Merge pull request #37 from CS3219-AY2425S1/add-generate-combi-util

Add queue name generation functions

Author: yuxuanleong

Backend/MatchingService/rabbitmq/setup.js

@@ -1,20 +1,16 @@
 const amqp = require("amqplib");
+const generator = require("../utils/generateQueues");
 
 const matching_exchange_name = "matching_exchange";
 const dead_letter_exchange_name = "dead_letter_exchange";
 const dead_letter_queue_name = "dead_letter_queue";
 const cancel_queue_name = "cancel_queue";
-const queueNames = [
-    'easy.python',
-    'easy.java',
-    'easy.cplusplus',
-    'medium.python',
-    'medium.java',
-    'medium.cplusplus',
-    'hard.python',
-    'hard.java',
-    'hard.cplusplus',
-];
+const difficulties = ["easy", "medium", "hard"];
+const languages = ["python", "java", "cplusplus"];
+
+const queueNames = generator.generateQueueNames(
+    generator.generateCombinations(difficulties, languages)
+);
 
 async function setupRabbitMQ() {
     try {

Backend/MatchingService/utils/generateQueues.js

@@ -0,0 +1,38 @@
+// Used to generate all possible combinations of criteria for matching
+/*
+  Order matters:
+  Example:
+    - First criteria is the difficulty
+    - Second criteria is the language
+    - Combinations are [easy, python], ... , [hard, cplusplus]
+    - Queue names are easy.python, ... , hard.cplusplus
+  If you switch the order of the criteria, the combinations will be reversed!
+  Example:
+    - Combinations become [python, easy], ... , [cplusplus, hard]
+    - Queue names become python.easy, ... , cplusplus.hard
+
+  Functions can be used with other criteria like difficulty, topic, etc.
+  These functions can be chained multiple times to generate routing criteria longer than 2
+ */
+
+function generateCombinations(criteria1, criteria2) {
+  const combinations = [];
+  for (let i = 0; i < criteria1.length; i++) {
+    for (let j = 0; j < criteria2.length; j++) {
+      combinations.push([criteria1[i], criteria2[j]]);
+    }
+  }
+  return combinations;
+}
+
+// output string is based on order of fields in the combinations array
+function generateQueueNames(combinations) {
+  const queueNames = [];
+  for (const combination of combinations) {
+    const queueName = `${combination[0]}.${combination[1]}`;
+    queueNames.push(queueName);
+  }
+  return queueNames;
+}
+
+module.exports = { generateCombinations, generateQueueNames };