Hot deploy Ruby just like PHP: FTP upload file and valid immediately - ruby-on-rails

Is it possible to hot deploy Ruby just like PHP?
Normally I used FTP to upload the PHP file, then it will be available automatically.
Can Ruby hot deploy its file like this?
Your comment welcome.

Are you talking about a ruby on rails application ?
If so, when deploying a rails application in production mode, the all application gets loaded in memory. So changing the files won't affect the running application.
For hot restarting a rails application you will need to use solution such as:
Unicorn
Puma
Passenger
For a first time, Puma is the easiest way.
However if you are looking for a zero-downtime, either Unicorn or Passenger enterprise are what you are looking for.
EDIT
Unicorn
Free
Complex configuration
zero-downtime when hot restarting. when hot-restarting unicorn, it keeps the old threads working until the new ones are fully functionnal. So if the new ones fail to start, nothing happens. The old ones just keep going.
Puma
Free
Simple configuration
hot restart but no zero-downtime. When hot-restarting puma, it shuts down the old threads and starts the new ones. Puma keeps the sockets open, so the client are not disconnected, but are waiting to get a response while the new threads restart. However if the new threads fail to start, Puma can't restart the old ones. So connections are lost and the server is down.
Passenger
Free edition
Free
The configuration is easier than unicorn
hot-restart, but no zero-downtime. Like Puma.
Enterprise edition
$29/mo
The configuration is easier than unicorn
zero-downtime when hot restarting. Like Unicorn.

Related

Rails production server (thin): pages occasionally load slower

I'm running my Rails application through thin on Windows OS.
thin start -e production
Since the number of users grew, now around 10 people using the app simultaneously, there are times when a same page takes a while longer to load.
Are there other configurations that I need to set when running the server on production?
I'm quite sure that it has to do with the server since the slow down happens on pages that normally loads fast.
The Thin webserver is not meant to production environment. Instead of this you should use a different webserver and application server like Nginx/Unicorn, Nginx/Passenger.
I would recommend Passenger to run your rails app as fast as possible in production mode.
The thin webserver is very fast for few requests, but if there are simultaneously requests, thin gets very slow.
The following document describes about how to deploy rails application in windows. I haven't done this personally but, believe the latest versions should allow that. Please check the below link to see how it can be done
http://weblog.rubyonrails.org/2006/5/11/deploying-rails-on-windows-servers/

Setting up multiple rails apps using nginx and Puma

I have a web server serving multiple Rails applications using a combination of nginx and Passenger. This is pretty straightforward, because the Passenger install sets-up pretty much everything you need to connect to nginx.
I found "Rails app with Puma" that seems to explain how to set up nginx and Puma together. How would this configuration need to be modified in order to serve a second Rails application on the same server?
Also, this guide doesn't say anything about restarting the application automatically if there is a system reboot or some other issue. Is there a way to do that? The nginx + Passenger combo seems to do it by default.

nginx doesn't stream file through thin runned rails app

Ive a rails 4 app running which is used for file exchange. Its basicly running very well but when I try to download a file that is bigger then some hundred mb its getting slow. I think this is because nginx doenst stream the file it's first loading the file to the ram and then sends it.
I have sendfile on; in my nginx config and config.action_dispatch.x_sendfile_header set to true in my config/environments/production.conf. Im using thin as a webserver.
Does anyone have an idea about what Im doing wrong?
I don't think thin supports Rails implementation of streaming out of the box.
There was some work done on that front, but afaik it was never merged to master branch.
Instead of thin, our team switched to using puma on our local machines, and we're using passenger on our production server (although in the light of recent article from Engine Yard, we're considering switching our production app server to either unicorn on puma).

OS X: Development & Production Deployment for RoR with Apache and Passenger

My head is about to explode from the mangled mess as a result of the following few days trying to setup a development environment for Rails, Apache and Passenger.
The questions I have are:
Do you NEED passenger for a development environment? Can I just develop with pow.cx instead? - I am 99.99% sure the answer is no (you don't use passenger for development), but I need confirmation since I am deeply confused now.
When I deploy, I only use Passenger for that, correct? I.e. I don't ever touch passenger until I deploy.
Is my development environment correct?
Production deployment is simply moving a rails application under the effects of Passenger coupled with an Apache VHOST?
Background (I suggest you read):
It seems that all the information on the web is concerned about explaining things for people who already know what they are doing, rather than explaining in detail how things work it's just a series of installation steps and that has left me extremely confused on the role of things, and how to setup a development environment and deploy a RoR application correctly - so please bear with this long question.
For the past 3 days I have been trying to setup a development environment on my Macbook Pro that isn't destroyed by Apple's rediculous limits on Apache installations. I installed a custom Apache install (from bitnami using their ruby stack, since I refuse to use Server.app) so that I can run Apache and upgrade things like PHP to 5.5 easily, and that works fine.
I am trying to get into RoR but so far it has been a struggle, and I am about ready to give up.
I understand you need Apache to serve Rails applications so that the server can handle requests concurrently rather than one at a time, and that various interfaces for this exist like Thin or whatever; Passenger was highly recommended.
I installed Passenger via their instructions and did some hackery to compile it for the Bitnami passenger installation, rather than the default Apache on Mac OS X - and it's working. When I start apache and run: passenger-memory-stats I get results expected from the installation guide, so that tells me passenger is running.
However, when I try and deploy a simple hello world Rails application I get a slew of "We're sorry…" or no result at all and just a blank page.
I am fairly sure my development environment is correct, everything works except this last bit. I can picture development taking place on a pow.cx server, and once deployment is ready you simply copy the Rails application and configure Apache's VHOST to point to your ready-to-deploy app while Passenger handles the rest, is that correct?
I am using PostgresSQL via the Postgress.app, the server works fine and I can connect to it.
I have gem 'pg' in my Gemfile.
I have already read, and tried every conceivable solution from the following SO questions, but I either get no result or empty logs which is… infuriating to say the least:
We're sorry, but something went wrong. - with Rails, Apache, Passenger
Ruby on Rails: How can i edit database.yml for postgresql?
How do I set up the database.yml file in Rails?
https://www.ruby-forum.com/topic/187128
So with all that said, I am trying to deploy this hello world application (which works on a standard rails server) using the following:
INVOKING APPLICATION VIA:
http://dmarket.local:8081/
VHOSTS:
<VirtualHost *:8081>
PassengerEnabled on
RailsEnv production
ErrorLog /Applications/rubystack/apache2/htdocs/helloworld/project_error.log
CustomLog /Applications/rubystack/apache2/htdocs/helloworld/project_error.log combined
ServerName dmarket.local:8081
ServerAlias www.dmarket.local:8081
DocumentRoot "/Applications/rubystack/apache2/htdocs/helloworld/public"
PassengerPreStart http://dmarket.local:8081
<Directory "/Applications/rubystack/apache2/htdocs/helloworld/public">
Allow from all
Options -MultiViews
</Directory>
</VirtualHost>
HOSTS FILE:
127.0.0.1 dmarket.local
127.0.0.1 www.dmarket.local
DATABASE.YML (same for development, test, and production):
adapter: postgresql
encoding: unicode
host: 127.0.0.1
port: 5432
database: tsujp
pool: 5
username: tsujp
password:
A summary of answers to your questions
You don't need Passenger in development. You can develop with Pow, and deploy with Passenger.
But you can use Passenger in development if you want to. It is a good idea to use Passenger in development because that way your development environment will match your production environment more, which reduces the risk of running into unexpected problems when you deploy.
Using Passenger in development is very easy. Use it's Standalone mode, and run passenger start instead of rails server.
Pow is strictly a development-only server. The authors recommend against using it in production.
When you deploy, you touch Passenger. You don't have to touch Passenger until deployment time, but you may.
Production deployment is indeed moving an application under the effects of Passenger, and setting up a virtual host. You will of course also need to install gems (bundle install) setup the database (editing config/database.yml), running database migrations (bundle exec rake db:migrate), etc.
I've also posted updates on the posts that you linked to, in order to make life easier for people who happened to have found those posts via search.
Apache vs Nginx
You will find a lot of people recommending Nginx (e.g. Sergio just did). I second that recommendation. Nginx is faster than Apache, handles slow clients better and is generally easier to use.
Passenger works great with Nginx. It has an Nginx integration mode that is just as easy as the Apache mode. Sergio suggested Nginx + Unicorn or Nginx + Puma, but Nginx + Passenger (which replaces Unicorn/Puma) is much easier to setup, performs great, uses less memory, works better and has more features. Nginx + Unicorn requires a lot of configuration, process management using init scripts, etc.
But this is just a recommendation. You don't have to use Nginx. Sticking with Apache + Passenger is fine. Apache works well enough for most people.
Regarding your Passenger problems
However, when I try and deploy a simple hello world Rails application I get a slew of "We're sorry…" or no result at all and just a blank page.
Whenever you get an unexpected error, the first thing you should do is to read the log files. There are two log files that are important to you:
The web server error log, typically /var/log/apache/error.log. This log file contains:
Phusion Passenger error messages.
Everything that the Rails application writes to STDERR. This typically consists of errors that Rails encounters during startup (but not errors that it encounters when it's handling requests).
The Rails development log (or production log, in case you're running in production), log/development.log (or log/production.log). When an error occurs during request handling, it is typically logged here. This file does not contain errors that Rails encounters during startup.
The error messages will often tell you what the problem is and how to solve it.
This tip can also be found in the Phusion Passenger manual, Troubleshooting section.
Capistrano
Sergio recommended Capistrano. I second that recommendation. You should remember that Capistrano complements Passenger; it does not replace Passenger. Capistrano is a tool for automating tasks. Do you currently create a tarball of your app and scp it to your server, and extract it there? Well, Capistrano automates this sort of thing for you.
For more information about how all the different pieces of the stack fit together (Apache, Passenger, Capistrano, HAProxy, Chef, etc), check out the section "The big picture" on the Phusion Passenger documentation page.
Recommendation summary
Use passenger start in development. It is by far the easiest to get started with. You don't have to edit any configuration files, it works immediately.
Use Phusion Passenger for Nginx in production.
You don't need Passenger in development. In fact, in development mode you don't need even apache. You can use built-in Webrick server ($ rails server) to run your app. And yes. Pow is a good tool, I use it all the time.
In production there are also multiple options. One of them is Apache+Passenger, yes. But you need to put Nginx in front of those (because Apache doesn't handle slow clients very well). If you have nginx, then you can replace apache+passenger with something else. For a long time I've been using Unicorn (ruby web server from github). Now my current favourite is Puma. It uses less resources than unicorn, but has more requirements to your code (it better be thread-safe, because puma is a threaded server).
Now, to the development-production discrepancy: it is known that development should resemble production as closely as possible, because it minimizes risks when deploying. So, my suggestion is: use unicorn everywhere (both development and production). Only on production put nginx in front of it.
Also,
for actually performing deploys, look into Capistrano. It became industry standard for deploying rails apps (but it can also deploy PHP, static files and what have you).

Adding rails apps to nginx avoiding high load time on 1st access

I'm trying to automate the deployment of multiple rails applications in one server with nginx + passenger. I have one server block for each application...
My problem is that everytime that I insert a new rails application to nginx I need to reload the config file and every rails application is reloaded. The reload with passenger takes a while because passenger loads all rails app to memory in first access...
I want to avoid this load time but i really don't know how.
Is possible to load only 1 server with nginx? Or should I have 1 nginx instance for each rails app (don't know if this is possible)?
Should I use other ruby app server? Probably thin would be faster on 1st load...
Thanks for your time.
Unicorn sounds like it might be a better fit for your deployment scenario. You can keep nginx up front, but instead of loading rails itself, it will just connect to a unicorn Unix socket. Further, you can reload your application with new code gracefully, while nginx stays up and Unicorn swaps out backend quietly.

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