func main() {
// Flag domain. Note that gRPC transitively registers flags via its import
// of glog. So, we define a new flag set, to keep those domains distinct.
fs := flag.NewFlagSet("", flag.ExitOnError)
var (
transport = fs.String("transport", "http", "http, netrpc")
httpAddr = fs.String("http.addr", "localhost:8001", "HTTP (JSON) address")
netrpcAddr = fs.String("netrpc.addr", "localhost:8003", "net/rpc address")
a = fs.Int64("a", 1, "a value")
b = fs.Int64("b", 2, "b value")
)
flag.Usage = fs.Usage // only show our flags
fs.Parse(os.Args[1:])
log.SetFlags(0)
log.SetOutput(os.Stdout)
var e endpoint.Endpoint
switch *transport {
case "http":
if !strings.HasPrefix(*httpAddr, "http") {
*httpAddr = "http://" + *httpAddr
}
u, err := url.Parse(*httpAddr)
if err != nil {
log.Fatalf("url.Parse: %v", err)
}
if u.Path == "" {
u.Path = "/add"
}
e = add.NewAdderAddHTTPClient("GET", u.String())
case "netrpc":
client, err := rpc.DialHTTP("tcp", *netrpcAddr)
if err != nil {
log.Fatalf("rpc.DialHTTP: %v", err)
}
e = add.NewAdderAddRPCClient(client)("Add.Add")
default:
log.Fatalf("unsupported transport %q", *transport)
}
response, err := e(context.Background(), add.AdderAddRequest{A: *a, B: *b})
if err != nil {
log.Fatalf("when invoking request: %v", err)
}
addResponse, ok := response.(add.AdderAddResponse)
if !ok {
log.Fatalf("when type-asserting response: %T", response)
}
log.Print(addResponse.V)
}
func main() {
// Flag domain. Note that gRPC transitively registers flags via its import
// of glog. So, we define a new flag set, to keep those domains distinct.
fs := flag.NewFlagSet("", flag.ExitOnError)
var (
debugAddr = fs.String("debug.addr", ":8000", "Address for HTTP debug/instrumentation server")
httpAddr = fs.String("http.addr", ":8001", "Address for HTTP (JSON) server")
netrpcAddr = fs.String("netrpc.addr", ":8003", "Address for net/rpc server")
proxyHTTPAddr = fs.String("proxy.http.url", "", "if set, proxy requests over HTTP to this addsvc")
zipkinServiceName = fs.String("zipkin.service.name", "addsvc", "Zipkin service name")
zipkinCollectorAddr = fs.String("zipkin.collector.addr", "", "Zipkin Scribe collector address (empty will log spans)")
zipkinCollectorTimeout = fs.Duration("zipkin.collector.timeout", time.Second, "Zipkin collector timeout")
zipkinCollectorBatchSize = fs.Int("zipkin.collector.batch.size", 100, "Zipkin collector batch size")
zipkinCollectorBatchInterval = fs.Duration("zipkin.collector.batch.interval", time.Second, "Zipkin collector batch interval")
)
flag.Usage = fs.Usage // only show our flags
fs.Parse(os.Args[1:])
// `package log` domain
var logger kitlog.Logger
logger = kitlog.NewLogfmtLogger(os.Stderr)
logger = kitlog.NewContext(logger).With("ts", kitlog.DefaultTimestampUTC)
stdlog.SetOutput(kitlog.NewStdlibAdapter(logger)) // redirect stdlib logging to us
stdlog.SetFlags(0) // flags are handled in our logger
// `package metrics` domain
requests := metrics.NewMultiCounter(
expvar.NewCounter("requests"),
statsd.NewCounter(ioutil.Discard, "requests_total", time.Second),
prometheus.NewCounter(stdprometheus.CounterOpts{
Namespace: "addsvc",
Subsystem: "add",
Name: "requests_total",
Help: "Total number of received requests.",
}, []string{}),
)
duration := metrics.NewTimeHistogram(time.Nanosecond, metrics.NewMultiHistogram(
expvar.NewHistogram("duration_nanoseconds_total", 0, 1e9, 3, 50, 95, 99),
statsd.NewHistogram(ioutil.Discard, "duration_nanoseconds_total", time.Second),
prometheus.NewSummary(stdprometheus.SummaryOpts{
Namespace: "addsvc",
Subsystem: "add",
Name: "duration_nanoseconds_total",
Help: "Total nanoseconds spend serving requests.",
}, []string{}),
))
_, _ = requests, duration
// `package tracing` domain
zipkinHostPort := "localhost:1234" // TODO Zipkin makes overly simple assumptions about services
var zipkinCollector zipkin.Collector = loggingCollector{logger}
if *zipkinCollectorAddr != "" {
var err error
if zipkinCollector, err = zipkin.NewScribeCollector(
*zipkinCollectorAddr,
*zipkinCollectorTimeout,
zipkin.ScribeBatchSize(*zipkinCollectorBatchSize),
zipkin.ScribeBatchInterval(*zipkinCollectorBatchInterval),
zipkin.ScribeLogger(logger),
); err != nil {
logger.Log("err", err)
os.Exit(1)
}
}
zipkinMethodName := "add"
zipkinSpanFunc := zipkin.MakeNewSpanFunc(zipkinHostPort, *zipkinServiceName, zipkinMethodName)
// Our business and operational domain
var a add.Adder = pureAdd{}
if *proxyHTTPAddr != "" {
var e endpoint.Endpoint
e = add.NewAdderAddHTTPClient("GET", *proxyHTTPAddr, zipkin.ToRequest(zipkinSpanFunc))
e = zipkin.AnnotateClient(zipkinSpanFunc, zipkinCollector)(e)
a = add.MakeAdderClient(func(method string) endpoint.Endpoint {
if method != "Add" {
panic(fmt.Errorf("unknown method %s", method))
}
return e
})
}
// This could happen at endpoint level.
// a = logging(logger)(a)
// a = instrument(requests, duration)(a)
// Server domain
var e endpoint.Endpoint
e = add.MakeAdderEndpoints(a).Add
e = zipkin.AnnotateServer(zipkinSpanFunc, zipkinCollector)(e)
// Mechanical stuff
rand.Seed(time.Now().UnixNano())
root := context.Background()
errc := make(chan error)
go func() {
errc <- interrupt()
}()
// Transport: HTTP (debug/instrumentation)
go func() {
logger.Log("addr", *debugAddr, "transport", "debug")
errc <- http.ListenAndServe(*debugAddr, nil)
}()
// Transport: HTTP (JSON)
go func() {
ctx, cancel := context.WithCancel(root)
defer cancel()
before := []httptransport.RequestFunc{zipkin.ToContext(zipkinSpanFunc, logger)}
after := []httptransport.ResponseFunc{}
handler := add.MakeAdderAddHTTPBinding(ctx, e, before, after)
logger.Log("addr", *httpAddr, "transport", "HTTP/JSON")
errc <- http.ListenAndServe(*httpAddr, handler)
}()
// Transport: net/rpc
go func() {
ctx, cancel := context.WithCancel(root)
defer cancel()
s := rpc.NewServer()
s.RegisterName("Add", add.AdderAddNetrpcBinding{ctx, e})
s.HandleHTTP(rpc.DefaultRPCPath, rpc.DefaultDebugPath)
logger.Log("addr", *netrpcAddr, "transport", "net/rpc")
errc <- http.ListenAndServe(*netrpcAddr, s)
}()
logger.Log("fatal", <-errc)
}