feat(apim-538): add environment variable for log format (#337)

## Introduction
Currently, all our log messages use the single line format which makes
them hard to read during local development but is good for the dev,
staging, and production environments.

## Resolution
- Added an environment variable that controls if we use single line or
multi-line logging format
- Use this to set the singleLine property in our logging config

## Misc
- Added tests for log level

---------

Co-authored-by: Alex Bramhill <abramhill@ukexportfinance.gov.uk>

.env.sample

@@ -3,6 +3,7 @@ PORT=
 
 LOG_LEVEL=debug
 REDACT_LOGS=false
+SINGLE_LINE_LOG_FORMAT=true
 
 # Swagger
 SWAGGER_USER=

src/config/app.config.test.ts

@@ -129,6 +129,56 @@ describe('appConfig', () => {
     });
   });
 
+  describe('parsing SINGLE_LINE_LOG_FORMAT', () => {
+    it('sets singleLineLogFormat to true if SINGLE_LINE_LOG_FORMAT is true', () => {
+      replaceEnvironmentVariables({
+        SINGLE_LINE_LOG_FORMAT: 'true',
+      });
+
+      const config = appConfig();
+
+      expect(config.singleLineLogFormat).toBe(true);
+    });
+
+    it('sets singleLineLogFormat to false if SINGLE_LINE_LOG_FORMAT is false', () => {
+      replaceEnvironmentVariables({
+        SINGLE_LINE_LOG_FORMAT: 'false',
+      });
+
+      const config = appConfig();
+
+      expect(config.singleLineLogFormat).toBe(false);
+    });
+
+    it('sets singleLineLogFormat to true if SINGLE_LINE_LOG_FORMAT is not specified', () => {
+      replaceEnvironmentVariables({});
+
+      const config = appConfig();
+
+      expect(config.singleLineLogFormat).toBe(true);
+    });
+
+    it('sets singleLineLogFormat to true if SINGLE_LINE_LOG_FORMAT is the empty string', () => {
+      replaceEnvironmentVariables({
+        SINGLE_LINE_LOG_FORMAT: '',
+      });
+
+      const config = appConfig();
+
+      expect(config.singleLineLogFormat).toBe(true);
+    });
+
+    it('sets singleLineLogFormat to true if SINGLE_LINE_LOG_FORMAT is any string other than true or false', () => {
+      replaceEnvironmentVariables({
+        SINGLE_LINE_LOG_FORMAT: valueGenerator.string(),
+      });
+
+      const config = appConfig();
+
+      expect(config.singleLineLogFormat).toBe(true);
+    });
+  });
+
   const replaceEnvironmentVariables = (newEnvVariables: Record<string, string>): void => {
     process.env = newEnvVariables;
   };

src/config/app.config.ts

@@ -24,5 +24,6 @@ export default registerAs('app', (): Record<string, any> => {
     apiKey: process.env.API_KEY,
     logLevel: process.env.LOG_LEVEL || 'info',
     redactLogs: process.env.REDACT_LOGS !== 'false',
+    singleLineLogFormat: process.env.SINGLE_LINE_LOG_FORMAT !== 'false',
   };
 });

src/main.module.ts

@@ -29,7 +29,7 @@ import { LoggingInterceptor } from './logging/logging-interceptor.helper';
           transport: {
             target: 'pino-pretty',
             options: {
-              singleLine: true,
+              singleLine: config.get<boolean>('app.singleLineLogLevel'),
             },
           },
           hooks: {

test/support/environment-variables.ts

@@ -6,6 +6,7 @@ export const ENVIRONMENT_VARIABLES = Object.freeze({
   NODE_ENV: 'test',
   LOG_LEVEL: 'debug',
   REDACT_LOGS: false,
+  SINGLE_LINE_LOG_FORMAT: true,
 
   SWAGGER_USER: valueGenerator.string(),
   SWAGGER_PASSWORD: valueGenerator.string(),
@@ -22,6 +23,7 @@ export const ENVIRONMENT_VARIABLES = Object.freeze({
 export const getEnvironmentVariablesForProcessEnv = (): NodeJS.ProcessEnv => ({
   ...ENVIRONMENT_VARIABLES,
   REDACT_LOGS: ENVIRONMENT_VARIABLES.REDACT_LOGS.toString(),
+  SINGLE_LINE_LOG_FORMAT: ENVIRONMENT_VARIABLES.SINGLE_LINE_LOG_FORMAT.toString(),
   APIM_INFORMATICA_MAX_REDIRECTS: ENVIRONMENT_VARIABLES.APIM_INFORMATICA_MAX_REDIRECTS.toString(),
   APIM_INFORMATICA_TIMEOUT: ENVIRONMENT_VARIABLES.APIM_INFORMATICA_TIMEOUT.toString(),
 });