Prometheus使用计数器对非静态数据进行计数

Question

I'm trying to count the number of unique URI's and keep a count of them. These URI's change over time and there can be multiple URIs of the same type. For example, there can be multiple "/foo" and "/bar" and a new URI can come in - lets say "pooh" - and I've to add them to the counter and keep count. In this case, I cannot use constant labels. For instance, if I were to count the number of http requests by method and/or status code, I can do this:

    httpRequestInfo := prometheus.NewCounterVec(
        prometheus.CounterOpts{
            Name:        "http_requests_sum",
            ConstLabels: prometheus.Labels{"component": "foo"},
            Help:        " A Counter of the number of each type of request by status code and method",
        },
        []string{"code", "method"},
    )

How could I use counters in this scenario? Thanks!

Answer 1

ConstLabels are generally to be avoided. What you want to do is httpRequestInfo.WithLabelValues("404", "get").Inc()

As this is a counter this should have a _total suffix rather than a _sum which used by summary metrics.

You probably want to use InstrumentHandlerCounter rather than implementing all the logic yourself for tracking HTTP requests.