CI flake: sccache failed to start: `cache storage failed to read: Unexpected (temporary) at read => send http request`

[clockwork-labs-bot]

Detected by CI Gremlin after a failed GitHub Actions attempt succeeded on rerun.

Tests:

• Smoketests (Linux)

Error:
error: process didn't exit successfully: sccache /home/runner/.rustup/toolchains/1.93.0-x86_64-unknown-linux-gnu/bin/rustc -vV (exit status: 2)
--- stderr

Failed job runs:

• https://github.com/clockworklabs/SpacetimeDB/actions/runs/29417989091/job/87398331602 (Smoketests (Linux), attempt 2 -> 3)

Timeout detection:

• none

Context:

• none

[clockwork-labs-bot]

Diagnosis for the exact linked job/attempt:

• Run/job: CI run 29417989091, job 87398331602, Smoketests (Linux), attempt 2.
• Job API confirms this job was attempt 2 and failed on runner ghr-github-self-hosted-ubuntu-14900k-07-spacetimedb-14-3a52eb82 at 2026-07-15T15:41:49Z.
• The job did not reach Run smoketests (Linux). That step was skipped. The failing step was Check v8 outputs.
• Failure signature: sccache /home/runner/.rustup/toolchains/1.93.0-x86_64-unknown-linux-gnu/bin/rustc -vV exited 2 because sccache could not start its server: cache storage failed to read: Unexpected (temporary) at read => send http request.
• Root cause visible in this attempt: the ghac cache backend tried to read .sccache_check from GitHub Actions cache storage at productionresultssa10.blob.core.windows.net, and the request failed with dns error: failed to lookup address information: Try again. This is CI/cache infrastructure, not a SpacetimeDB smoketest failure and not a V8 build/test assertion.

Suggested updated title:

CI infra flake: sccache GitHub Actions cache DNS lookup failure

Duplicate search:

• I searched existing SpacetimeDB Test Flakes/history by the distinctive signature: sccache, Server startup failed, cache storage failed to read, productionresultssa10.blob.core.windows.net, failed to lookup address information, and Check v8 outputs.
• Top duplicate candidate: none found. Similar CI-infra tickets exist in the broad sense, but I did not find a close Test Flakes duplicate for this exact sccache/GitHub Actions cache DNS failure signature.