Jan Novak
a588eb3b0e
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>
57 lines
1.3 KiB
Go
57 lines
1.3 KiB
Go
// Package probe measures per-phase HTTP request latency.
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package probe
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import (
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"io"
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"net/http"
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"time"
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)
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// Phase holds the measured duration of a single request phase.
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type Phase struct {
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Duration time.Duration
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// Present is false when the phase was skipped (e.g. no TLS for http://).
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Present bool
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}
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// Result holds all timing phases for a single HTTP request.
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type Result struct {
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URL string
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DNS Phase
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Connect Phase
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TLS Phase
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TTFB Phase // server processing: WroteRequest → GotFirstResponseByte
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Transfer Phase // body read: GotFirstResponseByte → body closed
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Total Phase
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// StatusCode is the HTTP response status code (0 on error).
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StatusCode int
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// Err is non-nil if the request failed.
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Err error
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}
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// Measure performs an HTTP GET to url and returns a Result.
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// In Step 1 only the Total phase is populated.
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func Measure(url string) Result {
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r := Result{URL: url}
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start := time.Now()
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resp, err := http.Get(url) //nolint:noctx
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if err != nil {
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r.Err = err
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r.Total = Phase{Duration: time.Since(start), Present: true}
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return r
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}
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defer resp.Body.Close()
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_, err = io.Copy(io.Discard, resp.Body)
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r.Total = Phase{Duration: time.Since(start), Present: true}
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r.StatusCode = resp.StatusCode
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if err != nil {
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r.Err = err
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}
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return r
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}
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