Inspect your application image

Buildpacks-built images contain metadata that allow you to audit both the image itself and the build process.

Information includes:

• The process types that are available and the commands associated with them
• The run-image the app image was based on
• The buildpacks were used to create the app image
• Whether the run-image can be rebased with a new version through the Rebasable label or not
• And more…!

pack offers a command to help you inspect the application image and view some of its contents as shown below:

pack inspect-image test-node-js-app

You should see the following:

Run Images:
  cnbs/sample-base-run:noble
...

Buildpacks:
  ID                   VERSION        HOMEPAGE
  examples/node-js        0.0.1          -

Processes:
  TYPE                 SHELL        COMMAND                           ARGS        WORK DIR
  web (default)        bash         node-js app.js                                   /workspace

Apart from the above standard metadata, buildpacks can also populate information about the dependencies they have provided in form of a Software Bill-of-Materials or SBOM.

Buildpacks-built images are constructed in a way that’s easy to understand, with each of the layers being meaningful and independent of all other layers. You can get more details about each layer and how it was created to better understand how the build actually worked.

There are a number of available tools that can help you achieve this and understand what is contained in your OCI image; a popular one is dive.

Dive can help you inspect OCI images and view their layers and each layer’s details. If you were to build an OCI image following the multi process app example and run dive on the generated image, you’ll be presented with some detailed information about all of the image layers and the contents of each layer.

You can use dive as follows:

dive multi-process-app

The output should look similar to the following:

PLACEHOLDER

As seen in the output above, you’re presented with Layers, Layer Details, Image Details, and Current Layer Contents. To view the contents or explore the file tree of any layer, you need to select the layer on the left using the arrow keys.