Fixes#104
@status filter was added to the master branch to support new status key from Alertmanager >=0.6.1
status ended up being nested in Alertmanager (it was added to solve AM issue 609 and that was a long PR with lots of changes), current unsee implementation ended being slightly off with how Alertmanager is naming this, it should actually be @state rather than @status.
We have a static list of matchers, one for each kind, but newMatcher() was writing to those on every filter creation. Remove writes, set the attribute on matcher init instead.
@silenced=true should now be marked as invalid filter, but it isn't, this commit refactors it so that instead of looping over all filters and falling back to fuzzy (which is very relaxed checking and can't find typos in filter names like @statuz=active) we tokenize the expression into '<filter name> <operator> <value>' and only fallback to fuzzy if there's only a static text (no filter name and operator). This is more manual but provides stronger checks so now @silenced=true is correctly marked as invalid
Now that Alertmanager provides status=(unprocessed|suppressed|active) in the API it doesn't make sense to keep having separate filters for each value, merge @silenced & @inhibited into a single filter, update docs and UI
Current filter factory rules are very relaxed, anything that doesn't match filter syntax perfectly is passed down to the fuzzy filter, that happily accepts every input and doesn't complain. This change makes syntax checks more strict, we explicitly look for roughly <anything><any of the chars used as operators><anything> (in reality we match the first <anything> used filter specific regex, but that can still be any regex) and only if evaluated filter expression doesn't match this regex we pass it to the fuzzy filter. Once we have a match we check if operator is supported by the filter and we're more strict there, in case of a===b we currently accept = as the operator and ==b as the value, now operator will be === (as we match for any of the operator chars in use) and fail once that doesn't match.
