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The legacy Rosetta warming job ran two commands — rosetta run warming to populate the caches, then /etc/aspect/workflows/bin/warming_archive to upload them to the warming bucket. aspect ci warming replaces both with a single task: it cleans the runner’s prior Bazel state, runs bazel build --nobuild against the given targets to populate the repository, output, and Bazel caches, and — on an Aspect Workflows runner — uploads the populated caches to the warming bucket itself. Warming runs on a schedule (typically daily) to pre-populate an Aspect Workflows runner group’s shared caches, so the first real CI job of the day starts warm instead of building everything from cold.
aspect ci warming requires Aspect CLI v2026.26.44 or newer.

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What changed

AreaRosettaaspect ci warming
Invocationrosetta run warming then /etc/aspect/workflows/bin/warming_archiveaspect ci warming -- //... (one step; runs the archiver itself on a runner)
TargetsWhole repo (from the .aspect/workflows/config.yaml warming task)Positional patterns, default //... (e.g. aspect ci warming -- //services/...)
Cache populaterosetta run warmingbazel build --nobuild against the targets
Archive uploadSeparate warming_archive invocationBuilt in — invoked automatically on a Workflows runner
Off a Workflows runnern/aThe cache-populate step still runs; the archive step is skipped with a warning
Workflows configNeeds .aspect/workflows/config.yaml with a warming taskNone

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Configuration

aspect ci warming takes positional target patterns plus a few flags:
  • Targets (positional, default //...) — the Bazel target patterns to warm.
  • --bazel-flag=<flag> (repeatable) — extra flags forwarded to the underlying bazel build (e.g. --bazel-flag=--config=ci).
  • --bazel-startup-flag=<flag> (repeatable) — extra Bazel startup flags.
aspect ci warming -- //...                       # warm everything (default)
aspect ci warming -- //services/... //libs/...    # warm a subset
aspect ci warming --bazel-flag=--config=ci -- //...

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Examples

Run warming on a schedule against your main branch. The job replaces the old two-command warming step with a single aspect ci warming. Before — .aspect/workflows/config.yaml plus a warming job running rosetta run warming + warming_archive. After — a scheduled CI job:
The warming task itself doesn’t need the setup-aspect plugin: it always runs on an Aspect Workflows CI runner where aspect is already on the PATH, and it makes no vanilla bazel calls. The GitHub Actions example still uses the action because it provides the auth aspect needs to post its status check; on other providers, supply ASPECT_API_TOKEN instead (see the comments in the examples).
name: Aspect Workflows Warming

on:
  schedule:
    - cron: '0 12 * * *'  # 7 AM ET (UTC-5)
  workflow_dispatch:

permissions:
  id-token: write

jobs:
  warming:
    runs-on: [self-hosted, aspect-workflows, aspect-default]
    steps:
      - uses: actions/checkout@v4
      - uses: aspect-build/setup-aspect@2306377a61c45954ab2df7c7311698b109364352 # v2026.26.9
        with:
          aspect-api-token: ${{ secrets.ASPECT_API_TOKEN }}
      - name: Warming
        run: aspect ci warming --task:name warming -- //...
Each provider triggers the job on its own schedule: a GitHub Actions schedule: cron, a Buildkite scheduled pipeline, a GitLab pipeline schedule, or a CircleCI scheduled pipeline — as shown in the examples above. Point it at your main branch and run it as often as your cache churn warrants (daily is typical).