change env separator from . to __

example.env

@@ -1,15 +1,15 @@
 RUST_LOG=debug
 DATABASE_URL=postgresql://shoutdotdev:callous@127.0.0.1:5447/shoutdotdev
-AUTH.CLIENT_ID=
-AUTH.CLIENT_SECRET=
-AUTH.REDIRECT_URL=http://localhost:3000/auth/callback
-AUTH.AUTH_URL=https://example.com/authorize
-AUTH.TOKEN_URL=https://example.com/token
-AUTH.USERINFO_URL=https://example.com/userinfo
+AUTH__CLIENT_ID=
+AUTH__CLIENT_SECRET=
+AUTH__REDIRECT_URL=http://localhost:3000/auth/callback
+AUTH__AUTH_URL=https://example.com/authorize
+AUTH__TOKEN_URL=https://example.com/token
+AUTH__USERINFO_URL=https://example.com/userinfo
 # The .env parser (dotenvy) requires quotes around any value with spaces. Note
 # that in this regard it is incompatible with Docker's --env-file parser.
-EMAIL.VERIFICATION_FROM=no-reply@shout.dev
-EMAIL.MESSAGE_FROM=no-reply@shout.dev
-EMAIL.SMTP.SERVER=smtp.example.com
-EMAIL.SMTP.USERNAME=
-EMAIL.SMTP.PASSWORD=
+EMAIL__VERIFICATION_FROM=no-reply@shout.dev
+EMAIL__MESSAGE_FROM=no-reply@shout.dev
+EMAIL__SMTP__SERVER=smtp.example.com
+EMAIL__SMTP__USERNAME=
+EMAIL__SMTP__PASSWORD=

src/settings.rs

@@ -103,7 +103,7 @@ impl Settings {
             }
         }
         let s = Config::builder()
-            .add_source(Environment::default())
+            .add_source(Environment::default().separator("__"))
             .build()
             .context("config error")?;
         Ok(s.try_deserialize().context("deserialize error")?)