Make sure we set the EdDSA algo on the jwk (#45)

This way the later code can fetch the value via Algorithm().

pkg/runner/mqtt.go

@@ -10,7 +10,6 @@ import (
 	"github.com/eclipse/paho.golang/autopaho"
 	"github.com/eclipse/paho.golang/autopaho/queue/file"
 	"github.com/eclipse/paho.golang/paho"
-	"github.com/lestrrat-go/jwx/v2/jwa"
 	"github.com/lestrrat-go/jwx/v2/jwk"
 	"github.com/lestrrat-go/jwx/v2/jws"
 )
@@ -113,7 +112,7 @@ func (edm *dnstapMinimiser) runAutoPaho(cm *autopaho.ConnectionManager, topic st
 			return
 		}
 
-		signedMsg, err := jws.Sign(unsignedMsg, jws.WithJSON(), jws.WithKey(jwa.ES256, mqttJWK))
+		signedMsg, err := jws.Sign(unsignedMsg, jws.WithJSON(), jws.WithKey(mqttJWK.Algorithm(), mqttJWK))
 		if err != nil {
 			edm.log.Error("runAutoPaho: failed to created JWS message", "error", err)
 			continue

pkg/runner/runner.go

@@ -37,6 +37,7 @@ import (
 	"github.com/fsnotify/fsnotify"
 	_ "github.com/grafana/pyroscope-go/godeltaprof/http/pprof" // revive linter: keep blank import close to where it is used for now.
 	lru "github.com/hashicorp/golang-lru/v2"
+	"github.com/lestrrat-go/jwx/v2/jwa"
 	"github.com/lestrrat-go/jwx/v2/jwk"
 	"github.com/miekg/dns"
 	"github.com/prometheus/client_golang/prometheus"
@@ -531,6 +532,11 @@ func (edm *dnstapMinimiser) setupMQTT(mqttClientCertStore *certStore) {
 		edm.log.Error("unable to create MQTT JWK key", "error", err)
 		os.Exit(1)
 	}
+	err = mqttJWK.Set(jwk.AlgorithmKey, jwa.EdDSA)
+	if err != nil {
+		edm.log.Error("unable to set MQTT JWK `alg`", "error", err)
+		os.Exit(1)
+	}
 
 	err = mqttJWK.Set(jwk.KeyIDKey, viper.GetString("mqtt-signing-key-id"))
 	if err != nil {