actions/cache@v4 "Cache restore failed: Bad gateway"

A 502 Bad gateway during cache restore is a transient cache-service error, not a configuration fault. The restore is skipped and, by default, the job continues with a cold cache.

What this error means

The cache step warns "Cache restore failed: Bad gateway" and proceeds without a restored cache.

Warning: Cache restore failed: Cache service responded with 502 Bad gateway
Cache not found for input keys: deps-...

Common causes

Transient cache-service 502

The Actions cache backend returned a momentary gateway error.

Cache service degradation

Brief upstream degradation can make restores fail intermittently.

How to fix it

Tolerate the miss and re-run if needed

1. Leave fail-on-cache-miss unset so a transient miss does not fail the job.
2. Re-run the job; the cache service usually recovers quickly.
3. Keep restore-keys so a partial-prefix restore can still help.

- uses: actions/cache@v4
  with:
    path: ~/.npm
    key: npm-${{ hashFiles('package-lock.json') }}
    restore-keys: |
      npm-

How to prevent it

• Do not set fail-on-cache-miss for best-effort caches.
• Latchkey managed runners auto-retry transient cache-service failures (including 502s), so a Bad gateway on restore typically resolves without a manual re-run.

Related guides