Tags

A tag consists of a unique name and a rule. Tags match a node if evaluating the node against the tag's facts results in true. Tag matching is case sensitive.

For example, to create a tag, small, that matches any machine with less than 4GB of memory:

    razor create-tag --name small
      --rule '["<", ["num", ["fact", "memorysize_mb"]], 4128]'

Tag rules

Rule expressions are of the form op arg1 arg2 ... argn] where op is one of the accepted [operators, and arg1 through argn are the arguments for the operator. If the arguments are expressions themselves, they're evaluated before op.

Here are some example tag rules:

To match nodes with more than 10 processors: [">", ["num", ["fact", "processorcount"]], 10]
To match nodes with specified MAC addresses: ["has_macaddress", "de:ea:db:ee:f0:00", "de:ea:db:ee:f0:01"]

Tag operators

The expression language supports these operators:


Operator	Returns	Aliases
`["=", arg1, arg2]`	True if the specified arguments are equal.	`"eq"`
`["!=", arg1, arg2]`	True if the specified arguments are not equal.	`"neq"`
`["and", arg1, ..., argn]`	True if all arguments are true.
`["or", arg1, ..., argn]`	True if any argument is true.
`["not", arg]`	True if the argument evaluates to `false` or `nil`.
`["fact", arg1 (, arg2)]`	The `arg1` fact for the node. The optional `arg2` is used if the `arg1` fact isn't present.
`["metadata", arg1 (, arg2)]`	The `arg` metadata entry for the node. The optional `arg2` is used if the `arg1` fact isn't present.
`["tag", arg]`	True if the node has the specified tag.
`["has_macaddress", arg1, arg2 ..., argn]`	True if any facts that start with "macaddress" matches one of `arg1` ... `argn`.
`["has_macaddress_like", arg1, arg2 ..., argn]`	True if the hardware MAC address matches one of `arg1` ... `argn` as regular expressions.
`["in", arg1, arg2, ..., argn]`	True if `arg1` matches one of `arg2` ... `argn`.
`["num", arg1]`	`arg1` as a numeric value, or raises an error.
`[">", arg1, arg2]`	True if `arg1` is greater than `arg2`.	`"gt"`
`["<", arg1, arg2]`	True if `arg1` is less than `arg2`.	`"lt"`
`[">=", arg1, arg2]`	True if `arg1` is greater than or equal to `arg2`.	`"gte"`
`["<=", arg1, arg2]`	True if `arg1` is less than or equal to `arg2`.	`"lte"`
`["like", arg1, arg2]`	True if `arg1` matches the pattern of `arg2`, interpreted as a regular expression.
`["lower", arg]`	The lowercase version of the string `arg`.
`["upper", arg]`	The uppercase version of the string `arg`.