limitDockerNodeUpdatesToLTS.json5

{
  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
  "customManagers": [
    {
      // match dockerfiles
      // https://github.com/renovatebot/renovate/blob/ae05eae500ad26ad93b0df7b00c26b85cc3be2ce/lib/modules/manager/dockerfile/index.ts#L10
      // https://github.com/hatena/renovate-config/blob/d7b0c790cc6300ff4f8bb455b13ff393f17ee44d/default.json#L20
      "fileMatch": [
        "(^|/|\\.)Dockerfile$",
        "(^|/)Dockerfile[^/]*$",
        "(^|/)Dockerfile-[^/]*$"
      ],
      // this regex matches the version portion within the dockerfile.
      // https://docs.renovatebot.com/modules/manager/regex/#regular-expression-capture-groups
      // https://regex101.com/r/sDsIb4/1
      "matchStrings": [
        "FROM node:(?<currentValue>[0-9.]+?)[^0-9.]*\\n"
      ],
      "depNameTemplate": "node",
      "datasourceTemplate": "node",
      "versioningTemplate": "node"
    }
  ],
  // since the regexManager above takes care of node versions within the dockerfile, the packageRule should be disabled as follows.
  "packageRules": [
    {
      "matchPackageNames": [
        "node"
      ],
      "matchManagers": [
        "dockerfile"
      ],
      "enabled": false
    }
  ]
}