Files
simplelog/webhook_handler.go
T
clawbot 151dd42b4b
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Return sink write errors from every handler (closes #22)
The console and JSON handlers threw away the error from their write to
stdout, so a lost log line looked delivered. They now return it,
wrapped. The webhook handler also returns an error for a status outside
2xx, and no longer follows redirects, which could resend the request
without the record. The multiplex handler passes the record to every
handler and returns their errors joined with errors.Join instead of
stopping at the first.

Both stdout handlers gain an unexported writer, nil meaning os.Stdout at
write time, so tests can supply a sink that fails. The README says what
each handler returns and that the slog.Logger methods discard a
handler's error.

Model: opus-5-5
2026-10-06 08:45:17 +02:00

116 lines
2.9 KiB
Go

package simplelog
import (
"bytes"
"context"
"encoding/json"
"errors"
"fmt"
"log/slog"
"net/http"
"net/url"
)
// errWebhookStatus is returned when the webhook answers with a status
// outside 2xx.
var errWebhookStatus = errors.New("webhook did not accept the record")
// WebhookHandler POSTs each log record as JSON to a configured webhook
// URL.
type WebhookHandler struct {
webhookURL string
client *http.Client
attrs handlerAttrs
}
// NewWebhookHandler returns a WebhookHandler that delivers records to
// the given URL, validating the URL first.
func NewWebhookHandler(webhookURL string) (*WebhookHandler, error) {
_, err := url.ParseRequestURI(webhookURL)
if err != nil {
return nil, fmt.Errorf("invalid webhook URL: %w", err)
}
return &WebhookHandler{
webhookURL: webhookURL,
client: &http.Client{
// Following a redirect can resend the request as a GET
// without the record, so Handle gets the redirect answer
// itself and returns it as an error.
CheckRedirect: func(*http.Request, []*http.Request) error {
return http.ErrUseLastResponse
},
},
}, nil
}
// Enabled reports whether the handler processes records at the given
// level; it always returns true.
func (w *WebhookHandler) Enabled(_ context.Context, _ slog.Level) bool {
return true
}
// WithAttrs returns a new handler that also emits attrs, qualified by the
// groups open now. The receiver is not modified.
func (w *WebhookHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
if len(attrs) == 0 {
return w
}
return &WebhookHandler{
webhookURL: w.webhookURL,
client: w.client,
attrs: w.attrs.withAttrs(attrs),
}
}
// WithGroup returns a new handler that nests later attributes in an
// object named after the group. An empty name returns the receiver.
func (w *WebhookHandler) WithGroup(name string) slog.Handler {
if name == "" {
return w
}
return &WebhookHandler{
webhookURL: w.webhookURL,
client: w.client,
attrs: w.attrs.withGroup(name),
}
}
// Handle marshals the record, with its attributes, to one JSON object and
// POSTs it to the webhook URL. It returns an error when the request fails
// or the server answers with a status outside 2xx.
func (w *WebhookHandler) Handle(ctx context.Context, record slog.Record) error {
jsonData, err := json.Marshal(recordToMap(record, w.attrs))
if err != nil {
return fmt.Errorf("error marshaling event: %w", err)
}
request, err := http.NewRequestWithContext(
ctx,
http.MethodPost,
w.webhookURL,
bytes.NewReader(jsonData),
)
if err != nil {
return fmt.Errorf("error creating webhook request: %w", err)
}
request.Header.Set("Content-Type", "application/json")
response, err := w.client.Do(request)
if err != nil {
return err
}
defer func() { _ = response.Body.Close() }()
if response.StatusCode < http.StatusOK ||
response.StatusCode >= http.StatusMultipleChoices {
return fmt.Errorf("%w: %s", errWebhookStatus, response.Status)
}
return nil
}