OpenHands/openhands/runtime/browser/browser_env.py

import atexit
import base64
import io
import json
import multiprocessing
import time
import uuid

import browsergym.core  # noqa F401 (we register the openended task as a gym environment)
import gymnasium as gym
import html2text
import numpy as np
import tenacity
from browsergym.utils.obs import flatten_dom_to_str
from PIL import Image

from openhands.core.exceptions import BrowserInitException
from openhands.core.logger import openhands_logger as logger
from openhands.runtime.utils.shutdown_listener import should_continue, should_exit
from openhands.utils.tenacity_stop import stop_if_should_exit

BROWSER_EVAL_GET_GOAL_ACTION = 'GET_EVAL_GOAL'
BROWSER_EVAL_GET_REWARDS_ACTION = 'GET_EVAL_REWARDS'


class BrowserEnv:
    def __init__(self, browsergym_eval_env: str | None = None):
        self.html_text_converter = self.get_html_text_converter()
        self.eval_mode = False
        self.eval_dir = ''

        # EVAL only: browsergym_eval_env must be provided for evaluation
        self.browsergym_eval_env = browsergym_eval_env
        self.eval_mode = bool(browsergym_eval_env)

        # Initialize browser environment process
        multiprocessing.set_start_method('spawn', force=True)
        self.browser_side, self.agent_side = multiprocessing.Pipe()

        self.init_browser()
        atexit.register(self.close)

    def get_html_text_converter(self):
        html_text_converter = html2text.HTML2Text()
        # ignore links and images
        html_text_converter.ignore_links = False
        html_text_converter.ignore_images = True
        # use alt text for images
        html_text_converter.images_to_alt = True
        # disable auto text wrapping
        html_text_converter.body_width = 0
        return html_text_converter

    @tenacity.retry(
        wait=tenacity.wait_fixed(1),
        stop=tenacity.stop_after_attempt(5) | stop_if_should_exit(),
        retry=tenacity.retry_if_exception_type(BrowserInitException),
    )
    def init_browser(self):
        logger.debug('Starting browser env...')
        try:
            self.process = multiprocessing.Process(target=self.browser_process)
            self.process.start()
        except Exception as e:
            logger.error(f'Failed to start browser process: {e}')
            raise

        if not self.check_alive():
            self.close()
            raise BrowserInitException('Failed to start browser environment.')

    def browser_process(self):
        if self.eval_mode:
            assert self.browsergym_eval_env is not None
            logger.debug('Initializing browser env for web browsing evaluation.')
            if 'webarena' in self.browsergym_eval_env:
                import browsergym.webarena  # noqa F401 register webarena tasks as gym environments
            elif 'miniwob' in self.browsergym_eval_env:
                import browsergym.miniwob  # noqa F401 register miniwob tasks as gym environments
            else:
                raise ValueError(
                    f'Unsupported browsergym eval env: {self.browsergym_eval_env}'
                )
            env = gym.make(
                self.browsergym_eval_env,
                tags_to_mark='all',
            )
        else:
            env = gym.make(
                'browsergym/openended',
                task_kwargs={'start_url': 'about:blank', 'goal': 'PLACEHOLDER_GOAL'},
                wait_for_user_message=False,
                headless=True,
                disable_env_checker=True,
                tags_to_mark='all',
            )

        obs, info = env.reset()

        # EVAL ONLY: save the goal into file for evaluation
        self.eval_goal = None
        self.eval_rewards: list[float] = []
        if self.eval_mode:
            logger.debug(f"Browsing goal: {obs['goal']}")
            self.eval_goal = obs['goal']

        logger.debug('Browser env started.')
        while should_continue():
            try:
                if self.browser_side.poll(timeout=0.01):
                    unique_request_id, action_data = self.browser_side.recv()

                    # shutdown the browser environment
                    if unique_request_id == 'SHUTDOWN':
                        logger.debug('SHUTDOWN recv, shutting down browser env...')
                        env.close()
                        return
                    elif unique_request_id == 'IS_ALIVE':
                        self.browser_side.send(('ALIVE', None))
                        continue

                    # EVAL ONLY: Get evaluation info
                    if action_data['action'] == BROWSER_EVAL_GET_GOAL_ACTION:
                        self.browser_side.send(
                            (unique_request_id, {'text_content': self.eval_goal})
                        )
                        continue
                    elif action_data['action'] == BROWSER_EVAL_GET_REWARDS_ACTION:
                        self.browser_side.send(
                            (
                                unique_request_id,
                                {'text_content': json.dumps(self.eval_rewards)},
                            )
                        )
                        continue

                    action = action_data['action']
                    obs, reward, terminated, truncated, info = env.step(action)

                    # EVAL ONLY: Save the rewards into file for evaluation
                    if self.eval_mode:
                        self.eval_rewards.append(reward)

                    # add text content of the page
                    html_str = flatten_dom_to_str(obs['dom_object'])
                    obs['text_content'] = self.html_text_converter.handle(html_str)
                    # make observation serializable
                    obs['screenshot'] = self.image_to_png_base64_url(obs['screenshot'])
                    obs['active_page_index'] = obs['active_page_index'].item()
                    obs['elapsed_time'] = obs['elapsed_time'].item()
                    self.browser_side.send((unique_request_id, obs))
            except KeyboardInterrupt:
                logger.debug('Browser env process interrupted by user.')
                try:
                    env.close()
                except Exception:
                    pass
                return

    def step(self, action_str: str, timeout: float = 30) -> dict:
        """Execute an action in the browser environment and return the observation."""
        unique_request_id = str(uuid.uuid4())
        self.agent_side.send((unique_request_id, {'action': action_str}))
        start_time = time.time()
        while True:
            if should_exit() or time.time() - start_time > timeout:
                raise TimeoutError('Browser environment took too long to respond.')
            if self.agent_side.poll(timeout=0.01):
                response_id, obs = self.agent_side.recv()
                if response_id == unique_request_id:
                    return obs

    def check_alive(self, timeout: float = 60):
        self.agent_side.send(('IS_ALIVE', None))
        if self.agent_side.poll(timeout=timeout):
            response_id, _ = self.agent_side.recv()
            if response_id == 'ALIVE':
                return True
            logger.debug(f'Browser env is not alive. Response ID: {response_id}')

    def close(self):
        if not self.process.is_alive():
            return
        try:
            self.agent_side.send(('SHUTDOWN', None))
            self.process.join(5)  # Wait for the process to terminate
            if self.process.is_alive():
                logger.error(
                    'Browser process did not terminate, forcefully terminating...'
                )
                self.process.terminate()
                self.process.join(5)  # Wait for the process to terminate
                if self.process.is_alive():
                    self.process.kill()
                    self.process.join(5)  # Wait for the process to terminate
            self.agent_side.close()
            self.browser_side.close()
        except Exception:
            logger.error('Encountered an error when closing browser env', exc_info=True)

    @staticmethod
    def image_to_png_base64_url(
        image: np.ndarray | Image.Image, add_data_prefix: bool = False
    ):
        """Convert a numpy array to a base64 encoded png image url."""
        if isinstance(image, np.ndarray):
            image = Image.fromarray(image)
        if image.mode in ('RGBA', 'LA'):
            image = image.convert('RGB')
        buffered = io.BytesIO()
        image.save(buffered, format='PNG')

        image_base64 = base64.b64encode(buffered.getvalue()).decode()
        return (
            f'data:image/png;base64,{image_base64}'
            if add_data_prefix
            else f'{image_base64}'
        )

    @staticmethod
    def image_to_jpg_base64_url(
        image: np.ndarray | Image.Image, add_data_prefix: bool = False
    ):
        """Convert a numpy array to a base64 encoded jpeg image url."""
        if isinstance(image, np.ndarray):
            image = Image.fromarray(image)
        if image.mode in ('RGBA', 'LA'):
            image = image.convert('RGB')
        buffered = io.BytesIO()
        image.save(buffered, format='JPEG')

        image_base64 = base64.b64encode(buffered.getvalue()).decode()
        return (
            f'data:image/jpeg;base64,{image_base64}'
            if add_data_prefix
            else f'{image_base64}'
        )