Files
deepseek-harness/packages/util/atomic-write
Yichen Jiang b0a2011d95 docs: bilingual credentials/settings-consumer documentation, catalogs, and gates
New credentials data-structure page (type-equiv manifested), group README,
rewritten llm-deepseek/llm-pi-ai READMEs (dynamic configuration, dict
profiles, credential chain), capability-seams/service-role registration,
Agent Note (bilingual), demo compositions mounting settings-local +
credentials-local with no inline key plumbing, installSettingsSection
consumer helper on the settings seam (deduplicating both adapters' wiring),
jscpd symmetry markers for the provider twins, runtime-closure additions for
python/sdk-runtime, and doc-budget ceilings AGENTS.md 1750→1755 /
packages/README.md 850→865 for the structural one-line group rows.
2026-07-29 14:20:06 +08:00
..

dsh-atomic-write

English | 中文

Zero-dependency atomic file replacement shared by file-backed stores that must never leave partial, symlink-hijacked, or wider-than-intended content on disk — the user-settings document (dsh-settings-local) and the credentials store (dsh-credentials-local).

Surface

import { writeFileAtomic } from '@deepseek-ai/dsh-atomic-write'

declare const text: string

await writeFileAtomic('/home/u/.dsh/settings.yaml', text, { mode: 0o600 })

One export. The contract, in the order failures would exploit it:

  • Exclusive-create temp (wx, random suffix): the open refuses to follow a symlink planted at a guessable temp path.
  • The fresh inode carries mode through the rename: replacing a wider-permission file narrows it without a chmod race. mode is required so the permission decision stays visible at every call site (subject to the process umask, like every fresh inode).
  • rename replaces a symlinked target itself, never writing through to its referent.
  • Same-directory sibling keeps the rename on one filesystem, so the swap stays atomic.
  • Parent directories are created; on any failure the temp is removed and the failure rethrown; readers observe either the old or the new complete content.

Model Experience

None, as this is a pure filesystem primitive; nothing here reaches a model request.

KV Cache effect

None; nothing here enters a request prefix.

Known Limitations and Deferred Work

  • Atomic, not durable — no fsync of the file or its directory, so after a crash the rename may be observed unwound. The file-backed stores here re-read and republish on boot, keeping durability the caller's policy.
  • String content only — no Buffer or stream form until a consumer needs one.