# Linux Agent

## Role

`Agent_Linux/ogp_agent.pl` is the Linux execution agent for GSP. It is responsible for:

- starting and stopping game servers
- managing `screen` sessions
- reading logs
- running update/install tasks
- handling scheduler jobs
- performing query checks and status checks

## Important Files

- `Agent_Linux/ogp_agent.pl`
- `Agent_Linux/startups/`
- `Agent_Linux/includes/`
- `Agent_Linux/php-query/`
- `Agent_Linux/Cfg/`
- `Agent_Linux/Schedule/`
- `Agent_Linux/steamcmd/`
- `Agent_Linux/systemd/`

## Startup Logic

The Linux agent creates a managed `screen` session per server.

Key flow in `ogp_agent.pl`:

- `universal_start_without_decrypt`
- `create_screen_cmd`
- `create_screen_cmd_loop`
- `replace_OGP_Env_Vars`

The agent builds the startup command from:

- the game XML template
- server parameters
- mod data
- control password
- path variables

The session name follows the OGP naming convention, for example:

```text
OGP_HOME_000000123
```

## Status Logic

Relevant functions:

- `is_screen_running_without_decrypt`
- `get_screen_pid_without_decrypt`
- `server_status_without_decrypt`
- `verify_server_stopped_without_decrypt`

The status implementation should check:

- screen/session existence
- PID or child process information when available
- whether the game port is listening
- whether query metadata can be fetched

Marker files such as `SERVER_STOPPED` should not be treated as the final source of truth.

## Logging

Relevant function:

- `get_log`

The agent reads screen logs and may also copy a local log file into the game home. Logs should be treated as runtime output, not as a state store.

## Scheduler

Linux scheduler functions live in `ogp_agent.pl`:

- `scheduler_dispatcher`
- `scheduler_server_action`
- `scheduler_log_events`
- `scheduler_add_task`
- `scheduler_del_task`
- `scheduler_edit_task`
- `scheduler_read_tasks`
- `scheduler_stop`
- `scheduler_list_tasks`

The scheduler is agent-driven. Panel pages create or edit jobs, but the agent executes them.

## Configuration Files

Useful configuration and runtime areas:

- `Agent_Linux/Cfg/`
- `Agent_Linux/startups/`
- `Agent_Linux/steamcmd/`
- `Agent_Linux/systemd/`

The agent also maintains screen logs and helper scripts inside its runtime area.

## Linux-Specific Notes

- The Linux agent uses `screen` and `sudo_exec_without_decrypt`.
- It can resolve server ownership and screen users via helper functions such as `find_user_by_screen_id`.
- It must remain portable across distro variants, so avoid assuming one exact init system or one exact binary path.
- For Windows-targeted games running under Linux, Wine-related path conversion appears in startup path handling.