forked from cerc-io/ipld-eth-server
95 lines
2.1 KiB
Go
95 lines
2.1 KiB
Go
// Copyright (c) 2015 Arista Networks, Inc.
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// Use of this source code is governed by the Apache License 2.0
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// that can be found in the COPYING file.
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// Package monitor provides an embedded HTTP server to expose
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// metrics for monitoring
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package monitor
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import (
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"expvar"
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"fmt"
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"net"
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"net/http"
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_ "net/http/pprof" // Go documentation recommended usage
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"github.com/aristanetworks/goarista/netns"
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"github.com/aristanetworks/glog"
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)
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// Server represents a monitoring server
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type Server interface {
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Run(serveMux *http.ServeMux)
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}
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// server contains information for the monitoring server
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type server struct {
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vrfName string
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// Server name e.g. host[:port]
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serverName string
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}
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// NewServer creates a new server struct
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func NewServer(address string) Server {
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vrfName, addr, err := netns.ParseAddress(address)
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if err != nil {
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glog.Errorf("Failed to parse address: %s", err)
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}
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return &server{
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vrfName: vrfName,
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serverName: addr,
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}
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}
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func debugHandler(w http.ResponseWriter, r *http.Request) {
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indexTmpl := `<html>
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<head>
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<title>/debug</title>
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</head>
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<body>
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<p>/debug</p>
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<div><a href="/debug/vars">vars</a></div>
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<div><a href="/debug/pprof">pprof</a></div>
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</body>
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</html>
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`
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fmt.Fprintf(w, indexTmpl)
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}
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// PrintableHistogram represents a Histogram that can be printed as
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// a chart.
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type PrintableHistogram interface {
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Print() string
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}
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// Pretty prints the latency histograms
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func histogramHandler(w http.ResponseWriter, r *http.Request) {
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expvar.Do(func(kv expvar.KeyValue) {
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if hist, ok := kv.Value.(PrintableHistogram); ok {
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w.Write([]byte(hist.Print()))
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}
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})
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}
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// Run sets up the HTTP server and any handlers
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func (s *server) Run(serveMux *http.ServeMux) {
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serveMux.HandleFunc("/debug", debugHandler)
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serveMux.HandleFunc("/debug/histograms", histogramHandler)
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var listener net.Listener
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err := netns.Do(s.vrfName, func() error {
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var err error
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listener, err = net.Listen("tcp", s.serverName)
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return err
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})
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if err != nil {
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glog.Fatalf("Could not start monitor server in VRF %q: %s", s.vrfName, err)
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}
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err = http.Serve(listener, serveMux)
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if err != nil {
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glog.Fatal("http serve returned with error:", err)
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}
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}
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