A library for parsing and generating range expressions.

A library for parsing and generating range expressions. libcrange for modules to add symbolic name lookup features as well as functions to retreive additional data.

##Requirements

• apr apr-devel flex pcre pcre-devel sqlite sqlite-devel libyaml libyaml-devel perl-YAML-Syck perl perl-core perl-devel perl-libs

• libapr1 libapr1-dev flex libpcre3 libpcre3-dev sqlite3 libsqlite3-dev libsqlite3-0 libyaml-0-2 libyaml-dev libyaml-syck-perl perl-base libperl5.14 libperl-dev

• node1,node2,node3,node4 == node1..node4 == node1..4
• node1000..1099 == node1000..99 # auto pads digits to the end of the range
• 1..100 # numeric only ranges
• foo1-2.domain.com == foo1.domain.com-foo2.domain.com # domain support
• 209.131.40.1-209.131.40.255 == 209.131.40.1-255 # IP ranges

A cluster is a way to store node membership into groups. Depending on your backend module how this is stored may vary. In the case of the YAML module, a cluster is defined by the membership of the CLUSTER key

• %cluster101 == nodes defined in /var/range/cluster101.yaml - Default key CLUSTER
• %cluster101:ALL or %cluster101:FOO == nodes defined in a specific key of ks301/nodes.cf
• %%all == assuming %all is a lust of clusters, the additional % will expand the list of clusters to node list that is their membership
• *node == returns the cluster(s) that node is a member of

• range1,range2 == union
• range1,-range2 == set difference
• range1,&range2 == intersection
• ^range1 == admins for the nodes in range1
• range1,-(range2,range3) == () can be used for grouping
• range1,&/regex/ # all nodes in range1 that match regex
• range1,-/regex/ # all nodes in range1 that do not match regex

• foo{1,3,5} == foo1,foo3,foo5
• %cluster30{1,3} == %cluster301,%cluster303
• %cluster301-7 == nodes in clusters cluster301 to cluster307
• %all:KEYS == all defined sections in cluster all
• %{%all} == expands all clusters in %all
• %all:dc1,-({f,k}s301-7) == names for clusters in dc1 except ks301-7,fs301-7
• %all:dc1,-|ks| == clusters in dc1, except those matching ks

libcrange modules can define certain functions to look up data about hosts or clusters The yaml module for instance implements some of the following functions.

• has(KEY;value) - looks for a cluster that has a key with some certain value
• allclusters() - returns a range of all clusters
• • and get_clusters(node) - return the first cluster a node is a member of
• clusters(node) - return all clusters a node is a member of
• has(ENVIRONMENT; production) would return any clusters with the a key called ENVIRONMENT set to production
• mem(CLUSTER; foo.example.com) => which keys under CLUSTER is foo.example.com a member of

Other functions can be added via modules that provide useful insight into your environment

• vlan(host) - return vlan for this host
• dc(host) - return datacenter for this host
• drac(host) - might do an API call on backend to central host db to look up a drac IP for a host