fix: Create a new console logger for each snapshot (#407)

* commit dist

This will be reverted soon. Just so I can test on a fork without publishing
anything (or dealing with symlinks).

*  test: Create memory leak test for logger util

* test: Throw error when memory leak is detected

* Update test script names, create console transport function

* fix: file clean up in logger test

* test: capture output

* Code review feedback

.circleci/config.yml

@@ -29,21 +29,21 @@ commands:
           name: Unit tests
           command: |
             mkdir -p reports
-            $NYC yarn test --reporter mocha-multi --reporter-options spec=-,mocha-junit-reporter=-
+            $NYC yarn test:unit --reporter mocha-multi --reporter-options spec=-,mocha-junit-reporter=-
       - run:
           name: Client tests
-          command: $NYC yarn test-client --singleRun
+          command: $NYC yarn test:client --singleRun
       - run:
           name: Integration tests
-          command: $NYC yarn test-integration
+          command: $NYC yarn test:integration
   cli_integration:
     steps:
       - run:
           name: Snapshot command test
-          command: yarn test-snapshot-command
+          command: yarn test:command:snapshot
       - run:
           name: Upload command test
-          command: yarn test-upload-command
+          command: yarn test:command:upload
   cli_commands:
     steps:
       - run:

package.json

@@ -144,11 +144,12 @@
     "posttest": "yarn lint",
     "prepublishOnly": "yarn build && oclif-dev manifest && oclif-dev readme",
     "preversion": "yarn clean",
-    "test": "yarn build-client && PERCY_TOKEN=abc mocha --forbid-only \"test/**/*.test.ts\" --exclude \"test/percy-agent-client/**/*.test.ts\" --exclude \"test/integration/**/*\"",
-    "test-client": "karma start ./test/percy-agent-client/karma.conf.js",
-    "test-integration": "yarn build-client && node ./bin/run exec -h *.localtest.me -c .ci.percy.yml -- mocha test/integration/**/*.test.ts",
-    "test-snapshot-command": "./bin/run snapshot test/integration/test-static-site -b /dummy-base-url/ -i **/red-keep.** -s **/*.{html}",
-    "test-upload-command": "./bin/run upload test/integration/test-static-images",
+    "test": "yarn test:unit && yarn test:client && yarn test:integration && yarn test:command:snapshot && yarn test:command:upload",
+    "test:unit": "PERCY_TOKEN=abc mocha \"test/**/*.test.ts\" --exclude \"test/percy-agent-client/**/*.test.ts\" --exclude \"test/integration/**/*\"",
+    "test:client": "karma start ./test/percy-agent-client/karma.conf.js",
+    "test:integration": "yarn build-client && node ./bin/run exec -h *.localtest.me -c .ci.percy.yml -- mocha test/integration/**/*.test.ts",
+    "test:command:snapshot": "./bin/run snapshot test/integration/test-static-site -b /dummy-base-url/ -i **/red-keep.** -s **/*.{html}",
+    "test:command:upload": "./bin/run upload test/integration/test-static-images",
     "version": "oclif-dev readme && git add README.md",
     "watch": "npm-watch"
   },

src/utils/logger.ts

@@ -3,17 +3,19 @@ import * as winston from 'winston'
 
 const LOG_LEVEL = process.env.LOG_LEVEL || 'info'
 
-const consoleTransport = new winston.transports.Console({
-  level: LOG_LEVEL,
-  stderrLevels: ['error'],
-  format: winston.format.combine(
-    winston.format.label({ label: colors.magenta('percy') }),
-    winston.format.printf(({ label, message }) => `[${label}] ${message}`),
-  ),
-})
+function createConsoleTransport() {
+  return new winston.transports.Console({
+    level: LOG_LEVEL,
+    stderrLevels: ['error'],
+    format: winston.format.combine(
+      winston.format.label({ label: colors.magenta('percy') }),
+      winston.format.printf(({ label, message }) => `[${label}] ${message}`),
+    ),
+  })
+}
 
 const logger = winston.createLogger({
-  transports: [consoleTransport],
+  transports: [createConsoleTransport()],
 })
 
 export function profile(id: string, meta?: any): winston.Logger | undefined {
@@ -29,7 +31,7 @@ export function logError(error: any) {
 
 export function createFileLogger(filename: string) {
   const fileTransport = new winston.transports.File({ filename, level: 'debug' })
-  return winston.createLogger({ transports: [consoleTransport, fileTransport] })
+  return winston.createLogger({ transports: [createConsoleTransport(), fileTransport] })
 }
 
 export default logger

test/utils/logger.test.ts

@@ -0,0 +1,33 @@
+import { expect } from 'chai'
+import { existsSync, unlinkSync } from 'fs'
+import { createFileLogger } from '../../src/utils/logger'
+import { captureStdErr } from '../helpers/stdout'
+
+describe('logger utils', () => {
+  describe('createFileLogger', () => {
+    const filesToCleanUp = [] as any
+
+    afterEach(() => {
+      if (filesToCleanUp) {
+        filesToCleanUp.forEach((file: string) => {
+          const filePath = `${process.cwd()}/${file}`
+          if (!existsSync(filePath)) { return }
+
+          unlinkSync(filePath)
+        })
+      }
+    })
+
+    it('does not leak memory', async () => {
+      const output = await captureStdErr(() => {
+        for (let index = 0; index < 600; index++) {
+          const fileName = `test-file-${index}`
+          createFileLogger(fileName)
+          filesToCleanUp.push(fileName)
+        }
+      })
+
+      expect(output).to.equal('')
+    })
+  })
+})