Hargo

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

NAME:
   hargo - work with HTTP Archive (.har) files

USAGE:
   hargo <command> [arguments] <.har file>

VERSION:
   0.1.2-dev.57 (da53069)

AUTHOR:
   Mark A. Richman <[email protected]>

COMMANDS:
     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

GLOBAL OPTIONS:
   --debug        Show debug output
   --help, -h     show help
   --version, -v  print the version

COPYRIGHT:
   (c) 2022 Mark A. Richman

Building and Running Hargo

git clone https://github.com/mrichman/hargo.git
cd hargo
make install
hargo validate test/golang.org.har

About HAR Files

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

1. Right-click anywhere on that page and click on Inspect Element to open Chrome's Developer Tools
2. The Developer Tools will open as a panel at the bottom of the page. Click on the Network tab.
3. 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.
4. Refresh the page and start working normally
5. Right-click within the Network tab and click Save as HAR with Content to save a copy of the activity that you recorded.
6. Within the file window, save the HAR file.

Commands

Fetch

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.

Curl

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

hargo curl foo.har

Run

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.

Validate

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

Dump prints information about all HTTP requests in .har file

hargo dump foo.har

Load

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.

Docker

Build container

docker build -t hargo .

Run container

docker run --rm -v `pwd`/test:/test hargo hargo run /test/golang.org.har

Docker-compose

The example docker-compose file will start three containers:

• hargo
• influxdb
• grafana

The hargo container will first needs to be built. See build. When the compose file is run it will start a hargo load process that will write the results to InfluxDB. This InfluxDB instance can be viewed using the grafana container. This contains an example dashboard showing the latency of the executed request. Username/password for all the containers is hargo/hargo.

commands

cd example/docker-compose
docker-compose up
docker-compose down -v