refactor(config): Better prefix handling and enhanced coverage

lib/workers/global/config/parse/env.spec.ts

@@ -1,5 +1,6 @@
 import type { RenovateOptions } from '../../../../config/types';
 import { PlatformId } from '../../../../constants';
+import { logger } from '../../../../logger';
 import * as env from './env';
 
 describe('workers/global/config/parse/env', () => {
@@ -32,12 +33,53 @@ describe('workers/global/config/parse/env', () => {
       const envParam: NodeJS.ProcessEnv = { RENOVATE_TOKEN: 'a' };
       expect(env.getConfig(envParam).token).toBe('a');
     });
+    it('supports custom prefixes', () => {
+      const envParam: NodeJS.ProcessEnv = {
+        ENV_PREFIX: 'FOOBAR_',
+        FOOBAR_TOKEN: 'abc',
+      };
+      const res = env.getConfig(envParam);
+      expect(res).toMatchObject({ token: 'abc' });
+    });
     it('supports json', () => {
       const envParam: NodeJS.ProcessEnv = {
         RENOVATE_LOCK_FILE_MAINTENANCE: '{}',
       };
       expect(env.getConfig(envParam).lockFileMaintenance).toEqual({});
     });
+    it('supports arrays of objects', () => {
+      const envParam: NodeJS.ProcessEnv = {
+        RENOVATE_HOST_RULES: JSON.stringify([{ foo: 'bar' }]),
+      };
+      const res = env.getConfig(envParam);
+      expect(res).toMatchObject({ hostRules: [{ foo: 'bar' }] });
+    });
+    it('skips misconfigured arrays', () => {
+      const envName = 'RENOVATE_HOST_RULES';
+      const val = JSON.stringify('foobar');
+      const envParam: NodeJS.ProcessEnv = { [envName]: val };
+
+      const res = env.getConfig(envParam);
+
+      expect(res).toEqual({ hostRules: [] });
+      expect(logger.debug).toHaveBeenLastCalledWith(
+        { val, envName },
+        'Could not parse object array'
+      );
+    });
+    it('skips garbage array values', () => {
+      const envName = 'RENOVATE_HOST_RULES';
+      const val = '!@#';
+      const envParam: NodeJS.ProcessEnv = { [envName]: val };
+
+      const res = env.getConfig(envParam);
+
+      expect(res).toEqual({ hostRules: [] });
+      expect(logger.debug).toHaveBeenLastCalledWith(
+        { val, envName },
+        'Could not parse environment variable'
+      );
+    });
     it('supports GitHub token', () => {
       const envParam: NodeJS.ProcessEnv = {
         RENOVATE_TOKEN: 'github.com token',
@@ -182,6 +224,25 @@ describe('workers/global/config/parse/env', () => {
       expect(config.enabled).toBe(false);
       expect(config.token).toBe('a');
     });
+    describe('malformed RENOVATE_CONFIG', () => {
+      let processExit;
+
+      beforeAll(() => {
+        processExit = jest
+          .spyOn(process, 'exit')
+          .mockImplementation((() => {}) as never);
+      });
+
+      afterAll(() => {
+        processExit.mockRestore();
+      });
+
+      it('crashes', () => {
+        const envParam: NodeJS.ProcessEnv = { RENOVATE_CONFIG: '!@#' };
+        env.getConfig(envParam);
+        expect(processExit).toHaveBeenCalledWith(1);
+      });
+    });
   });
   describe('.getEnvName(definition)', () => {
     it('returns empty', () => {

lib/workers/global/config/parse/env.ts

@@ -7,13 +7,21 @@ import { getDatasourceList } from '../../../../datasource';
 import { logger } from '../../../../logger';
 import type { HostRule } from '../../../../types';
 
-// istanbul ignore if
-if (process.env.ENV_PREFIX) {
-  for (const [key, val] of Object.entries(process.env)) {
-    if (key.startsWith(process.env.ENV_PREFIX)) {
-      process.env[key.replace(process.env.ENV_PREFIX, 'RENOVATE_')] = val;
+function normalizePrefixes(
+  env: NodeJS.ProcessEnv,
+  prefix: string | undefined
+): NodeJS.ProcessEnv {
+  const result = { ...env };
+  if (prefix) {
+    for (const [key, val] of Object.entries(result)) {
+      if (key.startsWith(prefix)) {
+        const newKey = key.replace(prefix, 'RENOVATE_');
+        result[newKey] = val;
+        delete result[key];
+      }
     }
   }
+  return result;
 }
 
 export function getEnvName(option: Partial<RenovateOptions>): string {
@@ -27,7 +35,9 @@ export function getEnvName(option: Partial<RenovateOptions>): string {
   return `RENOVATE_${nameWithUnderscores.toUpperCase()}`;
 }
 
-export function getConfig(env: NodeJS.ProcessEnv): AllConfig {
+export function getConfig(inputEnv: NodeJS.ProcessEnv): AllConfig {
+  const env = normalizePrefixes(inputEnv, inputEnv.ENV_PREFIX);
+
   const options = getOptions();
 
   let config: AllConfig = {};
@@ -36,7 +46,7 @@ export function getConfig(env: NodeJS.ProcessEnv): AllConfig {
     try {
       config = JSON.parse(env.RENOVATE_CONFIG);
       logger.debug({ config }, 'Detected config in env RENOVATE_CONFIG');
-    } catch (err) /* istanbul ignore next */ {
+    } catch (err) {
       logger.fatal({ err }, 'Could not parse RENOVATE_CONFIG');
       process.exit(1);
     }
@@ -56,7 +66,6 @@ export function getConfig(env: NodeJS.ProcessEnv): AllConfig {
     if (option.env !== false) {
       const envName = getEnvName(option);
       if (env[envName]) {
-        // istanbul ignore if
         if (option.type === 'array' && option.subType === 'object') {
           try {
             const parsed = JSON.parse(env[envName]);
@@ -69,7 +78,10 @@ export function getConfig(env: NodeJS.ProcessEnv): AllConfig {
               );
             }
           } catch (err) {
-            logger.debug({ val: env[envName], envName }, 'Could not parse CLI');
+            logger.debug(
+              { val: env[envName], envName },
+              'Could not parse environment variable'
+            );
           }
         } else {
           const coerce = coersions[option.type];