Prometheus middleware for negroni.
Instead of logging request times, it is considered best practice to provide an endpoint for instrumentation tools (like prometheus).
Use this middleware like the negroni.Logger middleware (after negroni.Recovery, before every other middleware).
Take a look at the example.
An endpoint with the following information (stripped output):
...
# HELP negroni_request_duration_milliseconds How long it took to process the request, partitioned by status code, method and HTTP path.
# TYPE negroni_request_duration_milliseconds histogram
negroni_request_duration_milliseconds_bucket{code="OK",method="GET",path="/metrics",service="serviceName",le="300"} 1
negroni_request_duration_milliseconds_bucket{code="OK",method="GET",path="/metrics",service="serviceName",le="1200"} 1
negroni_request_duration_milliseconds_bucket{code="OK",method="GET",path="/metrics",service="serviceName",le="5000"} 1
negroni_request_duration_milliseconds_bucket{code="OK",method="GET",path="/metrics",service="serviceName",le="+Inf"} 1
negroni_request_duration_milliseconds_sum{code="OK",method="GET",path="/metrics",service="serviceName"} 2.003123
negroni_request_duration_milliseconds_count{code="OK",method="GET",path="/metrics",service="serviceName"} 1
negroni_request_duration_milliseconds_bucket{code="OK",method="GET",path="/ok",service="serviceName",le="300"} 0
negroni_request_duration_milliseconds_bucket{code="OK",method="GET",path="/ok",service="serviceName",le="1200"} 0
negroni_request_duration_milliseconds_bucket{code="OK",method="GET",path="/ok",service="serviceName",le="5000"} 2
negroni_request_duration_milliseconds_bucket{code="OK",method="GET",path="/ok",service="serviceName",le="+Inf"} 2
negroni_request_duration_milliseconds_sum{code="OK",method="GET",path="/ok",service="serviceName"} 4747.529026
negroni_request_duration_milliseconds_count{code="OK",method="GET",path="/ok",service="serviceName"} 2
# HELP negroni_requests_total How many HTTP requests processed, partitioned by status code, method and HTTP path.
# TYPE negroni_requests_total counter
negroni_requests_total{code="OK",method="GET",path="/metrics",service="serviceName"} 1
negroni_requests_total{code="OK",method="GET",path="/ok",service="serviceName"} 2
...