image-syncer

README

image-syncer

Overview

image-syncer is used to safely copy container images from one registry to another. The main use case is to preserve images from third party registries in our own registry that we can rely on.

Syncing process steps:

1. Pull image from source.
2. Check if image name contains SHA256 digest.
3. If image name contains digest, re-tag target image with the tag instead of SHA256 digest.
4. Check if image exists in target.
5. If image does not exist, re-tag image and push to target registry.
   If image exists: compare IDs. If they are different, synchronization is interrupted. It means that something is wrong and the source image was changed (this should not happen).

These steps guarantee that images in our registry are immutable.

Usage

To run image-syncer, use:

go run main.go \ 
    --images-file={PATH_TO_A_YAML_FILE_CONTAINING_SYNC_DEFINITION} \
    --target-key-file={PATH_TO_A_JSON_KEY_FILE} \
    --dry-run=true

Definition file

image-syncer takes as an input parameter a file having the following structure:

targetRepoPrefix:  "eu.gcr.io/kyma-project/external/"
images:
- source: "bitnami/keycloak-gatekeeper:9.0.3"
- source: "bitnami/postgres-exporter:0.8.0-debian-10-r28"
- source: "busybox@sha256:31a54a0cf86d7354788a8265f60ae6acb4b348a67efbcf7c1007dd3cf7af05ab"
  tag: "1.32.0-v1"

Flags

Usage:
  image-syncer [flags]

Flags:
  -d, --dry-run                  dry run mode [SYNCER_DRY_RUN] (default true)
  -h, --help                     help for githubstats
  -i, --images-file string       yaml file containing list of images [SYNCER_IMAGES_FILE]
  -t, --target-key-file string   JSON key file used for authorization to target repo [SYNCER_TARGET_KEY_FILE]

exit status 1

Environment variables

All flags can also be set using these environment variables:

Name	Required	Description
SYNCER_IMAGES_FILE	Yes	Path to the YAML file with the sync definition, provided as a string.
SYNCER_TARGET_KEY_FILE	Yes	Path to the JSON key file, provided as a string.
SYNCER_DRY_RUN	No	Value controlling the dry run mode, provided as a boolean.