Get tag from public registry instead of private proxy

[jlimai]

How are you running Renovate?

Self-hosted Renovate

If you're self-hosting Renovate, tell us which platform (GitHub, GitLab, etc) and which version of Renovate.

Gitlab / Renovate 39.69.2

Please tell us more about your question or problem

I understand that Harbor proxy registry does not work with Renovate, therefore I want to replace my private registry to use public to get the latest tag and update my Dockerfile.

Dockerfile

ARG REGISTRY_URL=registry.harbor.io
ARG ALPINE_VERSION=3.16.0
FROM ${REGISTRY_URL}/docker/alpine:$ALPINE_VERSION

Current renovate.json

The following configuration works if my Dockerfile is referring to public Docker hub, but for internal private registry.harbor.io, I couldn't make it work.

{
  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
  "prHourlyLimit": 0,
  "prConcurrentLimit": 0,
  "separateMinorPatch": true,
  "automerge": true,
  "packageRules": [
    {
      "matchDatasources": ["docker"],
      "matchUpdateTypes": ["minor"]
    }
  ]
}

I have also tried the following renovate.json, while changing docker.io, index.docker.io....etc but still no luck

{
  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
  "extends": [
    "config:base"
  ],
  "registryAliases": {
      "$REGISTRY_URL": "https://index.docker.io"
  },
  "prHourlyLimit": 0,
  "prConcurrentLimit": 0,
  "separateMinorPatch": true,
  "automerge": false,
  "customManagers": [
    {
      "customType": "regex",
      "fileMatch": [
        "^.*?/Dockerfile$",
        "^Dockerfile$"
      ],
      "matchStrings": [
        "FROM\\s+(?<depName>registry\\.harbor\\.io/docker/alpine):(?<currentValue>[^\\s]+)"
      ],
      "depNameTemplate": "index.docker.io",
      "autoReplaceStringTemplate": "FROM {{{depName}}}:{{{newValue}}}",
      "datasourceTemplate": "docker"
    }
  ],
  "packageRules": [
    {
      "matchDatasources": ["docker"],
      "matchUpdateTypes": ["minor"]
    }
  ]
}

I have found multiple discussion thread that saying this could be done by replacing the private registry to use public registry for lookup but I couldn't figure out how to configure the renovate.json. Not sure to use regexManager or customManager and how would the configuration looks like.

• docker datasource registryUrls #24894
• Rule to update docker images to be prefixed with private registry url #19395

I would like to replace https://registry.harbor.io/docker/<repo>:<tag> to https://docker.io/<repo>:<tag> during the tag discovery. Some help will be very much appreciated. Thank you

Logs (if relevant)

The logs found empty tag as expected because of Harbor registry

DEBUG: Starting package releases lookups (repository=cet/container-images/renovate-test, baseBranch=main)
 INFO: Found no results from datasource that look like a version (repository=cet/container-images/renovate-test, dependency=registry.interos.io/docker/alpine)
       "result": {
         "registryUrl": "https://registry.harbor.io",
         "releases": [],
         "lookupName": "docker/alpine"
       }

[github-actions[bot]]

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[jlimai]

I have solved the problem by using customManagers to check on a specific custom environment file to detect version rather than using directly in Dockerfile.