Make DockerCommandLineCodeExecutor the default for MagenticOne team

[Copilot]

Summary

This PR changes MagenticOne to use DockerCommandLineCodeExecutor by default instead of LocalCommandLineCodeExecutor, addressing security concerns about local code execution.

Changes

Security Enhancement

• Docker-first approach: MagenticOne now defaults to containerized code execution when Docker is available
• Graceful fallback: Falls back to local execution with clear warning when Docker is unavailable
• User guidance: Provides actionable instructions for Docker installation when needed

Implementation Details

• Added _is_docker_available() function to detect Docker availability
• Added _create_default_code_executor() function that prioritizes Docker executor
• Updated deprecation warning to recommend Docker executor
• Enhanced docstring examples to demonstrate Docker usage patterns

Example Usage

Before (uses local execution by default):

from autogen_ext.teams.magentic_one import MagenticOne
from autogen_ext.models.openai import OpenAIChatCompletionClient

client = OpenAIChatCompletionClient(model="gpt-4o")
m1 = MagenticOne(client=client)  # Uses LocalCommandLineCodeExecutor

After (uses Docker by default when available):

from autogen_ext.teams.magentic_one import MagenticOne
from autogen_ext.models.openai import OpenAIChatCompletionClient

client = OpenAIChatCompletionClient(model="gpt-4o")
m1 = MagenticOne(client=client)  # Uses DockerCommandLineCodeExecutor when Docker is available

Backward Compatibility

• Existing code that explicitly provides a code_executor parameter continues to work unchanged
• When Docker is unavailable, the system falls back to local execution with a clear warning
• No breaking changes to the API

Testing

• Added comprehensive tests covering Docker availability scenarios
• Tests validate fallback behavior and warning messages
• Smoke tests confirm all functionality works as expected

This change aligns with the security-first principle mentioned in the MagenticOne documentation warnings about using containers for isolation.

Fixes #6683.

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[husseinmozannar]

@copilot no the only change should be to python/packages/autogen-ext/src/autogen_ext/teams/magentic_one.py change localcomandline in the warning to dockerexecutor

[Copilot]

@copilot no the only change should be to python/packages/autogen-ext/src/autogen_ext/teams/magentic_one.py change localcomandline in the warning to dockerexecutor

...

I've made the minimal change as requested - updated the deprecation warning in magentic_one.py to recommend DockerCommandLineCodeExecutor instead of LocalCommandLineCodeExecutor. The change is in commit c9b1891.