Files
uptime/internal/monitor/http.go
2026-03-22 11:30:31 -05:00

102 lines
2.4 KiB
Go

package monitor
import (
"fmt"
"io"
"net/http"
"strings"
"time"
"arclineit/arcline-uptime/internal/config"
)
type HTTPChecker struct {
cfg config.MonitorConfig
client *http.Client
}
func NewHTTPChecker(cfg config.MonitorConfig, timeout time.Duration) *HTTPChecker {
return &HTTPChecker{
cfg: cfg,
client: &http.Client{
Timeout: timeout,
CheckRedirect: redirectPolicy(cfg.ExpectedStatus),
},
}
}
// redirectPolicy stops at the first redirect when the expected status is 3xx so
// the raw redirect code is returned. Otherwise follows up to 10 redirects.
func redirectPolicy(expected int) func(*http.Request, []*http.Request) error {
if expected >= 300 && expected < 400 {
return func(_ *http.Request, _ []*http.Request) error {
return http.ErrUseLastResponse
}
}
return nil
}
func (h *HTTPChecker) Name() string { return h.cfg.Name }
func (h *HTTPChecker) Interval() time.Duration { return time.Duration(h.cfg.Interval) * time.Second }
func (h *HTTPChecker) Check() Result {
start := time.Now()
result := Result{
MonitorName: h.cfg.Name,
CheckedAt: start,
}
var bodyReader io.Reader
if h.cfg.Body != "" {
bodyReader = strings.NewReader(h.cfg.Body)
}
req, err := http.NewRequest(h.cfg.Method, h.cfg.URL, bodyReader)
if err != nil {
result.Error = fmt.Sprintf("build request: %v", err)
result.ResponseTime = time.Since(start)
return result
}
req.Header.Set("User-Agent", "arcline-uptime/1.0")
for k, v := range h.cfg.Headers {
req.Header.Set(k, v)
}
resp, err := h.client.Do(req)
result.ResponseTime = time.Since(start)
if err != nil {
result.Error = err.Error()
return result
}
defer resp.Body.Close()
result.StatusCode = resp.StatusCode
// Response time threshold check — before reading body to fail fast.
applyThreshold(&result, h.cfg.MaxResponseMS)
if !result.Up && result.Error != "" {
return result
}
if resp.StatusCode != h.cfg.ExpectedStatus {
result.Error = fmt.Sprintf("expected status %d, got %d", h.cfg.ExpectedStatus, resp.StatusCode)
return result
}
if h.cfg.Contains != "" {
body, err := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
if err != nil {
result.Error = fmt.Sprintf("read body: %v", err)
return result
}
if !strings.Contains(string(body), h.cfg.Contains) {
result.Error = fmt.Sprintf("body does not contain %q", h.cfg.Contains)
return result
}
}
result.Up = true
applyThreshold(&result, h.cfg.MaxResponseMS)
return result
}