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Caching

Dagger has two distinct caching mechanisms:

  1. The layers cache: This caches build instructions and the results of withExec() API calls. It is implemented by Buildkit.
  2. The volumes cache: This caches the contents of a Dagger volume and is persisted across Dagger Engine sessions. It is maintained locally and, where applicable, replicated to Dagger Cloud. It is implemented by Dagger (distinct from Buildkit).

Implementation​

Both cache mechanisms are namespaced by Dagger Cloud Organization name.

  • The cache key for the layers cache is bucket / organization-name / content-address.
  • The cache key for the volumes cache is bucket / organization-name / volume-name, where the volume name is set by the user using the Dagger API.
  • Manifests of the layers cache are sent to Dagger Cloud to support merging layers between runs (not supported by Buildkit).

The cache is shared across pipelines and runs, within the same Dagger Cloud organization. This implies that users in the same organization share the same cache.

important

No cache data is shared across organizations.

Security​

Both caching mechanisms use an object store (S3 or S3-compatible).

Data is encrypted in transit (the transport layer is HTTPS/TLS) and at rest (read more about data encryption in CloudFlare R2, AWS S3 and Google Cloud Storage).