[Update] Updating buildkite-agent not to fail a job when JWK is mis…

…sing and failure behaviour is set to `warn`.

agent/run_job.go

@@ -24,11 +24,12 @@ import (
 )
 
 const (
-	SignalReasonAgentRefused      = "agent_refused"
-	SignalReasonAgentStop         = "agent_stop"
-	SignalReasonCancel            = "cancel"
-	SignalReasonSignatureRejected = "signature_rejected"
-	SignalReasonProcessRunError   = "process_run_error"
+	SignalReasonAgentRefused            = "agent_refused"
+	SignalReasonAgentStop               = "agent_stop"
+	SignalReasonCancel                  = "cancel"
+	SignalReasonSignatureRejected       = "signature_rejected"
+	SignalReasonUnableToVerifySignature = "unable_to_verify_signature"
+	SignalReasonProcessRunError         = "process_run_error"
 )
 
 type missingKeyError struct {
@@ -92,11 +93,14 @@ func (r *JobRunner) Run(ctx context.Context) error {
 	if r.conf.JWKS == nil && job.Step.Signature != nil {
 		r.verificationFailureLogs(
 			VerificationBehaviourBlock,
-			&missingKeyError{signature: job.Step.Signature.Value},
+			fmt.Errorf("cannot verify signature. JWK for pipeline verification is not configured"),
 		)
-		exit.Status = -1
-		exit.SignalReason = SignalReasonSignatureRejected
-		return nil
+
+		if r.VerificationFailureBehavior == VerificationBehaviourBlock {
+			exit.Status = -1
+			exit.SignalReason = SignalReasonUnableToVerifySignature
+			return nil
+		}
 	}
 
 	if r.conf.JWKS != nil {