From fe3a4d96d559edcc30c2047109cd7b027e6258eb Mon Sep 17 00:00:00 2001
From: Justin Wind <justin.wind+git@gmail.com>
Date: Mon, 16 Aug 2021 11:38:48 -0700
Subject: [PATCH] ignore invocation of worker process if already running

also catch any errors thrown when invoking by admin api
---
 CHANGELOG.md        |  4 ++++
 src/manager.js      |  4 +++-
 src/worker.js       | 11 ++++++++++-
 test/src/manager.js |  8 +++++++-
 test/src/worker.js  | 12 ++++++++++++
 5 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0378b17..05ed31d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,10 @@ Releases and notable changes to this project are documented here.
 
 ## [Unreleased]
 
+### Fixed
+
+- Prevent task processor from being re-invoked if it is already running.
+
 ## [v1.1.3] - 2021-08-13
 
 ### Fixed
diff --git a/src/manager.js b/src/manager.js
index d7a07f1..fddc8e4 100644
--- a/src/manager.js
+++ b/src/manager.js
@@ -666,7 +666,9 @@ class Manager {
     this.logger.debug(_scope, 'called', { ctx });
 
     // N.B. no await on this
-    this.communication.worker.process();
+    this.communication.worker.process().catch((e) => {
+      this.logger.error(_scope, 'failed', { error: e, ctx });
+    });
 
     res.end();
     this.logger.info(_scope, 'invoked worker process', { ctx });
diff --git a/src/worker.js b/src/worker.js
index 9b6fd7a..4f566ad 100644
--- a/src/worker.js
+++ b/src/worker.js
@@ -42,6 +42,7 @@ class Worker {
     this.inFlight = []; // Our work heap of Promises  
     this.nextTimeout = undefined; // Allow clearTimeout() to reset waiting period.
     this.running = false;
+    this.isProcessing = false; // Only let one process() method execute on the work heap at a time
   }
 
   /**
@@ -177,7 +178,13 @@ class Worker {
   async process() {
     const _scope = _fileScope('process');
 
-    this.logger.debug(_scope, 'called', {});
+    this.logger.debug(_scope, 'called', { isProcessing: this.isProcessing });
+
+
+    if (this.isProcessing) {
+      return;
+    }
+    this.isProcessing = true;
 
     // Interrupt any pending sleep, if we were called out of timeout-cycle.
     clearTimeout(this.nextTimeout);
@@ -218,6 +225,8 @@ class Worker {
 
     // No more work, wait a while and retry
     this._recurr();
+
+    this.isProcessing = false;
   }
 
 }
diff --git a/test/src/manager.js b/test/src/manager.js
index d8c0921..7870a55 100644
--- a/test/src/manager.js
+++ b/test/src/manager.js
@@ -609,7 +609,13 @@ describe('Manager', function () {
 
   describe('processTasks', function () {
     it('covers', async function () {
-      sinon.stub(manager.communication.worker, 'process');
+      sinon.stub(manager.communication.worker, 'process').resolves();
+      await manager.processTasks(res, ctx);
+      assert(manager.communication.worker.process.called);
+      assert(res.end.called);
+    });
+    it('covers error', async function () {
+      sinon.stub(manager.communication.worker, 'process').rejects();
       await manager.processTasks(res, ctx);
       assert(manager.communication.worker.process.called);
       assert(res.end.called);
diff --git a/test/src/worker.js b/test/src/worker.js
index 32bd065..5c97c0b 100644
--- a/test/src/worker.js
+++ b/test/src/worker.js
@@ -204,6 +204,18 @@ describe('Worker', function () {
       assert.strictEqual(worker._getWork.callCount, 0);
       assert.strictEqual(worker._recurr.callCount, 1);
     });
+    it('covers double invocation', async function () {
+      const snooze = async (ms) => new Promise((resolve) => setTimeout(resolve, ms));
+
+      this.slow(300);
+      worker.inFlight = [
+        Worker.watchedPromise(snooze(100)),
+      ];
+
+      await Promise.all([worker.process(), worker.process()]);
+      assert.strictEqual(worker._getWork.callCount, 2);
+      assert.strictEqual(worker._recurr.callCount, 1);
+    });
   }); // process
 
 }); // Worker
-- 
2.45.2