Fix ds-identify's read_fs_info() to work on FreeBSD

[igalic]

previously, ds-identify would mostly just guess that the system in question is maybe OpenStack.

This patch makes it correctly recognize NoCloud.

Proposed Commit Message

Fix ds-identify's read_fs_info() to work on FreeBSD

FreeBSD doesn't have blkid, so we want to use geom to list devices and their fstypes and labels.

This PR also adds jail to the list of is_container()
And we now also properly cache geom and blkid output!

Finally, A test is added to verify the new behaviour by correctly identifying NoCloud on FreeBSD.

Additional Context

This fixes LP 1901174

Checklist:

• My code follows the process laid out in the documentation
• I have updated or added any unit tests accordingly
• I have updated or added any documentation accordingly

[smoser]

needs tests in test_dsidentify.

also... maybe we consider trying to render different versions ? freebsd and linux ?

rather than trying linux then trying freebsd.

probably that is not necessary if we're doing it based on uname.

[smoser]

bah. this needs fixing. we dont actually do anything to set that variable.
the intent of the variable is to say we've already run blkid and cached its output.

this isn't your fault. the intent of DI_BLKID_OUTPUT was to store the result of calling 'blkid', so that we didn't call that external program more than once. So I guess what I'd like from you:

a.) a comment in read_fs_info stating what variables it sets (DI_FS_LABELS, DI_ISO9660_DEVS, DI_FS_UUIDS)
b.) drop of the DI_BLKID_OUTPUT cache here
c.) add caching of call to 'geom'. the easiest way to do this might be just adding a variable 'DI_GEOM' and put the call to 'geom' in a function, something like:

geom_label_status_as() {
    # call the bsd program geom '-as', set DI_GEOM_LABEL_STATUS_OUT
    cached "$DI_GEOM_LABEL_STATUS_OUT" && return 0
    local out=""
    out=$(geom -as label status) &&  DI_GEOM_LABEL_STATUS="$out" ||
        DI_GEOM_LABEL_STATUS="$UNAVAILABLE"
    return
 }

d.) fixing of the caching of 'blkid' output (i realize i'm asking you to fix a bug that isn't your fault... go ahead and git blame this and see that it is mine. 😉 ), but having this variable/cache that doesn't do anything is just confusing.

[igalic]

i realize i'm asking you to fix a bug that isn't your fault...

i'm perfectly happy to do that, it just means this patch will take as long as all my other patches usually do 😅

[igalic]

i think this is done now

[smoser]

after adding the 'geom_label_status_as' function, then you'll just use the variable, so here this would look like:

geom_label_status_as
local out="$DI_GEOM_LABEL_STATUS_OUT"
...
[ "$out" ] = "$UNAVAILABLE" && return 0

and the rest of your function here.

[igalic]

you mean

[ "$out" = "$UNAVAILABLE" ] && return 0

right?

[smoser]

yes. good lint'ing.

[igalic]

hmmmm…
for now i'm passing on the return value instead of return 0… not sure that's a sensible thing to do

[igalic]

@smoser any comments on the test?

[smoser]

@smoser any comments on the test?

Sure, 2 comments:
a.) i dont think you actually added a test. (need to add a function name test_)
b.) other than that i thin your changes there look fine. the 'blkid_out' method that you mimic'd in "geom_out" was an attempt to be less verbose in tests. it feels like you did the right thing here in translating the data to geom output.

[igalic]

@smoser i naïvely assumed this would add a test case

[smoser]

still no test, right?

[igalic]

gimme a day or two, while i work my way thru https://pythontesting.net/start-here/

[igalic]

ℹ️

[smoser]

I like it. good work.