fix(ArchLinux): binary not downloaded when no release file is found. Plus other code fixes and cleanups (tnx @hasezoey)

* Add notes on what is needed to detect the linux-distro

fixes #248

* Adding basic Pull Request Template
Adding Inital Bug Issue Template
Adding Inital Question Issue Template

fixes #255

* Change note about ArchLinux

* Add TSDoc to MongoBinaryDownloadUrl
Add cases for ArchLinux & Alpine (no offical build)
ElementaryOS Error handling (warn lsb_release error)
Make some string assembling more readable

* Add sub-chapter "Known Incompatibilities" to "Requirements"

* Make "locationExists" async for non-blocking

* Shrink resolve-config functions thanks to "optional-chaining"
add function "envToBool" to resolve-config

* Convert "MONGOMS_MD5_CHECK" to use resolve-config
Shrink thanks to Nullish Coalescing
Add TSDoc
Remove "eslint-disable-line" (why was it there?)
Check agianst "this.dlProgress.length" instead of an constant number
Promisify sync-fs functions to make them non-blocking and awaitable

* MongoBinary: use envToBool instead of long line
postinstall: disable rule "@typescript-eslint/no-var-requires"

* fix tests

Author: hasezoey

.github/ISSUE_TEMPLATE/bug.md

@@ -0,0 +1,41 @@
+---
+name: Bug
+about: Create a bug report
+title: ''
+labels: bug
+assignees: ''
+---
+
+<!--
+Make sure you read [Mastering-Markdown](https://guides.github.com/features/mastering-markdown/)
+-->
+
+## Versions
+
+- NodeJS: 0.0.0
+- mongodb-memory-server-*: 0.0.0
+- mongodb: 0.0.0
+- mongoose: 0.0.0 <!--remove this if not used-->
+- system: <!--either Windows, MacOS, Linux (with distro and distro version)-->
+
+package: mongo-memory-server <!--State the package you are using-->
+<!--
+possible are:
+mongo-memory-server
+mongo-memory-server-core
+mongo-memory-server-global
+-->
+
+## What is the Problem?
+
+<!--Please add an description of what the bug / problem is-->
+
+## Code Example
+
+```ts
+code here
+```
+
+## Do you know *why* it happenes?
+
+*no*

.github/ISSUE_TEMPLATE/question.md

@@ -0,0 +1,31 @@
+---
+name: Question
+about: Ask a question
+title: ''
+labels: question
+assignees: ''
+---
+
+<!--
+Make sure you read [Mastering-Markdown](https://guides.github.com/features/mastering-markdown/)
+-->
+
+## Versions
+
+- NodeJS: 0.0.0
+- mongodb-memory-server-*: 0.0.0
+- mongodb: 0.0.0
+- mongoose: 0.0.0 <!--remove this if not used-->
+- system: <!--either Windows, MacOS, Linux (with distro and distro version)-->
+
+package: mongo-memory-server <!--State the package you are using-->
+<!--
+possible are:
+mongo-memory-server
+mongo-memory-server-core
+mongo-memory-server-global
+-->
+
+## What is your question?
+
+<!--Please include code samples if the question is about it-->

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,12 @@
+<!--
+## Make sure you have done these steps
+
+- Make sure you read [Mastering-Markdown](https://guides.github.com/features/mastering-markdown/)
+- remove the parts that are not applicable
+- Please have "Allow edits from maintainers" activated
+-->
+
+## Related Issues
+<!--Remove this part if not applicable-->
+
+- #1

README.md

@@ -34,6 +34,17 @@ Choose any package, because they are the same. Differs only by default configura
 NodeJS: 8+
 Typescript: 3.7+ (if used)
 
+One of those:
+
+- having `lsb-core` installed (or any that provides the `lsb_release` command)
+- having an `/etc/os-release` file that is compliant to the [OS-Release Spec](https://www.freedesktop.org/software/systemd/man/os-release.html)
+- having an `/etc/*-release` file that is compliant to the [OS-Release Spec](https://www.freedesktop.org/software/systemd/man/os-release.html) (and does not include `lsb`)
+
+#### Known Incompatibilities
+
+- ArchLinux & Alpine do not have an offical mongodb build
+- ArchLinux(Docker) does not have an `/etc/os-release` file by default
+
 ### `mongodb-memory-server`
 
 Auto-downloads the latest `mongod` binary on npm install to: `node_modules/.cache/mongodb-binaries`.

packages/mongodb-memory-server-core/src/util/MongoBinary.ts

@@ -9,7 +9,7 @@ import dedent from 'dedent';
 import { promisify } from 'util';
 import MongoBinaryDownload from './MongoBinaryDownload';
 import { DebugFn } from '../types';
-import resolveConfig from './resolve-config';
+import resolveConfig, { envToBool } from './resolve-config';
 
 // TODO: return back `latest` version when it will be fixed in MongoDB distro (for now use 4.0.3 😂)
 // More details in https://github.com/nodkz/mongodb-memory-server/issues/131
@@ -104,7 +104,6 @@ export default class MongoBinary {
 
   static async getPath(opts: MongoBinaryOpts = {}): Promise<string> {
     const legacyDLDir = path.resolve(os.homedir(), '.cache/mongodb-binaries');
-    const envDebug = resolveConfig('DEBUG');
 
     // if we're in postinstall script, npm will set the cwd too deep
     let nodeModulesDLDir = process.cwd();
@@ -128,8 +127,7 @@ export default class MongoBinary {
       arch: resolveConfig('ARCH') || os.arch(),
       version: resolveConfig('VERSION') || LATEST_VERSION,
       systemBinary: resolveConfig('SYSTEM_BINARY'),
-      debug:
-        typeof envDebug === 'string' ? ['1', 'on', 'yes', 'true'].indexOf(envDebug) !== -1 : false,
+      debug: envToBool(resolveConfig('DEBUG') ?? ''),
     };
 
     if (opts.debug) {

packages/mongodb-memory-server-core/src/util/MongoBinaryDownload.ts

@@ -9,6 +9,8 @@ import MongoBinaryDownloadUrl from './MongoBinaryDownloadUrl';
 import { DebugFn, DebugPropT, DownloadProgressT } from '../types';
 import { LATEST_VERSION } from './MongoBinary';
 import HttpsProxyAgent from 'https-proxy-agent';
+import { promisify } from 'util';
+import resolveConfig, { envToBool } from './resolve-config';
 
 export interface MongoBinaryDownloadOpts {
   version?: string;
@@ -39,17 +41,11 @@ export default class MongoBinaryDownload {
   platform: string;
 
   constructor({ platform, arch, downloadDir, version, checkMD5, debug }: MongoBinaryDownloadOpts) {
-    this.platform = platform || os.platform();
-    this.arch = arch || os.arch();
-    this.version = version || LATEST_VERSION;
+    this.platform = platform ?? os.platform();
+    this.arch = arch ?? os.arch();
+    this.version = version ?? LATEST_VERSION;
     this.downloadDir = path.resolve(downloadDir || 'mongodb-download');
-    if (checkMD5 === undefined) {
-      this.checkMD5 =
-        typeof process.env.MONGOMS_MD5_CHECK === 'string' &&
-        ['1', 'on', 'yes', 'true'].indexOf(process.env.MONGOMS_MD5_CHECK.toLowerCase()) !== -1;
-    } else {
-      this.checkMD5 = checkMD5;
-    }
+    this.checkMD5 = checkMD5 ?? envToBool(resolveConfig('MD5_CHECK') ?? '');
     this.dlProgress = {
       current: 0,
       length: 0,
@@ -68,24 +64,32 @@ export default class MongoBinaryDownload {
     }
   }
 
+  /**
+   * Get the path of the already downloaded "mongod" file
+   * otherwise download it and then return the path
+   */
   async getMongodPath(): Promise<string> {
     const binaryName = this.platform === 'win32' ? 'mongod.exe' : 'mongod';
     const mongodPath = path.resolve(this.downloadDir, this.version, binaryName);
-    if (this.locationExists(mongodPath)) {
+    if (await this.locationExists(mongodPath)) {
       return mongodPath;
     }
 
     const mongoDBArchive = await this.startDownload();
     await this.extract(mongoDBArchive);
     fs.unlinkSync(mongoDBArchive);
 
-    if (this.locationExists(mongodPath)) {
+    if (await this.locationExists(mongodPath)) {
       return mongodPath;
     }
 
     throw new Error(`Cannot find downloaded mongod binary by path ${mongodPath}`);
   }
 
+  /**
+   * Download the MongoDB Archive and check it against an MD5
+   * @returns The MongoDB Archive location
+   */
   async startDownload(): Promise<string> {
     const mbdUrl = new MongoBinaryDownloadUrl({
       platform: this.platform,
@@ -106,6 +110,11 @@ export default class MongoBinaryDownload {
     return mongoDBArchive;
   }
 
+  /**
+   * Download MD5 file and check it against the MongoDB Archive
+   * @param urlForReferenceMD5 URL to download the MD5
+   * @param mongoDBArchive The MongoDB Archive file location
+   */
   async makeMD5check(
     urlForReferenceMD5: string,
     mongoDBArchive: string
@@ -119,11 +128,15 @@ export default class MongoBinaryDownload {
     const md5Remote = m ? m[1] : null;
     const md5Local = md5File.sync(mongoDBArchive);
     if (md5Remote !== md5Local) {
-      throw new Error('MongoBinaryDownload: md5 check is failed');
+      throw new Error('MongoBinaryDownload: md5 check failed');
     }
     return true;
   }
 
+  /**
+   * Download file from downloadUrl
+   * @param downloadUrl URL to download a File
+   */
   async download(downloadUrl: string): Promise<string> {
     const proxy =
       process.env['yarn_https-proxy'] ||
@@ -165,6 +178,11 @@ export default class MongoBinaryDownload {
     return downloadedFile;
   }
 
+  /**
+   * Extract given Archive
+   * @param mongoDBArchive Archive location
+   * @returns extracted directory location
+   */
   async extract(mongoDBArchive: string): Promise<string> {
     const binaryName = this.platform === 'win32' ? 'mongod.exe' : 'mongod';
     const extractDir = path.resolve(this.downloadDir, this.version);
@@ -188,20 +206,26 @@ export default class MongoBinaryDownload {
       filter,
       // extract to root folder
       map: (file) => {
-        file.path = path.basename(file.path); // eslint-disable-line
+        file.path = path.basename(file.path);
         return file;
       },
     });
 
-    if (!this.locationExists(path.resolve(this.downloadDir, this.version, binaryName))) {
+    if (!(await this.locationExists(path.resolve(this.downloadDir, this.version, binaryName)))) {
       throw new Error(
         `MongoBinaryDownload: missing mongod binary in ${mongoDBArchive} (downloaded from ${this
-          ._downloadingUrl || ''}). Broken package in MongoDB distro?`
+          ._downloadingUrl ?? 'unkown'}). Broken archive from MongoDB Provider?`
       );
     }
     return extractDir;
   }
 
+  /**
+   * Downlaod given httpOptions to tempDownloadLocation, then move it to downloadLocation
+   * @param httpOptions The httpOptions directly passed to https.get
+   * @param downloadLocation The location the File should be after the download
+   * @param tempDownloadLocation The location the File should be while downloading
+   */
   async httpDownload(
     httpOptions: HttpDownloadOptions,
     downloadLocation: string,
@@ -210,15 +234,18 @@ export default class MongoBinaryDownload {
     return new Promise((resolve, reject) => {
       const fileStream = fs.createWriteStream(tempDownloadLocation);
 
-      const req: any = https.get(httpOptions, (response: any) => {
+      const req = https.get(httpOptions, (response: any) => {
         this.dlProgress.current = 0;
         this.dlProgress.length = parseInt(response.headers['content-length'], 10);
         this.dlProgress.totalMb = Math.round((this.dlProgress.length / 1048576) * 10) / 10;
 
         response.pipe(fileStream);
 
-        fileStream.on('finish', () => {
-          if (this.dlProgress.current < 1000000 && !httpOptions.path.endsWith('.md5')) {
+        fileStream.on('finish', async () => {
+          if (
+            this.dlProgress.current < this.dlProgress.length &&
+            !httpOptions.path.endsWith('.md5')
+          ) {
             const downloadUrl =
               this._downloadingUrl || `https://${httpOptions.hostname}/${httpOptions.path}`;
             reject(
@@ -228,24 +255,31 @@ export default class MongoBinaryDownload {
             );
             return;
           }
+
           fileStream.close();
-          fs.renameSync(tempDownloadLocation, downloadLocation);
+          await promisify(fs.rename)(tempDownloadLocation, downloadLocation);
           this.debug(`renamed ${tempDownloadLocation} to ${downloadLocation}`);
+
           resolve(downloadLocation);
         });
 
         response.on('data', (chunk: any) => {
           this.printDownloadProgress(chunk);
         });
 
-        req.on('error', (e: any) => {
-          this.debug('request error:', e);
+        req.on('error', (e: Error) => {
+          // log it without having debug enabled
+          console.error(`Couldnt download ${httpOptions.path}!`, e.message);
           reject(e);
         });
       });
     });
   }
 
+  /**
+   * Print the Download Progress to STDOUT
+   * @param chunk A chunk to get the length
+   */
   printDownloadProgress(chunk: any): void {
     this.dlProgress.current += chunk.length;
 
@@ -264,9 +298,14 @@ export default class MongoBinaryDownload {
     );
   }
 
-  locationExists(location: string): boolean {
+  /**
+   * Test if the location given is already used
+   * Does *not* dereference links
+   * @param location The Path to test
+   */
+  async locationExists(location: string): Promise<boolean> {
     try {
-      fs.lstatSync(location);
+      await promisify(fs.lstat)(location);
       return true;
     } catch (e) {
       if (e.code !== 'ENOENT') throw e;