Download Resources from Component Versions

Download Resources of a Component Version

Use the ocm download resources command to download specific resources from a component version. In this example we download the resource with name chart from the example component used in the last chapter and save it as local file:

ocm download resource ghcr.io/open-component-model/ocm//ocm.software/toi/demo/helmdemo:0.21.0 --identity name=chart --output helmchart.tgz
...
time=2025-08-14T13:03:54.372+02:00 level=INFO msg="resource downloaded successfully" output=helmchart.tgz

Because it is stored as OCI artifact in an OCI registry, the filesystem format used for OCI artifacts is the blob format.

What happened?

The file helmchart.tgz was downloaded.

tar xvf helmchart.tgz
blobs/sha256/ea8e5b44cd1aff1f3d9377d169ad795be20fbfcd58475a62341ed8fb74d4788c
blobs/sha256/8702d8d550075e410f3aae545d1191df9e5ab8747e5c5a8eda5ed834fd135366
blobs/sha256/8ab41f82c9a28535f1add8ffbcd6d625a19ece63c4e921f9c8358820019d1ec2
index.json
oci-layout

Under Construction

The file permissions and ownership may not be preserved when extracting the archive. This needs to be fixed. Currently you have to add at least read permissions to continue: chmod +r index.json

jq . index.json
{
  "schemaVersion": 2,
  "manifests": [
    {
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "digest": "sha256:8ab41f82c9a28535f1add8ffbcd6d625a19ece63c4e921f9c8358820019d1ec2",
      "size": 410,
      "annotations": {
        "org.opencontainers.image.ref.name": "ghcr.io/open-component-model/ocm/ocm.software/toi/demo/helmdemo/echoserver:0.1.0@sha256:8ab41f82c9a28535f1add8ffbcd6d625a19ece63c4e921f9c8358820019d1ec2"
      }
    }
  ]
}

Download using Transformers

Under Construction

Transformers are currently in development. We’ll extend the below section once they are ready to be used. Until then you can check out the Transformer ADR

To use a format more suitable for the content technology, you can use the --transformer to specify a transformer. The transformer will take care that the file will be saved using its correct media type, e.g. a Helm charts will be saved as .tgz file which on extraction will show the complete chart.

ocm download resource ghcr.io/open-component-model/ocm//ocm.software/toi/demo/helmdemo:0.12.0 chart --identity name=chart --output helmchart.tgz --transformer helm
  helmchart.tgz: 3763 byte(s) written
What happened?

The downloaded archive is now a regular Helm Chart archive:

tar tvf helmchart.tgz
  -rw-r--r--  0 0      0         136 Jul 19 16:32 echoserver/Chart.yaml
  -rw-r--r--  0 0      0        1842 Jul 19 16:32 echoserver/values.yaml
  -rw-r--r--  0 0      0        1755 Jul 19 16:32 echoserver/templates/NOTES.txt
  -rw-r--r--  0 0      0        1802 Jul 19 16:32 echoserver/templates/_helpers.tpl
  -rw-r--r--  0 0      0        1848 Jul 19 16:32 echoserver/templates/deployment.yaml
  -rw-r--r--  0 0      0         922 Jul 19 16:32 echoserver/templates/hpa.yaml
  -rw-r--r--  0 0      0        2083 Jul 19 16:32 echoserver/templates/ingress.yaml
  -rw-r--r--  0 0      0         367 Jul 19 16:32 echoserver/templates/service.yaml
  -rw-r--r--  0 0      0         324 Jul 19 16:32 echoserver/templates/serviceaccount.yaml
  -rw-r--r--  0 0      0         385 Jul 19 16:32 echoserver/templates/tests/test-connection.yaml
  -rw-r--r--  0 0      0         349 Jul 19 16:32 echoserver/.helmignore
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Example of a Component Descriptor