How to set React to production mode when running behind a python webserver

I need to run React in production mode, which presumably entails defining the following somewhere in the enviornment:

process.env.NODE_ENV = 'production';

The issue is that I'm running this behind Tornado (a python web-server), not Node.js. I also use Supervisord to manage the tornado instances, so it's not abundantly clear how to set this in the running environment.

I do however use Gulp to build my jsx files to javascript.

Is it possible to somehow set this inside Gulp? And if so, how do I check that React is running in production mode?

Here is my Gulpfile.js:

'use strict';

var gulp = require('gulp'),
        babelify = require('babelify'),
        browserify = require('browserify'),
        browserSync = require('browser-sync'),
        source = require('vinyl-source-stream'),
        uglify = require('gulp-uglify'),
        buffer = require('vinyl-buffer');

var vendors = [
    'react',
    'react-bootstrap',
    'jquery',
];

gulp.task('vendors', function () {
        var stream = browserify({
                        debug: false,
                        require: vendors
                });

        stream.bundle()
                    .pipe(source('vendors.min.js'))
                    .pipe(buffer())
                    .pipe(uglify())
                    .pipe(gulp.dest('build/js'));

        return stream;
});

gulp.task('app', function () {
        var stream = browserify({
                        entries: ['./app/app.jsx'],
                        transform: [babelify],
                        debug: false,
                        extensions: ['.jsx'],
                        fullPaths: false
                });

        vendors.forEach(function(vendor) {
                stream.external(vendor);
        });

        return stream.bundle()
                                 .pipe(source('build.min.js'))
                                 .pipe(buffer())
                                 .pipe(uglify())
                                 .pipe(gulp.dest('build/js'));

});

gulp.task('watch', [], function () {
    // gulp.watch(['./app/**/*.jsx'], ['app', browserSync.reload]);
    gulp.watch(['./app/**/*.jsx'], ['app']);
});

gulp.task('browsersync',['vendors','app'], function () {
        browserSync({
            server: {
                baseDir: './',
            },
            notify: false,
            browser: ["google chrome"]
    });
});

gulp.task('default',['browsersync','watch'], function() {});

via Chebli Mohamed