Files

Jan Novak a588eb3b0e feat(go): step 1 — total wall-clock latency per URL

probe.Measure performs an HTTP GET and records total elapsed time from
request start to body fully read. main.go prints URL, status code, and
total for each positional URL argument, exiting 1 on any failure.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

2026-07-01 00:21:12 +02:00

3.0 KiB

Raw Blame History

latprobe — Website Latency Probe

A command-line tool that measures the latency of one or more websites, with a full per-request phase breakdown — DNS resolution, TCP connect, TLS handshake, server processing (time-to-first-byte), and content transfer. Not just a ping: latprobe shows you where the time goes.

Why

A single total request time hides the root cause of slowness. Is it DNS? A slow TLS negotiation? A laggy server? latprobe breaks the request into its constituent phases so the bottleneck is immediately obvious.

Implementations

Language	Status	Location
Go	In progress	`go/`
Python	Planned	`python/`

Both implementations produce identical CLI behaviour and output formats.

Usage (Go)

latprobe [flags] <url> [url ...]

Flags:
  -n, --count int   Number of requests per URL (default 1)
      --json        Output results as JSON instead of text

Examples:
  latprobe https://example.com
  latprobe -n 5 https://example.com https://www.google.com
  latprobe --json https://example.com | jq .

Output

Text (default)

https://example.com
  DNS lookup    :   12.34 ms
  TCP connect   :    8.91 ms
  TLS handshake :   45.20 ms
  Server (TTFB) :   78.56 ms
  Transfer      :    2.10 ms
  ─────────────────────────
  Total         :  147.11 ms

With -n 5 (min / avg / max columns):

https://example.com  (5 samples)
                      min       avg       max
  DNS lookup    :   10.1ms   12.3ms   15.7ms
  TCP connect   :    7.8ms    9.0ms   11.2ms
  ...

JSON (`--json`)

{
  "url": "https://example.com",
  "samples": 1,
  "phases": {
    "dns":      { "ms": 12.34 },
    "connect":  { "ms":  8.91 },
    "tls":      { "ms": 45.20 },
    "ttfb":     { "ms": 78.56 },
    "transfer": { "ms":  2.10 },
    "total":    { "ms": 147.11 }
  }
}

Implementation Roadmap

Go

Step	Feature	Status
0	Project scaffold — directory structure, `go.mod`, minimal binary	✅ Done
1	Simple total latency — single URL, wall-clock time	✅ Done
2	Per-phase breakdown — DNS, TCP, TLS, TTFB, transfer (`net/http/httptrace`)	⬜ Pending
3	Multiple URLs + `--count`/`-n` — min/avg/max aggregates	⬜ Pending
4	`--json` output flag	⬜ Pending

Python

Begins after the Go implementation is approved. Will mirror the same CLI and output format. Timed using low-level socket hooks (DNS via socket.getaddrinfo, connection timings via custom socket wrap or httpx/urllib3 hooks).

Development Environment

Go 1.26.4 / darwin arm64
Python 3.14.6
No external dependencies (Go uses stdlib only; Python TBD at port time)

Project Conventions

See CLAUDE.md for the development conventions followed in this project:

Plans saved to docs/plans/ with timestamped filenames
Completed features logged in CHANGELOG.md with timestamps
Per-feature user docs in docs/usage/

3.0 KiB Raw Blame History