From 4d5de7f6edd1f89e4da0ab4f9c0af9d7b8b722bc Mon Sep 17 00:00:00 2001
From: Unitech <alexandre@keymetrics.io>
Date: Wed, 8 Apr 2020 23:14:28 +0200
Subject: [PATCH] instant trace sending + send only slow traces

---
 CHANGELOG.md            |  4 +++-
 NOTES.md                | 45 +++++++++++++++++++++++++++++++++++++++++
 src/census/constants.ts |  6 ++++--
 src/census/exporter.ts  |  9 +++++++--
 4 files changed, 59 insertions(+), 5 deletions(-)
 create mode 100644 NOTES.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c19cd70e..1e520cb0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,8 @@
 
 ## 4.3.4
 
+- Do not send trace faster than 1000ms
+- Instantly send traces to pm2.io (instead of ~60secs timeout)
 - Allow metrics to be a boolean
-- Add some examples
+- Add some examples/
 - Track changes via CHANGELOG.md
diff --git a/NOTES.md b/NOTES.md
new file mode 100644
index 00000000..306f7f36
--- /dev/null
+++ b/NOTES.md
@@ -0,0 +1,45 @@
+
+
+pm2-io-apm features are in src/features/:
+
+```
+src/features/
+├── dependencies.ts
+├── entrypoint.ts
+├── events.ts
+├── metrics.ts
+├── notify.ts
+├── profiling.ts
+└── tracing.ts
+```
+
+## Tracing
+
+- `./src/census` folder is essentially a dump of https://github.com/census-instrumentation/opencensus-node/tree/master/packages/opencensus-nodejs-base/src/trace with plugins added
+- Only traces higher than `MINIMUM_TRACE_DURATION: 1000 * 1000` are sent to transporter (sent in /src/census/exporter.ts:72)
+
+Trace sent looks like:
+
+```
+{
+  traceId: 'fac7052e9129416185a26d4935229620',
+  name: '/slow',
+  id: '66358f0a48be82c5',
+  parentId: '',
+  kind: 'SERVER',
+  timestamp: 1586380086251000,
+  duration: 2007559,
+  debug: false,
+  shared: false,
+  localEndpoint: { serviceName: 'tototransaction' },
+  tags: {
+    'http.host': 'localhost',
+    'http.method': 'GET',
+    'http.path': '/slow',
+    'http.route': '/slow',
+    'http.user_agent': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.70 Safari/537.36',
+    'http.status_code': '304',
+    'result.code': undefined
+  }
+}
+```
diff --git a/src/census/constants.ts b/src/census/constants.ts
index 87328fe1..c10e227c 100644
--- a/src/census/constants.ts
+++ b/src/census/constants.ts
@@ -18,10 +18,12 @@ import { resolve } from 'path'
 
 /** General purpose constants. */
 const constants = {
+  /* CUSTOM - MINIMUM_DURATION trace in uS to send to backend (avoid *vaportrace*)*/
+  MINIMUM_TRACE_DURATION: process.env.NODE_ENV == 'test' ? 0 : 1000 * 1000,
   /** Default maximum size of a buffer. */
-  DEFAULT_BUFFER_SIZE: 100,
+  DEFAULT_BUFFER_SIZE: 0,
   /** Default max timeout for a buffer before being flushed */
-  DEFAULT_BUFFER_TIMEOUT: 20000,
+  DEFAULT_BUFFER_TIMEOUT: 1000,
   /** Default list of target modules to be instrumented */
   DEFAULT_INSTRUMENTATION_MODULES: [],
   /** OpenCensus Scope */
diff --git a/src/census/exporter.ts b/src/census/exporter.ts
index cb71f959..c48285df 100644
--- a/src/census/exporter.ts
+++ b/src/census/exporter.ts
@@ -2,6 +2,8 @@ import { Transport } from '../services/transport'
 import { ServiceManager } from '../serviceManager'
 import { TracingConfig } from 'src/features/tracing'
 import { Exporter, ExporterBuffer, ExporterConfig, RootSpan, Span, SpanKind, Attributes, CanonicalCode } from '@opencensus/core'
+import { defaultConfig } from './config/default-config'
+import { Constants } from './constants'
 
 export interface ZipkinExporterOptions extends ExporterConfig {
   serviceName: string
@@ -49,7 +51,7 @@ export class CustomCensusExporter implements Exporter {
 
   constructor (config: TracingConfig) {
     this.config = config
-    this.buffer = new ExporterBuffer(this, {})
+    this.buffer = new ExporterBuffer(this, defaultConfig)
   }
 
   /**
@@ -73,7 +75,10 @@ export class CustomCensusExporter implements Exporter {
         const isRootClient = span.kind === 'CLIENT' && !span.parentId
         if (isRootClient && this.config.outbound === false) return
 
-        this.transport.send('trace-span', span)
+        /** CUSTOM - DROP USELESS TRACE **/
+        if (span.duration > Constants.MINIMUM_TRACE_DURATION) {
+          this.transport.send('trace-span', span)
+        }
       })
       resolve()
     })