Hargo - parse HAR files, convert to curl, and drive load tests

Hargo parses HAR files, can convert to curl format, and serve as a load test driver.

hargo - work with HTTP Archive (.har) files

hargo [arguments] <.har file>


Mark A. Richman mark@markrichman.com

fetch, f Fetch URLs in .har
curl, c Convert .har to curl
run, r Run .har file
validate, v Validate .har file
dump, d Dump .har file
load, l Load test .har file
help, h Shows a list of commands or help for one command

–debug enable verbose (debug) logging
–help, -h show help
–version, -v print the version

© 2016 Mark A. Richman
Running Hargo

go get github.com/mrichman/hargo
cd $GOPATH/src/github.com/mrichman/hargo
go run cmd/hargo/main.go validate test/golang.org.har
About HAR Files

If you use Google Chrome, you can record these files by following the steps below:

Right-click anywhere on that page and click on Inspect Element to open Chrome’s Developer Tools
The Developer Tools will open as a panel at the bottom of the page. Click on the Network tab.
Click the Record button, which is the solid black circle at the bottom of the Network tab, and you’ll start recording activity in your browser.
Refresh the page and start working normally
Right-click within the Network tab and click Save as HAR with Content to save a copy of the activity that you recorded.
Within the file window, save the HAR file.


The fetch command downloads all resources references in .har file:

hargo fetch foo.har

This will produce a directory named hargo-fetch-yyyymmddhhmmss containing all assets references by the .har file. This is similar to what you’d see when invoking wget on a particular URL.


The curl command will output a curl command line for each entry in the .har file.

hargo curl foo.har


The run command executes each HTTP request in .har file:

hargo run foo.har

This is similar to fetch but will not save any output.


The validate command will report any errors in the format of a .har file.

hargo validate foo.har

HAR file format is defined here: https://w3c.github.io/web-performance/specs/HAR/Overview.html


Dump prints information about all HTTP requests in .har file

hargo dump foo.har


Hargo can act as a load test agent. Given a .har file, hargo can spawn a number of concurrent workers to repeat each HTTP request in order. By default, hargo will spawn 10 workers and run for a duration of 60 seconds.

Hargo will also save its results to InfluxDB, if available. Each HTTP response is stored as a point of time-series data, which can be graphed by Chronograf, Grafana, or similar visualization tool for analysis.

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