mirror of
https://github.com/tailscale/tailscale.git
synced 2024-12-04 23:45:34 +00:00
e1c1d47991
Saves 1-2 allocs per HTTP request after warmup, thanks to avoiding strconv and fmt. Signed-off-by: David Anderson <danderson@tailscale.com>
645 lines
19 KiB
Go
645 lines
19 KiB
Go
// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
// Package tsweb contains code used in various Tailscale webservers.
|
|
package tsweb
|
|
|
|
import (
|
|
"bufio"
|
|
"bytes"
|
|
"context"
|
|
"errors"
|
|
"expvar"
|
|
"fmt"
|
|
"io"
|
|
"io/ioutil"
|
|
"net"
|
|
"net/http"
|
|
_ "net/http/pprof"
|
|
"os"
|
|
"path/filepath"
|
|
"reflect"
|
|
"runtime"
|
|
"strconv"
|
|
"strings"
|
|
"sync"
|
|
"time"
|
|
|
|
"go4.org/mem"
|
|
"inet.af/netaddr"
|
|
"tailscale.com/envknob"
|
|
"tailscale.com/metrics"
|
|
"tailscale.com/net/tsaddr"
|
|
"tailscale.com/types/logger"
|
|
"tailscale.com/version"
|
|
)
|
|
|
|
func init() {
|
|
expvar.Publish("process_start_unix_time", expvar.Func(func() any { return timeStart.Unix() }))
|
|
expvar.Publish("version", expvar.Func(func() any { return version.Long }))
|
|
expvar.Publish("counter_uptime_sec", expvar.Func(func() any { return int64(Uptime().Seconds()) }))
|
|
expvar.Publish("gauge_goroutines", expvar.Func(func() any { return runtime.NumGoroutine() }))
|
|
}
|
|
|
|
// DevMode controls whether extra output in shown, for when the binary is being run in dev mode.
|
|
var DevMode bool
|
|
|
|
func DefaultCertDir(leafDir string) string {
|
|
cacheDir, err := os.UserCacheDir()
|
|
if err == nil {
|
|
return filepath.Join(cacheDir, "tailscale", leafDir)
|
|
}
|
|
return ""
|
|
}
|
|
|
|
// IsProd443 reports whether addr is a Go listen address for port 443.
|
|
func IsProd443(addr string) bool {
|
|
_, port, _ := net.SplitHostPort(addr)
|
|
return port == "443" || port == "https"
|
|
}
|
|
|
|
// AllowDebugAccess reports whether r should be permitted to access
|
|
// various debug endpoints.
|
|
func AllowDebugAccess(r *http.Request) bool {
|
|
if r.Header.Get("X-Forwarded-For") != "" {
|
|
// TODO if/when needed. For now, conservative:
|
|
return false
|
|
}
|
|
ipStr, _, err := net.SplitHostPort(r.RemoteAddr)
|
|
if err != nil {
|
|
return false
|
|
}
|
|
ip, err := netaddr.ParseIP(ipStr)
|
|
if err != nil {
|
|
return false
|
|
}
|
|
if tsaddr.IsTailscaleIP(ip) || ip.IsLoopback() || ipStr == envknob.String("TS_ALLOW_DEBUG_IP") {
|
|
return true
|
|
}
|
|
if r.Method == "GET" {
|
|
urlKey := r.FormValue("debugkey")
|
|
keyPath := envknob.String("TS_DEBUG_KEY_PATH")
|
|
if urlKey != "" && keyPath != "" {
|
|
slurp, err := ioutil.ReadFile(keyPath)
|
|
if err == nil && string(bytes.TrimSpace(slurp)) == urlKey {
|
|
return true
|
|
}
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
// AcceptsEncoding reports whether r accepts the named encoding
|
|
// ("gzip", "br", etc).
|
|
func AcceptsEncoding(r *http.Request, enc string) bool {
|
|
h := r.Header.Get("Accept-Encoding")
|
|
if h == "" {
|
|
return false
|
|
}
|
|
if !strings.Contains(h, enc) && !mem.ContainsFold(mem.S(h), mem.S(enc)) {
|
|
return false
|
|
}
|
|
remain := h
|
|
for len(remain) > 0 {
|
|
var part string
|
|
part, remain, _ = strings.Cut(remain, ",")
|
|
part = strings.TrimSpace(part)
|
|
part, _, _ = strings.Cut(part, ";")
|
|
if part == enc {
|
|
return true
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
// Protected wraps a provided debug handler, h, returning a Handler
|
|
// that enforces AllowDebugAccess and returns forbidden replies for
|
|
// unauthorized requests.
|
|
func Protected(h http.Handler) http.Handler {
|
|
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
|
|
if !AllowDebugAccess(r) {
|
|
msg := "debug access denied"
|
|
if DevMode {
|
|
ipStr, _, _ := net.SplitHostPort(r.RemoteAddr)
|
|
msg += fmt.Sprintf("; to permit access, set TS_ALLOW_DEBUG_IP=%v", ipStr)
|
|
}
|
|
http.Error(w, msg, http.StatusForbidden)
|
|
return
|
|
}
|
|
h.ServeHTTP(w, r)
|
|
})
|
|
}
|
|
|
|
var timeStart = time.Now()
|
|
|
|
func Uptime() time.Duration { return time.Since(timeStart).Round(time.Second) }
|
|
|
|
// Port80Handler is the handler to be given to
|
|
// autocert.Manager.HTTPHandler. The inner handler is the mux
|
|
// returned by NewMux containing registered /debug handlers.
|
|
type Port80Handler struct {
|
|
Main http.Handler
|
|
// FQDN is used to redirect incoming requests to https://<FQDN>.
|
|
// If it is not set, the hostname is calculated from the incoming
|
|
// request.
|
|
FQDN string
|
|
}
|
|
|
|
func (h Port80Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
|
|
path := r.RequestURI
|
|
if path == "/debug" || strings.HasPrefix(path, "/debug") {
|
|
h.Main.ServeHTTP(w, r)
|
|
return
|
|
}
|
|
if r.Method != "GET" && r.Method != "HEAD" {
|
|
http.Error(w, "Use HTTPS", http.StatusBadRequest)
|
|
return
|
|
}
|
|
if path == "/" && AllowDebugAccess(r) {
|
|
// Redirect authorized user to the debug handler.
|
|
path = "/debug/"
|
|
}
|
|
host := h.FQDN
|
|
if host == "" {
|
|
host = r.URL.Hostname()
|
|
}
|
|
target := "https://" + host + path
|
|
http.Redirect(w, r, target, http.StatusFound)
|
|
}
|
|
|
|
// ReturnHandler is like net/http.Handler, but the handler can return an
|
|
// error instead of writing to its ResponseWriter.
|
|
type ReturnHandler interface {
|
|
// ServeHTTPReturn is like http.Handler.ServeHTTP, except that
|
|
// it can choose to return an error instead of writing to its
|
|
// http.ResponseWriter.
|
|
//
|
|
// If ServeHTTPReturn returns an error, it caller should handle
|
|
// an error by serving an HTTP 500 response to the user. The
|
|
// error details should not be sent to the client, as they may
|
|
// contain sensitive information. If the error is an
|
|
// HTTPError, though, callers should use the HTTP response
|
|
// code and message as the response to the client.
|
|
ServeHTTPReturn(http.ResponseWriter, *http.Request) error
|
|
}
|
|
|
|
type HandlerOptions struct {
|
|
Quiet200s bool // if set, do not log successfully handled HTTP requests
|
|
Logf logger.Logf
|
|
Now func() time.Time // if nil, defaults to time.Now
|
|
|
|
// If non-nil, StatusCodeCounters maintains counters
|
|
// of status codes for handled responses.
|
|
// The keys are "1xx", "2xx", "3xx", "4xx", and "5xx".
|
|
StatusCodeCounters *expvar.Map
|
|
// If non-nil, StatusCodeCountersFull maintains counters of status
|
|
// codes for handled responses.
|
|
// The keys are HTTP numeric response codes e.g. 200, 404, ...
|
|
StatusCodeCountersFull *expvar.Map
|
|
}
|
|
|
|
// ReturnHandlerFunc is an adapter to allow the use of ordinary
|
|
// functions as ReturnHandlers. If f is a function with the
|
|
// appropriate signature, ReturnHandlerFunc(f) is a ReturnHandler that
|
|
// calls f.
|
|
type ReturnHandlerFunc func(http.ResponseWriter, *http.Request) error
|
|
|
|
// ServeHTTPReturn calls f(w, r).
|
|
func (f ReturnHandlerFunc) ServeHTTPReturn(w http.ResponseWriter, r *http.Request) error {
|
|
return f(w, r)
|
|
}
|
|
|
|
// StdHandler converts a ReturnHandler into a standard http.Handler.
|
|
// Handled requests are logged using opts.Logf, as are any errors.
|
|
// Errors are handled as specified by the Handler interface.
|
|
func StdHandler(h ReturnHandler, opts HandlerOptions) http.Handler {
|
|
if opts.Now == nil {
|
|
opts.Now = time.Now
|
|
}
|
|
if opts.Logf == nil {
|
|
opts.Logf = logger.Discard
|
|
}
|
|
return retHandler{h, opts}
|
|
}
|
|
|
|
// retHandler is an http.Handler that wraps a Handler and handles errors.
|
|
type retHandler struct {
|
|
rh ReturnHandler
|
|
opts HandlerOptions
|
|
}
|
|
|
|
// ServeHTTP implements the http.Handler interface.
|
|
func (h retHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
|
|
msg := AccessLogRecord{
|
|
When: h.opts.Now(),
|
|
RemoteAddr: r.RemoteAddr,
|
|
Proto: r.Proto,
|
|
TLS: r.TLS != nil,
|
|
Host: r.Host,
|
|
Method: r.Method,
|
|
RequestURI: r.URL.RequestURI(),
|
|
UserAgent: r.UserAgent(),
|
|
Referer: r.Referer(),
|
|
}
|
|
|
|
lw := &loggingResponseWriter{ResponseWriter: w, logf: h.opts.Logf}
|
|
err := h.rh.ServeHTTPReturn(lw, r)
|
|
hErr, hErrOK := err.(HTTPError)
|
|
|
|
if lw.code == 0 && err == nil && !lw.hijacked {
|
|
// If the handler didn't write and didn't send a header, that still means 200.
|
|
// (See https://play.golang.org/p/4P7nx_Tap7p)
|
|
lw.code = 200
|
|
}
|
|
|
|
msg.Seconds = h.opts.Now().Sub(msg.When).Seconds()
|
|
msg.Code = lw.code
|
|
msg.Bytes = lw.bytes
|
|
|
|
switch {
|
|
case lw.hijacked:
|
|
// Connection no longer belongs to us, just log that we
|
|
// switched protocols away from HTTP.
|
|
if msg.Code == 0 {
|
|
msg.Code = http.StatusSwitchingProtocols
|
|
}
|
|
case err != nil && r.Context().Err() == context.Canceled:
|
|
msg.Code = 499 // nginx convention: Client Closed Request
|
|
msg.Err = context.Canceled.Error()
|
|
case hErrOK:
|
|
// Handler asked us to send an error. Do so, if we haven't
|
|
// already sent a response.
|
|
msg.Err = hErr.Msg
|
|
if hErr.Err != nil {
|
|
if msg.Err == "" {
|
|
msg.Err = hErr.Err.Error()
|
|
} else {
|
|
msg.Err = msg.Err + ": " + hErr.Err.Error()
|
|
}
|
|
}
|
|
if lw.code != 0 {
|
|
h.opts.Logf("[unexpected] handler returned HTTPError %v, but already sent a response with code %d", hErr, lw.code)
|
|
break
|
|
}
|
|
msg.Code = hErr.Code
|
|
if msg.Code == 0 {
|
|
h.opts.Logf("[unexpected] HTTPError %v did not contain an HTTP status code, sending internal server error", hErr)
|
|
msg.Code = http.StatusInternalServerError
|
|
}
|
|
http.Error(lw, hErr.Msg, msg.Code)
|
|
case err != nil:
|
|
// Handler returned a generic error. Serve an internal server
|
|
// error, if necessary.
|
|
msg.Err = err.Error()
|
|
if lw.code == 0 {
|
|
msg.Code = http.StatusInternalServerError
|
|
http.Error(lw, "internal server error", msg.Code)
|
|
}
|
|
}
|
|
|
|
if msg.Code != 200 || !h.opts.Quiet200s {
|
|
h.opts.Logf("%s", msg)
|
|
}
|
|
|
|
if h.opts.StatusCodeCounters != nil {
|
|
h.opts.StatusCodeCounters.Add(responseCodeString(msg.Code/100), 1)
|
|
}
|
|
|
|
if h.opts.StatusCodeCountersFull != nil {
|
|
h.opts.StatusCodeCountersFull.Add(responseCodeString(msg.Code), 1)
|
|
}
|
|
}
|
|
|
|
func responseCodeString(code int) string {
|
|
if v, ok := responseCodeCache.Load(code); ok {
|
|
return v.(string)
|
|
}
|
|
|
|
var ret string
|
|
if code < 10 {
|
|
ret = fmt.Sprintf("%dxx", code)
|
|
} else {
|
|
ret = strconv.Itoa(code)
|
|
}
|
|
responseCodeCache.Store(code, ret)
|
|
return ret
|
|
}
|
|
|
|
// responseCodeCache memoizes the string form of HTTP response codes,
|
|
// so that the hot request-handling codepath doesn't have to allocate
|
|
// in strconv/fmt for every request.
|
|
//
|
|
// Keys are either full HTTP response code ints (200, 404) or "family"
|
|
// ints representing entire families (e.g. 2 for 2xx codes). Values
|
|
// are the string form of that code/family.
|
|
var responseCodeCache sync.Map
|
|
|
|
// loggingResponseWriter wraps a ResponseWriter and record the HTTP
|
|
// response code that gets sent, if any.
|
|
type loggingResponseWriter struct {
|
|
http.ResponseWriter
|
|
code int
|
|
bytes int
|
|
hijacked bool
|
|
logf logger.Logf
|
|
}
|
|
|
|
// WriteHeader implements http.Handler.
|
|
func (l *loggingResponseWriter) WriteHeader(statusCode int) {
|
|
if l.code != 0 {
|
|
l.logf("[unexpected] HTTP handler set statusCode twice (%d and %d)", l.code, statusCode)
|
|
return
|
|
}
|
|
l.code = statusCode
|
|
l.ResponseWriter.WriteHeader(statusCode)
|
|
}
|
|
|
|
// Write implements http.Handler.
|
|
func (l *loggingResponseWriter) Write(bs []byte) (int, error) {
|
|
if l.code == 0 {
|
|
l.code = 200
|
|
}
|
|
n, err := l.ResponseWriter.Write(bs)
|
|
l.bytes += n
|
|
return n, err
|
|
}
|
|
|
|
// Hijack implements http.Hijacker. Note that hijacking can still fail
|
|
// because the wrapped ResponseWriter is not required to implement
|
|
// Hijacker, as this breaks HTTP/2.
|
|
func (l *loggingResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
|
|
h, ok := l.ResponseWriter.(http.Hijacker)
|
|
if !ok {
|
|
return nil, nil, errors.New("ResponseWriter is not a Hijacker")
|
|
}
|
|
conn, buf, err := h.Hijack()
|
|
if err == nil {
|
|
l.hijacked = true
|
|
}
|
|
return conn, buf, err
|
|
}
|
|
|
|
func (l loggingResponseWriter) Flush() {
|
|
f, _ := l.ResponseWriter.(http.Flusher)
|
|
if f == nil {
|
|
l.logf("[unexpected] tried to Flush a ResponseWriter that can't flush")
|
|
return
|
|
}
|
|
f.Flush()
|
|
}
|
|
|
|
// HTTPError is an error with embedded HTTP response information.
|
|
//
|
|
// It is the error type to be (optionally) used by Handler.ServeHTTPReturn.
|
|
type HTTPError struct {
|
|
Code int // HTTP response code to send to client; 0 means means 500
|
|
Msg string // Response body to send to client
|
|
Err error // Detailed error to log on the server
|
|
}
|
|
|
|
// Error implements the error interface.
|
|
func (e HTTPError) Error() string { return fmt.Sprintf("httperror{%d, %q, %v}", e.Code, e.Msg, e.Err) }
|
|
|
|
// Error returns an HTTPError containing the given information.
|
|
func Error(code int, msg string, err error) HTTPError {
|
|
return HTTPError{Code: code, Msg: msg, Err: err}
|
|
}
|
|
|
|
// PrometheusVar is a value that knows how to format itself into
|
|
// Prometheus metric syntax.
|
|
type PrometheusVar interface {
|
|
// WritePrometheus writes the value of the var to w, in Prometheus
|
|
// metric syntax. All variables names written out must start with
|
|
// prefix (or write out a single variable named exactly prefix)
|
|
WritePrometheus(w io.Writer, prefix string)
|
|
}
|
|
|
|
// WritePrometheusExpvar writes kv to w in Prometheus metrics format.
|
|
//
|
|
// See VarzHandler for conventions. This is exported primarily for
|
|
// people to test their varz.
|
|
func WritePrometheusExpvar(w io.Writer, kv expvar.KeyValue) {
|
|
writePromExpVar(w, "", kv)
|
|
}
|
|
|
|
func writePromExpVar(w io.Writer, prefix string, kv expvar.KeyValue) {
|
|
key := kv.Key
|
|
var typ string
|
|
var label string
|
|
switch {
|
|
case strings.HasPrefix(kv.Key, "gauge_"):
|
|
typ = "gauge"
|
|
key = strings.TrimPrefix(kv.Key, "gauge_")
|
|
|
|
case strings.HasPrefix(kv.Key, "counter_"):
|
|
typ = "counter"
|
|
key = strings.TrimPrefix(kv.Key, "counter_")
|
|
}
|
|
if strings.HasPrefix(key, "labelmap_") {
|
|
key = strings.TrimPrefix(key, "labelmap_")
|
|
if a, b, ok := strings.Cut(key, "_"); ok {
|
|
label, key = a, b
|
|
}
|
|
}
|
|
name := prefix + key
|
|
|
|
switch v := kv.Value.(type) {
|
|
case PrometheusVar:
|
|
v.WritePrometheus(w, name)
|
|
return
|
|
case *expvar.Int:
|
|
if typ == "" {
|
|
typ = "counter"
|
|
}
|
|
fmt.Fprintf(w, "# TYPE %s %s\n%s %v\n", name, typ, name, v.Value())
|
|
return
|
|
case *metrics.Set:
|
|
v.Do(func(kv expvar.KeyValue) {
|
|
writePromExpVar(w, name+"_", kv)
|
|
})
|
|
return
|
|
case PrometheusMetricsReflectRooter:
|
|
root := v.PrometheusMetricsReflectRoot()
|
|
rv := reflect.ValueOf(root)
|
|
if rv.Type().Kind() == reflect.Ptr {
|
|
if rv.IsNil() {
|
|
return
|
|
}
|
|
rv = rv.Elem()
|
|
}
|
|
if rv.Type().Kind() != reflect.Struct {
|
|
fmt.Fprintf(w, "# skipping expvar %q; unknown root type\n", name)
|
|
return
|
|
}
|
|
foreachExportedStructField(rv, func(fieldOrJSONName, metricType string, rv reflect.Value) {
|
|
mname := name + "_" + fieldOrJSONName
|
|
switch rv.Kind() {
|
|
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
|
|
fmt.Fprintf(w, "# TYPE %s %s\n%s %v\n", mname, metricType, mname, rv.Int())
|
|
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
|
|
fmt.Fprintf(w, "# TYPE %s %s\n%s %v\n", mname, metricType, mname, rv.Uint())
|
|
case reflect.Float32, reflect.Float64:
|
|
fmt.Fprintf(w, "# TYPE %s %s\n%s %v\n", mname, metricType, mname, rv.Float())
|
|
case reflect.Struct:
|
|
if rv.CanAddr() {
|
|
// Slight optimization, not copying big structs if they're addressable:
|
|
writePromExpVar(w, name+"_", expvar.KeyValue{Key: fieldOrJSONName, Value: expVarPromStructRoot{rv.Addr().Interface()}})
|
|
} else {
|
|
writePromExpVar(w, name+"_", expvar.KeyValue{Key: fieldOrJSONName, Value: expVarPromStructRoot{rv.Interface()}})
|
|
}
|
|
}
|
|
return
|
|
})
|
|
return
|
|
}
|
|
|
|
if typ == "" {
|
|
var funcRet string
|
|
if f, ok := kv.Value.(expvar.Func); ok {
|
|
v := f()
|
|
if ms, ok := v.(runtime.MemStats); ok && name == "memstats" {
|
|
writeMemstats(w, &ms)
|
|
return
|
|
}
|
|
switch v := v.(type) {
|
|
case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, uintptr, float32, float64:
|
|
fmt.Fprintf(w, "%s %v\n", name, v)
|
|
return
|
|
}
|
|
funcRet = fmt.Sprintf(" returning %T", v)
|
|
}
|
|
switch kv.Value.(type) {
|
|
default:
|
|
fmt.Fprintf(w, "# skipping expvar %q (Go type %T%s) with undeclared Prometheus type\n", name, kv.Value, funcRet)
|
|
return
|
|
case *metrics.LabelMap, *expvar.Map:
|
|
// Permit typeless LabelMap and expvar.Map for
|
|
// compatibility with old expvar-registered
|
|
// metrics.LabelMap.
|
|
}
|
|
}
|
|
|
|
switch v := kv.Value.(type) {
|
|
case expvar.Func:
|
|
val := v()
|
|
switch val.(type) {
|
|
case float64, int64, int:
|
|
fmt.Fprintf(w, "# TYPE %s %s\n%s %v\n", name, typ, name, val)
|
|
default:
|
|
fmt.Fprintf(w, "# skipping expvar func %q returning unknown type %T\n", name, val)
|
|
}
|
|
|
|
case *metrics.LabelMap:
|
|
if typ != "" {
|
|
fmt.Fprintf(w, "# TYPE %s %s\n", name, typ)
|
|
}
|
|
// IntMap uses expvar.Map on the inside, which presorts
|
|
// keys. The output ordering is deterministic.
|
|
v.Do(func(kv expvar.KeyValue) {
|
|
fmt.Fprintf(w, "%s{%s=%q} %v\n", name, v.Label, kv.Key, kv.Value)
|
|
})
|
|
case *expvar.Map:
|
|
if label != "" && typ != "" {
|
|
fmt.Fprintf(w, "# TYPE %s %s\n", name, typ)
|
|
v.Do(func(kv expvar.KeyValue) {
|
|
fmt.Fprintf(w, "%s{%s=%q} %v\n", name, label, kv.Key, kv.Value)
|
|
})
|
|
} else {
|
|
v.Do(func(kv expvar.KeyValue) {
|
|
fmt.Fprintf(w, "%s_%s %v\n", name, kv.Key, kv.Value)
|
|
})
|
|
}
|
|
}
|
|
}
|
|
|
|
// VarzHandler is an HTTP handler to write expvar values into the
|
|
// prometheus export format:
|
|
//
|
|
// https://github.com/prometheus/docs/blob/master/content/docs/instrumenting/exposition_formats.md
|
|
//
|
|
// It makes the following assumptions:
|
|
//
|
|
// * *expvar.Int are counters (unless marked as a gauge_; see below)
|
|
// * a *tailscale/metrics.Set is descended into, joining keys with
|
|
// underscores. So use underscores as your metric names.
|
|
// * an expvar named starting with "gauge_" or "counter_" is of that
|
|
// Prometheus type, and has that prefix stripped.
|
|
// * anything else is untyped and thus not exported.
|
|
// * expvar.Func can return an int or int64 (for now) and anything else
|
|
// is not exported.
|
|
//
|
|
// This will evolve over time, or perhaps be replaced.
|
|
func VarzHandler(w http.ResponseWriter, r *http.Request) {
|
|
w.Header().Set("Content-Type", "text/plain; version=0.0.4")
|
|
expvarDo(func(kv expvar.KeyValue) {
|
|
writePromExpVar(w, "", kv)
|
|
})
|
|
}
|
|
|
|
// PrometheusMetricsReflectRooter is an optional interface that expvar.Var implementations
|
|
// can implement to indicate that they should be walked recursively with reflect to find
|
|
// sets of fields to export.
|
|
type PrometheusMetricsReflectRooter interface {
|
|
expvar.Var
|
|
|
|
// PrometheusMetricsReflectRoot returns the struct or struct pointer to walk.
|
|
PrometheusMetricsReflectRoot() any
|
|
}
|
|
|
|
var expvarDo = expvar.Do // pulled out for tests
|
|
|
|
func writeMemstats(w io.Writer, ms *runtime.MemStats) {
|
|
out := func(name, typ string, v uint64, help string) {
|
|
if help != "" {
|
|
fmt.Fprintf(w, "# HELP memstats_%s %s\n", name, help)
|
|
}
|
|
fmt.Fprintf(w, "# TYPE memstats_%s %s\nmemstats_%s %v\n", name, typ, name, v)
|
|
}
|
|
g := func(name string, v uint64, help string) { out(name, "gauge", v, help) }
|
|
c := func(name string, v uint64, help string) { out(name, "counter", v, help) }
|
|
g("heap_alloc", ms.HeapAlloc, "current bytes of allocated heap objects (up/down smoothly)")
|
|
c("total_alloc", ms.TotalAlloc, "cumulative bytes allocated for heap objects")
|
|
g("sys", ms.Sys, "total bytes of memory obtained from the OS")
|
|
c("mallocs", ms.Mallocs, "cumulative count of heap objects allocated")
|
|
c("frees", ms.Frees, "cumulative count of heap objects freed")
|
|
c("num_gc", uint64(ms.NumGC), "number of completed GC cycles")
|
|
}
|
|
|
|
func foreachExportedStructField(rv reflect.Value, f func(fieldOrJSONName, metricType string, rv reflect.Value)) {
|
|
t := rv.Type()
|
|
for i, n := 0, t.NumField(); i < n; i++ {
|
|
sf := t.Field(i)
|
|
name := sf.Name
|
|
if v := sf.Tag.Get("json"); v != "" {
|
|
v, _, _ = strings.Cut(v, ",")
|
|
if v == "-" {
|
|
// Skip it, regardless of its metrictype.
|
|
continue
|
|
}
|
|
if v != "" {
|
|
name = v
|
|
}
|
|
}
|
|
metricType := sf.Tag.Get("metrictype")
|
|
if metricType != "" || sf.Type.Kind() == reflect.Struct {
|
|
f(name, metricType, rv.Field(i))
|
|
} else if sf.Type.Kind() == reflect.Ptr && sf.Type.Elem().Kind() == reflect.Struct {
|
|
fv := rv.Field(i)
|
|
if !fv.IsNil() {
|
|
f(name, metricType, fv.Elem())
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
type expVarPromStructRoot struct{ v any }
|
|
|
|
func (r expVarPromStructRoot) PrometheusMetricsReflectRoot() any { return r.v }
|
|
func (r expVarPromStructRoot) String() string { panic("unused") }
|
|
|
|
var (
|
|
_ PrometheusMetricsReflectRooter = expVarPromStructRoot{}
|
|
_ expvar.Var = expVarPromStructRoot{}
|
|
)
|