Artifact caching

In this chapter we will go through the caching feature of CEKit.

CEKit has a built-in cache for artifacts. It’s purpose is to speed up the build process for subsequent builds.

Technical design

By default cached artifacts are located in the ~/.cekit/cache/ directory.


Cache location can be changed when you specify the --work-dir parameter. In such case cache will be located in a cache directory located inside the directory specified by the --work-dir parameter.

Every cached artifact is identified with a UUID (version 4). This identifier is also used as the file name (in the cache directory) for the artifact itself.

Each cached artifact contains metadata too. This includes information about computed checksums for this artifact as well as names which were used to refer to the artifact. Metadata is stored in the cache directory too, the file name is the UUID of the artifact with a .yaml extension.


If your artifact will have 1258069e-7194-426d-a6ab-ade0a27b8290 UUID assigned with it, then it will be found under the ~/.cekit/cache/1258069e-7194-426d-a6ab-ade0a27b8290 path and the metadata can be found in the ~/.cekit/cache/1258069e-7194-426d-a6ab-ade0a27b8290.yaml file.

Artifacts in cache are discovered by the hash value.

While adding an artifact to the cache, CEKit is computing it’s checksums for all currently supported algorithms (md5, sha1, sha256, sha512). This makes it possible to refer the same artifact in descriptors using different algorithms.

This also means that CEKit is using cache only for artifacts which define at least one hash.

Automatic caching

CEKit is automatically caching all artifacts used to build the image. Consider following image descriptor snippet:

    - name: jolokia-1.3.6-bin.tar.gz
      md5: 75e5b5ba0b804cd9def9f20a70af649f

This artifact will be automatically added into the cache during image build. This is useful as the artifact will be automatically copied from cache instead of downloading it again on any rebuild.

Managing cache

CEKit provides command line tool called cekit-cache which is used to manage cache.

It has a --work-dir (by default set to ~/.cekit) parameter which sets CEKit’s working directory. This is where the cache directory will be located.


If you customize --work-dir – make sure you use the same path for cekit and cekit-cache commands. You can also set the path in the configuration file.

Caching artifacts manually

CEKit supports caching artifacts manually. This is very usefull if you need to introduce non-public artifact to a CEKit. To cache an artifact you need to specify path to the artifact on filesystem or its URL and at least one of the supported hashes (md5, sha1, sha256, sha512).


Caching local artifact

$ cekit-cache add path/to/file --md5 checksum

Caching remote artifact

$ cekit-cache add --sha256 checksum

Listing cached artifacts

To list all artifact known to CEKit cache you need to run following command:

$ cekit-cache ls

After running the command you can see following output:

  sha512: 5f4184e0fe7e5c8ae67f5e6bc5deee881051cc712e9ff8aeddf3529724c00e402c94bb75561dd9517a372f06c1fcb78dc7ae65dcbd4c156b3ba4d8e267ec2936
  sha256: c93c096c8d64062345b26b34c85127a6848cff95a4bb829333a06b83222a5cfa
  sha1: 3c3231e51248cb76ec97214f6224563d074111c1
  md5: c1a230474c21335c983f45e84dcf8fb9
    - spark-2.4.0-bin-hadoop2.7.tgz

  sha512: cf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e
  sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
  sha1: da39a3ee5e6b4b0d3255bfef95601890afd80709
  md5: d41d8cd98f00b204e9800998ecf8427e
    - artifact

Removing cached artifact

If you are not interested in particular artifact from cache, you can delete it by executing following command:

$ cekit-cache rm uuid


You can get uuid of any artifact by invoking cekit-cache ls command. Please consult Listing cached artifacts.

Wiping cache

To wipe whole artifact cache you need to run the cekit-cache clear command. This will ask you for confirmation of the removal step.

$ cekit-cache clear