From 6a59356200dd144d874206e389003dc1cf4b077a Mon Sep 17 00:00:00 2001
From: Jake McDermott <jmcdermott@ansible.com>
Date: Thu, 7 Jun 2018 18:51:09 -0400
Subject: [PATCH] apply a windowing function to buffered event stream

---
 .../features/output/index.controller.js       | 18 ++++++--
 .../client/features/output/slide.service.js   |  9 ++--
 .../client/features/output/stream.service.js  | 43 +++++++++----------
 3 files changed, 41 insertions(+), 29 deletions(-)

diff --git a/awx/ui/client/features/output/index.controller.js b/awx/ui/client/features/output/index.controller.js
index 6fc0746571..64d53b4faa 100644
--- a/awx/ui/client/features/output/index.controller.js
+++ b/awx/ui/client/features/output/index.controller.js
@@ -32,13 +32,23 @@ function bufferAdd (event) {
     bufferState[0] += 1;
     bufferState[1] += 1;
 
-    return bufferState;
+    return bufferState[1];
 }
 
-function bufferEmpty () {
-    bufferState[0] = 0;
+function bufferEmpty (min, max) {
+    let count = 0;
+    let removed = [];
 
-    return rx.splice(0, rx.length);
+    for (let i = bufferState[0] - 1; i >= 0; i--) {
+        if (rx[i].counter <= max) {
+            removed = removed.concat(rx.splice(i, 1));
+            count++;
+        }
+    }
+
+    bufferState[0] -= count;
+
+    return removed;
 }
 
 function onFrames (events) {
diff --git a/awx/ui/client/features/output/slide.service.js b/awx/ui/client/features/output/slide.service.js
index 96b32b2703..507a277733 100644
--- a/awx/ui/client/features/output/slide.service.js
+++ b/awx/ui/client/features/output/slide.service.js
@@ -309,10 +309,13 @@ function SlidingWindowService ($q) {
         return Number.isFinite(head) ? head : 0;
     };
 
-    this.compareRange = (a, b) => a[0] === b[0] && a[1] === b[1];
-    this.getRange = () => [this.getHeadCounter(), this.getTailCounter()];
+    this.getMaxCounter = () => {
+        const counter = this.api.getMaxCounter();
 
-    this.getMaxCounter = () => this.api.getMaxCounter();
+        return Number.isFinite(counter) ? counter : this.getTailCounter();
+    };
+
+    this.getRange = () => [this.getHeadCounter(), this.getTailCounter()];
     this.getRecordCount = () => Object.keys(this.records).length;
     this.getCapacity = () => EVENT_LIMIT - this.getRecordCount();
 }
diff --git a/awx/ui/client/features/output/stream.service.js b/awx/ui/client/features/output/stream.service.js
index da73f70c23..c710a1fc1a 100644
--- a/awx/ui/client/features/output/stream.service.js
+++ b/awx/ui/client/features/output/stream.service.js
@@ -16,6 +16,7 @@ function OutputStream ($q) {
             used: [],
             min: 1,
             max: 0,
+            last: null,
             ready: false,
         };
 
@@ -66,28 +67,30 @@ function OutputStream ($q) {
         }
 
         const missing = [];
-        const ready = [];
+        let minReady;
+        let maxReady;
 
-        for (let i = this.counters.min; i < this.counters.max; i++) {
+        for (let i = this.counters.min; i <= this.counters.max; i++) {
             if (this.counters.used.indexOf(i) === -1) {
                 missing.push(i);
             } else if (missing.length === 0) {
-                ready.push(i);
+                maxReady = i;
             }
         }
 
-        if (missing.length === 0) {
+        if (maxReady) {
+            minReady = this.counters.min;
+
             this.counters.ready = true;
-            this.counters.min = this.counters.max + 1;
-            this.counters.used = [];
+            this.counters.min = maxReady + 1;
+            this.counters.used = this.counters.used.filter(c => c > maxReady);
         } else {
             this.counters.ready = false;
         }
 
         this.counters.missing = missing;
-        this.counters.readyLines = ready;
 
-        return this.counters.ready;
+        return [minReady, maxReady];
     };
 
     this.pushJobEvent = data => {
@@ -97,40 +100,36 @@ function OutputStream ($q) {
             .then(() => {
                 if (data.event === JOB_END) {
                     this.state.ending = true;
+                    this.counters.last = data.counter;
                 }
 
-                const isMissingCounters = !this.updateCounterState(data);
-                const [length, count] = this.hooks.bufferAdd(data);
+                const [minReady, maxReady] = this.updateCounterState(data);
+                const count = this.hooks.bufferAdd(data);
 
                 if (count % PAGE_SIZE === 0) {
                     this.setFramesPerRender();
                 }
 
-                const isBatchReady = length % this.framesPerRender === 0;
-                const isReady = this.state.ended || (!isMissingCounters && isBatchReady);
+                const isReady = maxReady && (this.state.ending ||
+                    (maxReady - minReady) % this.framesPerRender === 0);
 
                 if (!isReady) {
                     return $q.resolve();
                 }
 
-                const events = this.hooks.bufferEmpty();
+                const isLastFrame = this.state.ending && (maxReady >= this.counters.last);
+                const events = this.hooks.bufferEmpty(minReady, maxReady);
 
-                return this.emitFrames(events);
+                return this.emitFrames(events, isLastFrame);
             })
             .then(() => --this.lag);
 
         return this.chain;
     };
 
-    this.emitFrames = events => this.hooks.onFrames(events)
+    this.emitFrames = (events, last) => this.hooks.onFrames(events)
         .then(() => {
-            if (this.state.ending) {
-                const lastEvents = this.hooks.bufferEmpty();
-
-                if (lastEvents.length) {
-                    return this.emitFrames(lastEvents);
-                }
-
+            if (last) {
                 this.state.ending = false;
                 this.state.ended = true;