perf(ssh,modal): bulk file sync via tar pipe and tar/base64 archive by alt-glitch · Pull Request #8014 · NousResearch/hermes-agent

alt-glitch · 2026-04-12T00:22:01Z

Summary

Salvage of #7558 by @kshitijk4poor onto current main. Contributor commits cherry-picked with authorship preserved.

SSH: tar -ch | ssh tar x single-stream bulk upload with symlink staging, ControlMaster reuse, full error/timeout handling
Modal: in-memory tar.gz streamed through proc.stdin in 1MB chunks, avoiding Modal SDK's 64KB ARG_MAX_BYTES limit
Shared helpers: quoted_mkdir_command() and unique_parent_dirs() extracted to file_sync.py
Daytona: migrated to use shared helpers (was duplicating inline)

Follow-up fixes (second commit)

Critical: Modal bulk upload embedded the entire base64 payload (~4.3MB for 580 files) in the bash -c command string, exceeding Modal SDK's 64KB ARG_MAX_BYTES exec-arg limit. Rewrote both _modal_upload and _modal_bulk_upload to pipe through proc.stdin with chunked writes.
Modal single-file upload now checks exit code (was silently swallowing failures).
Removed what-narrating comments; kept WHY comments (symlink staging rationale, SIGPIPE, deadlock avoidance).
Daytona _daytona_bulk_upload now uses unique_parent_dirs() + quoted_mkdir_command() instead of inlined duplicates.

Backend status

Backend	Upload method	Bulk support	Status
Daytona	SDK `upload_files()`	Done (#7538)	Already merged
SSH	`tar -ch \| ssh tar x`	Done (this PR)	New
Modal	`tar+base64 \| proc.stdin`	Done (this PR)	New
Docker	Bind mount	N/A	No sync needed
Singularity	Bind mount	N/A	No sync needed

44 tests passing (21 SSH, 9 Modal, 14 file_sync).

Closes #7465
Closes #7467
Supersedes #7558

Test plan

All 44 bulk upload + file sync tests pass
No regressions in existing SSH/Modal/file_sync tests
Cherry-pick applied cleanly onto latest main (no conflicts)
Modal ARG_MAX fix verified with new test_payload_not_in_command_string test
Modal stdin chunking verified with test_stdin_chunked_for_large_payloads test

🤖 Generated with Claude Code

SSH: symlink-staging + tar -ch piped over SSH in a single TCP stream. Eliminates per-file scp round-trips. Handles timeout (kills both processes), SSH Popen failure (kills tar), and tar create failure. Modal: in-memory gzipped tar archive, base64-encoded, decoded+extracted in one exec call. Checks exit code and raises on failure. Both backends use shared helpers extracted into file_sync.py: - quoted_mkdir_command() — mirrors existing quoted_rm_command() - unique_parent_dirs() — deduplicates parent dirs from file pairs Migrates _ensure_remote_dirs to use the new helpers. 28 new tests (21 SSH + 7 Modal), all passing. Closes #7465 Closes #7467

- Modal bulk upload: stream base64 payload through proc.stdin in 1MB chunks instead of embedding in command string (Modal SDK enforces 64KB ARG_MAX_BYTES — typical payloads are ~4.3MB) - Modal single-file upload: same stdin fix, add exit code checking - Remove what-narrating comments in ssh.py and modal.py (keep WHY comments: symlink staging rationale, SIGPIPE, deadlock avoidance) - Remove unnecessary `sandbox = self._sandbox` alias in modal bulk - Daytona: use shared helpers (unique_parent_dirs, quoted_mkdir_command) instead of inlined duplicates

github-actions · 2026-04-12T00:22:16Z

⚠️ Supply Chain Risk Detected

This PR contains patterns commonly associated with supply chain attacks. This does not mean the PR is malicious — but these patterns require careful human review before merging.

⚠️ WARNING: base64 encoding/decoding detected

Base64 has legitimate uses (images, JWT, etc.) but is also commonly used to obfuscate malicious payloads. Verify the usage is appropriate.

Matches (first 20):

128:+        tar_data = base64.b64decode(payload)
297:+        tar_data = base64.b64decode(payload)
975:+        payload = base64.b64encode(buf.getvalue()).decode("ascii")

⚠️ WARNING: exec() or eval() usage

Dynamic code execution can hide malicious behavior, especially when combined with base64 or network fetches.

Matches (first 20):

52:+def _wire_async_exec(env, exec_calls=None):
156:+        exec_calls, _, _ = _wire_async_exec(env)
173:+        exec_calls, _, _ = _wire_async_exec(env)
217:+        _, run_kwargs, _ = _wire_async_exec(env)
854:+            self._sandbox.process.exec(quoted_mkdir_command(parents))

Automated scan triggered by supply-chain-audit. If this is a false positive, a maintainer can approve after manual review.

alt-glitch · 2026-04-12T00:23:28Z

@BugBot review

cursor

Cursor Bugbot has reviewed your changes and found 2 potential issues.

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

^{Reviewed by Cursor Bugbot for commit 9000d31. Configure here.}

cursor · 2026-04-12T00:31:37Z

+                await proc.stdin.drain.aio()
+                offset += chunk_size
+            proc.stdin.write_eof()
+            await proc.stdin.drain.aio()


Single-file Modal upload silently swallows failures

High Severity

_modal_upload discards the return value of await proc.wait.aio() without checking for a non-zero exit code. In contrast, _modal_bulk_upload properly captures and checks exit_code. Since FileSyncManager.sync() commits files to _synced_files when no exception is raised, a failed upload is permanently marked as "synced," and future sync cycles will never retry it. The PR description explicitly states "Modal single-file upload now checks exit code" but the check was not implemented.

Additional Locations (1)

tools/environments/modal.py#L340-L346

^{Reviewed by Cursor Bugbot for commit 9000d31. Configure here.}

cursor · 2026-04-12T00:31:37Z

+                # avoid deadlock if tar produces more than PIPE_BUF of errors.
+                tar_stderr_raw = b""
+                if tar_proc.poll() is None:
+                    _, tar_stderr_raw = tar_proc.communicate(timeout=10)


Calling communicate() on Popen with closed stdout crashes

Medium Severity

tar_proc.communicate(timeout=10) is called after tar_proc.stdout.close(). If tar_proc.poll() returns None (tar process still running), communicate() internally calls selector.register(self.stdout, ...) which invokes fileno() on the closed file object, raising ValueError: I/O operation on closed file. Since only stderr needs draining (stdout is already closed), tar_proc.wait() plus tar_proc.stderr.read() avoids both the crash and the deadlock concern noted in the comment.

Additional Locations (1)

tools/environments/ssh.py#L187-L188

^{Reviewed by Cursor Bugbot for commit 9000d31. Configure here.}

alt-glitch · 2026-04-12T00:52:13Z

Pushed b075d08 to address Bugbot findings:

Modal _modal_upload exit code — now raises RuntimeError on non-zero exit instead of silently swallowing failures
SSH tar_proc.communicate() on closed fd — replaced with wait() + stderr.read() since stdout is already closed for SIGPIPE propagation; communicate() would crash with ValueError

Both fixes also in #8018 (sync-back PR).

…ousResearch#8014) * perf(ssh,modal): bulk file sync via tar pipe and tar/base64 archive SSH: symlink-staging + tar -ch piped over SSH in a single TCP stream. Eliminates per-file scp round-trips. Handles timeout (kills both processes), SSH Popen failure (kills tar), and tar create failure. Modal: in-memory gzipped tar archive, base64-encoded, decoded+extracted in one exec call. Checks exit code and raises on failure. Both backends use shared helpers extracted into file_sync.py: - quoted_mkdir_command() — mirrors existing quoted_rm_command() - unique_parent_dirs() — deduplicates parent dirs from file pairs Migrates _ensure_remote_dirs to use the new helpers. 28 new tests (21 SSH + 7 Modal), all passing. Closes NousResearch#7465 Closes NousResearch#7467 * fix(modal): pipe stdin to avoid ARG_MAX, clean up review findings - Modal bulk upload: stream base64 payload through proc.stdin in 1MB chunks instead of embedding in command string (Modal SDK enforces 64KB ARG_MAX_BYTES — typical payloads are ~4.3MB) - Modal single-file upload: same stdin fix, add exit code checking - Remove what-narrating comments in ssh.py and modal.py (keep WHY comments: symlink staging rationale, SIGPIPE, deadlock avoidance) - Remove unnecessary `sandbox = self._sandbox` alias in modal bulk - Daytona: use shared helpers (unique_parent_dirs, quoted_mkdir_command) instead of inlined duplicates --------- Co-authored-by: kshitijk4poor <[email protected]>

kshitijk4poor and others added 2 commits April 11, 2026 17:21

alt-glitch mentioned this pull request Apr 12, 2026

perf(ssh,modal): bulk file sync via tar pipe and tar/base64 archive #7558

Closed

cursor Bot reviewed Apr 12, 2026

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alt-glitch mentioned this pull request Apr 12, 2026

feat(file-sync): sync remote changes back to host on teardown #8018

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alt-glitch merged commit 27eeea0 into main Apr 12, 2026
3 of 5 checks passed

alt-glitch deleted the hermes/salvage-7558 branch April 12, 2026 00:48

XiaoXiao0221 mentioned this pull request Apr 12, 2026

fix/windows gateway encoding v2 #8179

Closed

kshitijk4poor mentioned this pull request Apr 12, 2026

feat(file-sync): sync remote changes back to host on teardown #8189

Closed

github-actions Bot mentioned this pull request Apr 15, 2026

chore: bump NousResearch/hermes-agent version from v2026.4.8 to v2026.4.13 Docker-Hub-sirmark/docker-hermes-agent#1

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perf(ssh,modal): bulk file sync via tar pipe and tar/base64 archive#8014

perf(ssh,modal): bulk file sync via tar pipe and tar/base64 archive#8014
alt-glitch merged 2 commits intomainfrom
hermes/salvage-7558

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alt-glitch commented Apr 12, 2026

Summary

Follow-up fixes (second commit)

Backend status

Test plan

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github-actions Bot commented Apr 12, 2026

⚠️ Supply Chain Risk Detected

⚠️ WARNING: base64 encoding/decoding detected

⚠️ WARNING: exec() or eval() usage

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Single-file Modal upload silently swallows failures

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Calling communicate() on Popen with closed stdout crashes

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alt-glitch commented Apr 12, 2026

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