> ## Documentation Index
> Fetch the complete documentation index at: https://developer.upsun.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Local development

> Sync Upsun with your local environments to start contributing.


When you develop a Symfony project, a significant amount of work takes place
locally rather than on an active Upsun environment. You want to ensure
that the process of local development is as close as possible to a deployed
environment.

You can achieve this through various approaches. For example, you can use
Symfony Server with tethered data.

To do so, when testing changes locally, you can connect your locally running
Symfony Server to service containers on an active Upsun environment.

This methodology has several advantages:

* It avoids installing anything on your local machine but PHP;
* It ensures that you are using the same versions of all services on your local
  machine and in production.

<Warning>
  <h4>Warning</h4>
  Never use this method on the **main** environment as changes made on your local
  machine will impact production data.
</Warning>

## Before you begin

You need:

* A local copy of the repository for a project running on Upsun.
  You can clone an integrated source repository and set the remote branch.
  To do so, run `symfony cloud:project:set-remote PROJECT_ID`.
* The [Symfony CLI](https://symfony.com/download)

## 1. Start your Symfony Server

To start your [Symfony
Server](https://symfony.com/doc/current/setup/symfony_server.html) locally and
display your Symfony app, run the following command:

```bash theme={null}
symfony server:start -d
symfony open:local
```

This starts the Symfony Server and opens the app in your local browser.

## 2. Create the tethered connection

1. Create a new environment off of production:

   ```bash theme={null}
   symfony branch new-feature main
   ```

2. Open an SSH tunnel to the new environment's services:

   ```bash theme={null}
   symfony tunnel:open
   ```

   This command returns the addresses for SSH tunnels to all of your services:

   ```bash theme={null}
   symfony tunnel:open
       SSH tunnel opened to rediscache at: redis://127.0.0.1:30000
       SSH tunnel opened to database at: pgsql://main:main@127.0.0.1:30001/main

       Logs are written to: /Users/acmeUser/.platformsh/tunnels.log

       List tunnels with: symfony tunnels
       View tunnel details with: symfony tunnel:info
       Close tunnels with: symfony tunnel:close

       Save encoded tunnel details to the PLATFORM_RELATIONSHIPS variable using:
       export PLATFORM_RELATIONSHIPS="$(symfony tunnel:info --encode)"
   ```

3. To expose Upsun services to your Symfony app, run the following
   command:

   ```bash theme={null}
   symfony var:expose-from-tunnel
   ```

   This automatically configures your local Symfony app to use all your
   remote Upsun services (remote database, remote Redis component, etc.).

   To check that you're now using remote data and components from Upsun,
   reload your local app within your browser.

4. When you've finished your work,
   close the tunnels to your services by running the following command:

   ```bash theme={null}
   symfony var:expose-from-tunnel --off
   symfony tunnel:close --all -y
   ```