# Use environment variables from .env file in a Swift Package

You can use Environment variables to pass secret information to a process at runtime instead of hardcoding that information during build time.

Multiple environment variables can be stored in a `.env` file but should not be committed to your repository.

In my example I want to pass `MY_API_KEY` variable with value `12345` to my Swift Package.

I will use [ProcessInfo.processInfo.environment](https://developer.apple.com/documentation/foundation/processinfo/1417911-environment) to access the value in my Swift Package .

```Swift
public var myApiKey: String? {
    ProcessInfo.processInfo.environment["MY_API_KEY"]
}
```

But how to pass the environment value in the first place?

# Pass a single environment variable

A test case with the following assertion ...

```Swift
XCTAssertEqual(MySecrets().myApiKey, "12345")
```

... will fail because of the missing environment variable.

Once I set the individual environment variable and then run the tests ...

```Shell
export MY_API_KEY='12345'
swift test
```

... the test will pass successfully.

# Pass all environment variables from a `.env` file

I created the following `.env` file on my local machine.

```Text
MY_API_KEY=12345
```

I can pass all environment variables with the following utility script `setenv.sh`

```Bash
#!/usr/bin/env bash

# Credit: https://zwbetz.com/set-environment-variables-in-your-bash-shell-from-a-env-file/

# Show env vars
grep -v '^#' .env

# Export env vars
export $(grep -v '^#' .env | xargs)
```

Only two commands are needed to pass all environment variables and run the tests. 

```Shell
source setenv.sh
swift test
```