feat(): try using process env for cold start check; add tests; cleanu…

…p tests
mikaelvesavuori · Nov 14, 2022 · e5f5953 · e5f5953
1 parent baaa7f2
commit e5f5953
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Showing 4 changed files with 73 additions and 109 deletions.
diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "mikrolog",
   "description": "The JSON logger you always wanted for Lambda.",
-  "version": "2.1.7",
+  "version": "2.1.8",
   "author": "Mikael Vesavuori",
   "license": "MIT",
   "main": "./lib/index.js",

diff --git a/src/entities/MikroLog.ts b/src/entities/MikroLog.ts
@@ -41,7 +41,6 @@ export class MikroLog {
   private static correlationId: string;
   private static debugSamplingLevel: number;
   private static isDebugLogSampled: boolean;
-  private coldStart = true;
 
   private constructor() {
     MikroLog.metadataConfig = {};
@@ -50,6 +49,8 @@ export class MikroLog {
     MikroLog.correlationId = '';
     MikroLog.debugSamplingLevel = this.initDebugSampleLevel();
     MikroLog.isDebugLogSampled = true;
+
+    process.env.IS_COLD_START = 'true';
   }
 
   /**
@@ -93,13 +94,12 @@ export class MikroLog {
 
   /**
    * @description Is this a Lambda cold start?
+   *
+   * Setting the value in the process environment makes it possible
+   * to persist the value to subsequent calls, also by other libraries.
    */
   public isColdStart(): boolean {
-    if (this.coldStart) {
-      this.coldStart = false;
-      return true;
-    }
-
+    if (process.env.IS_COLD_START === 'true') return true;
     return false;
   }
 

diff --git a/tests/MikroLog.test.ts b/tests/MikroLog.test.ts
@@ -4,6 +4,27 @@ import { MikroLog } from '../src/entities/MikroLog';
 
 import { metadataConfig } from '../testdata/config';
 
+const fullLog = {
+  version: 1,
+  owner: 'MyCompany',
+  hostPlatform: 'aws',
+  domain: 'CustomerAcquisition',
+  system: 'ShowroomActivities',
+  service: 'UserSignUp',
+  team: 'MyDemoTeam',
+  tags: [''],
+  dataSensitivity: 'public',
+  message: 'Hello World',
+  error: false,
+  httpStatusCode: 200,
+  isColdStart: true,
+  level: 'INFO',
+  id: '1256767f-c875-4d82-813d-bc260bd0ba07',
+  timestamp: '2022-07-25T08:52:21.121Z',
+  timestampEpoch: '1656438566041',
+  jurisdiction: 'EU'
+};
+
 /**
  * POSITIVE TESTS
  */
@@ -64,26 +85,7 @@ test.serial('It should return (print out) a structured log when given a string m
   const logger = MikroLog.start({ metadataConfig });
   const response: any = logger.log(message);
 
-  const expected: any = {
-    version: 1,
-    owner: 'MyCompany',
-    hostPlatform: 'aws',
-    domain: 'CustomerAcquisition',
-    system: 'ShowroomActivities',
-    service: 'UserSignUp',
-    team: 'MyDemoTeam',
-    tags: [''],
-    dataSensitivity: 'public',
-    message: 'Hello World',
-    error: false,
-    httpStatusCode: 200,
-    isColdStart: true,
-    level: 'INFO',
-    id: '1256767f-c875-4d82-813d-bc260bd0ba07',
-    timestamp: '2022-07-25T08:52:21.121Z',
-    timestampEpoch: '1656438566041',
-    jurisdiction: 'EU'
-  };
+  const expected: any = JSON.parse(JSON.stringify(fullLog));
 
   // Ensure exactness of message field
   t.is(response['message'], message);
@@ -114,26 +116,7 @@ test.serial(
     const logger = MikroLog.start({ metadataConfig });
     const response: any = logger.info(message);
 
-    const expected: any = {
-      version: 1,
-      owner: 'MyCompany',
-      hostPlatform: 'aws',
-      domain: 'CustomerAcquisition',
-      system: 'ShowroomActivities',
-      service: 'UserSignUp',
-      team: 'MyDemoTeam',
-      tags: [''],
-      dataSensitivity: 'public',
-      message: 'Hello World',
-      error: false,
-      httpStatusCode: 200,
-      isColdStart: true,
-      level: 'INFO',
-      id: '1256767f-c875-4d82-813d-bc260bd0ba07',
-      timestamp: '2022-07-25T08:52:21.121Z',
-      timestampEpoch: '1656438566041',
-      jurisdiction: 'EU'
-    };
+    const expected: any = JSON.parse(JSON.stringify(fullLog));
 
     // Ensure exactness of message field
     t.is(response['message'], message);
@@ -165,26 +148,8 @@ test.serial(
     const logger = MikroLog.start({ metadataConfig });
     const response: any = logger.debug(message);
 
-    const expected: any = {
-      version: 1,
-      owner: 'MyCompany',
-      hostPlatform: 'aws',
-      domain: 'CustomerAcquisition',
-      system: 'ShowroomActivities',
-      service: 'UserSignUp',
-      team: 'MyDemoTeam',
-      tags: [''],
-      dataSensitivity: 'public',
-      message: 'Hello World',
-      error: false,
-      httpStatusCode: 200,
-      isColdStart: true,
-      level: 'DEBUG',
-      id: '1256767f-c875-4d82-813d-bc260bd0ba07',
-      timestamp: '2022-07-25T08:52:21.121Z',
-      timestampEpoch: '1656438566041',
-      jurisdiction: 'EU'
-    };
+    const expected: any = JSON.parse(JSON.stringify(fullLog));
+    expected['level'] = 'DEBUG';
 
     // Ensure exactness of message field
     t.is(response['message'], message);
@@ -216,26 +181,8 @@ test.serial(
     const logger = MikroLog.start({ metadataConfig });
     const response: any = logger.warn(message);
 
-    const expected: any = {
-      version: 1,
-      owner: 'MyCompany',
-      hostPlatform: 'aws',
-      domain: 'CustomerAcquisition',
-      system: 'ShowroomActivities',
-      service: 'UserSignUp',
-      team: 'MyDemoTeam',
-      tags: [''],
-      dataSensitivity: 'public',
-      message: 'Hello World',
-      error: false,
-      httpStatusCode: 200,
-      isColdStart: true,
-      level: 'WARN',
-      id: '1256767f-c875-4d82-813d-bc260bd0ba07',
-      timestamp: '2022-07-25T08:52:21.121Z',
-      timestampEpoch: '1656438566041',
-      jurisdiction: 'EU'
-    };
+    const expected: any = JSON.parse(JSON.stringify(fullLog));
+    expected['level'] = 'WARN';
 
     // Ensure exactness of message field
     t.is(response['message'], message);
@@ -267,26 +214,10 @@ test.serial(
     const logger = MikroLog.start({ metadataConfig });
     const response: any = logger.error(message);
 
-    const expected: any = {
-      version: 1,
-      owner: 'MyCompany',
-      hostPlatform: 'aws',
-      domain: 'CustomerAcquisition',
-      system: 'ShowroomActivities',
-      service: 'UserSignUp',
-      team: 'MyDemoTeam',
-      tags: [''],
-      dataSensitivity: 'public',
-      message: 'Hello World',
-      error: true,
-      httpStatusCode: 400,
-      isColdStart: true,
-      level: 'ERROR',
-      id: '1256767f-c875-4d82-813d-bc260bd0ba07',
-      timestamp: '2022-07-25T08:52:21.121Z',
-      timestampEpoch: '1656438566041',
-      jurisdiction: 'EU'
-    };
+    const expected: any = JSON.parse(JSON.stringify(fullLog));
+    expected['level'] = 'ERROR';
+    expected['error'] = true;
+    expected['httpStatusCode'] = 400;
 
     // Ensure exactness of message field
     t.is(response['message'], message);
@@ -658,3 +589,36 @@ test.serial('It should be able to merge enrichment even if input is essentially
   // @ts-ignore
   t.deepEqual(response, expected);
 });
+
+test.serial(
+  'It should retain the cold start status between multiple calls in the same process',
+  (t) => {
+    MikroLog.reset();
+
+    const logger = MikroLog.start({ metadataConfig });
+    const response1: any = logger.log('');
+    const response2: any = logger.log('');
+
+    const expected = response1.isColdStart === true && response2.isColdStart === true;
+
+    // @ts-ignore
+    t.is(expected, true);
+  }
+);
+
+test.serial(
+  'It should not reuse the cold start status between calls when "IS_COLD_START" is not set',
+  (t) => {
+    MikroLog.reset();
+
+    const logger = MikroLog.start({ metadataConfig });
+    const response1: any = logger.log('');
+    process.env.IS_COLD_START = 'false';
+    const response2: any = logger.log('');
+
+    const expected = response1.isColdStart === true && response2.isColdStart === false;
+
+    // @ts-ignore
+    t.is(expected, true);
+  }
+);