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"

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 AppName is zenrpc. It exposes two metrics: appName_rpc_error_requests_count and appName_rpc_responses_duration_seconds. Labels: method, code, platform, version.

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.

ip= platform="Test1" version="v1.0.0 alpha1" method=errordevel.arith.checkzenrpcerror duration=30.786µs params=[ true ] err="test"

XRequestID

Handler for adding X-Request-ID header to all requests and responses.

	s := http.NewServer(middleware.XRequestID(http.HandlerFunc(rpc.ServeHTTP)))

EchoIPContext

Echo middleware for adding client IP info to context for zenrpc middleware

    e.Use(middleware.EchoIPContext())

EchoSentryHubContext

Echo middleware for adding sentry hub info to context for zenrpc middleware

    e.Use(middleware.EchoSentryHubContext())

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

Handler snippets

// sentry init
sentry.Init(sentry.ClientOptions{
    Dsn:         cfg.Sentry.DSN,
    Environment: cfg.Sentry.Environment,
    Release:     version,
}

// sentry middleware for Echo
e.Use(sentryecho.New(sentryecho.Options{
    Repanic:         true,
    WaitForDelivery: true,
}))

// register handler
a.echo.Any("/v1/rpc/", middleware.EchoHandler(rpc))

---  OR ---

e.Use(middleware.EchoIPContext()), middleware.EchoSentryHubContext())
// register handler
e.Any("/int/rpc/", echo.WrapHandler(XRequestID(rpc)))