feat(): add support for one-time enrichment; add back comments in bui…

…ld so they are visible for library users

README.md

@@ -234,6 +234,28 @@ headers['X-Log-Sampled'] ? logger.setDebugSamplingRate(100) : logger.setDebugSam
 
 ## Metadata
 
+### One-time root-level enrichment
+
+If you want a one-time root-level enrichment, you can do:
+
+```typescript
+const logger = MikroLog.start();
+logger.enrichNext({ someId: '123456789abcdefghi' });
+logger.info('Ping!'); // Enrichment is present on log
+logger.info('Ping!'); // Enrichment is longer present
+```
+
+This works just as well on nested object:
+
+```typescript
+const logger = MikroLog.start();
+logger.enrichNext({ myObject: { myValue: 'Something here', otherValue: 'Something else' } });
+logger.info('Ping!'); // Enrichment is present on log
+logger.info('Ping!'); // Enrichment is longer present
+```
+
+Note that only object input is allowed for this method.
+
 ### Static metadata
 
 _Static metadata_ is the metadata that you may provide at the time of instantiation. These fields will then be used automatically in all subsequent logs.

package.json

@@ -1,7 +1,7 @@
 {
   "name": "mikrolog",
   "description": "The JSON logger you always wanted for Lambda.",
-  "version": "2.1.12",
+  "version": "2.1.13",
   "author": "Mikael Vesavuori",
   "license": "MIT",
   "main": "./lib/index.js",

src/entities/MikroLog.ts

@@ -42,6 +42,7 @@ export class MikroLog {
   private static debugSamplingLevel: number;
   private static isDebugLogSampled: boolean;
   private static isColdStart = true;
+  private nextLogEnrichment: Record<string, any>;
 
   private constructor() {
     MikroLog.metadataConfig = {};
@@ -50,6 +51,7 @@ export class MikroLog {
     MikroLog.correlationId = '';
     MikroLog.debugSamplingLevel = this.initDebugSampleLevel();
     MikroLog.isDebugLogSampled = true;
+    this.nextLogEnrichment = {};
   }
 
   /**
@@ -105,6 +107,13 @@ export class MikroLog {
     MikroLog.correlationId = input?.correlationId || this.correlationId || '';
   }
 
+  /**
+   * @description TODO
+   */
+  public enrichNext(input: Record<string, any>) {
+    this.nextLogEnrichment = input;
+  }
+
   /**
    * @description Set correlation ID manually, for example for use in cross-boundary calls.
    *
@@ -295,15 +304,24 @@ export class MikroLog {
 
     const dynamicMetadata = this.produceDynamicMetadata();
 
-    const logOutput = {
-      ...dynamicMetadata,
-      ...staticMetadata,
-      message: log.message,
-      error: log.level === 'ERROR',
-      level: log.level,
-      httpStatusCode: log.httpStatusCode,
-      isColdStart: MikroLog.context.isColdStart
-    };
+    const logOutput = (() => {
+      const output = {
+        ...dynamicMetadata,
+        ...staticMetadata,
+        message: log.message,
+        error: log.level === 'ERROR',
+        level: log.level,
+        httpStatusCode: log.httpStatusCode,
+        isColdStart: MikroLog.context.isColdStart
+      };
+
+      if (this.nextLogEnrichment && JSON.stringify(this.nextLogEnrichment) !== '{}')
+        return Object.assign(output, this.nextLogEnrichment);
+
+      return output;
+    })();
+
+    this.nextLogEnrichment = {};
 
     const filteredOutput = this.filterOutput(logOutput, redactedKeys, maskedValues);
     return this.sortOutput(filteredOutput);

tests/MikroLog.test.ts

@@ -570,3 +570,37 @@ test.serial('It should be able to enrich with correlation ID', (t) => {
 
   t.deepEqual(cleanedResponse, cleanedExpected);
 });
+
+test.serial(
+  'It should enrich a single-level log with a one-time root item and ensure it is not present in later calls',
+  (t) => {
+    MikroLog.reset();
+    const message = 'Hello World';
+
+    const logger = MikroLog.start();
+    logger.enrichNext({ myValue: 'abc123' });
+
+    const responseFirst: Record<string, any> = logger.info(message);
+    const responseSecond: Record<string, any> = logger.info(message);
+
+    t.is(responseFirst.hasOwnProperty('myValue'), true);
+    t.is(responseSecond.hasOwnProperty('myValue'), false);
+  }
+);
+
+test.serial(
+  'It should enrich a multi-level log with a one-time root item and ensure it is not present in later calls',
+  (t) => {
+    MikroLog.reset();
+    const message = 'Hello World';
+
+    const logger = MikroLog.start();
+    logger.enrichNext({ dd: { trace_id: 'abc123' } });
+
+    const responseFirst: Record<string, any> = logger.info(message);
+    const responseSecond: Record<string, any> = logger.info(message);
+
+    t.is(responseFirst['dd']['trace_id'], 'abc123');
+    t.is(responseSecond.hasOwnProperty('dd'), false);
+  }
+);

tsconfig.json

@@ -13,7 +13,7 @@
     "noFallthroughCasesInSwitch": true,
     "noUnusedLocals": true,
     "noUnusedParameters": true,
-    "removeComments": true,
+    "removeComments": false,
     "resolveJsonModule": true,
     "sourceMap": true,
     "strict": true,