How to configure Rails app for deployment to Tomcat - ruby-on-rails

I have a Rails app that I package as a war file for deploying to Tomcat using Warbler. And it works, but the problem is I don't know how to configure the runtime properties like secret_key_base. I use the standard setup of using secrets.yml, with production variables coming from environment variables. But I don't know how to set the variables while still keeping them out of source control.
Ideally I'd still like to be able to deploy the war file automatically, by just dropping it into the webapps/ directory, but I suppose I could edit the server config file? Or is there a better way of handling this?

either do it the same way as you would in a Rails server ... let it read from ENV (of course you will need to make sure Tomcat has the environment variable set).
alternatively you can set it in a web.xml if you're packaging and than do a $servlet_context.getAttribute('foo') in secrets.yml ... or read it from a file location that only the server's tomcat username can access etc.
sky is the limit here - you basically need to decide what fits your deployments the best.

Related

Rails config/local_env.yml vs .env vs bashrc environment variables

I was reading from this article that you can create a config/local_env.yml with environment variables and then use config/application.rb to read it to replace/take priority before the environment variables that you export in your .bashrc. What then is the .env used for then? Does it serve the same purpose as the config/local_env.yml?
All of these methods are used to feed environment variables to your rails application. So, from an app's point of view, it serves the same purpose whether you export it from .env or .bashrc or config/local_env.yml files.
The differences in these methods are really a matter of personal choice among the team members involved in maintaining the app's development and deployment environments. However, here are few things to consider while opting for either of these choices.
.bashrc - Use this if you manually configure deployment servers and really comfortable with linux/unix command line system administration. This configuration file is specific to bash shell (Bourne Again Shell). You need to configure different file if your server uses different shell (for example: .zshrc if it uses Z Shell)
.env - Use this if you want to keep your app centric environment variables within the app itself while maintaining different variations of environment variables for different runtime environments of your rails app. For example: .env.development and .env.test files with specific values of the environment variables for your development and test environments respectively. This gives you more control of your app's environment variables and do not have to rely on the platform (terminal shell) you want to deploy your app.
config/local_env.yml - This is similar to .env approach, which is provided out of the box by rails gem that allows you to configure environment variables for your app in yml format. This method also keeps your app's configuration within the app irrespective of the shell you are using to run your app.
In addition to the previous answer, another downside of using .bashrc is that it is specific to only one user, so if you're e.g. starting your app server as a systemd service then I believe it won't see your variables.
Meanwhile, .env's Github readme says that it is not the most recommended thing to use outside of the development environment, although it is OK for that purpose.
Another two options to consider are:
Rails secrets. The benefit of this approach is that you get to commit it to git since it's encrypted, so when working in a team you will all have access to the same file. The downside is that it is coupled to the RAILS_ENV variable, so you can't use it to set that e.g. to production on your production app (but you can manually pass it every time it's invoked). Another downside is that if you have a staging environment, then apparently Heroku discourages using RAILS_ENV=staging, which you sometimes really need, so if you need it then you can either do it anyway, or you'll need to set the differing variables via a different mechanism - for example my app has a variable which points to the URL of another part of my app, this URL needs to point to its staging variant on staging, and to its production variant on production, so it needs to differ between my production and staging environment.
Using an /etc/environment file - note that systemd services don't have access to it by default so you'd have to add the line EnvironmentFile=/etc/environment. Also if you're running a shell script from a non-login shell (which happens sometimes), they it won't load them either, but the solution is to just include in your script this: set -a; source /etc/environment; set +a. You should be careful not to commit this to git. If you're working in a team and you need to manage this file then it gets a little complicated since it's not committed to git, but maybe there's a way to have it encrypted. (systemd services note: you might optionally use LoadCredential= for sensitive variables such as private keys, so that other processes won't have access to them; if you do this then you can also commit to git /etc/environment which should now contain non-sensitive variables only).
In my opinion both of those are valid and it's fine to pick whatever is easier to do in your app.

Pheonix Framework Environment Variables

I am just learning Phoenix and Elixir I am confused, what is the best way to handle environment variables for multiple machines and environments? I keep running into different approaches, from using System.get_env, .env files and mentions of Mix env's. I also keep reading about problems compiling env variables at deployment.
Does anyone have an explanation of how Mix variables, system environment variables and possible .env files or .secret files should be used for local development, stage and production servers?
I have been working mostly in Rails and Python recently so that maybe a helpful contextual piece.
Thanks for the help,
Cory
I personally stick with what Phoenix is giving you by default, e.g. using config files for different environments. Since config files are meant for application configuration, e.g. configuring database adapters, they are checked into source control. By default, these are controlled by the MIX_ENV environment variable. If you look at the bottom of your main config/config.exs file, you will notice this:
import_config "#{Mix.env}.exs"
From what I understand from the documentation, Mix.env is just a shorthand for getting the MIX_ENV value.
Phoenix comes with config files for "develop", "prod" and "test" (all in the config directory) which you can modify for your own use. You can also easily add more configurations — if you want to have a "staging"-specific configuration, for example, just set MIX_ENV=staging on the relevant server, and create config/staging.exs.
For sensitive information, like API keys, environment variables are better, since they're not checked into source control and can be easily changed. You can access those env variables from within your config files or from anywhere within your application.
Hope that helps!

Load environment variables in rails app without restarting server

How can I make my rails app aware of the new environment variables after I have edited my /etc/environment file on my remote EC2 instance?
I frequently add new (minor) things in my secrets.yml but I don't want to restart my server for it, nor do I want to use an existing secret.
In linux every process inherits envvars from its parent process and the values are passed by value, not by reference. Also, they don't behave like closures. So, child process (your rails/ruby app process) will not get any new environment variables of its parent (the shell process where you started your rails/ruby app).
That's why it is not possible. However, you can use gems like dotenv and figaro to watch some file with your environment variables and reload them when they are changed.
You should be able to add a line to your config/spring.rb:
Spring.watch "config/secrets.yml"
This will allow Spring to detect when changes have occurred in your secrets.yml file.
However, if you're actually asking about how to make your app aware that you've changed environment variables in a file, then it's not possible. Config values may be detected in files, but environment variables are detected in the shell environment. You have to load those into your shell for them to take any effect, and this would require stopping your server, sourcing the new changes into the environment, and starting the server again.
Understanding the difference between a config value in a file (.yml, .xml, .ini, etc) versus an environment variable in a shell script is important, because how it's applied and made usable is entirely different.

How to Tell Engine Yard to Not Delete a File in the .gitignore

To give you some context, I'm trying to use Figaro to safely add in environment variables without having to worry about security risks. The problem is is that I can't seem to get Engine Yard to play nice with production.
I went and did a touch application.yml and then vim application.yml, i, and then command+v to insert that api keys and what not. I know the ENV['VARIABLES'] work because of development and all my rspec and cucumber tests (which utilize the APIs), passed.
When I've got everything ready, I add within the .gitignore:
# Ignore application configuration
/config/application.yml
Afterwards, I deploy the site. I open it up and data isn't going to the APIs anymore. OK...
cd into config and discover application.yml isn't there anymore. Paste it back in... Redeploy the site since now it understands it has to ignore that file and I'm not seeing changes on production. Check back... and its gone again!
Stumped on what's going on.
Simply putting a file into your deployed application's filesystem will not work because you get a clean environment each time you deploy. EngineYard cannot know that you want that particular file copied to that particular location without a little bit of extra work.
Their official recommendation is to put your YAML configuration files in /data/<app>/shared/config and symlink them to /data/<app>/current/config each time you deploy using deploy hooks.

Using different settings locally versus remotely in files such as application.yml

In my app I have some code that changes when running locally versus in development on the remote server, such as app_domain in application.yml, etc. Besides having to manually change them each time I run locally versus deploy to remote machine, is there a better way of managing this?
EDIT - for yml
It depends a bit on how you are loading the application.yml but generally when you load yml files ruby parses it all into a hash for you. Thus you can set something up like the database.yml and structure all the yml under your different environments:
development:
domain: localhost
production:
domain: mydomain.com
test:
domain: foo
and then when you load your yml file you want to grab the settings for the specific environment you are in, like this:
MY_CONFIGS = YAML.load_file("[path to my yaml file]/application.yml")[RAILS_ENV]
I like Matthew's answer unless you have some secrets in those files (passwords).
If you have passwords you don't want in source, what I tell my UrbanDeploy customers when they have this type of scenario is to use a script (or we have a built-in script) that effectively does a token replace based on environment. Where the replacements are coming from the deployment system, or a magic file somewhere on the deployment target.
Either way, treat an environment as a first order thing that has data about it that needs to be managed.
Using kwateeSDCM you can customize any file at deployment time on a server by server basis. This way you only need one templatized application.xml and parametrize it depending on the target server.

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