feat: make .env optional (#19)

docs/app-structure.md

@@ -9,7 +9,7 @@ Glee expects your project to have some files and folders with special names. The
 ├─ lifecycle          (optional)
 │  ├─ onConnect.js
 │  └─ ...
-├─ .env               (required)
+├─ .env               (optional)
 ├─ asyncapi.yaml      (required)
 ├─ glee.config.js     (optional)
 ├─ package.json       (required)
@@ -19,7 +19,8 @@ Glee expects your project to have some files and folders with special names. The
 |---|---|
 |functions|**Required.** This directory contains all the functions that Glee must execute when it receives a message from the server. Each file must export a default async function. [Read more about the functions signature](./functions.md).
 |lifecycle|This directory contains application lifecycle functions. These functions will be executed when certain events happen in the application. E.g., `onConnect`, `onServerReady`, `onDisconnect`, etc. [Read the full list of lifecycle events](./lifecycle-events.md).
-|.env|**Required.** The environment variables of your application. At the very minimum, it must contain the `GLEE_SERVER_NAMES` variable with a comma-separated list of the servers you want to load at startup. **DO NOT PUT SECRETS HERE**.
+|.env|The environment variables of your application. Read more about the Glee [environment variables](./env-vars.md). **DO NOT PUT SECRETS HERE**.
 |asyncapi.yaml|**Required.** The [AsyncAPI](https://www.asyncapi.com/docs/specifications/latest) file defining your API. Make sure all the `publish` operations have an assigned `operationId` that matches a file name (excluding the extension) in the `functions` directory.
 |glee.config.js|The Glee configuration file. [Read more about how to use this file](./config-file.md).
-|package.json|**Required.** The Node.js package definition file. Make sure you include `@asyncapi/glee` as a dependency and add two scripts: `dev` and `start`. They should be running `glee dev` and `glee start` respectively.
+|package.json|**Required.** The Node.js package definition file. Make sure you include `@asyncapi/glee` as a dependency and add two scripts: `dev` and `start`. They should be running `glee dev` and `glee start` respectively.
+

docs/env-vars.md

@@ -0,0 +1,9 @@
+# Environment Variables
+
+Glee provides a few environment variables for you to customize the experience:
+
+|Variable|Description|Example|
+|---|---|---|
+|GLEE_SERVER_NAMES|A comma-separated list of the servers to load on startup.|`GLEE_SERVER_NAMES=websockets,mosquitto`
+|GLEE_SERVER_CERTS|A comma-separated list of `${serverName}:${pathToCertificateFile}`. These are the certificates to use when establishing the connection to the given server.|`GLEE_SERVER_CERTS=mosquitto:mosquitto.org.crt`
+|GLEE_SERVER_VARIABLES|A comma-separated list of `${serverName}:${serverVariable}:${value}`. These are the values to use for each server variable.|`GLEE_SERVER_VARIABLES=websockets:namespace:public`

examples/dummy/.env

@@ -1,4 +1 @@
-GLEE_SERVER_NAMES=mosquitto,websockets
 GLEE_SERVER_CERTS=mosquitto:mosquitto.org.crt
-# GLEE_USERNAME=testing
-# GLEE_PASSWORD=Test1ng!

src/index.js

@@ -1,7 +1,5 @@
 import dotenv from 'dotenv'
 import dotenvExpand from 'dotenv-expand'
-import { readFile } from 'fs/promises'
-import asyncapi from '@asyncapi/parser'
 import Glee from './lib/glee.js'
 import { logWelcome, logLineWithIcon } from './lib/logger.js'
 import experimentalFlags from './lib/experimentalFlags.js'
@@ -19,14 +17,12 @@ import validateConnection from './middlewares/validateConnection.js'
 import { startRuntimeServers } from './lib/runtimes/index.js'
 import { setConstants } from './lib/constants.js'
 import { triggerFunction } from './lib/runtimes/index.js'
+import { getParsedAsyncAPI } from './lib/asyncapiFile.js'
+import { getSelectedServerNames } from './lib/servers.js'
 
 dotenvExpand(dotenv.config())
 
 export default async function GleeAppInitializer (config = {}) {
-  if (!process.env.GLEE_SERVER_NAMES) {
-    throw new Error('Missing "GLEE_SERVER_NAMES" environment variable.')
-  }
-
   const {
     GLEE_DIR,
     GLEE_LIFECYCLE_DIR,
@@ -37,7 +33,7 @@ export default async function GleeAppInitializer (config = {}) {
 
   logWelcome({
     dev: process.env.NODE_ENV === 'development',
-    servers: process.env.GLEE_SERVER_NAMES.split(','),
+    servers: await getSelectedServerNames(),
     dir: GLEE_DIR,
     functionsDir: GLEE_FUNCTIONS_DIR,
     experimentalFlags,
@@ -60,13 +56,12 @@ export default async function GleeAppInitializer (config = {}) {
     }
   }
 
-  const asyncapiFileContent = await readFile(ASYNCAPI_FILE_PATH, 'utf-8')
-  const parsedAsyncAPI = await asyncapi.parse(asyncapiFileContent)
+  const parsedAsyncAPI = await getParsedAsyncAPI()
   const channelNames = parsedAsyncAPI.channelNames()
 
   const app = new Glee(config)
 
-  registerAdapters(app, parsedAsyncAPI, config)
+  await registerAdapters(app, parsedAsyncAPI, config)
 
   app.use(existsInAsyncAPI(parsedAsyncAPI))
   app.useOutbound(existsInAsyncAPI(parsedAsyncAPI))

src/lib/asyncapiFile.js

@@ -0,0 +1,9 @@
+import { readFile } from 'fs/promises'
+import asyncapi from '@asyncapi/parser'
+import { getConstants } from './constants.js'
+
+export async function getParsedAsyncAPI() {
+  const { ASYNCAPI_FILE_PATH } = getConstants()
+  const asyncapiFileContent = await readFile(ASYNCAPI_FILE_PATH, 'utf-8')
+  return asyncapi.parse(asyncapiFileContent)
+}

src/lib/servers.js

@@ -0,0 +1,14 @@
+import { getParsedAsyncAPI } from './asyncapiFile.js'
+
+export async function getSelectedServerNames() {
+  const parsedAsyncAPI = await getParsedAsyncAPI()
+
+  if (!process.env.GLEE_SERVER_NAMES) {
+    return parsedAsyncAPI.serverNames()
+  }
+
+  const arrayOfNames = process.env.GLEE_SERVER_NAMES.split(',')
+  return parsedAsyncAPI.serverNames().filter(name => {
+    return arrayOfNames.includes(name)
+  })
+}

src/registerAdapters.js

@@ -1,9 +1,10 @@
 import MqttAdapter from './adapters/mqtt/index.js'
 import WebSocketAdapter from './adapters/ws/index.js'
 import SocketIOAdapter from './adapters/socket.io/index.js'
+import { getSelectedServerNames } from './lib/servers.js'
 
-export default (app, parsedAsyncAPI, config) => {
-  const serverNames = process.env.GLEE_SERVER_NAMES.split(',')
+export default async (app, parsedAsyncAPI, config) => {
+  const serverNames = await getSelectedServerNames()
 
   serverNames.forEach(serverName => {
     const server = parsedAsyncAPI.server(serverName)