[augeas-devel] fstab lens

[Raphaël Pinson]

Hi,


The problem is indeed your code. opt nodes must be all in the same
place. In order to do so, all you need to do is create a new new opt
node after the last existing one before you assign it a value. Use ins
for that:


define opt ( $fname, $opt, $value ) {
        $key = $name
        $context = "/files/etc/fstab"

        augeas { "$key-$fname-$opt-$value":
            context => "$context",
            onlyif => "match *[spec='$key'][file='$fname']/opt[.='$opt']
 size == 0",
            changes => [
 "ins opt after *[spec='$key'][file='$fname']/opt[last()]",
 "set *[spec='$key'][file='$fname']/opt[last()] $opt",
 "set *[spec='$key'][file='$fname']/opt[last()]/value $value",
 ],
 }
}


should do.


Cheers,

Raphaël

On Sat, Jan 14, 2012 at 3:16 PM, Lance Dillon <riffraff169 at yahoo.com> wrote:
> I'm trying to edit /etc/fstab.  I'm trying to change the following line:
>
> tmpfs                   /dev/shm                tmpfs   defaults        0 0
>
> and add size=256m (and a few other options, but just testing with that for
> now).
>
> I have this puppet bit:
>
>     define opt ( $fname, $opt, $value ) {
>         $key = $name
>         $context = "/files/etc/fstab"
>
>         augeas { "$key-$fname-$opt-$value":
>             context => "$context",
>             onlyif => "match *[spec='$key'][file='$fname']/opt[.='$opt']
> size == 0",
>             changes => [ "set *[spec='$key'][file='$fname']/opt[last()+1]
> $opt",
>                          "set
> *[spec='$key'][file='$fname']/opt[last()]/value $value",
>                        ],
>         }
>     }
>
> Which basically does what I want to do in augtool:
>
> augtool> print /files/etc/fstab/*[spec='tmpfs']/files/etc/fstab/12
> /files/etc/fstab/12/spec = "tmpfs"
> /files/etc/fstab/12/file = "/dev/shm"
> /files/etc/fstab/12/vfstype = "tmpfs"
> /files/etc/fstab/12/opt = "defaults"
> /files/etc/fstab/12/dump = "0"
> /files/etc/fstab/12/passno = "0"
> augtool> set /files/etc/fstab/*[spec='tmpfs'][file='/dev/shm']/opt[last()+1]
> size
> augtool> set /files/etc/fstab/*[spec='tmpfs'][file='/dev/shm']/opt[last()]
> 256m
> augtool> print /files/etc/fstab/*[spec='tmpfs']/files/etc/fstab/12
> /files/etc/fstab/12/spec = "tmpfs"
> /files/etc/fstab/12/file = "/dev/shm"
> /files/etc/fstab/12/vfstype = "tmpfs"
> /files/etc/fstab/12/opt[1] = "defaults"
> /files/etc/fstab/12/dump = "0"
> /files/etc/fstab/12/passno = "0"
> /files/etc/fstab/12/opt[2] = "256m"
>
> However, there seems to be an error here:
>
> augtool> save
> error: Failed to execute command
> error: saving failed (run 'print /augeas//error' for details)
> augtool> print /augeas//error
> /augeas/files/etc/fstab/error = "put_failed"
> /augeas/files/etc/fstab/error/path = "/files/etc/fstab/12"
> /augeas/files/etc/fstab/error/lens =
> "/usr/share/augeas/lenses/dist/fstab.aug:23.17-30.22:"
> /augeas/files/etc/fstab/error/message = "Failed to match \n    { /spec/ =
> /[^\\001-\\004\\t\\n #,][^\\001-\\004\\t\\n ]*/ }{ /file/ =
> /[^\\001-\\004\\t\\n #,]+/ }{ /vfstype/ = /[^\\001-\\004\\t\\n #,=]+/ }({
> /vfstype/ = /[^\\001-\\004\\t\\n #,=]+/ })*{ /opt/ = /[^\\001-\\004\\t\\n
> #,=]+/ }({ /opt/ = /[^\\001-\\004\\t\\n #,=]+/ })*({ /dump/ = /[0-9]+/ }({
> /passno/ = /[0-9]+/ })?)?\n  with tree\n    { \"spec\" = \"tmpfs\" } {
> \"file\" = \"/dev/shm\" } { \"vfstype\" = \"tmpfs\" } { \"opt\" =
> \"defaults\" } { \"dump\" = \"0\" } { \"passno\" = \"0\" } { \"opt\" =
> \"256m\" }"
>
> I'm guessing it is from this:
>
> #fstab.aug
>   let record = [ seq "mntent" .
>                    [ label "spec" . store spec ] . sep_tab .
>                    [ label "file" . store Rx.neg1 ] . sep_tab .
>                    comma_sep_list "vfstype" . sep_tab .
>                    comma_sep_list "opt" .
>                    (sep_tab . [ label "dump" . store /[0-9]+/ ] .
>                     ( sep_spc . [ label "passno" . store /[0-9]+/ ])? )?
>                  . eol ]
>
> where the "opt" comma_sep_list is only allowed in one place, but the augtool
> change (and the puppet augeas change) converts it to an array/list (from a
> single entry), but puts the second entry at the end instead of with the
> other entry.
>
> Is this a defect in the lens, or in my code?  What would be the best way of
> fixing this problem.
>
> I'd rather use augeas rather than the puppet mount type for flexibility.
>
> Thanks
>
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