Simple .env file injector for Vapor 3

(1) Environment+EnvFile.swift

import Foundation
import Service

#if os(Linux)
import Glibc
#else
import Darwin
#endif

extension Environment {
    func injectEnvFile(_ path: String) {
        guard let data = FileManager.default.contents(atPath: path), let string = String(data: data, encoding: .utf8) else {
            return
        }

        string.components(separatedBy: "\n")
            .map { $0.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines) }
            .compactMap { (line: String) -> (String, String)? in
                guard let equalsIndex = line.index(of: "=") else {
                    return nil
                }

                let key = String(line.prefix(through: line.index(before: equalsIndex)))
                let value = String(line.suffix(from: line.index(after: equalsIndex)))
                return (key, value)
            }
            .forEach {
                setenv($0.0, $0.1, 1)
            }
    }
}

(2) .env

DATABASE_URL=postgres://blablabla:password@server:5432/test

(3) configure.swift

import Vapor
import Leaf

public func configure(_ config: inout Config, _ env: inout Environment, _ services: inout Services) throws {
    env.injectEnvFile(DirectoryConfig.detect().workDir + ".env")

    // Environment, ProcessInfo, etc. all see the overridden value
    let databaseURL = Environment.get("DATABASE_URL") ?? "..."

    
    // ... registering providers, services, etc. truncated ...
}