feat(backend): new config handling based on file

* Config should be provided as Yaml file now
* Other way to provide configuration are now deprectaed
* The config format is checked agaist a schema with the json-schema standard
* Tests are are added to the project (in the backend for config parsing)

config.default.yml

@@ -0,0 +1,17 @@
+backend:
+  # TODO
+  accessToken: ""
+  # TODO
+  webdav: false
+  performance:
+    # Whiteboard information broadcasting frequency (in /s)
+    # => diminishing this will result in more latency
+    whiteboardInfoBroadcastFreq: 1
+
+frontend:
+  # When an editable whiteboard is loading in a client,
+  # should it be started in read-only mode.
+  setReadOnlyOnWhiteboardLoad: false
+  # Show smallest screen indicator
+  showSmallestScreenIndicator: true
+  # performance:

package.json

@@ -8,7 +8,7 @@
     "build": "webpack --config config/webpack.build.js",
     "start:dev": "node scripts/server.js --mode=development",
     "start:prod": "npm run build && node scripts/server.js --mode=production",
-    "test": "echo \"No tests needed!\" && exit 1",
+    "test": "jest",
     "pretty-quick": "pretty-quick",
     "format": "prettier --write .",
     "style": "prettier --check ."
@@ -28,10 +28,12 @@
     }
   },
   "dependencies": {
+    "ajv": "6.12.2",
     "dompurify": "^2.0.7",
     "express": "4.*",
     "formidable": "1.*",
     "fs-extra": "7.*",
+    "js-yaml": "3.13.1",
     "jsdom": "^14.0.0",
     "pdfjs-dist": "^2.3.200",
     "socket.io": "2.*",
@@ -54,6 +56,7 @@
     "css-loader": "^3.5.2",
     "html-webpack-plugin": "^4.2.0",
     "husky": "^4.2.5",
+    "jest": "26.0.1",
     "jquery": "^3.2.1",
     "jquery-ui": "^1.12.1",
     "keymage": "^1.1.3",

scripts/WhiteboardServerSideInfo.js

@@ -85,7 +85,7 @@ class WhiteboardServerSideInfo {
             nbConnectedUsers: this._nbConnectedUsers,
         };
 
-        if (!config.disableSmallestScreen) {
+        if (config.frontend.showSmallestScreenIndicator) {
             out.smallestScreenResolution = this.getSmallestScreenResolution();
         }
 

scripts/config-schema.json

@@ -0,0 +1,46 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "title": "Whiteboard config",
+  "type": "object",
+  "properties": {
+    "backend": {
+      "type": "object",
+      "required": ["accessToken", "performance", "webdav"],
+      "additionalProperties": false,
+      "properties": {
+        "accessToken": {
+          "type": "string"
+        },
+        "webdav": {
+          "type": "boolean"
+        },
+        "performance": {
+          "additionalProperties": false,
+          "type": "object",
+          "required": ["whiteboardInfoBroadcastFreq"],
+          "properties": {
+            "whiteboardInfoBroadcastFreq": {
+              "type": "number",
+              "minimum": 0
+            }
+          }
+        }
+      }
+    },
+    "frontend": {
+      "type": "object",
+      "additionalProperties": false,
+      "required": ["setReadOnlyOnWhiteboardLoad", "showSmallestScreenIndicator"],
+      "properties": {
+        "setReadOnlyOnWhiteboardLoad": {
+          "type": "boolean"
+        },
+        "showSmallestScreenIndicator": {
+          "type": "boolean"
+        }
+      }
+    }
+  },
+  "required": ["backend", "frontend"],
+  "additionalProperties": false
+}

scripts/config.js

@@ -1,45 +1,84 @@
-const { getArgs } = require("./utils");
+const util = require("util");
 
-const config = {
-    accessToken: "",
-    disableSmallestScreen: false,
-    webdav: false,
+const {
+    getArgs,
+    getDefaultConfig,
+    getConfig,
+    deepMergeConfigs,
+    isConfigValid,
+} = require("./utils");
 
-    whiteboardInfoBroadcastFreq: 1, // once per second
-};
+const defaultConfig = getDefaultConfig();
+
+const cliArgs = getArgs();
+let userConfig = {};
+
+if (cliArgs["config"]) {
+    userConfig = getConfig(cliArgs["config"]);
+}
+
+const config = deepMergeConfigs(defaultConfig, userConfig);
 
 /**
  * Update the config based on the CLI args
  * @param {object} startArgs
  */
 function updateConfigFromStartArgs(startArgs) {
-    if (startArgs["accesstoken"]) {
-        config.accessToken = startArgs["accesstoken"];
-    }
-    if (startArgs["disablesmallestscreen"]) {
-        config.disableSmallestScreen = true;
-    }
-    if (startArgs["webdav"]) {
-        config.webdav = true;
+    function deprecateCliArg(key, callback) {
+        const val = startArgs[key];
+        if (val) {
+            console.warn(
+                "\x1b[33m\x1b[1m",
+                `Setting config values (${key}) from the CLI is deprecated. ` +
+                    "This ability will be removed in the next major version. " +
+                    "You should use the config file. "
+            );
+            callback(val);
+        }
     }
+
+    deprecateCliArg("accesstoken", (val) => (config.backend.accessToken = val));
+    deprecateCliArg(
+        "disablesmallestscreen",
+        () => (config.backend.showSmallestScreenIndicator = false)
+    );
+    deprecateCliArg("webdav", () => (config.backend.webdav = true));
 }
 
 /**
  * Update the config based on the env variables
  */
 function updateConfigFromEnv() {
-    if (process.env.accesstoken) {
-        config.accessToken = process.env.accesstoken;
-    }
-    if (process.env.disablesmallestscreen) {
-        config.disablesmallestscreen = true;
-    }
-    if (process.env.webdav) {
-        config.webdav = true;
+    function deprecateEnv(key, callback) {
+        const val = process.env[key];
+        if (val) {
+            console.warn(
+                "\x1b[33m\x1b[1m",
+                `Setting config values (${key}) from the environment is deprecated. ` +
+                    "This ability will be removed in the next major version. " +
+                    "You should use the config file. "
+            );
+            callback(val);
+        }
     }
+
+    deprecateEnv("accesstoken", (val) => (config.backend.accessToken = val));
+    deprecateEnv(
+        "disablesmallestscreen",
+        () => (config.backend.showSmallestScreenIndicator = false)
+    );
+    deprecateEnv("webdav", () => (config.backend.webdav = true));
 }
 
+// compatibility layer
+// FIXME: remove this in next major
 updateConfigFromEnv();
-updateConfigFromStartArgs(getArgs());
+// FIXME: remove this in next major
+updateConfigFromStartArgs(cliArgs);
+
+if (!isConfigValid(config, true)) {
+    throw new Error("Config is not valid. Check logs for details");
+}
+console.info(util.inspect(config, { showHidden: false, depth: null, colors: true }));
 
 module.exports = config;

scripts/server-backend.js

@@ -4,8 +4,6 @@ const config = require("./config");
 const WhiteboardServerSideInfo = require("./WhiteboardServerSideInfo");
 
 function startBackendServer(port) {
-    console.info("Starting backend server with config", config);
-
     var fs = require("fs-extra");
     var express = require("express");
     var formidable = require("formidable"); //form upload processing
@@ -27,7 +25,7 @@ function startBackendServer(port) {
     var io = require("socket.io")(server, { path: "/ws-api" });
     console.log("Webserver & socketserver running on port:" + port);
 
-    const { accessToken, webdav } = config;
+    const { accessToken, webdav } = config.backend;
 
     app.get("/api/loadwhiteboard", function (req, res) {
         var wid = req["query"]["wid"];
@@ -191,7 +189,7 @@ function startBackendServer(port) {
                 info.infoWasSent();
             }
         });
-    }, (1 / config.whiteboardInfoBroadcastFreq) * 1000);
+    }, (1 / config.backend.performance.whiteboardInfoBroadcastFreq) * 1000);
 
     io.on("connection", function (socket) {
         var whiteboardId = null;

scripts/utils.js

@@ -1,3 +1,12 @@
+const path = require("path");
+const fs = require("fs");
+const yaml = require("js-yaml");
+
+const Ajv = require("ajv");
+const ajv = new Ajv({ allErrors: true });
+
+const configSchema = require("./config-schema.json");
+
 function getArgs() {
     const args = {};
     process.argv.slice(2, process.argv.length).forEach((arg) => {
@@ -17,4 +26,68 @@ function getArgs() {
     return args;
 }
 
+/**
+ * TODO
+ *
+ * @param path
+ * @return {any}
+ */
+function getConfig(path) {
+    return yaml.safeLoad(fs.readFileSync(path, "utf8"));
+}
+
+/**
+ * TODO
+ * @param config
+ * @param warn
+ * @return {*}
+ */
+function isConfigValid(config, warn = true) {
+    const validate = ajv.compile(configSchema);
+    const isValid = validate(config);
+
+    if (!isValid && warn) console.warn(validate.errors);
+
+    return isValid;
+}
+
+/**
+ * TODO
+ * @return {*}
+ */
+function getDefaultConfig() {
+    const defaultConfigPath = path.join(__dirname, "..", "config.default.yml");
+    return getConfig(defaultConfigPath);
+}
+
+/**
+ * TODO
+ * Deep merges objects, not arrays.
+ *
+ * @param baseConfig
+ * @param overrideConfig
+ * @return {{}}
+ */
+function deepMergeConfigs(baseConfig, overrideConfig) {
+    const out = {};
+
+    Object.entries(baseConfig).forEach(([key, val]) => {
+        out[key] = val;
+        if (overrideConfig.hasOwnProperty(key)) {
+            const overrideVal = overrideConfig[key];
+            if (typeof val === "object" && !Array.isArray(val) && val !== null) {
+                out[key] = deepMergeConfigs(val, overrideVal);
+            } else {
+                out[key] = overrideVal;
+            }
+        }
+    });
+
+    return out;
+}
+
 module.exports.getArgs = getArgs;
+module.exports.getConfig = getConfig;
+module.exports.getDefaultConfig = getDefaultConfig;
+module.exports.deepMergeConfigs = deepMergeConfigs;
+module.exports.isConfigValid = isConfigValid;

scripts/utils.test.js

@@ -0,0 +1,48 @@
+const { getDefaultConfig, deepMergeConfigs, isConfigValid } = require("./utils");
+
+test("Load default config", () => {
+    const defaultConfig = getDefaultConfig();
+    expect(typeof defaultConfig).toBe("object");
+});
+
+test("Full config override", () => {
+    const defaultConfig = getDefaultConfig();
+    expect(deepMergeConfigs(defaultConfig, defaultConfig)).toEqual(defaultConfig);
+});
+
+test("Simple partial config override", () => {
+    expect(deepMergeConfigs({ test: true }, { test: false }).test).toBe(false);
+    expect(deepMergeConfigs({ test: false }, { test: true }).test).toBe(true);
+});
+
+test("Simple deep config override", () => {
+    expect(deepMergeConfigs({ stage1: { stage2: true } }, { stage1: { stage2: false } })).toEqual({
+        stage1: { stage2: false },
+    });
+});
+
+test("Complex object config override", () => {
+    expect(
+        deepMergeConfigs({ stage1: { stage2: true, stage2b: true } }, { stage1: { stage2: false } })
+    ).toEqual({
+        stage1: { stage2: false, stage2b: true },
+    });
+});
+
+test("Override default config", () => {
+    const defaultConfig = getDefaultConfig();
+    const overrideConfig1 = { frontend: { setReadOnlyOnWhiteboardLoad: true } };
+
+    expect(
+        deepMergeConfigs(defaultConfig, overrideConfig1).frontend.setReadOnlyOnWhiteboardLoad
+    ).toBe(true);
+});
+
+test("Dumb config is not valid", () => {
+    expect(isConfigValid({}, false)).toBe(false);
+});
+
+test("Default config is valid", () => {
+    const defaultConfig = getDefaultConfig();
+    expect(isConfigValid(defaultConfig)).toBe(true);
+});