File: link.go

package info (click to toggle)
toxiproxy 2.0.0+dfsg1-6
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 388 kB
  • sloc: sh: 91; makefile: 59
file content (159 lines) | stat: -rw-r--r-- 4,376 bytes parent folder | download | duplicates (2)
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
package toxiproxy

import (
	"io"

	"github.com/Shopify/toxiproxy/stream"
	"github.com/Shopify/toxiproxy/toxics"
	"github.com/Sirupsen/logrus"
)

// ToxicLinks are single direction pipelines that connects an input and output via
// a chain of toxics. The chain always starts with a NoopToxic, and toxics are added
// and removed as they are enabled/disabled. New toxics are always added to the end
// of the chain.
//
//         NoopToxic  LatencyToxic
//             v           v
// Input > ToxicStub > ToxicStub > Output
//
type ToxicLink struct {
	stubs     []*toxics.ToxicStub
	proxy     *Proxy
	toxics    *ToxicCollection
	input     *stream.ChanWriter
	output    *stream.ChanReader
	direction stream.Direction
}

func NewToxicLink(proxy *Proxy, collection *ToxicCollection, direction stream.Direction) *ToxicLink {
	link := &ToxicLink{
		stubs:     make([]*toxics.ToxicStub, len(collection.chain[direction]), cap(collection.chain[direction])),
		proxy:     proxy,
		toxics:    collection,
		direction: direction,
	}

	// Initialize the link with ToxicStubs
	last := make(chan *stream.StreamChunk) // The first toxic is always a noop
	link.input = stream.NewChanWriter(last)
	for i := 0; i < len(link.stubs); i++ {
		var next chan *stream.StreamChunk
		if i+1 < len(link.stubs) {
			next = make(chan *stream.StreamChunk, link.toxics.chain[direction][i+1].BufferSize)
		} else {
			next = make(chan *stream.StreamChunk)
		}

		link.stubs[i] = toxics.NewToxicStub(last, next)
		last = next
	}
	link.output = stream.NewChanReader(last)
	return link
}

// Start the link with the specified toxics
func (link *ToxicLink) Start(name string, source io.Reader, dest io.WriteCloser) {
	go func() {
		bytes, err := io.Copy(link.input, source)
		if err != nil {
			logrus.WithFields(logrus.Fields{
				"name":  link.proxy.Name,
				"bytes": bytes,
				"err":   err,
			}).Warn("Source terminated")
		}
		link.input.Close()
	}()
	for i, toxic := range link.toxics.chain[link.direction] {
		go link.stubs[i].Run(toxic)
	}
	go func() {
		bytes, err := io.Copy(dest, link.output)
		if err != nil {
			logrus.WithFields(logrus.Fields{
				"name":  link.proxy.Name,
				"bytes": bytes,
				"err":   err,
			}).Warn("Destination terminated")
		}
		dest.Close()
		link.toxics.RemoveLink(name)
		link.proxy.RemoveConnection(name)
	}()
}

// Add a toxic to the end of the chain.
func (link *ToxicLink) AddToxic(toxic *toxics.ToxicWrapper) {
	i := len(link.stubs)

	newin := make(chan *stream.StreamChunk, toxic.BufferSize)
	link.stubs = append(link.stubs, toxics.NewToxicStub(newin, link.stubs[i-1].Output))

	// Interrupt the last toxic so that we don't have a race when moving channels
	if link.stubs[i-1].InterruptToxic() {
		link.stubs[i-1].Output = newin

		go link.stubs[i].Run(toxic)
		go link.stubs[i-1].Run(link.toxics.chain[link.direction][i-1])
	} else {
		// This link is already closed, make sure the new toxic matches
		link.stubs[i].Output = newin // The real output is already closed, close this instead
		link.stubs[i].Close()
	}
}

// Update an existing toxic in the chain.
func (link *ToxicLink) UpdateToxic(toxic *toxics.ToxicWrapper) {
	if link.stubs[toxic.Index].InterruptToxic() {
		go link.stubs[toxic.Index].Run(toxic)
	}
}

// Remove an existing toxic from the chain.
func (link *ToxicLink) RemoveToxic(toxic *toxics.ToxicWrapper) {
	i := toxic.Index

	if link.stubs[i].InterruptToxic() {
		stop := make(chan bool)
		// Interrupt the previous toxic to update its output
		go func() {
			stop <- link.stubs[i-1].InterruptToxic()
		}()

		// Unblock the previous toxic if it is trying to flush
		// If the previous toxic is closed, continue flusing until we reach the end.
		interrupted := false
		stopped := false
		for !interrupted {
			select {
			case interrupted = <-stop:
				stopped = true
			case tmp := <-link.stubs[i].Input:
				if tmp == nil {
					link.stubs[i].Close()
					if !stopped {
						<-stop
					}
					return
				}
				link.stubs[i].Output <- tmp
			}
		}

		// Empty the toxic's buffer if necessary
		for len(link.stubs[i].Input) > 0 {
			tmp := <-link.stubs[i].Input
			if tmp == nil {
				link.stubs[i].Close()
				return
			}
			link.stubs[i].Output <- tmp
		}

		link.stubs[i-1].Output = link.stubs[i].Output
		link.stubs = append(link.stubs[:i], link.stubs[i+1:]...)

		go link.stubs[i-1].Run(link.toxics.chain[link.direction][i-1])
	}
}