Stream template build-context upload from disk instead of buffering in memory

[mishushakov]

Summary

Template builds previously buffered the entire gzipped build-context tar archive in memory before uploading it. This PR spools the archive to a temporary file and streams it from disk during upload — in the JS SDK and both sync and async Python SDKs — so memory usage no longer scales with the size of the build context.

The upload keeps an explicit Content-Length header (taken from the spooled file's size), which S3 presigned PUT URLs require — they reject Transfer-Encoding: chunked with 501 NotImplemented (#1243).

Changes

• JS (packages/js-sdk/src/template/): tarFileStream/tarFileStreamUpload are replaced by tarFileToTempFile, which writes the archive to a temp file and returns its path, size, and a cleanup callback. uploadFile streams the file via fs.createReadStream with duplex: 'half' and an explicit Content-Length, and removes the temp file afterwards.
• Python (packages/python-sdk/e2b/template/utils.py, template_async/build_api.py, template_sync/build_api.py): tar_file_stream now writes to a tempfile.TemporaryFile instead of io.BytesIO and returns the file object positioned at the start; the upload streams from it and closes it (deleting the temp file) when done.
• Tests updated for the new return shapes (JS tarFileToTempFile.test.ts, Python upload/tar tests).

Usage

No API changes — Template.build() / template builds behave the same, just without holding the build context in memory:

await Template.build(template, { alias: 'my-template' })

Template.build(template, alias="my-template")

Split out of #1433, which covers streaming for sandbox/volume file uploads and downloads.

🤖 Generated with Claude Code

[changeset-bot]

🦋 Changeset detected

Latest commit: 0a76482

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
e2b	Patch
@e2b/python-sdk	Patch

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[cursor]

PR Summary

Medium Risk
Touches presigned S3 PUT behavior for template builds; a regression on Content-Length or chunked encoding would break uploads (#1243).

Overview
Template build context uploads no longer load the full gzipped tar into RAM. JS writes the archive with tarFileToTempFile, streams it via createReadStream with explicit Content-Length and duplex: 'half', then deletes the temp dir. Python tar_file_stream uses tempfile.TemporaryFile; sync upload passes the file to httpx, async upload uses aiter_io_chunks plus Content-Length. Public template build APIs are unchanged; tests were updated for the new shapes.

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[github-actions]

Package Artifacts

Built from 1642b31. Download artifacts from this workflow run.

JS SDK (e2b@2.29.2-mishushakov-stream-template-build-upload.0):

npm install ./e2b-2.29.2-mishushakov-stream-template-build-upload.0.tgz

CLI (@e2b/cli@2.11.2-mishushakov-stream-template-build-upload.0):

npm install ./e2b-cli-2.11.2-mishushakov-stream-template-build-upload.0.tgz

Python SDK (e2b==2.28.2+mishushakov-stream-template-build-upload):

pip install ./e2b-2.28.2+mishushakov.stream.template.build.upload-py3-none-any.whl