translate: support deprecated create filesystem object

[tormath1]

Hi,

In this PR, we add support for create object in the filesystem configuration:

  "storage": {
    "filesystems": [
      {
        "mount": {
          "device": "/dev/disk/by-label/ROOT",
          "format": "btrfs",
          "create": {
            "force": true,
            "options": [
              "--label=ROOT",
              "--uuid=9aa5237a-ab6b-458b-a7e8-f25e2baef1a3"
            ]
          }
        }
      }
    ]

ign-converter will try to use value from f.Mount.WipeFilesystem if this one is nil and we have a f.Mount.Create struct, we try to parse the options (label and uuid) and wipeFilesystem is conditionally bound to f.Mount.Create.Force.

Even if create object is deprecated, I feel that supporting into the ign-converter will help users to migrate to newer versions of ignition.

[bgilbert]

Thanks for the PR!

[bgilbert]

If Force is true, it's safe to set WipeFilesystem true. But if Mount.Create is non-nil and Force is false, I think we should fail the translation. In that situation, the config is asking for the FS to be created if it doesn't exist, and for Ignition to fail otherwise. For the case where the filesystem exists and matches the specified parameters (format etc.), Ignition 2.x can't deliver those semantics: provisioning would succeed instead.

[tormath1]

I get your point - and this is something I'd like to talk with you; maybe in a dedicated issue. Currently ign-converter expects a fsMap to map file systems with path, what if we could generate this value on the fly, with something like:

 @@ -49,7 +50,13 @@ func Check2_4(cfg old.Config, fsMap map[string]string) error {
        fsMap["root"] = "/"
        for _, fs := range cfg.Storage.Filesystems {
                if _, ok := fsMap[fs.Name]; !ok {
-                       return util.NoFilesystemError(fs.Name)
+                       // generate a random path
+                       p, err := ioutil.TempDir("", fs.Name)
+                       if err != nil {
+                               return fmt.Errorf("creating tmp fs directory: %w", err)
+                       }
+
+                       fsMap[fs.Name] = p
                }

[bgilbert]

Let's discuss that change in a separate issue. I don't think it's relevant here, though? The problem here isn't the mountpoint, but what to do if the specified Device already has a filesystem superblock on it.

[tormath1]

Ok, the issue is created in here: #30

The problem here isn't the mountpoint, but what to do if the specified Device already has a filesystem superblock on it.

Got it.

[bgilbert]

Okay, cool. So let's add an error return in Check2_* if f.Mount.Create != nil && !f.Mount.Create.Force, and a comment here referring to that.

[tormath1]

@bgilbert fixup! commits have been squased since you resolved the conversations and two new commits have been pushed to add the check config and its associated test dicussed in here: #28 (comment).