fix(logging): Added check for log level value

lib/config/validation.spec.ts

@@ -1,3 +1,4 @@
+import bunyan from 'bunyan';
 import type { RenovateConfig } from './types';
 import * as configValidation from './validation';
 
@@ -716,5 +717,32 @@ describe('config/validation', () => {
         },
       ]);
     });
+
+    it('checks for valid log level', () => {
+      expect(
+        configValidation.isValidLogLevel('warning' as bunyan.LogLevel)
+      ).toBeFalsy();
+      expect(
+        configValidation.isValidLogLevel('warn' as bunyan.LogLevel)
+      ).toBeTruthy();
+      expect(
+        configValidation.isValidLogLevel('trace' as bunyan.LogLevel)
+      ).toBeTruthy();
+      expect(
+        configValidation.isValidLogLevel(' ' as bunyan.LogLevel)
+      ).toBeTruthy();
+      expect(
+        configValidation.isValidLogLevel('' as bunyan.LogLevel)
+      ).toBeTruthy();
+      expect(
+        configValidation.isValidLogLevel(20 as bunyan.LogLevel)
+      ).toBeTruthy();
+      expect(
+        configValidation.isValidLogLevel(10 as bunyan.LogLevel)
+      ).toBeTruthy();
+      expect(
+        configValidation.isValidLogLevel(100 as bunyan.LogLevel)
+      ).toBeFalsy();
+    });
   });
 });

lib/config/validation.ts

@@ -1,4 +1,5 @@
 import is from '@sindresorhus/is';
+import bunyan from 'bunyan';
 import { getLanguageList, getManagerList } from '../manager';
 import { configRegexPredicate, isConfigRegex, regEx } from '../util/regex';
 import * as template from '../util/template';
@@ -570,3 +571,41 @@ export async function validateConfig(
   warnings.sort(sortAll);
   return { errors, warnings };
 }
+
+export function isValidLogLevel(
+  logLevelToCheck: bunyan.LogLevel
+): logLevelToCheck is bunyan.LogLevel {
+  const allowedValues: bunyan.LogLevel[] = [
+    'trace',
+    'debug',
+    'info',
+    'warn',
+    'error',
+    'fatal',
+    bunyan.TRACE,
+    bunyan.DEBUG,
+    bunyan.INFO,
+    bunyan.WARN,
+    bunyan.ERROR,
+    bunyan.FATAL,
+  ];
+  const result: boolean =
+    allowedValues.indexOf(logLevelToCheck) !== -1 ||
+    (typeof logLevelToCheck === 'string' &&
+      logLevelToCheck.trim().length === 0);
+
+  if (!result) {
+    const Logger = bunyan.createLogger({
+      name: 'log level error log',
+      streams: [
+        {
+          level: 'fatal',
+          stream: process.stdout, // log INFO and above to stdout
+        },
+      ],
+    });
+    Logger.fatal(`${logLevelToCheck} is not a valid log level terminating`);
+  }
+
+  return result;
+}

lib/logger/index.ts

@@ -1,6 +1,7 @@
 import is from '@sindresorhus/is';
 import * as bunyan from 'bunyan';
 import { nanoid } from 'nanoid';
+import { isValidLogLevel } from '../config/validation';
 import cmdSerializer from './cmd-serializer';
 import configSerializer from './config-serializer';
 import errSerializer from './err-serializer';
@@ -13,6 +14,10 @@ let curMeta: Record<string, unknown> = {};
 
 const problems = new ProblemStream();
 
+process.env.LOG_LEVEL.toLocaleLowerCase();
+if (!isValidLogLevel(process.env.LOG_LEVEL as bunyan.LogLevel)) {
+  process.exit(1);
+}
 const stdout: bunyan.Stream = {
   name: 'stdout',
   level: