imagedeps

README

Image Deps

This is a utility designed to take a list of images as input, and to generate FQN's of each input image including the latest tag and output this information into an environment file, and a Go source file containing constant declarations. It is designed to be run as a script, for example:

go run github.com/replicatedhq/kots/cmd/imagedeps 
2021/09/15 10:33:46 started tagged image file generator
2021/09/15 10:33:48 successfully generated constant file "pkg/image/constants.go"
2021/09/15 10:33:48 successfully generated dot env file ".image.env"

If successful it will generate two files, a file of constant declarations pkg/image/constants.go and .image.env. The Go file contains constant declarations of image references with the latest version tags. The .env file contains environment variables defining the latest tags for images.

Input

Latest tags will be found for images that are defined in a text file cmd/imagedeps/image-spec. Each line contains space delimited information about an image and an optional filter. If the filter is present, only tags that match will be included. This is useful to restrict release tags to a major version, or to filter out garbage tags.

Name	Image URI	Matcher Regexp (Optional)
Name of the image for example minio	Untagged image reference ghcr.io/dexidp/dex	An optional regular expression, only matching tags will be included.

Sample image-spec

minio minio/minio
postgres-alpine postgres ^10.\d+-alpine$
postgres-debian postgres ^10.\d+$
dex ghcr.io/dexidp/dex

The preceding image spec will produce the following environment and Go files. Note how the override tags are applied to the Postgres definitions.

MINIO_TAG='RELEASE.2021-09-15T04-54-25Z'
POSTGRES_ALPINE_TAG='10.17-alpine'
POSTGRES_DEBIAN_TAG='10.17'
DEX_TAG='v2.30.0'

package image

const (
	Minio = "minio/minio:RELEASE.2021-09-15T04-54-25Z"
	PostgresAlpine = "postgres:10.17-alpine"
	PostgresDebian = "postgres:10.17"
	Dex = "ghcr.io/dexidp/dex:v2.30.0"
)

Github

Some of the image tags are resolved by looking at the Github release history of their associated projects. This involves interacting with the Github API. The program uses an optional environment variable GITHUB_AUTH_TOKEN which is a Github API token with public_repo scope for the purpose of avoiding rate limiting. The program will work without GITHUB_AUTH_TOKEN but it is not recommended.