status: Add version into status --json

[cgwalters]

I wanted to add some code into openshift/machine-config-operator
which checked the rpm-ostree version. We can do this today with
rpm-ostree --version or rpm -q rpm-ostree, but the MCO today
already reads rpm-ostree status --json.

It's much more natural to parse JSON for this as opposed to forking
the binary again or querying rpm. (The latter in particular would
require splitting on the upstream version vs release tag etc.)

[jlebon]

Hmm, just forking rpm-ostree --version again doesn't seem like a big deal. It's in YAML format too, so it's ready to parse and has even more versioning info! :)

Having it in status --json feels a bit odd IMO, but not strongly against either.

[cgwalters]

Hmm, just forking rpm-ostree --version again doesn't seem like a big deal. It's in YAML format too, so it's ready to parse and has even more versioning info! :)

I wrote a whole rationale in the commit message about this - specifically JSON vs YAML, and the fact that we are already parsing the status output.

Probably though what we really want here is official Go bindings #2389

[jlebon]

Hmm, just forking rpm-ostree --version again doesn't seem like a big deal. It's in YAML format too, so it's ready to parse and has even more versioning info! :)

I wrote a whole rationale in the commit message about this - specifically JSON vs YAML, and the fact that we are already parsing the status output.

Right, I get that it's the most convenient thing to do for the MCO. But we should still weigh the different options. For example, I see you've already got something using rpm-ostree --version in openshift/machine-config-operator#2859. Most of that code is parsing the string itself, which would be the same regardless. But we could make that easier if we add a e.g. VersionYear and VersionRelease already integer typed in the --version output.

Probably though what we really want here is official Go bindings #2389

👍

[cgwalters]

For example, I see you've already got something using rpm-ostree --version in openshift/machine-config-operator#2859. Most of that code is parsing the string itself, which would be the same regardless

Yes, but I only wrote all that code because we didn't have the version in status 😄

[jlebon]

For example, I see you've already got something using rpm-ostree --version in openshift/machine-config-operator#2859. Most of that code is parsing the string itself, which would be the same regardless

Yes, but I only wrote all that code because we didn't have the version in status 😄

What I mean is wouldn't most of that code be the same though? Since we'd still have to parse a version string.

(Again to clarify, I'm OK with this. But I think there's an opportunity to make that MCO code way simpler if we just extend rpm-ostree --version. Or we could throw the new integer fields into status --json too, but that's even more awkward.)

[cgwalters]

Eh, we can revisit this later.