feat(): ensure cold start check is only done in start method; add tes…

…ts; cleanup tests; add isColdStart to Metadata type; allow 0 and false to be retained in filterMetadata()

package.json

@@ -1,7 +1,7 @@
 {
   "name": "mikrolog",
   "description": "The JSON logger you always wanted for Lambda.",
-  "version": "2.1.10",
+  "version": "2.1.11",
   "author": "Mikael Vesavuori",
   "license": "MIT",
   "main": "./lib/index.js",

src/entities/MikroLog.ts

@@ -41,7 +41,7 @@ export class MikroLog {
   private static correlationId: string;
   private static debugSamplingLevel: number;
   private static isDebugLogSampled: boolean;
-  private coldStart = true;
+  private static isColdStart = true;
 
   private constructor() {
     MikroLog.metadataConfig = {};
@@ -60,6 +60,8 @@ export class MikroLog {
    * If the `start` method receives any input, that input will
    * overwrite any existing metadata, event, and context.
    *
+   * It will also, consequently, wipe the Lambda cold start state.
+   *
    * If you want to "add" to these, you should instead call
    * `enrich()` and pass in your additional data there.
    */
@@ -68,10 +70,23 @@ export class MikroLog {
     MikroLog.metadataConfig = input?.metadataConfig || {};
     MikroLog.event = input?.event || {};
     MikroLog.context = input?.context || {};
+    MikroLog.context.isColdStart = MikroLog.getColdStart();
     MikroLog.correlationId = input?.correlationId || '';
     return MikroLog.instance;
   }
 
+  /**
+   * @description Is this a Lambda cold start?
+   */
+  private static getColdStart(): boolean {
+    if (MikroLog.isColdStart) {
+      MikroLog.isColdStart = false;
+      return true;
+    }
+
+    return false;
+  }
+
   /**
    * @description An emergency mechanism if you absolutely need to
    * reset the instance to its empty default state.
@@ -89,18 +104,6 @@ export class MikroLog {
     MikroLog.context = Object.assign(MikroLog.context, input.context || {});
   }
 
-  /**
-   * @description Is this a Lambda cold start?
-   */
-  public isColdStart(): boolean {
-    if (this.coldStart) {
-      this.coldStart = false;
-      return true;
-    }
-
-    return false;
-  }
-
   /**
    * @description Set correlation ID manually, for example for use in cross-boundary calls.
    *
@@ -234,6 +237,7 @@ export class MikroLog {
    */
   private getDynamicMetadata() {
     const metadata = getMetadata(MikroLog.event, MikroLog.context);
+
     return {
       ...metadata,
       correlationId: MikroLog.correlationId || metadata.correlationId
@@ -248,7 +252,7 @@ export class MikroLog {
 
     Object.entries(metadata).forEach((entry: any) => {
       const [key, value] = entry;
-      if (value) filteredMetadata[key] = value;
+      if (value || value === false || value === 0) filteredMetadata[key] = value;
     });
 
     return filteredMetadata;
@@ -297,7 +301,7 @@ export class MikroLog {
       error: log.level === 'ERROR',
       level: log.level,
       httpStatusCode: log.httpStatusCode,
-      isColdStart: this.isColdStart()
+      isColdStart: MikroLog.context.isColdStart
     };
 
     const filteredOutput = this.filterOutput(logOutput, redactedKeys, maskedValues);

src/interfaces/Metadata.ts

@@ -111,6 +111,10 @@ export interface DynamicMetadataOutput {
    * @description The AWS account ID that the system is running in.
    */
   accountId: string;
+  /**
+   * @description Is this a Lambda cold start?
+   */
+  isColdStart: boolean;
 }
 
 /**

testdata/fullLog.json

@@ -0,0 +1,20 @@
+{
+  "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"
+}