Vegeta is a versatile HTTP load testing tool built out of a need to drill HTTP services with a constant request rate. It can be used both as a command line utility and a library.

Get them here.

You can install Vegeta using the Homebrew package manager on Mac OS X:

$ brew update && brew install vegeta

You need go installed and GOBIN in your PATH. Once that is done, run the command:

$ go get github.com/tsenart/vegeta
$ go install github.com/tsenart/vegeta

$ vegeta -h
Usage: vegeta [globals] <command> [options]

attack command:
  -body="": Requests body file
  -cert="": x509 Certificate file
  -duration=10s: Duration of the test
  -header=: Request header
  -keepalive=true: Use persistent connections
  -laddr=0.0.0.0: Local IP address
  -lazy=false: Read targets lazily
  -output="stdout": Output file
  -rate=50: Requests per second
  -redirects=10: Number of redirects to follow. -1 will not follow but marks as success
  -targets="stdin": Targets file
  -timeout=0: Requests timeout
  -workers=0: Number of workers

report command:
  -inputs="stdin": Input files (comma separated)
  -output="stdout": Output file
  -reporter="text": Reporter [text, json, plot, hist[buckets]]

dump command:
  -dumper="": Dumper [json, csv]
  -inputs="stdin": Input files (comma separated)
  -output="stdout": Output file

global flags:
  -cpus=8 Number of CPUs to use

examples:
  echo "GET http://localhost/" | vegeta attack -duration=5s | tee results.bin | vegeta report
  vegeta attack -targets=targets.txt > results.bin
  vegeta report -inputs=results.bin -reporter=json > metrics.json
  cat results.bin | vegeta report -reporter=plot > plot.html
  cat results.bin | vegeta report -reporter="hist[0,100ms,200ms,300ms]"

Specifies the number of CPUs to be used internally. It defaults to the amount of CPUs available in the system.

$ vegeta attack -h
Usage of vegeta attack:
  -body="": Requests body file
  -cert="": x509 Certificate file
  -duration=10s: Duration of the test
  -header=: Request header
  -keepalive=true: Use persistent connections
  -laddr=0.0.0.0: Local IP address
  -lazy=false: Read targets lazily
  -output="stdout": Output file
  -rate=50: Requests per second
  -redirects=10: Number of redirects to follow
  -targets="stdin": Targets file
  -timeout=30s: Requests timeout
  -workers=0: Number of workers

Specifies the file whose content will be set as the body of every request unless overridden per attack target, see -targets.

Specifies the x509 TLS certificate to be used with HTTPS requests.

Specifies the amount of time to issue request to the targets. The internal concurrency structure's setup has this value as a variable. The actual run time of the test can be longer than specified due to the responses delay.

Specifies a request header to be used in all targets defined, see -targets. You can specify as many as needed by repeating the flag.

Specifies whether to reuse TCP connections between HTTP requests.

Specifies the local IP address to be used.

Specifies whether to read the input targets lazily instead of eagerly. This allows streaming targets into the attack command and reduces memory footprint. The trade-off is one of added latency in each hit against the targets.

Specifies the output file to which the binary results will be written to. Made to be piped to the report command input. Defaults to stdout.

Specifies the requests per second rate to issue against the targets. The actual request rate can vary slightly due to things like garbage collection, but overall it should stay very close to the specified.

Specifies the max number of redirects followed on each request. The default is 10. When the value is -1, redirects are not followed but the response is marked as successful.

Specifies the attack targets in a line separated file, defaulting to stdin. The format should be as follows, combining any or all of the following:

Simple targets

GET http://goku:9090/path/to/dragon?item=balls
GET http://user:password@goku:9090/path/to
HEAD http://goku:9090/path/to/success

Targets with custom headers

GET http://user:password@goku:9090/path/to
X-Account-ID: 8675309

DELETE http://goku:9090/path/to/remove
Confirmation-Token: 90215
Authorization: Token DEADBEEF

Targets with custom bodies

POST http://goku:9090/things
@/path/to/newthing.json

PATCH http://goku:9090/thing/71988591
@/path/to/thing-71988591.json

Targets with custom bodies and headers

POST http://goku:9090/things
X-Account-ID: 99
@/path/to/newthing.json

Specifies the timeout for each request. The default is 0 which disables timeouts.

Specifies the number of workers used in the attack. The default 0 means every single hit runs in its own worker.

$ vegeta report -h
Usage of vegeta report:
  -inputs="stdin": Input files (comma separated)
  -output="stdout": Output file
  -reporter="text": Reporter [text, json, plot, hist[buckets]]

Specifies the input files to generate the report of, defaulting to stdin. These are the output of vegeta attack. You can specify more than one (comma separated) and they will be merged and sorted before being used by the reports.

Specifies the output file to which the report will be written to.

Specifies the kind of report to be generated. It defaults to text.

Requests      [total]                   1200
Duration      [total, attack, wait]     10.094965987s, 9.949883921s, 145.082066ms
Latencies     [mean, 50, 95, 99, max]   113.172398ms, 108.272568ms, 140.18235ms, 247.771566ms, 264.815246ms
Bytes In      [total, mean]             3714690, 3095.57
Bytes Out     [total, mean]             0, 0.00
Success       [ratio]                   55.42%
Status Codes  [code:count]              0:535  200:665
Error Set:
Get http://localhost:6060: dial tcp 127.0.0.1:6060: connection refused
Get http://localhost:6060: read tcp 127.0.0.1:6060: connection reset by peer
Get http://localhost:6060: dial tcp 127.0.0.1:6060: connection reset by peer
Get http://localhost:6060: write tcp 127.0.0.1:6060: broken pipe
Get http://localhost:6060: net/http: transport closed before response was received
Get http://localhost:6060: http: can't write HTTP request on broken connection

{
  "latencies": {
    "mean": 9093653647,
    "50th": 2401223400,
    "95th": 12553709381,
    "99th": 12604629125,
    "max": 12604629125
  },
  "bytes_in": {
    "total": 782040,
    "mean": 651.7
  },
  "bytes_out": {
    "total": 0,
    "mean": 0
  },
  "duration": 9949883921,
  "wait": 145082066,
  "requests": 1200,
  "success": 0.11666666666666667,
  "status_codes": {
    "0": 1060,
    "200": 140
  },
  "errors": [
    "Get http://localhost:6060: dial tcp 127.0.0.1:6060: operation timed out"
  ]
}

Generates an HTML5 page with an interactive plot based on Dygraphs. Click and drag to select a region to zoom into. Double click to zoom out. Input a different number on the bottom left corner input field to change the moving average window size (in data points).

Computes and prints a text based histogram for the given buckets. Each bucket upper bound is non-inclusive.

cat results.bin | vegeta report -reporter='hist[0,2ms,4ms,6ms]'
Bucket         #     %       Histogram
[0,     2ms]   6007  32.65%  ########################
[2ms,   4ms]   5505  29.92%  ######################
[4ms,   6ms]   2117  11.51%  ########
[6ms,   +Inf]  4771  25.93%  ###################

$ vegeta dump -h
Usage of vegeta dump:
  -dumper="": Dumper [json, csv]
  -inputs="stdin": Input files (comma separated)
  -output="stdout": Output file

Specifies the input files containing attack results to be dumped. You can specify more than one (comma separated).

Specifies the output file to which the dump will be written to.

Specifies the dump format.

Dumps attack results as JSON objects.

Dumps attack results as CSV records with six columns. The columns are: unix timestamp in ns since epoch, http status code, request latency in ns, bytes out, bytes in, and lastly the error.

package main

import (
  "time"
  "fmt"

  vegeta "github.com/tsenart/vegeta/lib"
)

func main() {

  rate := uint64(100) // per second
  duration := 4 * time.Second
  targeter := vegeta.NewStaticTargeter(&vegeta.Target{
    Method: "GET",
    URL:    "http://localhost:9100/",
  })
  attacker := vegeta.NewAttacker()

  var results vegeta.Results
  for res := range attacker.Attack(targeter, rate, duration) {
    results = append(results, res)
  }

  metrics := vegeta.NewMetrics(results)
  fmt.Printf("99th percentile: %s\n", metrics.Latencies.P99)
}

There will be an upper bound of the supported rate which varies on the machine being used. You could be CPU bound (unlikely), memory bound (more likely) or have system resource limits being reached which ought to be tuned for the process execution. The important limits for us are file descriptors and processes. On a UNIX system you can get and set the current soft-limit values for a user.

$ ulimit -n # file descriptors
2560
$ ulimit -u # processes / threads
709

Just pass a new number as the argument to change it.

The MIT License (MIT)

Copyright (c) 2013-2015 Tomás Senart

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