[RAILS] Find out about environment variables (memo)

I'm using this for some reason Examine deeply so that it can be properly verbalized

What are environment variables?

Environment variables are ** external service passwords **, ** API private keys **, etc. To prevent leakage of confidential information that I do not want to give to Github A mechanism that saves in the OS such as a server and passes it to the application → If you give it to Github as it is, an external service will be used Be careful because I have seen articles such as a large amount of billing ...

Variables used when the OS is running Required when executing a program, etc.

Setting method

What to do this time How to use the gem "** dotenv-rails **" Normally a command is needed to load .env, It seems that it will be automatically loaded by introducing a gem called "dotenv-rails"

There seems to be another way to describe it in "**. Bash_profile **"

Try setting using "Doten v-rails"

Install Gem

First, install Gem

Gem.file

gem 'dotenv-rails'

promise

bundle install

Create ".env file"

Create a file called ".env" in the root directory

I am creating with sample_app

~/environment/rails/sample_app
❯ pwd

/Users/username/environment/rails/sample_app
❯ touch .env

~/environment/rails/sample_app
❯ ls
Gemfile      Rakefile     config       lib          public       tmp
Gemfile.lock app          config.ru    log          storage      vendor
README.md    bin          db           package.json test

~/environment/rails/sample_app
❯ ls -A
.env          .ruby-version Rakefile      config.ru     package.json  tmp
.git          Gemfile       app           db            public        vendor
.gitignore    Gemfile.lock  bin           lib           storage
.history      README.md     config        log           test

→ I haven't even created a file and used the ls command! Don't rush You can see it by adding "-A" as an option.

Try setting environment variables

Describe the environment variables in the created .env file. Please edit with vim

.env

#Describe the key and password you want to use
KEY='*******'
SECRET_KEY='*******'
```

#### Edit gitignore
 To prevent unauthorized use of the information defined in the ".env file"
 ** Need to be removed from Git control **
 Therefore, set .gitignore


#### **`gitignore`**
```python

#Add the following
.env
```
 Now you don't have to worry about giving it to Git

##### If you put it under the control of Git
 If you have already pushed to git, use the following command
 You can remove ".env file" from git management

```
git rm --cached .env
```

#### Call environment variables

 Calling is the same as .bash_profile.


#### **`sample.rb`**
```rb

#Calling the set environment variable
ENV['KEY']
ENV['SECRET_KEY']
```

 You can also check with "** rails c **"

```rb
irb(main):002:0> ENV['KEY']
=> '*******'
```

## Reference article
https://railsguides.jp/configuring.html
https://wa3.i-3-i.info/word11027.html
https://qiita.com/yuichir43705457/items/7cfcae6546876086b849
http://e-words.jp/w/%E7%92%B0%E5%A2%83%E5%A4%89%E6%95%B0.html
https://qiita.com/hayatokunn/items/d8a9e9deec33e9022b4f
https://qiita.com/ryosuketter/items/ceb592dc6b23a20e51b5