1202;
 export const DOCUMENT_NOT_FOUND = 1202;
 export const COLLECTION_NOT_FOUND = 1203;