Lucy -- Layer Update Check Yeoman v1.0

This tool checks to see if a container image is stale, per the image layers it relies on and should therefore be re-built.

It can work with any registry that supports Registry API. It has special support for Docker Hub and GitHub Container Registry.

Lucy has following required syntax.

lucy targetImageAddress baseImageAddress

You can see this with the following examples.

$ ./lucy ghcr.io/richlander/lucy:main mcr.microsoft.com/dotnet/runtime:7.0
{"image":"ghcr.io/richlander/lucy:main","baseImage":"mcr.microsoft.com/dotnet/runtime:7.0","state":"fresh","layer":"sha256:058f65a20fb5ccb9c513d000e1a8ef5b1eefa936edf2503afb391dd9233c3034"}
$ ./lucy mcr.microsoft.com/dotnet/runtime:7.0 debian:bullseye-slim             
{"image":"mcr.microsoft.com/dotnet/runtime:7.0","baseImage":"debian:bullseye-slim","state":"stale","layer":"sha256:0df644382ba7fd23e9e4166ec2a03ec88b6cc5f640fb45413ecd913ceb901e41"}
$ ./lucy ghcr.io/richlander/dotnet-docker/aspnetapp:nightly mcr.microsoft.com/dotnet/aspnet:7.0 | jq -r .state
fresh

The tool has various verbosity modes. The demonstrated verbosity is the default or --verbosity 0.

The following example demonstrates --verbosity 1.

$ lucy mcr.microsoft.com/dotnet/samples:aspnetapp mcr.microsoft.com/dotnet/aspnet:7.0 --verbosity 1
Layer Update Check Yeoman (Lucy) v1.0
Target image: mcr.microsoft.com/dotnet/samples:aspnetapp
Base image  : mcr.microsoft.com/dotnet/aspnet:7.0

Both images type: application/vnd.docker.distribution.manifest.list.v2+json
Image includes 5 manifests that will be validated.

Image state:
fresh

The following example demonstrates --verbosity 2.

$ lucy mcr.microsoft.com/dotnet/samples:aspnetapp mcr.microsoft.com/dotnet/aspnet:7.0 --verbosity 2
Layer Update Check Yeoman (Lucy) v1.0
Target image: mcr.microsoft.com/dotnet/samples:aspnetapp
Base image  : mcr.microsoft.com/dotnet/aspnet:7.0

Both images type: application/vnd.docker.distribution.manifest.list.v2+json
Image includes 5 manifests that will be validated.

Validate for: linux/amd64
Layer match: sha256:bd159e379b3b1bc0134341e4ffdeab5f966ec422ae04818bb69ecef08a823b05
Layer match: sha256:e55a07b7e890c54fa94df56be9590be6835718888c746f061dfc526ed2d529ec
Layer match: sha256:81957ac33dd22b8cc7db206b57ff1aa08540a8727d70f775509d9a18ff94f6a4
Layer match: sha256:eefb39c22ce5dbe64ad685b76b831041c95f6262ad7198f0944aebafa66175ea
Layer match: sha256:fc64b2e24534785dcaf98ff5acf03fcb1e5e261751dfbd2529a92498bc24331a

Validate for: linux/arm
Layer match: sha256:2bc64aeac2e429577e497affc8a416d2fc59158aa967f07aced793368e19455f
Layer match: sha256:9d08e29ce3eec8c7f44a3fb502900ef8c2436dcdfb450725dd7c0f3a12466930
Layer match: sha256:4d5be00e05469cd22347ba13a8842dce3d9d677ae57c3f933a6bc192c3dc6cee
Layer match: sha256:8a4730357f770d9d6431edd46c42a4bd029f957952d3c600541a203202b5fdfb
Layer match: sha256:6d8e696456b278ef2b0ae7fb5ea20ddeedd64f4935118884d84d793abb008e39

Validate for: linux/arm64
Layer match: sha256:df8e44b0463f16c791d040e02e9c3ef8ec2a84245d365f088a80a22a455c71e8
Layer match: sha256:21c9038c1a953871c0a5f731499cbf9d37d2dafe200c9dd404f1550948adcfe0
Layer match: sha256:1b471a2fe1f9ad70ffb7ef80f17c96ae8a2e7dd98e56cff1e81a754cc45fbbce
Layer match: sha256:a8fef95352377aa992b4f643b8629a421660b2189e7ba138f8272de0e3ea3a6d
Layer match: sha256:191a955a3ef70a2fccc98e41e5e36825289d32b6b1e5a6173ae1d70089791cd2

Validate for: windows:10.0.17763.3532/amd64
Layer match: sha256:5ead999142ecce15e02523c49706a633fa708374d94bb65a254e3a3c117d609b
Layer match: sha256:e17326ec6b7ff7ab34fb7d29b001527a8c7fa4ec19b01fe6c271200e688c0d07
Layer match: sha256:631a0ae392689ecc59fde470bb76f48d75bbcffb98d67198f437f3e5f4174121
Layer match: sha256:4e77dc6b3804367a8a316a32663d62088e004fb1c4ebe9d073195a3f60a1c5f3
Layer match: sha256:55ff1c4fe1d67f279dc08e16a8fbc5a723786b195fe6808881ca79407bb20ccb
Layer match: sha256:0966ea5c7a216101260c1550fd515ceeb928bb54505d964e5df6a5da346e5281
Layer match: sha256:128bee0e6c7136266de2b83359591568cb96d6e8a8ddde9d5363e70fcf306148
Layer match: sha256:00ef2c7674320260031ca90efe861454abfdc94e01104ae3f2846e87a7824769

Validate for: windows:10.0.20348.1129/amd64
Layer match: sha256:38fa349577729651ac1fc3ec785f908719a8100da5f5ba9bd3f549411061f583
Layer match: sha256:ba6a6e4eb4c99f20a2a419c2cd42a5e854ab523d89eaf0606a88f83193365d7a
Layer match: sha256:269f0b75372c644c015aecdf99408f2190103fc9cb367cc96000f851422afe5d
Layer match: sha256:c2275f439f28c1225f70a02c393547e414a097a0c4ed85e2aaf7cc1ac61f8b45
Layer match: sha256:194ddcc24e2f69642195b508a928f2f535d32183a3ccb84071dd78421b0647f1
Layer match: sha256:e99c2f84a223b79e739f5a6c182006f19ef721da331f424c19d83642d8ee4afc
Layer match: sha256:210bff8f18ee08b13debfc5a7dc03165ac4e875db16fac54b61309a14fa74379
Layer match: sha256:6ae7a7d977cc2e5664c762fe74c94ee57370dfc802ddcc73eabf64c45ddb4b32

Image state:
fresh

Other features to consider

The following other features may be added.

• Call URL if image is stale (likely modeled around repository-dispatch) per CLI-provided URL.
• Enable setting platform of target image (instead of assuming linux/amd64).
• Retry logic for registry.
• Better error handling
• Move to dotnet org.
• Publish as global tool.
• Publish as GitHub action.
• Publish as a container image.
• Action keeps the container image up to date. It's circular!

Useful links

• https://github.com/orgs/community/discussions/26279
• https://gist.github.com/eggplants/a046346571de66656f4d4d34de69fdd0
• https://www.flypenguin.de/2021/07/30/auto-rebuild-docker-images-if-base-image-changes-using-github-actions/
• https://github.com/lucacome/docker-image-update-checker