Open ocharles opened 9 years ago
This is in the plans but I haven't had time to work on it yet. I'd like a design where creating e.g. a counter indexed by N dimensions (e.g. integers and strings) can be done in a type safe manner i.e. once the counter is created calling inc
on that counter requires that you pass N dimension values of the right type. Here's how to not do it:
data Dim = T Text | I Int
newCounter :: [Dim] -> IO Counter
inc :: Counter -> [Dim] -> IO ()
I was thinking of using e.g. a phantom type to track the dimensions for a given counter by using a more untyped representation internally. Needs some thought.
Interesting idea. Keep me posted!
Just saw this issue, was replying on https://github.com/tibbe/ekg-core/issues/12#issuecomment-295464493 that I've started a patch. I'll be updating only this issue starting from now.
I'll fix ekg-json soon (very likely adding a key to the ToJSON instance), then ekg will take me more work (in particular, the HTML+JS rendering).
Then, we can imagine a typeful API using typelevel strings or a typeclass to add a variable number of arguments. This typeful API could live in another package.
I'm still unsure whether we should add a hashmap-like interface to "manage" counters for points using new dimensional breakdowns. In particular, there's a risk to have an unbounded number of counters growth if library users do not pay attention + I don't like exposing a lookupOrCreate function when I often use counters in tight-loops on-the-fly -- imho, such a lookupOrCreate function should live in another package.
OpenTSDB - the time series database used by bosun - uses a different naming convention than EKG. Metrics have an arbitrary name, but they also have a list of key-value pairs (tags). The idea is that you can now have more general metrics such as
http.response_time
, and then tag data points with specific information such asroute=/api/list-foos
.I wonder if EKG should support such a thing, or if I should add support for "post-processing" metrics to ekg-bosun -
postProcess :: Name -> (Name, [Tag])
, or something to that effect.Thoughts?