/
main.go
245 lines (203 loc) · 4.85 KB
/
main.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
// Copyright (C) 2022 Storj Labs, Inc.
// See LICENSE for copying information.
package main
import (
"bytes"
"context"
"encoding/json"
"log"
"net/http"
"os"
"strconv"
"strings"
"sync"
"github.com/apache/thrift/lib/go/thrift"
"github.com/google/gopacket"
"github.com/google/gopacket/layers"
"github.com/google/gopacket/pcapgo"
"github.com/zeebo/errs"
"storj.io/monkit-jaeger/gen-go/agent"
"storj.io/monkit-jaeger/gen-go/jaeger"
)
func main() {
if err := run(context.Background(), os.Args[1], os.Args[2]); err != nil {
log.Fatalf("%+v", err)
}
}
type subscription struct {
traceID int64
ch chan *jaeger.Span
}
type server struct {
mu sync.Mutex
active map[*http.Request]*subscription
rbufs map[int64][]*jaeger.Span
rbuft []int64
rbufn int
}
func run(ctx context.Context, iface, laddr string) (err error) {
ctx, cancel := context.WithCancel(ctx)
defer cancel()
handle, err := pcapgo.NewEthernetHandle(iface)
if err != nil {
return err
}
src := gopacket.NewPacketSource(handle, layers.LinkTypeEthernet)
s := &server{
active: make(map[*http.Request]*subscription),
rbufs: make(map[int64][]*jaeger.Span),
}
errch := make(chan error, 2)
go func() { errch <- errs.Wrap(s.handlePackets(ctx, src)) }()
go func() { errch <- errs.Wrap(http.ListenAndServe(laddr, s)) }()
select {
case err := <-errch:
return errs.Wrap(err)
case <-ctx.Done():
return ctx.Err()
}
}
func (s *server) handlePackets(ctx context.Context, src *gopacket.PacketSource) error {
for {
packet, err := src.NextPacket()
if err != nil {
return err
}
udp, _ := packet.Layer(layers.LayerTypeUDP).(*layers.UDP)
if udp == nil || udp.DstPort != 5775 {
continue
}
if err := s.handlePacket(ctx, udp.Payload); err != nil {
log.Printf("%+v", err)
}
}
}
func (s *server) handlePacket(ctx context.Context, buf []byte) (err error) {
var batch agent.AgentEmitBatchArgs
var mbuf thrift.TMemoryBuffer
mbuf.Buffer = bytes.NewBuffer(buf)
proto := thrift.NewTCompactProtocol(&mbuf)
if _, _, _, err := proto.ReadMessageBegin(); err != nil {
return errs.Wrap(err)
}
if err := batch.Read(proto); err != nil {
return errs.Wrap(err)
}
if err := proto.ReadMessageEnd(); err != nil {
return errs.Wrap(err)
}
s.mu.Lock()
defer s.mu.Unlock()
for _, span := range batch.Batch.GetSpans() {
rbuf, ok := s.rbufs[span.TraceIdLow]
if !ok {
s.rbuft = append(s.rbuft, span.TraceIdLow)
}
s.rbufs[span.TraceIdLow] = append(rbuf, span)
s.rbufn++
if s.rbufn >= 1024*1024 {
evict := s.rbuft[0]
s.rbuft = s.rbuft[1:]
s.rbufn -= len(s.rbufs[evict])
delete(s.rbufs, evict)
}
// this _should_ be relatively small compared to the other buffer
for _, sub := range s.active {
if sub.traceID == span.TraceIdLow {
select {
case sub.ch <- span:
default:
log.Printf("dropped trace for %d", span.TraceIdLow)
}
}
}
}
return nil
}
func (s *server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
w.Header().Add("Access-Control-Allow-Origin", "*")
accept := r.Header.Get("Accept")
switch {
case accept == "application/json":
s.Subscribe(w, r)
default:
s.Visualize(w, r)
}
}
func (s *server) Subscribe(w http.ResponseWriter, r *http.Request) {
fl, _ := w.(interface{ Flush() })
q := r.URL.Query()
// wait for additional traces to be returned
wait := true
if w := q.Get("wait"); w != "" {
wait, _ = strconv.ParseBool(w)
}
// which trace we're looking at
traceID, err := strconv.ParseInt(strings.TrimPrefix(r.URL.Path, "/"), 0, 64)
if err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
log.Printf("filtering traces for %d (wait=%s)", traceID, strconv.FormatBool(wait))
defer log.Printf("done filtering traces for %d (wait=%s)", traceID, strconv.FormatBool(wait))
// stream json spans back to the client
w.Header().Set("Content-Type", "application/json")
w.Header().Set("Transfer-Encoding", "chunked")
w.WriteHeader(http.StatusOK)
out := json.NewEncoder(w)
sub := &subscription{
traceID: traceID,
ch: make(chan *jaeger.Span, 64),
}
defer func() {
s.mu.Lock()
defer s.mu.Unlock()
if s.active[r] != nil {
delete(s.active, r)
}
close(sub.ch)
}()
err = func() error {
s.mu.Lock()
defer s.mu.Unlock()
s.active[r] = sub
for _, span := range s.rbufs[traceID] {
err = out.Encode(span)
if err != nil {
return err
}
}
if fl != nil {
fl.Flush()
}
return nil
}()
switch {
case err != nil:
// json encoding err, or output closed
// log err
return
case !wait:
// only return the buffer, don't wait for new data
return
}
for {
select {
case <-r.Context().Done():
// log r.Context().Err()
return
case span := <-sub.ch:
err = out.Encode(span)
if err != nil {
// log err
return
}
if fl != nil {
fl.Flush()
}
}
}
}
func (s *server) Visualize(w http.ResponseWriter, r *http.Request) {
// render UI
}