refactor: rename email-server-worker to email-worker

Rename directory from email-server-worker to email-worker for clarity and brevity. Update all references in CLAUDE.md documentation.

email-worker/src/lib/initTools.ts

@@ -0,0 +1,8 @@
+
+/**
+ * Za neinicijaliziranu env varijablu vraća default vrijednost
+ * @param value vrijednost env varijable
+ * @param defaultValue default vrijednost
+ * @returns 
+ */
+export const coalesce = (value:string|undefined, defaultValue:string):string => value===undefined ? defaultValue : (value==="" ? defaultValue : value);

email-worker/src/lib/logger.ts

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+import debug from 'debug';
+
+/**
+ * Logs to console / stdout
+ * @param namespace 
+ * @returns instance of Debug
+ */
+export const createLogger = (namespace:string):debug.Debugger => {
+    const dbg = debug(namespace);
+
+    const rx = /nodemon/gi;
+    
+    if(rx.test(process.env?.npm_lifecycle_script ?? "")) {
+        // When started via nodemon:
+        // forcing the use of console insted of stdout
+        // -> nodemon doesn't work with stdout
+        dbg.log = console.log.bind(console);
+    }
+
+    return(dbg);
+};

email-worker/src/lib/metricsCounters.ts

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+import { Counter, Histogram, register } from 'prom-client';
+import { coalesce } from './initTools';
+
+/** Histogram Buckets */
+const PROMETHEUS_HISTOGRAM_BUCKETS = coalesce(process.env.PROMETHEUS_HISTOGRAM_BUCKETS, "0.1, 0.5, 1, 5, 10");
+
+/** Labela kojom želimo da bude označena metrika prikupljena na ovom web servisu */
+const PROMETHEUS_APP_LABEL = coalesce(process.env.PROMETHEUS_APP_LABEL, 'email-worker');
+
+// na "app" labele ćemo razdvajanje rezultata u Grafani
+register.setDefaultLabels({ app: PROMETHEUS_APP_LABEL });
+
+/**
+ * Broji koliko je ukupno zahtjeva zaprimljeno za obradu
+ */
+ export const totalRequestCounter = new Counter({
+    name: "request_operations_total",
+    help: "ukupan broj zaprimljenih zahtjeva",
+    /** countere razdvajamo po vrsti zahtjeva */
+    labelNames: ['path'],
+});
+
+/**
+ * Broji zahtjeve koji su uspješno obrađeni
+ */
+export const successfulRequestCounter = new Counter({
+    name: "request_operations_ok",
+    help: "broj zahtjeva koji su uspješno obrađeni",
+    /** countere razdvajamo po vrsti zahtjeva */
+    labelNames: ['path'],
+});
+
+/**
+ * Broji zahtjeve kod čije obrade je došlo do greške
+ */
+export const failedRequestCounter = new Counter({
+    name: "request_operations_failed",
+    help: "broj zahtjeva kod čije obrade je došlo do greške",
+    /** countere razdvajamo po vrsti zahtjeva i rezultatu izvođenja */
+    labelNames: ["path", "status"],
+});
+
+/** Histogram mjeri koliko traje obrada pristiglog zahtjeva */
+export const requestDurationHistogram = new Histogram({
+    name: "request_duration_seconds",
+    help: "Trajanje request-a u sekundama",
+    /** countere razdvajamo po vrsti zahtjeva i rezultatu izvođenja */
+    labelNames: ["path", "status"],
+    buckets: PROMETHEUS_HISTOGRAM_BUCKETS?.split(',').map((el) => parseFloat(el))
+});

email-worker/src/lib/serializeError.ts

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+
+
+/**
+ * This function serializes an error object into a string that can be logged
+ * @param ex error object
+ * @returns string
+ * @description SQL Server may generate more than one error for one request so you can access preceding errors with `err.precedingErrors`, while the `ex` itself is a generic error without any useful information
+ */
+export const serializeError = (ex:Error | Error & { precedingErrors?:Error[] }):string => {
+    const { name, message, stack, precedingErrors } = (ex as Error & { precedingErrors?:Error[] });
+
+    // SQL Server may generate more than one error for one request so you can access preceding errors with `ex.precedingErrors`,
+    // while the `ex` itself is a generic error without any useful information
+    if(precedingErrors) {
+        return(serializeError(precedingErrors[0]));
+    }
+
+    return `${name}:${message}`;
+}