zenrpc-middleware: Middlewares for vmkteam/zenrpc

zenrpc-middleware is a set of common middlewares for zenrpc implementing logging, metrics and error tracking.

Middlewares

WithDevel

Sets bool flag to context for detecting development environment.

WithHeaders

Sets User-Agent, Platform, Version, X-Country headers to context. User-Agent strips to 2048 chars, Platform and Version – to 64, X-Country - to 16.

WithAPILogger

Logs via Printf function (e.g. log.Printf) all requests. For example

ip= platform="" version="" method=nodevel.arith.divide duration=63.659µs params="{ \"a\": 1, \"b\": 24 }" err=<nil> userAgent="Go-http-client/1.1"

WithSLog

Logs via slog.InfoContext (or similar) function all requests with custom attrs support.

WithSentry

Sets additional parameters for current Sentry scope. Extras: params, duration, ip. Tags: platform, version, method.

WithNoCancelContext

Ignores Cancel func from context. This is useful for passing context to go-pg.

WithMetrics

Logs duration of RPC requests via Prometheus. Default serverName is rpc (will be in server label). It exposes two metrics: app_rpc_error_requests_total and app_rpc_responses_duration_seconds. Labels: method, code, platform, version, server.

WithTiming

Adds timings in JSON-RPC 2.0 Response via extensions field (not in spec). Middleware is active when isDevel=true or AllowDebugFunc returns true. Sample AllowDebugFunc (checks GET/POST parameters for "true" value, like ?d=true):

allowDebugFn := func (param string) middleware.AllowDebugFunc {
    return func (req *http.Request) bool {
        return req.FormValue(param) == "true"
    }
}

DurationLocal – total method execution time in ms.

If DurationRemote or DurationDiff are set then DurationLocal excludes these values.

WithSQLLogger

Adds SQL or DurationSQL fields in JSON-RPC 2.0 Response extensions field (not in spec).

DurationSQL field is set then isDevel=true or AllowDebugFunc(allowDebugFunc) returns true.

SQL field is set then isDevel=true or AllowDebugFunc(allowDebugFunc, allowSqlDebugFunc) returns true.

WithErrorLogger

Logs all errors (ErrorCode==500 or < 0) via Printf func and sends them to Sentry. It also removes sensitive error data from response. It is good to use pkg/errors for stack trace support in sentry.

WithErrorSLog

Same as WithErrorLogger, but for slog.

Examples

Basic usage

package main

import (
	"log"
	"net/http"
	"os"

	"github.com/go-pg/pg/v10"
	"github.com/vmkteam/zenrpc-middleware"
	"github.com/vmkteam/zenrpc/v2"
)

func main() {
	dbс := pg.Connect(&pg.Options{User: "postgres"})
	defer dbс.Close()

	isDevel := true
	elog := log.New(os.Stderr, "E", log.LstdFlags|log.Lshortfile)
	dlog := log.New(os.Stdout, "D", log.LstdFlags|log.Lshortfile)

	allowDebug := func(param string) middleware.AllowDebugFunc {
		return func(req *http.Request) bool {
			return req.FormValue(param) == "true"
		}
	}

	rpc := zenrpc.NewServer(zenrpc.Options{
		ExposeSMD: true,
		AllowCORS: true,
	})

	rpc.Use(
		middleware.WithDevel(isDevel),
		middleware.WithHeaders(),
		middleware.WithAPILogger(dlog.Printf, middleware.DefaultServerName),
		middleware.WithSentry(middleware.DefaultServerName),
		middleware.WithNoCancelContext(),
		middleware.WithMetrics(middleware.DefaultServerName),
		middleware.WithTiming(isDevel, allowDebug("d")),
		middleware.WithSQLLogger(dbc, isDevel, allowDebug("d"), allowDebug("s")),
		middleware.WithErrorLogger(elog.Printf, middleware.DefaultServerName),
	)
}


    // rpc.Register and server