Improve app

images-ubi/apps/greetings/.containerignore

@@ -1,4 +1,5 @@
 .git
+.npm
 .containerignore
 node_modules
 Containerfile

images-ubi/apps/greetings/Containerfile

@@ -1,19 +1,18 @@
-FROM registry.access.redhat.com/ubi9/nodejs-18-minimal:1-51
+FROM registry.access.redhat.com/ubi9/nodejs-18-minimal
 
 # Use root user to listen on port 80
 USER root
 
-
 # Application listens on this port
 ENV PORT=80
 EXPOSE ${PORT}
 
-# Install application dependencies
-COPY package*.json ./
-RUN npm ci --omit=dev
+# Add application sources
+ADD . $HOME
 
-# Copy the application source code
-COPY . .
+# Install dependencies.
+# Clean up cache when finished.
+RUN npm ci --omit=dev && rm -rf .npm
 
 # Run the server
 CMD npm start

images-ubi/apps/greetings/LocalizationService.js

@@ -0,0 +1,93 @@
+/**
+ * Simulate an external localization service
+ */
+const fs = require("fs").promises;
+
+
+const TRANSLATIONS = {
+    "greeting": {
+        "de-de": "Guten tag",
+        "en-us": "Hi!",
+        "es-es": "Hola, ¿que tal?",
+        "fr-be": "Bonjour, ça va bien?",
+        "it-it": "Ciao, come stai?",
+        "ca": "Bon dia",
+        "pt-pt": "Olá, tudo bem?",
+        "hi": "Namaste",
+        "nl-nl": "Hallo",
+        "no-no": "Hei!",
+        "el": "Yassou",
+        "cs": "Ahoj!",
+        "pl": "Cześć!",
+        "sv-se": "Hej",
+        "ru": "Privet",
+        "tr": "Selam"
+    }
+}
+
+
+async function translate(key, locale) {
+    let translated;
+
+    try {
+        translated = await readFromFileCache(key, locale);
+        console.info(`${locale} '${key}' found in cache`);
+    } catch (error) {
+        // Only handle the not found case (ENOENT)
+        if (error.code !== "ENOENT") {
+            throw err;
+        }
+
+        translated = await getTranslationFromExternalService(key, locale);
+
+        await writeToFileCache(key, locale, translated);
+    }
+
+    return translated;
+}
+
+
+async function readFromFileCache(key, locale) {
+    const buffer = await fs.readFile(generateCacheFilename(key, locale));
+    return buffer.toString();
+}
+
+
+function writeToFileCache(key, locale, value) {
+    return fs.writeFile(generateCacheFilename(key, locale), value);
+}
+
+
+function generateCacheFilename(key, locale) {
+    return `/var/cache/translation_${key}_${locale}`;
+}
+
+
+function getTranslationFromExternalService(key, locale) {
+    // Simulate a network delay of 500 millis
+    return new Promise((resolve) => {
+        setTimeout(() => {
+            const translated = TRANSLATIONS[key][locale];
+            resolve(translated);
+        }, 500);
+    });
+}
+
+
+function getSupportedLocaleIDs() {
+    return Object.keys(TRANSLATIONS.greeting);
+}
+
+
+function getRandomLocaleID() {
+    const locales = getSupportedLocaleIDs();
+    const localeIndex = Math.floor(Math.random() * locales.length);
+    return locales[localeIndex];
+}
+
+
+module.exports = {
+    translate,
+    getRandomLocaleID,
+    getSupportedLocaleIDs
+}

images-ubi/apps/greetings/index.js

@@ -1,47 +1,39 @@
 const os = require("os");
 const http = require("http");
+const localization = require("./LocalizationService");
 
 
 const hostname = "0.0.0.0";
 const userInfo = os.userInfo();
-const port = process.env.PORT || 80;
-const greetings = [
-    "Guten tag",
-    "Hi!",
-    "Hello, how are you?",
-    "Hola, ¿que tal?",
-    "Bonjour, ça va bien?",
-    "Ciao, come stai?",
-    "Bon dia",
-    "Salve",
-    "Olá, tudo bem?",
-    "Namaste",
-    "Hallo",
-    "Hei!",
-    "Yassou",
-    "Ahoj!",
-    "Cześć!",
-    "Hej",
-    "Hey",
-    "Privet",
-    "Annyeong",
-    "Selam"
-];
-
-
-console.log(`User ID: ${userInfo.uid}, group ID: ${userInfo.gid}`);
-
-
-http
-    .createServer(handleRequest)
-    .listen(port, hostname, () => {
-        console.log(`Server running as at http://${hostname}:${port}/`);
-    });
-
-
-function handleRequest(req, res)  {
-    const randomGreetingIndex = Math.floor(Math.random() * greetings.length);
-    const message = greetings[randomGreetingIndex];
+const port = process.env.PORT || 8080;
+
+
+main();
+
+
+async function main() {
+    console.info(`Running with user ID: ${userInfo.uid}, group ID: ${userInfo.gid}`);
+
+    console.info("Verifying file cache...");
+    await localization
+        .translate("greeting", "en-us")
+        .catch((error) => {
+            console.error("File cache does not work due to", error);
+        });
+
+    console.info("Starting server...");
+    http
+        .createServer(handleRequest)
+        .listen(port, hostname, () => {
+            console.log(`Server listening at http://${hostname}:${port}/`);
+        });
+}
+
+
+async function handleRequest(req, res) {
+    // Return a greeting message in a random language
+    const locale = localization.getRandomLocaleID();
+    const message = await localization.translate("greeting", locale);
 
     res.statusCode = 200;
     res.setHeader("Content-Type", "application/json");