Request: respect https_proxy and http_proxy env variables for network requests

[wanliqun]

Description

I encountered an issue where exo does not respect the https_proxy and http_proxy environment variables for network requests, even though the system environment is properly configured.

The root cause appears to be the way aiohttp is used in the exo codebase. aiohttp supports proxy usage via environment variables through setting trust_env=True for aiohttp.ClientSession . However, it seems the current implementation in exo does not leverage this feature.

This limitation prevents users from routing traffic through a proxy, which is critical in certain network setups such as corporate environments or restricted networks.

Steps to Reproduce

1. Set up proxy environment variables:

   export http_proxy=http://proxy-server:port
   export https_proxy=http://proxy-server:port

2. Run exo with a command that makes network requests (e.g., model downloading).
3. Observe that the requests do not route through the specified proxy, and connections fail in environments where direct access is blocked.

Expected Behavior

exo should honor the http_proxy, https_proxy, and no_proxy environment variables automatically when making network requests.

Actual Behavior

exo fails to use the proxy settings, resulting in connection errors in proxied environments.

Proposed Solution

Update the aiohttp usage in exo to automatically respect environment proxy settings. This can be achieved by ensuring that trust_env=True is explicitly passed to aiohttp.ClientSession() like this:

async with aiohttp.ClientSession(trust_env=True) as session:
        async with session.get(url) as response:
            print(await response.text())

Environment

exo version: latest main branch
aiohttp version: aiohttp-3.10.11
Operating System: windows11+wsl(ubuntu 20.04)
Python Version: 3.12

[wanliqun]

As seen in PR #519