From 3fdd200e986d69768dc60825ef64e7cf64300a82 Mon Sep 17 00:00:00 2001
From: Vilsol <me@vil.so>
Date: Wed, 10 Aug 2022 16:37:50 +0300
Subject: [PATCH] fix(logger): do not crash on circular json

---
 packages/logger/src/console.ts       |  6 +++---
 packages/logger/src/elasticsearch.ts |  4 ++--
 packages/logger/src/utils.ts         | 13 +++++++++++++
 packages/logger/tests/test.ts        |  6 ++++++
 4 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/packages/logger/src/console.ts b/packages/logger/src/console.ts
index 5aa5de18..b53c6094 100644
--- a/packages/logger/src/console.ts
+++ b/packages/logger/src/console.ts
@@ -1,6 +1,6 @@
 import { format, transports } from 'winston';
 import * as rTracer from 'cls-rtracer';
-import { globalLoggerCtxKey, traceFormatter } from './utils';
+import { getCircularReplacer, globalLoggerCtxKey, traceFormatter } from './utils';
 
 export interface RestoreLoggerConsoleTransportOptions extends transports.ConsoleTransportOptions {
   prettyPrint?:  boolean | any;
@@ -23,10 +23,10 @@ function createTracerFormat(opts: RestoreLoggerConsoleTransportOptions) {
     delete info.timestamp;
     let object = {};
     if (splat) {
-      object = JSON.stringify(splat);
+      object = JSON.stringify(splat, getCircularReplacer());
     }
     if (message && Object.entries(message).length !== 0 && message.constructor === Object) {
-      message = JSON.stringify(message);
+      message = JSON.stringify(message, getCircularReplacer());
     }
     let ret: string[] = [];
     ret.push(`${level}: ${time}`);
diff --git a/packages/logger/src/elasticsearch.ts b/packages/logger/src/elasticsearch.ts
index 03a9fdfd..80b3613e 100644
--- a/packages/logger/src/elasticsearch.ts
+++ b/packages/logger/src/elasticsearch.ts
@@ -1,7 +1,7 @@
 import { ElasticsearchTransport, ElasticsearchTransportOptions, Transformer } from 'winston-elasticsearch';
 import * as os from 'os';
 import * as rTracer from 'cls-rtracer';
-import { globalLoggerCtxKey, getRealTrace } from './utils';
+import { globalLoggerCtxKey, getRealTrace, getCircularReplacer } from './utils';
 
 export const indexTemplate = require('../elasticsearch-index-template.json');
 
@@ -42,7 +42,7 @@ function createTransformer(opts: RestoreLoggerElasticsearchTransportOptions) {
     transformed.source_host = os.hostname();
     transformed.message = logData.message;
     if (typeof transformed.message === 'object') {
-      transformed.message = JSON.stringify(transformed.message);
+      transformed.message = JSON.stringify(transformed.message, getCircularReplacer());
     }
     transformed.severity = logData.level;
     transformed.fields = logData.meta;
diff --git a/packages/logger/src/utils.ts b/packages/logger/src/utils.ts
index db58e030..4689e4da 100644
--- a/packages/logger/src/utils.ts
+++ b/packages/logger/src/utils.ts
@@ -136,3 +136,16 @@ export const getRealTrace = (): any => {
 
 // A symbol used as key in the global name space to put the AsyncLocalStorage store under
 export const globalLoggerCtxKey = Symbol('loggerCtx');
+
+export const getCircularReplacer = () => {
+  const seen = new WeakSet();
+  return (key: string, value: unknown) => {
+    if (typeof value === 'object' && value !== null) {
+      if (seen.has(value)) {
+        return;
+      }
+      seen.add(value);
+    }
+    return value;
+  };
+};
diff --git a/packages/logger/tests/test.ts b/packages/logger/tests/test.ts
index e1c26b9f..9327439e 100644
--- a/packages/logger/tests/test.ts
+++ b/packages/logger/tests/test.ts
@@ -66,6 +66,12 @@ describe('a logger', () => {
     it('an error with stack trace', (done) => {
       logger.error('Generic Error!');
       done();
+    });
+    it('a circular object', (done) => {
+      const obj: any = {name: "Bob"};
+      obj.child = obj;
+      logger.info(obj);
+      done();
     });
         esTransport.bulkWriter.stop();
   });