From 375b70dd4027736cbd69c78066090492c57f87e8 Mon Sep 17 00:00:00 2001
From: Echo009 <ech0.extreme@foxmail.com>
Date: Mon, 8 Mar 2021 16:34:13 +0800
Subject: [PATCH] fix: concurrency problem when dispatch job instance

---
 .../java/tech/powerjob/server/core/DispatchService.java    | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/powerjob-server/powerjob-server-core/src/main/java/tech/powerjob/server/core/DispatchService.java b/powerjob-server/powerjob-server-core/src/main/java/tech/powerjob/server/core/DispatchService.java
index 5de28d6b..bf79bd8e 100644
--- a/powerjob-server/powerjob-server-core/src/main/java/tech/powerjob/server/core/DispatchService.java
+++ b/powerjob-server/powerjob-server-core/src/main/java/tech/powerjob/server/core/DispatchService.java
@@ -86,6 +86,12 @@ public class DispatchService {
             log.info("[Dispatcher-{}|{}] cancel dispatch due to instance has been canceled", jobId, instanceId);
             return;
         }
+        // 已经被派发过则不再派发
+        // fix 并发场景下重复派发的问题
+        if (instanceInfo.getStatus() != WAITING_DISPATCH.getV()) {
+            log.info("[Dispatcher-{}|{}] cancel dispatch due to instance has been dispatched", jobId, instanceId);
+            return;
+        }
         // 任务信息已经被删除
         if (jobInfo.getId() == null) {
             log.warn("[Dispatcher-{}|{}] cancel dispatch due to job(id={}) has been deleted!", jobId, instanceId, jobId);
@@ -194,6 +200,7 @@ public class DispatchService {
                 return workerInfos.get(0);
             case RANDOM:
                 return workerInfos.get(ThreadLocalRandom.current().nextInt(workerInfos.size()));
+            default:
         }
         // impossible, indian java
         return workerInfos.get(0);