hloader

hloader is a lightweight HTTP/HTTPS load testing tool designed for generating concurrent HTTP requests with configurable rate limiting and connection management.

Scope and Limitations

hloader is specifically designed for HTTP/HTTPS load testing only. It supports:

• HTTP/1.1 and HTTP/2 protocols
• Configurable request rates and concurrency
• TLS/SSL connections with optional certificate verification
• HTTP keepalive connections
• Optional Prometheus metrics endpoint for continuous load generation

Out of Scope: hloader does not support other transport protocols such as TCP, UDP, or SCTP. For protocol-level load testing including SCTP support for telco use-cases, please refer to k8s-netperf.

 $ ./bin/hloader -h
HTTP loader

Usage:
  ./bin/hloader [flags]
  ./bin/hloader [command]

Available Commands:
  completion  Generate the autocompletion script for the specified shell
  help        Help about any command
  version     Get version info

Flags:
  -u, --url string                   Target URL
  -r, --rate int                     Request rate, 0 means unlimited
  -c, --concurrency int              Number of concurrent connections (default 1)
  -d, --duration duration            Test duration (default 10s)
  -t, --timeout duration             Request timeout (default 1s)
  -i, --insecure                     Skip server's certificate verification (default true)
  -k, --keepalive                    Enable HTTP keepalive (default true)
      --http2                        Use HTTP2 protocol, if possible (default true)
      --pprof                        Enable pprof endpoint in localhost:6060
  -o, --output string                Dump request outputs in the given CSV file
  -m, --enable-prometheus-metrics    Enable Prometheus metrics; run until interrupted (ignores --duration)
  -p, --metrics-port int             Metrics port (default 9000)
  -h, --help                         help for ./bin/hloader

Compilation

$ make build
GOARCH=amd64 CGO_ENABLED=0 go build -v -ldflags "-X github.com/cloud-bulldozer/go-commons/version.GitCommit=a5c03b3c983255096635b872d4153c98419f8bd1 -X github.com/cloud-bulldozer/go-commons/version.Version=main -X github.com/cloud-bulldozer/go-commons/version.BuildDate=2023-10-24-12:13:18" -o bin/hloader cmd/hloader.go

CSV output

The csv output has the following format:

1699016948650,200,276028,537,false,false
<timestamp in milliseconds>,<status code>,<latency in microseconds>,<bytes read>,<timeout>,<http error>

Like for example:

1699016948640,200,283085,537,false,false
1699016948650,200,276028,537,false,false
1699016948670,200,255849,537,false,false
1699016948700,200,225850,537,false,false
1699016948709,200,216579,537,false,false

Prometheus metrics

When --enable-prometheus-metrics (-m) is set, hloader runs until interrupted (--duration is ignored) and exposes a Prometheus scrape endpoint at http://localhost:<metrics-port>/metrics (default port 9000). Results are streamed as metrics instead of being aggregated into the JSON summary or CSV output. Stop the load with SIGINT (Ctrl+C).

Example:

$ ./bin/hloader -u https://example.com -c 10 -r 100 -m
$ curl localhost:9000/metrics

Exposed metrics:

Metric	Type	Description
hloader_http_requests_total	Counter (label: code)	Total HTTP requests by status code
hloader_http_timeouts_total	Counter	Total HTTP request timeouts
hloader_http_read_errors_total	Counter	Total response body read errors
hloader_request_latency_seconds	Histogram	Request latency in seconds
hloader_bytes_read_total	Counter	Total bytes read from responses