Refactor bash output capture to use file-based streaming

openhands/runtime/utils/bash.py

@@ -2,6 +2,7 @@
 import time
 import uuid
 from enum import Enum
+from pathlib import Path
 
 import bashlex
 import libtmux
@@ -90,12 +91,18 @@ def __init__(
     ):
         self.NO_CHANGE_TIMEOUT_SECONDS = no_change_timeout_seconds
 
+        # Create output directory
+        self.command_id = str(uuid.uuid4())
+        self.output_dir = Path('/openhands/commands')
+        self.output_dir.mkdir(parents=True, exist_ok=True)
+        self.output_file = self.output_dir / f'{self.command_id}.txt'
+
         self.server = libtmux.Server()
         window_command = '/bin/bash'
         if username:
             window_command = f'su {username}'
 
-        session_name = f'openhands-{username}-{uuid.uuid4()}'
+        session_name = f'openhands-{username}-{self.command_id}'
         self.session = self.server.new_session(
             session_name=session_name,
             window_name='bash',
@@ -105,10 +112,6 @@ def __init__(
             x=1000,
             y=1000,
         )
-        # https://unix.stackexchange.com/questions/43414/unlimited-history-in-tmux
-        _history_limit = 999999999
-        self.session.set_option('history-limit', str(_history_limit), _global=True)
-        self.session.history_limit = _history_limit
 
         # We need to create a new pane because the initial pane's history limit is (default) 2000
         _initial_window = self.session.attached_window
@@ -117,12 +120,13 @@ def __init__(
             start_directory=work_dir,
         )
         self.pane = self.window.attached_pane
-        logger.debug(f'pane: {self.pane}; history_limit: {self.session.history_limit}')
         _initial_window.kill_window()
 
-        # Configure bash to use simple PS1 and disable PS2
+        # Configure bash to use simple PS1, disable PS2, and redirect all output to file
         self.pane.send_keys(
-            f'export PROMPT_COMMAND=\'export PS1="{self.PS1}"\'; export PS2=""'
+            f'export PROMPT_COMMAND=\'export PS1="{self.PS1}"\'; '
+            f'export PS2=""; '
+            f'exec > >(tee -a "{self.output_file}") 2>&1'
         )
         time.sleep(0.2)  # Wait for command to take effect
         self._clear_screen()
@@ -137,6 +141,10 @@ def __init__(
 
     def close(self):
         self.session.kill_session()
+        try:
+            self.output_file.unlink()
+        except FileNotFoundError:
+            pass
 
     @property
     def pwd(self):
@@ -158,16 +166,14 @@ def _get_pane_content(self, full: bool = False) -> str:
         """Get the current content of the tmux pane.
 
         Args:
-            full: If True, capture the entire history of the pane.
+            full: If True, read the entire file. Otherwise read only the last part.
         """
-        # https://man7.org/linux/man-pages/man1/tmux.1.html
-        # -J preserves trailing spaces and joins any wrapped lines;
-        # -p direct output to stdout
-        # -S -: start from the start of history
-        if full:
-            # Capture the entire history of the pane
-            return '\n'.join(self.pane.cmd('capture-pane', '-J', '-pS', '-').stdout)
-        return '\n'.join(self.pane.cmd('capture-pane', '-J', '-p').stdout)
+        try:
+            with open(self.output_file, 'r') as f:
+                content = f.read()
+                return content
+        except FileNotFoundError:
+            return ""
 
     def _get_command_output(
         self,