First commit

.github/workflows/tests.yml

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+name: CI
+
+on:
+  push:
+    branches:
+      - '*'
+      - '!stable/**'
+
+jobs:
+  build:
+    timeout-minutes: 7
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-node@v1
+      with:
+        node-version: '15'
+    - name: Install npm dependencies
+      run: npm ci
+    - name: Run docker-compose
+      run: docker-compose up -d
+    - name: Run tests
+      run: docker-compose exec -T node npm run test

.gitignore

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+package-lock.json
+.idea
+node_modules

.mocharc.json

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+{
+  "extension": ["ts"],
+  "exit": true,
+  "recursive": true,
+  "require": ["ts-node/register"],
+  "inspect": "0.0.0.0:9231"
+}

.npmignore

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+test
+tsconfig.json
+.mocharc.json
+LICENCE
+node_modules
+.gitignore
+docker-compose.yml
+package-lock.json

LICENCE

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+MIT License
+
+Copyright (c) 2021 Alexander Dmitryuk
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# Redis functions balancer
+[![NPM](https://nodei.co/coden/redis-functions-balancer.png?downloads=true&downloadRank=true&stars=true)](https://nodei.co/npm/coden/redis-functions-balancer)
+
+Balance executable NodeJs function with redis.
+
+For example, if you have several functions (A, B, C) doing the same things (http requests, long-running code), and you want to execute it evenly.
+
+Working in clusters (PM2, NodeJs Cluster).
+
+Uses [Redis][0] list with rank and [Javascript iterators][1].
+
+Ready to use with TypeScript and JavaScript.
+
+## Installation
+```
+npm install @coden/redis-functions-balancer --save-prod
+```
+
+## Usage
+```typescript
+import CallableBalancer from "@coden/redis-functions-balancer";
+const redis = require("redis");
+const redisClient = redis.createClient(6379, 'redis');
+
+// Your functions here
+// ... //
+const A = () => {};
+const B = () => {};
+const C = () => {};
+// ... //
+let balancer = new CallableBalancer([A, B, C], redisClient);
+// or reuse balancer variable with another functions
+balancer.setMethods([A, B]);
+// ... //
+// Get async iterator {done, value}
+while ( (foo = await balancer.getAsyncIterator().next()) && !foo.done) {
+    // Your function A|B|C will be here evenly
+    let method = foo.value;
+
+    try {
+        // Executing on your way (
+        foo.value();
+    } catch (e) {
+        // something happen badly and you want to postpone executes of the function next 10 runs
+        balancer.increaseMethodRank(method, 10);
+    }
+}
+
+```
+
+[0]: https://www.npmjs.com/package/redis
+[1]: https://www.typescriptlang.org/docs/handbook/iterators-and-generators.html

docker-compose.yml

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+version: "3.5"
+services:
+  redis:
+    image: redis:alpine
+    depends_on:
+      - node
+  node:
+    image: node:latest
+    volumes:
+      - .:/app
+    working_dir: /app
+    entrypoint: "sleep 100"
+    ports:
+      - 9231:9231

index.js

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+"use strict";
+var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
+    return new (P || (P = Promise))(function (resolve, reject) {
+        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
+        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
+        step((generator = generator.apply(thisArg, _arguments || [])).next());
+    });
+};
+var __generator = (this && this.__generator) || function (thisArg, body) {
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
+    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    function verb(n) { return function (v) { return step([n, v]); }; }
+    function step(op) {
+        if (f) throw new TypeError("Generator is already executing.");
+        while (_) try {
+            if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
+            if (y = 0, t) op = [op[0] & 2, t.value];
+            switch (op[0]) {
+                case 0: case 1: t = op; break;
+                case 4: _.label++; return { value: op[1], done: false };
+                case 5: _.label++; y = op[1]; op = [0]; continue;
+                case 7: op = _.ops.pop(); _.trys.pop(); continue;
+                default:
+                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
+                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
+                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
+                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
+                    if (t[2]) _.ops.pop();
+                    _.trys.pop(); continue;
+            }
+            op = body.call(thisArg, _);
+        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
+        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
+    }
+};
+var __await = (this && this.__await) || function (v) { return this instanceof __await ? (this.v = v, this) : new __await(v); }
+var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
+    var g = generator.apply(thisArg, _arguments || []), i, q = [];
+    return i = {}, verb("next"), verb("throw"), verb("return"), i[Symbol.asyncIterator] = function () { return this; }, i;
+    function verb(n) { if (g[n]) i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; }
+    function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
+    function step(r) { r.value instanceof __await ? Promise.resolve(r.value.v).then(fulfill, reject) : settle(q[0][2], r); }
+    function fulfill(value) { resume("next", value); }
+    function reject(value) { resume("throw", value); }
+    function settle(f, v) { if (f(v), q.shift(), q.length) resume(q[0][0], q[0][1]); }
+};
+var __spreadArrays = (this && this.__spreadArrays) || function () {
+    for (var s = 0, i = 0, il = arguments.length; i < il; i++) s += arguments[i].length;
+    for (var r = Array(s), k = 0, i = 0; i < il; i++)
+        for (var a = arguments[i], j = 0, jl = a.length; j < jl; j++, k++)
+            r[k] = a[j];
+    return r;
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+var util_1 = require("util");
+var CallableBalancer = /** @class */ (function () {
+    /**
+     *
+     * @param methods not empty array of functions
+     * @param redisClient
+     */
+    function CallableBalancer(methods, redisClient) {
+        this._STORE_PREFIX = 'balancer';
+        this.INC_VALUE = 1;
+        this._redisClient = redisClient;
+        this._methods = methods;
+        this._storeKey = this.makeStoreKey(methods);
+        // Initialize Redis functions as async await
+        this._functions = {
+            delAsync: util_1.promisify(redisClient.DEL).bind(this._redisClient),
+            zAddAsync: util_1.promisify(redisClient.ZADD).bind(this._redisClient),
+            zRangeAsync: util_1.promisify(redisClient.zrange).bind(this._redisClient),
+            zIncRbyAsync: util_1.promisify(redisClient.zincrby).bind(this._redisClient),
+        };
+    }
+    CallableBalancer.prototype.setMethods = function (methods) {
+        this._methods = methods;
+        this._storeKey = this.makeStoreKey(methods);
+    };
+    CallableBalancer.prototype.increaseMethodRank = function (method, incValue) {
+        if (incValue === void 0) { incValue = this.INC_VALUE; }
+        return __awaiter(this, void 0, void 0, function () {
+            return __generator(this, function (_a) {
+                switch (_a.label) {
+                    case 0: return [4 /*yield*/, this._functions.zIncRbyAsync(this._storeKey, incValue, method.name)];
+                    case 1:
+                        _a.sent();
+                        return [2 /*return*/];
+                }
+            });
+        });
+    };
+    CallableBalancer.prototype.getAsyncIterator = function () {
+        return __asyncGenerator(this, arguments, function getAsyncIterator_1() {
+            var storedMethodNames, _i, storedMethodNames_1, methodName, _a, _b, method;
+            return __generator(this, function (_c) {
+                switch (_c.label) {
+                    case 0: return [4 /*yield*/, __await(this.getRange())];
+                    case 1:
+                        storedMethodNames = _c.sent();
+                        _i = 0, storedMethodNames_1 = storedMethodNames;
+                        _c.label = 2;
+                    case 2:
+                        if (!(_i < storedMethodNames_1.length)) return [3 /*break*/, 9];
+                        methodName = storedMethodNames_1[_i];
+                        _a = 0, _b = this._methods;
+                        _c.label = 3;
+                    case 3:
+                        if (!(_a < _b.length)) return [3 /*break*/, 8];
+                        method = _b[_a];
+                        if (!(method.name === methodName)) return [3 /*break*/, 7];
+                        return [4 /*yield*/, __await(this.increaseMethodRank(method, this.INC_VALUE))];
+                    case 4:
+                        _c.sent();
+                        return [4 /*yield*/, __await(method)];
+                    case 5: return [4 /*yield*/, _c.sent()];
+                    case 6:
+                        _c.sent();
+                        _c.label = 7;
+                    case 7:
+                        _a++;
+                        return [3 /*break*/, 3];
+                    case 8:
+                        _i++;
+                        return [3 /*break*/, 2];
+                    case 9: return [2 /*return*/];
+                }
+            });
+        });
+    };
+    /**
+     * Clear store
+     */
+    CallableBalancer.prototype.resetStore = function () {
+        return __awaiter(this, void 0, void 0, function () {
+            return __generator(this, function (_a) {
+                switch (_a.label) {
+                    case 0: return [4 /*yield*/, this._functions.delAsync(this._storeKey)];
+                    case 1:
+                        _a.sent();
+                        return [2 /*return*/];
+                }
+            });
+        });
+    };
+    CallableBalancer.prototype.getStoreKey = function () {
+        return this._storeKey;
+    };
+    /**
+     * Return redis key to store list of methods with ranks
+     * @param methods
+     * @protected
+     */
+    CallableBalancer.prototype.makeStoreKey = function (methods) {
+        var storeKeyArray = [this._STORE_PREFIX];
+        methods.forEach(function (method) {
+            storeKeyArray.push(method.name);
+        });
+        return storeKeyArray.join('.');
+    };
+    /**
+     * Returns an Array stored in Redis in Rank order
+     * @private
+     */
+    CallableBalancer.prototype.getRange = function () {
+        return __awaiter(this, void 0, void 0, function () {
+            var storedMethodNames, args_1, result_1;
+            var _a;
+            return __generator(this, function (_b) {
+                switch (_b.label) {
+                    case 0: return [4 /*yield*/, this._functions.zRangeAsync(this._storeKey, 0, -1)];
+                    case 1:
+                        storedMethodNames = _b.sent();
+                        if (!(storedMethodNames.length !== this._methods.length)) return [3 /*break*/, 3];
+                        args_1 = [], result_1 = [];
+                        this._methods.forEach(function (method) {
+                            // Default rank is 1
+                            args_1.push("1", method.name);
+                            result_1.push(method.name);
+                        });
+                        return [4 /*yield*/, (_a = this._functions).zAddAsync.apply(_a, __spreadArrays([this._storeKey, 'NX'], args_1))];
+                    case 2:
+                        _b.sent();
+                        return [2 /*return*/, result_1];
+                    case 3: return [2 /*return*/, storedMethodNames];
+                }
+            });
+        });
+    };
+    return CallableBalancer;
+}());
+exports.default = CallableBalancer;