Files
sendico/api/edge/callbacks/internal/signing/service.go
2026-02-28 10:10:26 +01:00

81 lines
2.1 KiB
Go

package signing
import (
"context"
"crypto/hmac"
"crypto/sha256"
"encoding/hex"
"strconv"
"strings"
"time"
"github.com/tech/sendico/edge/callbacks/internal/secrets"
"github.com/tech/sendico/pkg/merrors"
"github.com/tech/sendico/pkg/mlogger"
"go.uber.org/zap"
)
type service struct {
logger mlogger.Logger
provider secrets.Provider
}
func newService(deps Dependencies) (Signer, error) {
if deps.Provider == nil {
return nil, merrors.InvalidArgument("signing: secrets provider is required", "provider")
}
logger := deps.Logger
if logger == nil {
logger = zap.NewNop()
}
return &service{
logger: logger.Named("signing"),
provider: deps.Provider,
}, nil
}
func (s *service) Sign(ctx context.Context, mode, secretRef string, payload []byte, now time.Time) (*SignedPayload, error) {
normalizedMode := strings.ToLower(strings.TrimSpace(mode))
if normalizedMode == "" {
normalizedMode = ModeNone
}
switch normalizedMode {
case ModeNone:
return &SignedPayload{
Body: append([]byte(nil), payload...),
Headers: map[string]string{},
}, nil
case ModeHMACSHA256:
if strings.TrimSpace(secretRef) == "" {
return nil, merrors.InvalidArgument("signing: secret reference is required for hmac", "secret_ref")
}
secret, err := s.provider.GetSecret(ctx, secretRef)
if err != nil {
s.logger.Warn("Failed to load signing secret", zap.String("secret_ref", secretRef), zap.Error(err))
return nil, err
}
ts := now.UTC().Format(time.RFC3339Nano)
mac := hmac.New(sha256.New, []byte(secret))
message := append([]byte(ts+"."), payload...)
if _, err := mac.Write(message); err != nil {
return nil, merrors.InternalWrap(err, "signing: failed to compute hmac")
}
signature := hex.EncodeToString(mac.Sum(nil))
return &SignedPayload{
Body: append([]byte(nil), payload...),
Headers: map[string]string{
"X-Callback-Timestamp": ts,
"X-Callback-Signature": signature,
"X-Callback-Algorithm": "hmac-sha256",
"Content-Length": strconv.Itoa(len(payload)),
},
}, nil
default:
return nil, merrors.InvalidArgument("signing: unsupported mode", "mode")
}
}