I am developing on an open source rails application and as a rails 3 project, it includes a Gemfile. The application is also dependent on a database adapter for active record. I can specify a specific adapter (like gem 'sqlite3') within the Gemfile but this is not what I want to do. I advertise the app as beeing compatible with all the adapters active record is compatible with. Is there any way to specify that the app depends on a single database adapter (out of a selection) but that one is sufficient? Something like
any_of do
gem 'sqlite'
gem 'mysql'
etc.
end
Thanks for any help or suggestions how to approach the problem differently.
I just recently installed something that generated an error, until I realized how they handled this.
group :postgresql do
gem 'pg'
end
group :mysql do
gem 'mysql2'
end
and then when you run bundler:
bundle install --without postgresql
Related
I have encountered this in my Gemfile while learning ruby on rails:
group :development, :test do
gem 'sqlite3', '~> 1.4'
group :production do
gem 'pg'
So far I have understood that sqlite3 is not a production-ready database as it does not support multiple users to write the database at the same time. In this case, why don't we just use postgres in development?
There is no reason you can’t. It just requires additional configuration. It’s actually best practice to use the same database in development and production. SQLite is included for ease of use, and would probably fine for a lot of applications. But SQLite cannot be used on Heroku and some other hosting platforms. So you are better off setting up Postgres on your local machine for development in my opinion.
I am trying to deploy a Rails project on Heroku. My Rails application uses mysql2.
I have tried using the taps gem but its not working. I get the following error when I run the command taps server mysql://root#localhost/heroku_ex tempuser tempass:
Failed to connect to database: Sequel::AdapterNotFound -> LoadError: cannot load such file -- mysql
Is there any way to deploy my application on Heroku? I would prefer to only use free add-ons if possible.
There are a few moving parts here.
First of all, Heroku doesn't support MySQL by default. If you want to use MySQL instead of PostgreSQL you will have to provision an add-on that provides it. There are currently at least two add-ons that provide MySQL or MariaDB¹ support with a free tier².
Next, Heroku doesn't run database servers on localhost. How can you handle different database configurations between your development machine and your Heroku server?
One strategy that is endorsed by Heroku is to store configuration in the environment. Following this model lets you alter your application's configuration by modifying environment variables instead of editing files. Luckily, Rails appears to override config/database.yml with configuration from the DATABASE_URL variable by default, so this approach should be a good fit.
Very often database add-ons will automatically set an environment variable for you. For example, the JawsDB Maria add-on sets JAWSDB_MARIA_URL when it is provisioned. This isn't the variable that Rails looks for, so you'll either have to tell Rails to look for JAWSDB_MARIA_URL instead of DATABASE_URL or manually set DATABASE_URL to contain the same URL that JawsDB provides in JAWSDB_MARIA_URL.
¹MariaDB is a fork of MySQL that aims to be fully-compatible.
²Note that the free tier may be quite limited, e.g. by only providing 5MB of storage. You may have to upgrade to a paid database tier as you continue to develop your application.
I have solved this by adding the pg gem in production and mysql2 in development environment.
group :development, :test do
gem 'mysql2'
end
group :production do
gem 'listen', '~> 3.0.5'
gem 'pg'
# Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
gem 'spring'
gem 'spring-watcher-listen', '~> 2.0.0'
end
I have just scaffolded a Rails 5 app but the gemfile does not have any Mongodb gem or even the database.yml file does not even have any mongoDB. But when i run 'rails s' command it always outputs an error
Could not load 'active_record/connection_adapters/mongodb_adapter'. Make sure that the adapter in config/database.yml is valid. If you use an adapter other than 'mysql2', 'postgresql' or 'sqlite3' add the necessary adapter gem to the Gemfile.
Not able to understand how to even debug this as even google search does not point towards any meaningful solution
Any pointers would be greatly appreciated. Thank you in advance
I have about 3 apps on a Windows Server 2012 and all of them are different versions of rails. So far, I can run locally the app with the latest version of rails, but not the other two, which were deployed from Heroku. I wanted to make changes locally before I push them to Heroku but no luck. Is there any reference to that or is this even possible? thanks a lot!
Your problem is that you are trying to use sqlite with Heroku. Heroku requires using 'postgres' as the database
change the gemfile to the following
group :development do
gem 'sqlite3'
end
group :production do
gem 'pg'
end
And then change your database.yml file to this
adapter: postgresql
I will try my best to explain my issue.
I have a SQLite3 database file of about 50,000 records that I compiled and use in my app. This database is read only and is only used to query and pull data from. I created a model for it in rails and it looks like this.
class Locations < ActiveRecord::Base
establish_connection(
:adapter => 'sqlite3',
:database => 'db/locs.sqlite3'
)
set_table_name "Locations"
end
Everything works great on the development end, but fails when I deploy to Heroku. I'm assuming the issue is that Heroku runs on Postrgres but I need this database to be separate from the main production database and I don't need something fancy. All I need is for the app to query some records from this file.
Is there a solution out there? Thanks
Allowing SQLite3 read only can be enabled by following the steps from this git repo.
https://github.com/yotsumoto/heroku-buildpack-ruby-with-sqlite3
After running:
$ heroku config:set BUILDPACK_URL=https://github.com/yotsumoto/heroku-buildpack-ruby-with-sqlite3
I was able to git push heroku master with gem 'sqlite3' still in the Gemfile.
I'm really not understanding your question but I'm assuming you want to use sq in dev & testing but want to use postrgres in product, correct? If so, the code below should help. Switching from sqlite to pg is rather seamless so you shouldn't have a problem doing so.
group :development, :test do
gem 'sqlite3'
end
group :production do
gem 'pg', '0.12.2'
end
The simple answer to your question is it's not possible to do what you're trying to do. Heroku don't have necessary prerequisites installed to even let you install the sqlite gem.