README
¶
badnet
badnet is a TCP proxy for tests. Release notes are on GitHub Releases. It sits between your application and the service it talks to so you can simulate latency, bandwidth limits, and connection failures without changing application code.
- Start a proxy with
badnet.ForTest - Point the application at
proxy.BindAddr() - Run the tests you already have
Zero-config is a transparent TCP forwarder. Impairments are optional and applied from the connecting client's point of view.
proxy := badnet.ForTest(t, badnet.Config{
Listen: "127.0.0.1:0",
Target: "127.0.0.1:8080", // host:port, http://..., https://..., or [IPv6]
Read: badnet.Direction{ // data the client receives
Latency: 50 * time.Millisecond,
MaxKBps: 32,
FailureRatio: 10, // percent of connections
},
Write: badnet.Direction{ // data the client sends
FailureRatio: 5,
},
})
// App dials the proxy instead of the real target.
addr := proxy.BindAddr()
Config
| Field | Meaning |
|---|---|
Listen |
Local address to accept on. 127.0.0.1:0 picks a free port. |
Target |
Upstream host:port. http:// defaults to 80, https:// / wss:// to 443. IPv6 works with or without brackets. |
Read |
Impairments on bytes the client reads (server → client). |
Write |
Impairments on bytes the client writes (client → server). |
DialTimeout |
Timeout when the proxy dials Target. Default 5s. |
Each Direction:
| Field | Meaning |
|---|---|
Latency |
Delay applied once, on the first I/O in that direction. |
MaxKBps |
Throughput cap in kilobytes/second. 0 is unlimited. |
FailureRatio |
0–100. Chance this connection fails in that direction (partial I/O, then an error). Not per Read/Write call. |
ForTest shuts the proxy down in t.Cleanup. Target dial failures are counted in stats; they do not fail the caller’s test.
Stats
proxy.Port() // listening port, or -1
proxy.BindAddr() // host:port to dial
proxy.FailureRatio() // failed connections / accepted connections
Notes
- This is a TCP proxy. HTTP clients must set
Hostthemselves if the upstream is name-based. - Both directions are copied to completion. A client
CloseWriteis forwarded so protocols that half-close still get a response. - See
examples/for HTTP, latency, and concurrent TCP.
Related
Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
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Types ¶
type Config ¶
type Config struct {
Listen string // local address, e.g. "127.0.0.1:0"
Target string // upstream host:port or URL
Read Direction
Write Direction
DialTimeout time.Duration // 0 uses a 5s default
}
Config describes a test proxy. Read and Write are from the connecting client's point of view: Read impairs data the client receives, Write impairs data the client sends.
type Direction ¶
Direction impairs one direction of traffic, from the connecting client's point of view. FailureRatio is the percent (0-100) of connections that fail in this direction. Latency is applied once, on the first I/O. MaxKBps of 0 means unlimited.
type Proxy ¶
type Proxy struct {
// contains filtered or unexported fields
}
func ForTest ¶
ForTest starts a proxy that shuts down when the test ends. Listen errors fail the test; later target dial errors do not.
func (*Proxy) FailureRatio ¶ added in v0.3.0
FailureRatio is the fraction of accepted connections that had a dial failure or an injected/copy failure.
Source Files