peerleaders

Prototype: peerleaders(filename, regex, groupsize)

Return type: slist

Description: Returns a list of peer leaders from the named partitioning.

Peers are defined according to a list of hosts, provided in filename. This file should contain a list (one per line), possibly with comments matching regex, of fully qualified host names. CFEngine breaks up this list into non-overlapping groups of up to groupsize, each of which has a leader that is the first host in the group.

The current host does not need to belong to this file.

Arguments:

• filename : File name of host list, in the range "?(/.*)

A path to a file containing the list of hosts.

• regex : Comment regex pattern, in the range .*

A pattern that matches a legal comment in the file. The regex is unanchored, meaning it may match a partial line. Comments are stripped as the file is read.

• arg3 : Peer group size, in the range 0,99999999999
  

A number between 2 and 64 which represents the number of peers in a peer-group. An arbitrary limit of 64 is set on groups to avoid nonsensical promises.

Example:

Example file:

     one
     two
     three # this is a comment
     four
     five
     six
     seven
     eight
     nine
     ten
     eleven
     twelve
     etc

    bundle agent peers
    {
    vars:

      "mygroup" slist => peers("/tmp/hostlist","#.*",4);

      "myleader" string => peerleader("/tmp/hostlist","#.*",4);

      "all_leaders" slist => peerleaders("/tmp/hostlist","#.*",4);

    reports:

       "mypeer $(mygroup)";
       "myleader $(myleader)";
       "another leader $(all_leaders)";

    }