Client Update for Fixing Multiple Sandbox StreamWriter Issue [ART-8]

[aadit-juneja]

Client Update for Fixing Multiple Sandbox StreamWriter Issue

This issue fixes an issue in which multiple stdin StreamWriters cannot be opened to a Sandbox. Previously, only one StreamWriter could be opened to write messages to stdin. Our new fix, at a high level, more explicitly enforces only one open StreamWriter, assigning a uuid to each writer and adds an active_writer_id attribute for sandboxes. Protobuf changes include adding a writer_id to RuntimeInputMessage and toSandboxStdinWriteRequest.

The Linear issue contains a Slack Thread for a relevant client problem.

Checklists

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Compatibility checklist

Check these boxes or delete any item (or this section) if not relevant for this PR.

• Client+Server: this change is compatible with old servers
• Client forward compatibility: this change ensures client can accept data intended for later versions of itself

Note on protobuf: protobuf message changes in one place may have impact to
multiple entities (client, server, worker, database). See points above.

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Release checklist

If you intend for this commit to trigger a full release to PyPI, please ensure that the following steps have been taken:

• Version file (modal_version/__init__.py) has been updated with the next logical version
• Changelog has been cleaned up and given an appropriate subhead

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Changelog

[rolyatmax]

I think there are two spots where we create RuntimeInputMessages in the client. Do those need to be updated to take this new writer_id value, too?

[aadit-juneja]

I included the field because RuntimeInputMessage was used in server code for the code flow of a SandboxStdinWriteRequest and it needs to be sent over to the worker for deduplication (monorepo PR). The us of RuntimeInputMessage PR in the client looks like it's once for non-sandbox tasks and another for modal shell.

I think that if the field is not included in when it is sent it gets set to a default string value ("") and it'll be ignored on the code paths for those two.