prober.go RawHistoryFolder

1// Package httpprober provides HTTP probing functionality for health checks.
2package httpprober
3
4import (
5	"context"
6	"crypto/tls"
7	"fmt"
8	"net/http"
9	"time"
10
11	out "github.com/bnema/gordon/internal/boundaries/out"
12)
13
14// DefaultTimeout is the default timeout for HTTP probes.
15const DefaultTimeout = 5 * time.Second
16
17// Prober implements the HTTPProber interface for health checking.
18type Prober struct {
19	client  *http.Client
20	timeout time.Duration
21}
22
23// Option configures the Prober.
24type Option func(*Prober)
25
26// WithTimeout sets the probe timeout.
27func WithTimeout(timeout time.Duration) Option {
28	return func(p *Prober) {
29		p.timeout = timeout
30	}
31}
32
33// WithHTTPClient sets a custom HTTP client.
34func WithHTTPClient(client *http.Client) Option {
35	return func(p *Prober) {
36		p.client = client
37	}
38}
39
40// New creates a new HTTP prober.
41func New(opts ...Option) *Prober {
42	p := &Prober{
43		timeout: DefaultTimeout,
44	}
45
46	for _, opt := range opts {
47		opt(p)
48	}
49
50	if p.client == nil {
51		p.client = &http.Client{
52			Timeout: p.timeout,
53			Transport: &http.Transport{
54				// #nosec G402 - InsecureSkipVerify is intentional for health probing
55				// internal services that may use self-signed certificates.
56				// This prober only checks reachability, not data integrity.
57				TLSClientConfig: &tls.Config{
58					InsecureSkipVerify: true,
59				},
60				DisableKeepAlives: true,
61			},
62			// Don't follow redirects - we want to see the actual response
63			CheckRedirect: func(req *http.Request, via []*http.Request) error {
64				return http.ErrUseLastResponse
65			},
66		}
67	}
68
69	return p
70}
71
72// Probe sends an HTTP GET request and returns the status code and response time.
73func (p *Prober) Probe(ctx context.Context, url string) (int, int64, error) {
74	start := time.Now()
75
76	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
77	if err != nil {
78		return 0, 0, fmt.Errorf("failed to create request: %w", err)
79	}
80
81	// Set a recognisable user agent so access-log filters can exclude probe traffic.
82	req.Header.Set("User-Agent", out.HealthCheckUserAgentPrefix+"1.0")
83
84	resp, err := p.client.Do(req)
85	if err != nil {
86		elapsed := time.Since(start).Milliseconds()
87		return 0, elapsed, fmt.Errorf("request failed: %w", err)
88	}
89	defer resp.Body.Close()
90
91	elapsed := time.Since(start).Milliseconds()
92	return resp.StatusCode, elapsed, nil
93}