* Introduce MetricVecOpts and add constraints to VariableLabels
MetricVecOpts exposes options specific to MetricVec initialisation. The
first option exposed by MetricVecOpts are constraints on VariableLabels,
allowing restrictions on the possible values a label can take, to
prevent cardinality explosion when the label value comes from a
non-trusted source (as a user input or HTTP header).
Signed-off-by: Quentin Devos <4972091+Okhoshi@users.noreply.github.com>
* Add tests
Signed-off-by: Quentin Devos <4972091+Okhoshi@users.noreply.github.com>
Signed-off-by: Quentin Devos <4972091+Okhoshi@users.noreply.github.com>