dotenv example and console.log overwrite

b3-dev/node/.gitignore

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+log*.txt
+log.txt
+*.log
+.env
+.env.*
+**/package-lock.json

b3-dev/node/session3/config.env/package.json

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+{
+  "dependencies": {
+    "dotenv": "^16.0.1"
+  }
+}

b3-dev/node/session3/config.env/server.js

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+const http = require('http')
+const url   = require('url');
+// fs = filesystem
+const fs = require('fs');
+// utils 
+var util = require('util');
+
+// si on veut conserver les logs d'un instance à l'autre on "append"
+// var logfile = fs.createWriteStream(process.cwd() + '/server.log', { flags: 'a' });
+// si on veut reste on "write"
+var logfile = fs.createWriteStream(process.cwd() + '/server.log', { flags: 'w' });
+console.log = function () {
+    logfile.write(util.format.apply(null, arguments) + '\n');
+    process.stdout.write(util.format.apply(null, arguments) + '\n');
+}
+
+const server = http.createServer(function (request, response) {
+  parsedUrl = url.parse(request.url, false);
+  json_response(200,{status : "active"},response);
+});
+
+//cwd = current working dir
+var default_env_file = process.cwd()+'/.env';
+console.log(default_env_file);
+var local_env_file = process.cwd()+'/.env.'+process.env['NODE_ENV'];
+console.log(local_env_file);
+// j'utilise fs pour savoir si j'a le droit de lire mon fichier env local
+fs.access(local_env_file, fs.constants.R_OK, (err) => {
+    //si je n'est pas le droit
+    if(err) {
+        console.log('loading  : '+ default_env_file);
+        require('dotenv').config({ path: default_env_file });
+    }
+    //si ok charger l'environnement
+    else {
+        console.log('loading  : '+ local_env_file);
+        require('dotenv').config({ path: local_env_file });
+    }
+    console.log('server port ? '+ process.env.SERVER_PORT);
+    console.log('DB name ? '+ process.env.DB_NAME);
+    server.listen(process.env.SERVER_PORT || 8080);
+    datetime=new Date();
+    console.log('server started at :'+datetime.toLocaleString('fr-FR', {hour12: false}));
+    console.log('server started at :'+datetime.toLocaleString('en-EN'),'server started at :'+datetime);
+});
+
+//usefull functions 
+function json_response(code, object, response) {
+    response.statusCode = 200;
+    response.setHeader('content-type', 'Application/json');
+    response.end(JSON.stringify(object));
+}