refactor(logger): addressed feedback from team meeting

Author: saragerion

.eslintrc.js

@@ -48,6 +48,7 @@ module.exports = {
     'no-console': 0,
     'no-multi-spaces': [ 'error', { 'ignoreEOLComments': false } ],
     'no-multiple-empty-lines': [ 'error', { 'max': 1, 'maxBOF': 0 } ],
+    'no-throw-literal': 'error',
     'object-curly-spacing': [ 'error', 'always' ],
     'prefer-arrow-callback': 'error',
     'quotes': [ 'error', 'single', { 'allowTemplateLiterals': true } ],

packages/logger/README.md

@@ -54,7 +54,6 @@ logger.error('This is an ERROR log');
 // Environment variables set for the Lambda
 process.env.LOG_LEVEL = 'WARN';
 process.env.POWERTOOLS_SERVICE_NAME = 'hello-world';
-process.env.POWERTOOLS_CONTEXT_ENABLED = 'TRUE';
 
 const logger = new Logger();
 
@@ -286,9 +285,7 @@ const lambdaHandler: Handler = async () => {
 ## Custom logger options: log level, service name, sample rate value, log attributes, variables source, log format
 
 ```typescript
-
 process.env.CUSTOM_ENV = 'prod';
-process.env.POWERTOOLS_CONTEXT_ENABLED = 'TRUE';
 
 // Custom configuration service for variables, and custom formatter to comply to different log JSON schema
 import { CustomConfigService } from './config/CustomConfigService';

packages/logger/examples/custom-logger-options.ts

@@ -4,7 +4,6 @@ import { populateEnvironmentVariables } from '../tests/helpers';
 populateEnvironmentVariables();
 // Additional runtime variables
 process.env.CUSTOM_ENV = 'prod';
-process.env.POWERTOOLS_CONTEXT_ENABLED = 'TRUE';
 
 import * as dummyEvent from '../../../tests/resources/events/custom/hello-world.json';
 import * as powertool from '../../../package.json';
@@ -18,7 +17,7 @@ const logger = new Logger({
   logLevel: 'INFO', // Override options
   serviceName: 'foo-bar',
   sampleRateValue: 0.00001,
-  customAttributes: { // Custom attributes that will be added in every log
+  persistentLogAttributes: { // Custom attributes that will be added in every log
     awsAccountId: '123456789012',
     logger: {
       name: powertool.name,

packages/logger/examples/ephemeral-attributes.ts

@@ -0,0 +1,38 @@
+import { populateEnvironmentVariables } from '../tests/helpers';
+
+// Populate runtime
+populateEnvironmentVariables();
+// Additional runtime variables
+process.env.LOG_LEVEL = 'WARN';
+process.env.POWERTOOLS_SERVICE_NAME = 'hello-world';
+
+import * as dummyEvent from '../../../tests/resources/events/custom/hello-world.json';
+import { context as dummyContext } from '../../../tests/resources/contexts/hello-world';
+import { Handler } from 'aws-lambda';
+import { Logger } from '../src';
+
+const logger = new Logger();
+
+const lambdaHandler: Handler = async () => {
+
+  // Example of use case:
+  // Log an error with a message (informative string) and
+  // some extra ephemeral custom attributes to help debugging (like a correlation ID)
+
+  // Logs below will result in the same JSON output
+
+  const error = new Error('Something bad happened!');
+
+  // You can add ephemeral extra custom attributes like this:
+  logger.error('This is an ERROR log', error, { correlationIds: { myCustomCorrelationId: 'foo-bar-baz' } });
+
+  // Or you can also add them like this (same log output):
+  logger.error({ message: 'This is an ERROR log', correlationIds: { myCustomCorrelationId: 'foo-bar-baz' } }, error);
+
+  return {
+    foo: 'bar'
+  };
+
+};
+
+lambdaHandler(dummyEvent, dummyContext, () => console.log('Lambda invoked!'));

packages/logger/examples/errors.ts

@@ -0,0 +1,36 @@
+import { populateEnvironmentVariables } from '../tests/helpers';
+
+// Populate runtime
+populateEnvironmentVariables();
+// Additional runtime variables
+process.env.LOG_LEVEL = 'WARN';
+process.env.POWERTOOLS_SERVICE_NAME = 'hello-world';
+
+import * as dummyEvent from '../../../tests/resources/events/custom/hello-world.json';
+import { context as dummyContext } from '../../../tests/resources/contexts/hello-world';
+import { Handler } from 'aws-lambda';
+import { Logger } from '../src';
+
+const logger = new Logger();
+
+const lambdaHandler: Handler = async () => {
+
+  try {
+    throw new Error('Unexpected error #1');
+  } catch (error) {
+    logger.error('This is an ERROR log', error);
+  }
+
+  try {
+    throw new Error('Unexpected error #2');
+  } catch (error) {
+    logger.error('This is an ERROR log', { myCustomErrorKey: error } );
+  }
+
+  return {
+    foo: 'bar'
+  };
+
+};
+
+lambdaHandler(dummyEvent, dummyContext, () => console.log('Lambda invoked!'));

packages/logger/examples/formatters/CustomLogFormatter.ts

@@ -5,7 +5,7 @@ type MyCompanyLog = LogAttributes;
 
 class CustomLogFormatter extends LogFormatter {
 
-  public format(attributes: UnformattedAttributes): MyCompanyLog {
+  public formatAttributes(attributes: UnformattedAttributes): MyCompanyLog {
     return {
       message: attributes.message,
       service: attributes.serviceName,
@@ -16,10 +16,10 @@ class CustomLogFormatter extends LogFormatter {
         xRayTraceId: attributes.xRayTraceId
       },
       lambdaFunction: {
-        name: attributes.lambdaContext?.name,
-        arn: attributes.lambdaContext?.arn,
+        name: attributes.lambdaContext?.functionName,
+        arn: attributes.lambdaContext?.invokedFunctionArn,
         memoryLimitInMB: attributes.lambdaContext?.memoryLimitInMB,
-        version: attributes.lambdaContext?.version,
+        version: attributes.lambdaContext?.functionVersion,
         coldStart: attributes.lambdaContext?.coldStart,
       },
       logLevel: attributes.logLevel,

packages/logger/examples/hello-world-with-context.ts renamed to packages/logger/examples/inject-context.ts

@@ -5,7 +5,6 @@ populateEnvironmentVariables();
 // Additional runtime variables
 process.env.LOG_LEVEL = 'WARN';
 process.env.POWERTOOLS_SERVICE_NAME = 'hello-world';
-process.env.POWERTOOLS_CONTEXT_ENABLED = 'TRUE';
 
 import * as dummyEvent from '../../../tests/resources/events/custom/hello-world.json';
 import { context as dummyContext } from '../../../tests/resources/contexts/hello-world';

packages/logger/examples/persistent-attributes.ts

@@ -0,0 +1,40 @@
+import { populateEnvironmentVariables } from '../tests/helpers';
+
+// Populate runtime
+populateEnvironmentVariables();
+// Additional runtime variables
+process.env.LOG_LEVEL = 'INFO';
+process.env.POWERTOOLS_SERVICE_NAME = 'hello-world';
+
+import * as dummyEvent from '../../../tests/resources/events/custom/hello-world.json';
+import * as powertool from '../../../package.json';
+import { context as dummyContext } from '../../../tests/resources/contexts/hello-world';
+import { Handler } from 'aws-lambda';
+import { Logger } from '../src';
+
+// You can add persistent extra custom attributes directly in the constructor of the logger:
+const logger = new Logger();
+
+const lambdaHandler: Handler = async () => {
+
+  // Or you can choose to add persistent log keys to an existing Logger instance:
+  logger.appendKeys({
+    aws_account_id: '123456789012',
+    aws_region: 'eu-central-1',
+    logger: {
+      name: powertool.name,
+      version: powertool.version,
+    }
+  });
+
+  // This info log will print all extra custom attributes added above
+  // Extra attributes: logger object with name and version of this library, awsAccountId, awsRegion
+  logger.info('This is an INFO log');
+
+  return {
+    foo: 'bar'
+  };
+
+};
+
+lambdaHandler(dummyEvent, dummyContext, () => console.log('Lambda invoked!'));

packages/logger/examples/sample-rate.ts

@@ -21,6 +21,9 @@ const lambdaHandler: Handler = async () => {
   logger.info('This is INFO log #3');
   logger.info('This is INFO log #4');
 
+  // Refresh sample rate calculation on runtime
+  logger.refreshSampleRateCalculation();
+
   return {
     foo: 'bar'
   };

packages/logger/package.json

@@ -19,11 +19,14 @@
     "version": "npm run format && git add -A src",
     "postversion": "git push && git push --tags",
     "example:hello-world": "ts-node examples/hello-world.ts",
-    "example:hello-world-with-context": "ts-node examples/hello-world-with-context.ts",
+    "example:hello-world-with-context": "ts-node examples/inject-context.ts",
+    "example:hello-world-errors": "ts-node examples/errors.ts",
     "example:custom-logger-options": "ts-node examples/custom-logger-options.ts",
     "example:child-logger": "ts-node examples/child-logger.ts",
     "example:additional-keys": "ts-node examples/additional-keys.ts",
-    "example:sample-rate": "ts-node examples/sample-rate.ts"
+    "example:sample-rate": "ts-node examples/sample-rate.ts",
+    "example:persistent-attributes": "ts-node examples/persistent-attributes.ts",
+    "example:ephemeral-attributes": "ts-node examples/ephemeral-attributes.ts"
   },
   "homepage": "https://github.com/awslabs/aws-lambda-powertools-typescript/tree/master/packages/logging#readme",
   "license": "MIT",