[Pacemaker] how to determin crm version / features from within a RA

[Lars Ellenberg]

On Thu, Jun 11, 2009 at 01:59:56PM +0200, Dejan Muhamedagic wrote:
> > so, to summarize, I hacked up a compare_version.
> > and I think I even avoided bashisms! that is once in a life time :)
> 
> Exemplary ;-)

It may depend on some GNU stuff in sed and sort, though.

> > comments?
> > overkill?
> > useful?
> 
> Yes. Unfortunately, the thing got quite complicated. Some
> comments:
> 
> 	sort_keys=$(seq $l | sed -e 's/.*/ -k&,&/;2~2 s/$/n/')
>
> Won't even try to unravel this magic.

l was set to the number or version parts (non-numeric, numeric).
so I get $l "columns", need that many sort keys.
and they need to do "ascii" and "numeric" sort.

seq 3
1
2
3
seq 3 | sed -e 's/.*/ -k&,&/'
 -k1,1
 -k2,2
 -k3,3
... | -e '2~2 s/$/n/'
"every second of two lines, append an n" (for numeric sort).
 -k1,1
 -k2,2n
 -k3,3

> eval $(cibadmin -Ql |
>     sed -n -e '1 s/^<cib validate-with=\("[^"]*"\).*$/_CIB_VALIDATE_WITH=\1/p' \
>
> Beware: Attributes may come in any order. AFAIK, no guarantee at
> all about it.
> 
>            -e 's/^[[:space:]]*<nvpair id="cib.bootstrap.options.dc.version".*
> 
> Also, the id may be just about anything, can't rely on that,
> better use the name attribute.

is it, really arbitrary for the cib bootstrap things?
> 		   value="\([0-9.:]*\).*$/_DC_VERSION=\1/p')
> 
> Hmm, don't really like eval here. If you really can't do without
> it, at least protect the value with quotes. The same above with
> _CIB_VALIDATE_WITH.

of course I can do without it.
I want to avoid to have to do it in two passes.
but no need.  the _DC_VERSION value only contains [0-9.:],
which does not need to be quoted.
for the _CIB_VALIDATE_WITH, the \("[^"]*"\) intentionally
captures the enclosing quotes. ok, it could theoretically
at one point in the future contain a backslash.
but would 
<cib validate-with="something\" ...> be valid xml?
and yes, it could in theory contain "`rm -rf /`" ;)

Ok. I'll add some comments,
and rewrite that part to
sed -ne '/^<cib/ { s/^.*\bvalidate-with="\([^"]*\)".*$/\1/;s/[^-%+.\/0-9:=@A-Z_a-z]/\\&/g;s/^/_CIB_VALIDATE_WITH=/;p;}'
     -e '1,/<cluster_property_set\b/d;/<\/cluster_property_set>/q;'
     -e '/^[[:space:]]*<nvpair .*\bname="dc-version"/ s/^.*\bvalue="\([0-9.:]*\).*$/_DC_VERSION=\1/p'

hey, you asked for it

 ;)


-- 
: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

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