phs

README

phs

Default HTTP server and client prometheus instrumentation for go. This library provides easy to use and non-intrusive methods to wrap HandlerFunc and http Clients so that they automatically provide useful prometheus metrics.

Server side metrics

All the server side metrics have the following labels:

• code which is the http status code of the request
• handler which is the name of the endpointk. It is set when wrapping a HandlerFunc. You should not use the local path of the URL for this, but choose a meaniingful name.
• method the http method name like get or post

The default instrumentation provides metrics for

• http_server_request_total is the number of requests received
• http_server_requests_inflight is the number of requests currently being handled
• http_server_request_duration is the prefix for the http latency buckets and percentile. The buckets and the percentiles can be defined. Defaults are provided.

The metrics are provided on a seperate port, using its own HttpServer structure. This is good practice, because you don't want to block the server providing the metrics in case the server serving the real application data is overloaded or runs in a dead lock.

Getting started

This project requires Go > 12.x. The main.go program provides an example of a server which also performs as an http client. The server offers two endpoints, /expensive and /cheap. The /expensive endpoint also calls back into the same server's /cheap endpoint to demo the client side wrapping.

Running it then should be as simple as:

$ make build
$ ./bin/phs

Testing

make test